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Emergency And Acute Medicine – Poisoning, Antidotes
Antidote therapy is used in specific toxicologic emergencies and should be administered in conjunction with supportive care and consultation with a poison control center or medical toxicologist when appropriate.
N-acetylcysteine (NAC) is indicated for acetaminophen overdose. It is most effective when given within the first 8 hours after ingestion. Common adverse effects include unpleasant odor, nausea, and vomiting. Oral dosing consists of 140 mg/kg followed by 70 mg/kg every 4 hours for 17 doses. Intravenous dosing includes 150 mg/kg in 200 mL D5W over 60 minutes, then 50 mg/kg in 500 mL D5W over 4 hours, followed by 100 mg/kg in 1,000 mL D5W over 16 hours. In pediatric patients, IV fluid volumes must be reduced to avoid fluid overload and hyponatremia.
Atropine is used for bradycardia due to drugs and for organophosphate insecticide poisoning. Caution is advised in myasthenia gravis, narrow-angle glaucoma, hypertension, coronary ischemia, and urinary obstruction. Adult dose is 1–2 mg IV. Pediatric dose is 0.02 mg/kg IV (minimum 0.1 mg). Large repeated doses may be required in organophosphate poisoning.
Benztropine (Cogentin) is indicated for acute dystonic reactions. It should be used cautiously in carbamate exposure, myasthenia gravis, narrow-angle glaucoma, hypertension, coronary ischemia, and urinary obstruction. Adult dosing is 1–2 mg IV for acute reactions or orally for prevention. Pediatric dose is 0.02 mg/kg IV or PO.
Benzodiazepines are indicated for agitation, stimulant toxicity, and seizures. Respiratory and CNS depression are potential adverse effects. Midazolam dosing is 1 mg IV or IM every 2–3 minutes as needed in adults, and 0.1 mg/kg IV or IM in children. Diazepam dosing is 2–5 mg IV or IM in adults (repeat in 10–15 minutes) and 0.1 mg/kg IV or IM in pediatrics.
Sodium bicarbonate is used for tricyclic antidepressant poisoning, metabolic acidosis, and urinary alkalinization. Adverse effects include congestive heart failure, excessive alkalosis, and hypokalemia. For serum alkalinization, give 1 mEq/kg IV push. For urine alkalinization, administer 100–150 mEq in 1 L D5W at 2–3 mL/kg/hour IV with a urine pH goal of 7–8.
Black widow spider antivenin (Latrodectus mactans) is indicated for severe hypertension and muscle spasms not relieved by analgesics and muscle relaxants, and may be considered in young children, elderly patients, and pregnant women with threatened abortion. It is equine-derived and may cause immediate hypersensitivity or delayed serum sickness. Dose is 1–2 vials IM or slow IV over 15–30 minutes; dilute one vial in 50 mL saline for IV use.
Botulinum antitoxin (trivalent A, B, E) is indicated in clinical botulism before onset of paralysis. It binds only free toxin and is not used for infant botulism. It is equine-derived with risk of hypersensitivity. Administer 1–2 vials IV every 4 hours for 4–5 doses after reconstitution.
Calcium is indicated for hyperkalemia with cardiac toxicity, hydrofluoric acid burns, calcium channel blocker overdose, and citrate, oxalate, or phosphate poisoning. Avoid in digoxin toxicity and hypercalcemia. Adult dose is 5–10 mL of 10% calcium chloride or 10–20 mL of 10% calcium gluconate IV. Pediatric dose is 0.1–0.2 mL/kg of 10% calcium chloride or 0.2–0.3 mL/kg of 10% calcium gluconate IV.
Calcium EDTA is used for lead and certain heavy metal toxicities. It may cause nephrotoxicity and other adverse effects. Dose is 1 g/m²/day IV over 8–12 hours for 5 days, with repeat cycles guided by blood lead levels.
Cyanide poisoning can be treated with a cyanide antidote kit or hydroxocobalamin. The cyanide kit includes amyl nitrite (inhaled until IV access is established), sodium nitrite (300 mg IV in adults; 0.3 mL/kg of 3% solution in children), and sodium thiosulfate (12.5 g IV in adults; 50 mg/kg in children). Hydroxocobalamin is given as 5 g IV over 15 minutes in adults, repeatable once; suggested pediatric dose is 70 mg/kg IV.
Dantrolene is indicated for malignant hyperthermia, neuroleptic malignant syndrome, serotonin syndrome, and severe muscle rigidity. Dose is 1–2 mg/kg IV bolus, repeated every 10–15 minutes as needed, maximum 10 mg/kg.
Deferoxamine treats iron toxicity. It should not be used for more than 24 hours due to risk of delayed ARDS. Dose is 10–15 mg/kg/hour IV, increased in severe cases.
Digoxin-specific antibody fragments (Digibind) are used in digoxin or digitoxin toxicity. One vial (40 mg) binds 0.6 mg digoxin. Dose estimation is based on serum level and patient weight, with typical dosing of 10–20 vials in acute overdose and 4–6 vials in chronic toxicity.
Dimercaprol (BAL) is indicated for arsenic, gold, mercury, and severe lead toxicity with encephalopathy. Dose is 3 mg/kg IM every 4 hours for 2 days, then every 12 hours for 7 days.
Flumazenil reverses benzodiazepine effects but is contraindicated in tricyclic antidepressant overdose and may precipitate seizures or withdrawal. Adult dose is 0.2 mg IV slow push, repeated every 2–3 minutes up to 1 mg. Pediatric dose is 0.01–0.05 mg/kg IV.
Fomepizole is used for methanol and ethylene glycol toxicity. Dose is 15 mg/kg IV loading, then 10 mg/kg every 12 hours for four doses, then 15 mg/kg every 12 hours thereafter.
Glucagon is used for β-blocker or calcium channel blocker overdose with bradycardia or hypotension. Adult dose is 5–10 mg IV over 1 minute; pediatric dose is 0.15 mg/kg IV.
High-dose insulin with glucose is used in severe calcium channel blocker overdose or hyperkalemia refractory to other therapy. Close glucose monitoring is required.
Naloxone (Narcan) reverses opioid toxicity. Adult dose is 0.4–2 mg IV or IM, repeat up to 10 mg. Pediatric dose is 0.1 mg/kg IV or IM. Acute withdrawal and agitation may occur.
Octreotide treats sulfonylurea-induced hypoglycemia. Adult dose is 50 micrograms subcutaneously every 6 hours. Pediatric dose is 4–5 micrograms/kg/day divided every 6 hours.
Pralidoxime (2-PAM) is used in organophosphate toxicity in conjunction with atropine. Adult dose is 1–2 g IV over 15 minutes, repeat as needed. Pediatric dose is 25–50 mg/kg over 15 minutes.
Protamine reverses heparin anticoagulation. Dose is 1 mg per 100 IU of heparin administered, given slowly IV.
Pyridoxine (vitamin B6) is used for isoniazid-induced seizures. If ingestion amount is unknown, give 5 g IV in adults or 1 g in children.
Vitamin K (phytonadione) reverses warfarin anticoagulation. Dose ranges from 2–10 mg PO or slow IV, repeat as needed based on INR.
Hyperbaric oxygen is indicated for severe carbon monoxide poisoning.
Many antivenins, including those for coral snake and rattlesnake envenomation, are animal-derived and carry risk of hypersensitivity and serum sickness. Premedication and close monitoring are required.
Antidote therapy should always accompany appropriate supportive care, monitoring, and consultation with poison control.
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Emergency And Acute Medicine – Poisoning
Poisoning may be intentional or unintentional. Any patient presenting with an unexplained change in mental status should be evaluated for possible intoxication or overdose. Intentional poisoning may be related to depression, suicide attempts, homicide, or recreational drug abuse. Unintentional poisoning commonly occurs in children and may result from accidental ingestion, therapeutic errors such as double dosing, or recreational experimentation. In pediatric patients, most accidental ingestions occur in children aged 1–5 years. A history that is inconsistent or suspicious should raise concern for possible child abuse.
Clinical presentation varies depending on the substance involved. Neurologic findings may include lethargy, agitation, coma, hallucinations, or seizures. Respiratory effects may range from tachypnea to bradypnea or apnea, with possible inability to protect the airway. Cardiovascular manifestations include dysrhythmias and conduction abnormalities. Vital sign abnormalities may include hyperthermia or hypothermia, tachycardia or bradycardia, and hypertension or hypotension.
Recognition of toxidromes can guide management. Anticholinergic toxicity presents with altered mental status, dry skin and mucous membranes, fixed dilated pupils, tachycardia, hyperthermia, flushing, and urinary retention. Cholinergic toxicity presents with excessive secretions including salivation, lacrimation, urination, diaphoresis, miosis, bronchospasm, and wheezing. Opiate toxicity is characterized by central nervous system and respiratory depression with miosis. Sympathomimetic toxicity presents with CNS excitation, seizures, tachycardia, hypertension, and diaphoresis.
Initial evaluation requires complete vital signs including core temperature and a thorough physical examination, paying attention to pupils, skin findings, and unusual odors. Laboratory testing typically includes electrolytes, BUN, creatinine, and glucose. Calculation of the anion gap (normal 8–12) is essential when metabolic acidosis is suspected. Elevated anion gap metabolic acidosis can be remembered using the mnemonic “A CAT MUD PILES,” which includes causes such as alcoholic ketoacidosis, cyanide, carbon monoxide, salicylates, methanol, uremia, diabetic ketoacidosis, iron, lactic acidosis, and ethylene glycol. Serum osmol gap should be calculated when toxic alcohol ingestion is suspected. The calculated osmolality is 2(Na⁺) + glucose/18 + BUN/2.8 + ethanol/4.6 (if ethanol in mg/dL). An osmol gap greater than 10 suggests substances remembered by the mnemonic “ME DIE A”: methanol, ethanol, diuretics (mannitol, glycerin, sorbitol), isopropyl alcohol, ethylene glycol, and acetone. A normal osmol gap does not completely exclude toxic alcohol ingestion. Additional testing may include pregnancy testing, acetaminophen level in suicidal ingestions, toxicology screening, ECG for conduction abnormalities or QRS/QT prolongation, head CT for unexplained altered mental status, and chest radiograph if aspiration is suspected.
The differential diagnosis for altered mental status includes intracranial mass or hemorrhage, infection or sepsis, endocrine abnormalities, hypothermia, hypoxia, metabolic disturbances, and psychogenic causes. These must always be considered alongside toxicologic causes.
Pre-hospital management includes searching the scene for clues such as pill bottles or drug paraphernalia and transporting all medications for identification. Uncooperative patients may require restraint for safety. Comorbid trauma, medical illness, or environmental exposures should be considered. Activated charcoal may be administered pre-hospital in selected cases if transport time is prolonged.
Initial stabilization in the emergency department follows standard ABC principles. Endotracheal intubation is performed as needed for airway protection, oxygenation, and ventilation. Supplemental oxygen, pulse oximetry, cardiac monitoring, and IV access are established. Hypotension is treated with intravenous 0.9% normal saline boluses and vasopressors if persistent. Bradycardia may require atropine or pacing. In patients with altered mental status, administration of thiamine, dextrose (after checking glucose), and naloxone is appropriate.
Decontamination strategies depend on the timing and substance ingested. Orogastric lavage may be considered within one hour of potentially lethal ingestion without a known antidote, provided the airway is protected. Activated charcoal is most effective within a few hours of ingestion and is contraindicated in caustic ingestions, unprotected airways, or bowel obstruction. Charcoal does not effectively bind metals (iron, lithium), alcohols, or potassium. Whole-bowel irrigation with polyethylene glycol solution may be used for sustained-release preparations, iron or lithium ingestion, and body packers, but is contraindicated in bowel obstruction, perforation, or hypotension.
Enhanced elimination techniques include multiple-dose activated charcoal for drugs such as theophylline, carbamazepine, and phenobarbital. Urinary alkalinization is used for salicylates and phenobarbital. Hemodialysis is indicated for lithium, salicylates, theophylline, toxic alcohols, and valproate in selected cases. Seizures are treated initially with benzodiazepines such as diazepam or lorazepam. Persistent seizures may require phenobarbital. Phenytoin is generally not effective for toxicologic seizures unless related to epilepsy or status epilepticus of other etiology.
Specific antidotes are used when appropriate. Examples include N-acetylcysteine for acetaminophen toxicity, physostigmine for severe anticholinergic toxicity, flumazenil for selected benzodiazepine overdoses, glucagon for β-blocker toxicity, calcium and insulin for calcium-channel blocker overdose, oxygen or hyperbaric oxygen for carbon monoxide, vitamin K for warfarin toxicity, hydroxocobalamin or cyanide antidote kit for cyanide, digoxin-specific antibody fragments for digoxin toxicity, fomepizole or ethanol for methanol and ethylene glycol, deferoxamine for iron, pyridoxine for isoniazid, methylene blue for methemoglobinemia, naloxone for opioid toxicity, atropine and pralidoxime for organophosphates, and sodium bicarbonate for tricyclic antidepressant toxicity.
Admission is required for patients with altered mental status, cardiopulmonary instability, suicidal intent, significant laboratory abnormalities, or risk of delayed decompensation. Discharge may be considered for patients who are psychiatrically cleared, detoxified, hemodynamically stable, and medically safe. Accidental poisonings require prevention counseling, while intentional poisonings require psychiatric evaluation. Substance abuse referral should be considered when appropriate. In pregnancy, treatment of the mother is generally the best treatment for the fetus.
Clinicians must avoid overlooking non-toxicologic causes of altered mental status and should not rely solely on urine drug screens, as these test for a limited number of substances and may produce false-positive or false-negative results.
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Emergency And Acute Medicine – Pneumothorax
Pneumothorax is defined as the presence of free air within the intrapleural space. Spontaneous pneumothorax occurs due to atraumatic rupture of an alveolus, bronchiole, or subpleural bleb. Primary spontaneous pneumothorax accounts for approximately two-thirds of cases and occurs in patients without known underlying lung disease, typically young, tall, thin individuals aged 20–40 years. Risk factors include smoking, family history, Marfan syndrome, homocystinuria, and thoracic endometriosis. Secondary spontaneous pneumothorax occurs in the presence of underlying pulmonary pathology. Tension pneumothorax is a life-threatening form in which air enters the pleural space and becomes trapped through a “ball-valve” mechanism, leading to increased intrapleural pressure, decreased venous return, reduced cardiac output, mediastinal shift, ventilation–perfusion mismatch, and hypoxemia.
Secondary pneumothorax may result from airway diseases such as chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis; infections including necrotizing bacterial pneumonia, tuberculosis, fungal pneumonia, and Pneumocystis jirovecii infection; neoplasms; interstitial lung diseases such as sarcoidosis and idiopathic pulmonary fibrosis; lymphangiomyomatosis; tuberous sclerosis; pneumoconioses; connective tissue diseases; pulmonary infarction; endometriosis; blunt or penetrating chest trauma; and iatrogenic causes such as central line placement or other vascular access procedures.
Symptoms typically correlate with the size of the pneumothorax. Patients often present with sudden-onset, sharp, pleuritic chest pain on the affected side and shortness of breath. Some may report a dull ache in delayed presentations. Cough, malaise, or minimal symptoms may occur in small pneumothoraces. On examination, patients may have tachypnea and asymmetric decreased breath sounds with hyperresonance to percussion on the affected side. Simple spontaneous pneumothoraces usually have heart rates under 120 bpm. In tension pneumothorax, findings may include hypotension, tachycardia greater than 120 bpm, diaphoresis, cyanosis, jugular venous distention, tracheal deviation away from the affected side, and cardiovascular collapse.
Imaging is central to diagnosis. However, in hemodynamically unstable patients with strong clinical suspicion of tension pneumothorax, chest decompression must not be delayed for imaging. Upright chest radiography is the standard initial test and demonstrates absence of lung markings beyond a visible visceral pleural line. Additional findings may include mediastinal shift, the deep sulcus sign (particularly in supine trauma patients), inversion of the diaphragm, or displacement of the anterior junction line. Expiratory films do not significantly increase diagnostic yield. Chest CT is highly sensitive for small pneumothoraces but is rarely necessary for routine diagnosis. Point-of-care ultrasound is increasingly used; absence of lung sliding and comet-tail artifacts, along with characteristic M-mode findings, strongly suggests pneumothorax and may be more sensitive than chest radiography in experienced hands. ECG may show nonspecific changes and is often obtained to exclude cardiac causes of chest pain.
Initial stabilization includes cardiac monitoring, pulse oximetry, 100% oxygen via nonrebreather mask, and intravenous access. Unstable patients with suspected tension pneumothorax require immediate needle thoracostomy followed by tube thoracostomy. Needle decompression is performed using a 14–18 gauge angiocatheter in the second intercostal space at the midclavicular line or the fourth or fifth intercostal space at the anterior axillary line. Standard angiocatheters may be too short in larger patients; longer catheters may be required.
Management depends on size and clinical stability. Small primary spontaneous pneumothoraces with less than 15% lung collapse and no respiratory or cardiovascular compromise may be observed with 100% oxygen for 4–6 hours, followed by repeat chest radiography. Simple aspiration using an 8F catheter with a three-way stopcock may be attempted for 15–30% collapse or enlarging small pneumothoraces. Air is aspirated until resistance is met or up to 3 liters have been removed. If imaging confirms resolution, the catheter can be removed and the patient discharged with follow-up. A second aspiration may be attempted if the first fails. A Heimlich valve may be used for persistent but stable pneumothoraces with less than 30% collapse after failed aspiration. Suction at 20 cm H₂O may be applied if necessary.
Tube thoracostomy is indicated for tension pneumothorax, traumatic pneumothorax, pneumothorax in patients requiring positive-pressure ventilation, pneumothorax with greater than 30% collapse, most secondary pneumothoraces, or definitive management after needle decompression. Small-caliber tubes (7–14F) are appropriate for primary spontaneous pneumothorax, whereas larger tubes (20–28F) are used for secondary pneumothorax or when pleural fluid or mechanical ventilation is anticipated. All side holes must remain within the thoracic cavity to prevent air leak. The tube is connected to a water-seal device or Heimlich valve in stable patients without effusion. Complications include intercostal vessel bleeding, tube kinking or clogging, malposition, and re-expansion pulmonary edema, which requires supportive care.
Local anesthesia with 1% lidocaine with epinephrine (maximum 7 mg/kg up to 500 mg) is used for procedures, and procedural sedation may be considered in stable patients. Antibiotics are not indicated for clean procedures.
Admission is required for tension pneumothorax or any patient requiring chest tube placement. Stable patients with small pneumothoraces managed conservatively or with successful aspiration may be discharged with close follow-up at 24 hours and one week, including repeat chest radiographs. Patients must receive clear instructions to return immediately for recurrent chest pain or dyspnea. Persistent failure of lung re-expansion at one week warrants cardiothoracic surgery consultation.
Timely recognition and decompression of tension pneumothorax are critical to prevent rapid hemodynamic compromise. Proper tube placement and awareness of associated injuries, including mediastinal or esophageal pathology when pneumomediastinum is present, are essential to avoid complications.
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Emergency And Acute Medicine – Pneumomediastinum
Pneumomediastinum refers to the presence of free air within the mediastinum. It may arise from the esophagus, lungs, or bronchial tree and can occur spontaneously (primary pneumomediastinum) or secondary to trauma, instrumentation, surgery, infection, or barotrauma. Spontaneous pneumomediastinum results from increased intra-alveolar pressure with subsequent alveolar rupture, allowing air to dissect along bronchovascular sheaths toward the hilum and into the mediastinum. Air may then track into fascial planes of the neck, producing subcutaneous emphysema. This condition is most common in young males and often follows Valsalva maneuvers such as forceful vomiting, coughing, strenuous exercise, labor, or inhalational drug use. Secondary pneumomediastinum may result from thoracic trauma, positive-pressure ventilation, esophageal rupture, or mediastinal infection. Tension pneumomediastinum is rare but life-threatening and may occur in ventilated patients.
Chest pain is the most common presenting symptom and is typically sharp, pleuritic, retrosternal, and sometimes radiates to the back or arms. Dyspnea is common. Patients may report neck pain, throat discomfort, dysphagia, or a sensation of neck swelling due to air tracking into cervical tissues. Subcutaneous emphysema is frequently found in the supraclavicular region and anterior neck. Dysphonia or hoarseness may occur. Hamman crunch, a precordial crunching sound synchronous with the heartbeat and best heard in the left lateral decubitus position, is pathognomonic but uncommon. In suspected esophageal rupture, Meckler triad of vomiting, lower chest pain, and cervical subcutaneous emphysema should raise immediate concern.
Evaluation must focus on excluding secondary causes, particularly esophageal rupture. Chest radiography is the most valuable initial test and should include a lateral view, as mediastinal air may be missed on a standard posteroanterior film. Radiographic findings may include mediastinal air outlining cardiac borders, subcutaneous emphysema, the continuous diaphragm sign, or the spinnaker sail sign in pediatric patients. Up to one-third of cases may have a normal chest radiograph. Chest CT is the imaging modality of choice when suspicion remains high despite a negative radiograph and is more sensitive for small air collections and associated pathology. If esophageal rupture is suspected, a water-soluble contrast esophagram is indicated. Laboratory studies are generally not diagnostic but should include CBC if mediastinitis is a concern.
Management depends on the underlying cause. Spontaneous pneumomediastinum is usually benign and self-limited, resolving within several days. Treatment consists of oxygen supplementation, analgesia, rest, and reassurance. High-flow oxygen may accelerate reabsorption of mediastinal air. Oral intake should be withheld if an esophageal source is suspected until diagnostic evaluation is complete. Secondary pneumomediastinum requires directed therapy toward the underlying condition, such as management of asthma exacerbation, diabetic ketoacidosis, trauma, or esophageal injury. Broad-spectrum antibiotics are indicated if mediastinitis is suspected. Tube thoracostomy is reserved for associated significant pneumothorax, and pericardiocentesis is indicated only in tension pneumopericardium with hemodynamic compromise.
Admission is warranted for secondary pneumomediastinum, suspected esophageal rupture, associated pneumothorax, abnormal vital signs, significant comorbidities, or unreliable follow-up. Patients with uncomplicated spontaneous pneumomediastinum, stable vital signs, no pneumothorax, and symptom improvement after observation may be discharged with close outpatient follow-up. Recurrent cases may require cardiothoracic evaluation.
Clinicians must maintain a high index of suspicion in patients with chest pain, dyspnea, and neck swelling, particularly in the setting of vomiting, asthma exacerbation, or inhalational drug use. Although often benign, failure to exclude esophageal rupture or other serious secondary causes can result in significant morbidity and mortality.
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Emergency And Acute Medicine – Pneumocystis Pneumonia
Pneumocystis pneumonia, commonly referred to as PCP, is caused by Pneumocystis jirovecii and remains the most common opportunistic infection in patients with HIV, particularly when the CD4 count is less than 200 cells/mm³. Although previously known as Pneumocystis carinii pneumonia, the organism is now classified as a fungus. Transmission is believed to occur via the respiratory aerosol route. Organisms colonize the respiratory tract, cysts rupture, and trophozoites proliferate within the alveoli, producing a characteristic foamy exudate that interferes with gas exchange. Most cases likely represent reactivation of latent infection, although person-to-person transmission has been suggested. PCP also occurs in patients with impaired cellular immunity due to cancer, chronic corticosteroid therapy, organ transplantation, or malnutrition. In children, infection tends to be more severe.
The clinical presentation is typically subacute. Up to 7% of patients may initially be asymptomatic. Patients often report fever, nonproductive or minimally productive cough, and progressive dyspnea. In HIV-positive patients, symptoms may develop gradually over weeks to months, whereas in non–HIV immunocompromised hosts the course may progress over days. Dyspnea on exertion with exercise-induced oxygen desaturation is common. Associated symptoms include chills, fatigue, weight loss, and chest discomfort. Patients receiving inhaled pentamidine prophylaxis may present with milder pulmonary symptoms but have a higher incidence of pneumothorax and extrapulmonary disease. On examination, tachypnea and tachycardia are common, and lung auscultation may reveal crackles or rhonchi, although findings can be minimal relative to the degree of hypoxemia.
Essential evaluation includes complete blood count, electrolytes, arterial blood gas, lactate dehydrogenase (LDH), blood cultures, and chest imaging. Arterial blood gas analysis should be obtained in all suspected cases to calculate the alveolar–arterial gradient, which is usually elevated. Adjunctive corticosteroids are indicated when the A–a gradient exceeds 35 mm Hg or the PaO₂ is less than 70 mm Hg. LDH is often elevated in HIV-associated PCP and higher levels may correlate with worse prognosis, though it is nonspecific. Chest radiography classically demonstrates bilateral interstitial or diffuse alveolar infiltrates. However, up to 25% of patients may have a normal radiograph early in the disease. Atypical findings include lobar infiltrates, cysts, pneumothoraces, pleural effusions, or nodular infiltrates. High-resolution CT is highly sensitive and typically shows patchy ground-glass opacities.
Definitive diagnosis requires identification of Pneumocystis organisms in respiratory specimens. Induced sputum examination has high specificity but variable sensitivity depending on specimen quality and laboratory expertise, and it is less sensitive in non–HIV patients or those on pentamidine prophylaxis. Bronchoalveolar lavage is recommended when induced sputum is nondiagnostic and clinical suspicion remains high, with sensitivity approaching 80–100%.
Initial management follows airway, breathing, and circulation principles. Supplemental oxygen should be administered, escalating from nasal cannula to nonrebreather mask as needed. Endotracheal intubation is required for refractory hypoxemia or hypercapnic respiratory failure. Intravenous fluids should be given for hypotension or dehydration. Empiric antimicrobial therapy should be initiated promptly when PCP is suspected. Intravenous trimethoprim–sulfamethoxazole is the first-line therapy and should be continued for 21 days. Intravenous pentamidine is an alternative for patients intolerant of first-line therapy. Oral therapy may be appropriate in mild cases. Alternative regimens include trimethoprim–dapsone, clindamycin–primaquine, or atovaquone. Adjunctive corticosteroids must be started within the first 72 hours in patients with significant hypoxemia to reduce mortality and the risk of respiratory failure. Suspected PCP patients should be isolated from other immunocompromised individuals.
Admission is indicated for moderate to severe disease, defined by hypoxemia or elevated A–a gradient, inability to tolerate oral medications, or unreliable follow-up. Intensive monitoring is required for patients with respiratory compromise. Selected patients with mild disease, stable oxygenation, and reliable follow-up may be managed as outpatients. Close follow-up with an infectious disease specialist is essential.
PCP should always be considered in immunocompromised patients presenting with dyspnea and diffuse infiltrates, particularly those with HIV or suspected undiagnosed HIV infection. Well-appearing patients with unexpectedly low oxygen saturation are at higher risk for rapid deterioration. Clinicians must also consider coexisting infections such as tuberculosis or atypical bacterial pneumonia in this population.
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Emergency And Acute Medicine – Pneumonia in Adults
Pneumonia in adults is an acute infection of the lung parenchyma and is the seventh leading cause of death and the leading infectious cause of mortality in the United States. Mortality is highest in elderly patients and those with chronic heart, lung, liver, or kidney disease, diabetes mellitus, alcoholism, malignancy, asplenia, immunosuppression, or recent antimicrobial use. Pneumonia is classified by source as community-acquired (CAP), healthcare-associated (HCAP), hospital-acquired (HAP), or ventilator-associated (VAP), and by presentation as typical or atypical. Complications include bacteremia, sepsis, lung abscess, empyema, and respiratory failure.
The most common cause of community-acquired pneumonia is Streptococcus pneumoniae. Other typical CAP pathogens include Haemophilus influenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Streptococcus pyogenes, and Staphylococcus aureus. Atypical CAP pathogens include Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, and respiratory viruses. Healthcare- and hospital-associated pneumonias are more commonly caused by gram-negative organisms such as Pseudomonas and Stenotrophomonas, as well as methicillin-resistant Staphylococcus aureus (MRSA). Immunocompromised patients are at risk for organisms such as Mycobacterium tuberculosis and Pneumocystis jirovecii. Aspiration pneumonia may involve chemical pneumonitis with or without oral and gastric anaerobes.
Typical pneumonia presents with acute onset of fever, chills, rigors, productive cough, dyspnea, and pleuritic chest pain. Atypical pneumonia has a more subacute onset with a viral prodrome, nonproductive cough, low-grade fever, headache, myalgias, and malaise, often without pleuritic pain or rigors. On examination, patients may demonstrate tachypnea, tachycardia, hypoxia, and fever. Lung findings can include dullness to percussion, increased tactile fremitus, egophony, rales, rhonchi, or decreased breath sounds, although pneumonia may be present without classic consolidation findings. Elderly patients frequently present atypically, sometimes with confusion or functional decline as the primary symptom.
Diagnosis is based on clinical findings supported by imaging. Laboratory evaluation generally includes a complete blood count and serum chemistry panel. Blood and sputum cultures are typically reserved for ICU patients. Urine antigen testing for S. pneumoniae and Legionella may be helpful in select cases. Lactate levels may assist in identifying sepsis. Chest radiography is the primary imaging modality and may demonstrate consolidation, air bronchograms, interstitial infiltrates, pleural effusion, empyema, or cavitation. Radiographic findings are nonspecific for particular pathogens. Imaging may be deferred in young, healthy patients treated empirically as outpatients, and a negative radiograph does not exclude pneumonia if clinical suspicion is high.
Initial management includes supplemental oxygen, IV access, fluid resuscitation when indicated, cardiac monitoring, bronchodilators if bronchospasm is present, and airway management in cases of severe respiratory distress. Empiric antibiotic therapy should follow established guidelines. Previously healthy outpatients may receive azithromycin or doxycycline. Patients with significant comorbidities should receive a β-lactam plus macrolide combination or a respiratory fluoroquinolone alone. Inpatients not requiring ICU care may receive a β-lactam plus macrolide or a respiratory fluoroquinolone. ICU patients should receive a β-lactam plus either a macrolide or respiratory fluoroquinolone, with additional coverage for Pseudomonas or MRSA when risk factors are present. Aspiration pneumonia may require anaerobic coverage such as clindamycin or metronidazole. Prompt antibiotic administration is critical in ill-appearing patients.
Disposition decisions are guided by clinical judgment and validated tools such as the CURB-65 score and the Pneumonia Severity Index. CURB-65 evaluates confusion, elevated BUN, respiratory rate ≥30, hypotension, and age ≥65. Scores of 0–1 generally support outpatient management, while higher scores favor admission and possible ICU care. Admission is also indicated for unstable vital signs, hypoxia, significant comorbidities, failure of outpatient therapy, or inability to ensure follow-up. Discharge may be appropriate for patients younger than 65 without comorbidities, with normal vital signs and reliable follow-up within 72 hours.
Clinicians must avoid delays in antibiotic initiation in critically ill patients and remain vigilant for pneumonia in those presenting with presumed exacerbations of chronic lung disease. Tuberculosis and HIV risk factors should always be assessed. Elderly and immunocompromised patients may lack classic symptoms, making a high index of suspicion essential for timely diagnosis and management.
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KembaraXtra -Medicine- Emergency and Acute Medicine – Perilunate Dislocation
Perilunate dislocation is a serious high-energy wrist injury in which the lunate remains aligned with the distal radius, while the distal carpal bones—most notably the capitate—are displaced dorsally in approximately 95% of cases and volarly in about 5%. It is an unstable injury that requires early surgical treatment because it carries a high risk of long-term complications, particularly post-traumatic arthritis. The scaphoid is frequently fractured in association with perilunate dislocations.
The usual mechanism of injury is wrist hyperextension combined with ulnar deviation. These injuries typically result from significant trauma such as falls from height, motor vehicle accidents, industrial accidents, or sporting injuries. Because of the force involved, concomitant upper extremity injuries are common and must always be assessed.
Patients typically present with severe wrist pain, marked swelling, and diffuse tenderness. There may be decreased range of motion and sometimes visible deformity. Paresthesias in the median nerve distribution are common due to swelling and compression within the carpal tunnel. A careful history often reveals a high-energy injury. On examination, the wrist is swollen and painful with limited motion. Sensory changes in the median nerve distribution may be present, and neurovascular status—including capillary refill and 2-point discrimination—must be carefully assessed and documented. Skin integrity should be evaluated, as open injuries can occur. Importantly, this diagnosis is frequently missed on initial evaluation.
Radiographs of the wrist are essential and must include AP, lateral, and oblique views. The true lateral view is most diagnostic. Normally, the radius, lunate, and capitate should align in a straight line on the lateral film. In perilunate dislocation, the lunate remains aligned with the radius, but the capitate is displaced dorsally (most commonly) or volarly. CT or MRI is generally not required in the emergency department but may be used for preoperative planning.
The differential diagnosis includes lunate dislocation, lunate fracture, scapholunate dissociation, distal radius fracture, and other ligamentous wrist injuries. In pediatric patients, nonaccidental trauma should be considered.
Management begins with assessment for more serious associated injuries, followed by immobilization, elevation, ice application, and adequate pain control. Closed reduction should be attempted emergently. Traction is applied for approximately 10 minutes using finger traps with counterweights, followed by manual traction. The injury is briefly recreated with wrist extension while volar pressure is applied over the lunate, and then slow wrist flexion is performed to relocate the distal carpal bones. After reduction, the wrist should be immobilized in a sugar-tong splint in neutral position, post-reduction radiographs obtained, and neurovascular status reassessed. Procedural sedation is often required.
Definitive treatment requires operative fixation with ligament repair to restore stability and minimize long-term complications. All patients should have urgent hand surgery consultation.
Patients should be admitted if the injury is open, irreducible, associated with neurovascular compromise, or part of multiple trauma. Closed injuries with successful reduction and intact neurovascular status may be discharged with reliable orthopedic follow-up within 2–3 days, though all cases ultimately require surgical evaluation.
Complications are common even with appropriate treatment and include median nerve injury, tendon problems, wrist instability, complex regional pain syndrome, decreased grip strength, and post-traumatic arthritis. Up to 25% of these injuries are missed at initial presentation. Delayed diagnosis significantly worsens outcomes and may necessitate salvage procedures.
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Emergency and Acute Medicine – Periodic Paralysis
Periodic paralysis is a disorder of skeletal muscle ion channel function that results in episodic flaccid weakness of the extremities. It is usually inherited and is triggered by abnormalities in serum potassium levels or thyrotoxicosis. Primary forms are familial and typically autosomal dominant mutations affecting skeletal muscle sodium, calcium, or potassium channels. Secondary forms include thyrotoxic, hypokalemic, and hyperkalemic variants.
Hypokalemic periodic paralysis is the most common form, with a prevalence of approximately 1 in 100,000, and about one-third of cases arise from new autosomal dominant mutations. Hyperkalemic periodic paralysis is less common, with a prevalence of 1 in 200,000, and most individuals with the mutation develop symptoms. Thyrotoxic periodic paralysis occurs in approximately 2% of patients with thyrotoxicosis, is more common in Asian populations, and is clinically similar to hypokalemic periodic paralysis. Andersen–Tawil syndrome is a rare subtype associated with periodic paralysis and cardiac arrhythmias.
The disorder results from mutations in skeletal muscle ion channel genes. Mutations in SCN4A affect sodium channels and are associated with both hypokalemic and hyperkalemic forms. Mutations in CACNA1S affect calcium channels and are linked to hypokalemic periodic paralysis. Andersen–Tawil syndrome is associated with mutations in the KCNJ2 gene. Age of onset varies: hypokalemic and Andersen–Tawil forms typically begin in the first or second decade, hyperkalemic in the first decade, and thyrotoxic periodic paralysis usually presents in the second to fifth decades.
Patients present with intermittent episodes of symmetrical muscle weakness, typically affecting the legs more than the arms. Attacks often have rapid onset and may recur, with some patients experiencing persistent mild weakness between episodes. Triggers include carbohydrate-rich meals, rest after strenuous exercise, illness, lack of sleep, medications such as insulin or β-agonists, cold exposure, menstruation, pregnancy, and thyroid dysfunction. Hypokalemic attacks may last from one hour to several days, hyperkalemic attacks usually last 15 minutes to 4 hours, and thyrotoxic attacks resemble hypokalemic episodes in duration.
On examination, patients are alert with intact sensation and normal sphincter tone. Weakness is symmetrical, reflexes are reduced or absent, and proximal muscles are often more affected. In thyrotoxic periodic paralysis, findings may include tachycardia, warm moist skin, goiter, or exophthalmos. Andersen–Tawil syndrome may present with dysmorphic features such as short stature, low-set ears, broad nasal base, and micrognathia, along with cardiac arrhythmias. Severe hypokalemia may rarely involve respiratory muscles.
Essential evaluation includes serum electrolytes and electrocardiography. In hypokalemic periodic paralysis, potassium is low or normal during attacks, and ECG may show sinus bradycardia, flattened T waves, or ST depression. In hyperkalemic periodic paralysis, potassium is normal or elevated and ECG may rarely show peaked T waves. In thyrotoxic periodic paralysis, potassium is decreased during attacks, and thyroid studies reveal suppressed TSH with elevated T4. ECG may show tachyarrhythmias, conduction abnormalities, or widened QRS complexes. Andersen–Tawil syndrome is associated with prolonged QT interval and ventricular arrhythmias. Imaging is not required in the emergency setting.
Management is primarily supportive with airway, breathing, and circulation stabilization, oxygen, IV access, and monitoring. In hypokalemic periodic paralysis, oral potassium replacement is preferred, typically 40 mEq, with cautious IV replacement if needed. Overcorrection must be avoided. In hyperkalemic periodic paralysis, many attacks resolve spontaneously, but IV calcium gluconate may help terminate an episode. In thyrotoxic periodic paralysis, treatment includes potassium replacement and management of thyrotoxicosis, often with a nonselective β-blocker for tachycardia. Andersen–Tawil syndrome requires careful potassium management and monitoring for arrhythmias. Patients with hypokalemic periodic paralysis should avoid volatile anesthetics and depolarizing neuromuscular blockers, as these may trigger attacks or malignant hyperthermia.
Admission is recommended for patients with severe electrolyte abnormalities, persistent weakness, cardiac arrhythmias, respiratory compromise, or Andersen–Tawil syndrome due to the risk of sudden cardiac death. Patients with resolved symptoms and no cardiopulmonary compromise may be discharged with referral to neurology, and endocrinology in cases of thyrotoxic periodic paralysis. Genetic counseling is appropriate in primary forms due to the 50% inheritance risk.
Early recognition and appropriate correction of electrolyte abnormalities are critical. Andersen–Tawil patients and those with persistent symptoms should be admitted. Caution with anesthetic agents is essential in all forms of periodic paralysis.
Periodic paralysis is a disorder of skeletal muscle ion channel function that results in episodic flaccid weakness of the extremities. It is usually inherited and is triggered by abnormalities in serum potassium levels or thyrotoxicosis. Primary forms are familial and typically autosomal dominant mutations affecting skeletal muscle sodium, calcium, or potassium channels. Secondary forms include thyrotoxic, hypokalemic, and hyperkalemic variants.
Hypokalemic periodic paralysis is the most common form, with a prevalence of approximately 1 in 100,000, and about one-third of cases arise from new autosomal dominant mutations. Hyperkalemic periodic paralysis is less common, with a prevalence of 1 in 200,000, and most individuals with the mutation develop symptoms. Thyrotoxic periodic paralysis occurs in approximately 2% of patients with thyrotoxicosis, is more common in Asian populations, and is clinically similar to hypokalemic periodic paralysis. Andersen–Tawil syndrome is a rare subtype associated with periodic paralysis and cardiac arrhythmias.
The disorder results from mutations in skeletal muscle ion channel genes. Mutations in SCN4A affect sodium channels and are associated with both hypokalemic and hyperkalemic forms. Mutations in CACNA1S affect calcium channels and are linked to hypokalemic periodic paralysis. Andersen–Tawil syndrome is associated with mutations in the KCNJ2 gene. Age of onset varies: hypokalemic and Andersen–Tawil forms typically begin in the first or second decade, hyperkalemic in the first decade, and thyrotoxic periodic paralysis usually presents in the second to fifth decades.
Patients present with intermittent episodes of symmetrical muscle weakness, typically affecting the legs more than the arms. Attacks often have rapid onset and may recur, with some patients experiencing persistent mild weakness between episodes. Triggers include carbohydrate-rich meals, rest after strenuous exercise, illness, lack of sleep, medications such as insulin or β-agonists, cold exposure, menstruation, pregnancy, and thyroid dysfunction. Hypokalemic attacks may last from one hour to several days, hyperkalemic attacks usually last 15 minutes to 4 hours, and thyrotoxic attacks resemble hypokalemic episodes in duration.
On examination, patients are alert with intact sensation and normal sphincter tone. Weakness is symmetrical, reflexes are reduced or absent, and proximal muscles are often more affected. In thyrotoxic periodic paralysis, findings may include tachycardia, warm moist skin, goiter, or exophthalmos. Andersen–Tawil syndrome may present with dysmorphic features such as short stature, low-set ears, broad nasal base, and micrognathia, along with cardiac arrhythmias. Severe hypokalemia may rarely involve respiratory muscles.
Essential evaluation includes serum electrolytes and electrocardiography. In hypokalemic periodic paralysis, potassium is low or normal during attacks, and ECG may show sinus bradycardia, flattened T waves, or ST depression. In hyperkalemic periodic paralysis, potassium is normal or elevated and ECG may rarely show peaked T waves. In thyrotoxic periodic paralysis, potassium is decreased during attacks, and thyroid studies reveal suppressed TSH with elevated T4. ECG may show tachyarrhythmias, conduction abnormalities, or widened QRS complexes. Andersen–Tawil syndrome is associated with prolonged QT interval and ventricular arrhythmias. Imaging is not required in the emergency setting.
Management is primarily supportive with airway, breathing, and circulation stabilization, oxygen, IV access, and monitoring. In hypokalemic periodic paralysis, oral potassium replacement is preferred, typically 40 mEq, with cautious IV replacement if needed. Overcorrection must be avoided. In hyperkalemic periodic paralysis, many attacks resolve spontaneously, but IV calcium gluconate may help terminate an episode. In thyrotoxic periodic paralysis, treatment includes potassium replacement and management of thyrotoxicosis, often with a nonselective β-blocker for tachycardia. Andersen–Tawil syndrome requires careful potassium management and monitoring for arrhythmias. Patients with hypokalemic periodic paralysis should avoid volatile anesthetics and depolarizing neuromuscular blockers, as these may trigger attacks or malignant hyperthermia.
Admission is recommended for patients with severe electrolyte abnormalities, persistent weakness, cardiac arrhythmias, respiratory compromise, or Andersen–Tawil syndrome due to the risk of sudden cardiac death. Patients with resolved symptoms and no cardiopulmonary compromise may be discharged with referral to neurology, and endocrinology in cases of thyrotoxic periodic paralysis. Genetic counseling is appropriate in primary forms due to the 50% inheritance risk.
Early recognition and appropriate correction of electrolyte abnormalities are critical. Andersen–Tawil patients and those with persistent symptoms should be admitted. Caution with anesthetic agents is essential in all forms of periodic paralysis.
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Emergency and Acute Medicine – Periodontal Abscess
A periodontal abscess is a localized collection of pus within the supporting structures of the teeth, including the periodontal ligament and alveolar bone. It typically develops as a complication of progressive periodontal disease, where bone loss leads to the formation of periodontal pockets. Food particles and debris accumulate within these pockets. Coronal epithelial tissues may reattach to the tooth surface while bacteria and debris remain trapped, impairing drainage. This environment promotes secondary infection and abscess formation.
Although primarily localized, periodontal abscesses can lead to serious complications if untreated. These include osteomyelitis, dentocutaneous fistula, cavernous sinus thrombosis, Ludwig angina, maxillary sinusitis, mediastinitis, tooth loss, and sepsis. In children, periodontal abscesses are rare; periapical abscesses are more common and typically originate in the pulp, often associated with dental caries.
The infection is usually polymicrobial. Common pathogens include anaerobic gram-negative rods, Peptostreptococci, viridans group streptococci, and Neisseria species.
Diagnosis is clinical. Patients typically present with localized dental pain, facial swelling, malaise, and sometimes fever. On examination, there may be focal gingival swelling or fluctuance, tenderness to palpation, increased tooth mobility, and possible lymphadenopathy. A parulis—a pimple-like lesion on the gingiva—may be present in chronic abscesses, representing the end of a draining sinus tract. Pus may be expressed from the sinus tract. Heat sensitivity may occur. Trismus is generally absent unless infection has spread to the muscles of mastication.
Imaging and laboratory studies are not routinely required for diagnosis. However, panoramic, periapical, or occlusal radiographs may help confirm the diagnosis and determine the extent of disease. Bedside ultrasound can assist in identifying fluid collections. CT imaging may be indicated if there is concern for extension into adjacent structures. Anaerobic cultures may be considered in complicated cases or in immunocompromised patients. Electric pulp testing, performed by a dental specialist during follow-up, helps assess tooth viability.
The differential diagnosis includes periapical abscess, maxillary sinusitis, aphthous ulcers, oral herpes, salivary gland tumors, mumps, sialadenitis, localized adenopathy, facial cellulitis, acute otitis media, and peritonsillar abscess. In children, periapical abscess is more likely. For asymptomatic parulis, fibroma, pyogenic granuloma, peripheral ossifying granuloma, or Kaposi sarcoma should be considered.
Prehospital management rarely involves airway emergencies. However, if signs of airway compromise are present, airway equipment should be available, the patient transported upright, and supplemental oxygen provided. Initial stabilization in the emergency setting includes assessment of airway patency and securing the airway if there is respiratory distress, inability to manage secretions, or significant oropharyngeal swelling.
Emergency department management focuses on analgesia and drainage. NSAIDs or opioids may be used for pain control. Incision and drainage are performed under local anesthesia, typically using 2% lidocaine with epinephrine. A small stab incision is made toward the alveolar bone, followed by blunt dissection and irrigation with saline. If the cavity is large, a small iodoform gauze or Penrose drain may be placed for 24–48 hours and secured to prevent aspiration.
Antibiotics are indicated when the abscess is extensive or when systemic signs are present. Penicillin VK is considered first-line therapy. For penicillin-allergic patients, azithromycin, erythromycin, or clindamycin may be used. Clindamycin is also appropriate for patients who fail penicillin therapy. Ampicillin/sulbactam may be required for severe infections. Warm salt water rinses are recommended hourly while awake for 24–48 hours.
Admission is required for severe infections, complications such as cavernous sinus thrombosis or osteomyelitis, airway compromise, Ludwig angina, systemic toxicity, immunocompromised patients, treatment failure, or inability to manage the condition at home. Uncomplicated cases may be discharged with close dental follow-up within 24–48 hours.
Dental follow-up is essential for definitive care, including assessment of tooth viability, possible extraction, root canal therapy, and removal of drains. Without proper dental evaluation, symptoms may recur and long-term tooth preservation may be compromised. Maxillary sinusitis may be misdiagnosed if a thorough oral examination is not performed, underscoring the importance of careful assessment and timely referral.
A periodontal abscess is a localized collection of pus within the supporting structures of the teeth, including the periodontal ligament and alveolar bone. It typically develops as a complication of progressive periodontal disease, where bone loss leads to the formation of periodontal pockets. Food particles and debris accumulate within these pockets. Coronal epithelial tissues may reattach to the tooth surface while bacteria and debris remain trapped, impairing drainage. This environment promotes secondary infection and abscess formation.
Although primarily localized, periodontal abscesses can lead to serious complications if untreated. These include osteomyelitis, dentocutaneous fistula, cavernous sinus thrombosis, Ludwig angina, maxillary sinusitis, mediastinitis, tooth loss, and sepsis. In children, periodontal abscesses are rare; periapical abscesses are more common and typically originate in the pulp, often associated with dental caries.
The infection is usually polymicrobial. Common pathogens include anaerobic gram-negative rods, Peptostreptococci, viridans group streptococci, and Neisseria species.
Diagnosis is clinical. Patients typically present with localized dental pain, facial swelling, malaise, and sometimes fever. On examination, there may be focal gingival swelling or fluctuance, tenderness to palpation, increased tooth mobility, and possible lymphadenopathy. A parulis—a pimple-like lesion on the gingiva—may be present in chronic abscesses, representing the end of a draining sinus tract. Pus may be expressed from the sinus tract. Heat sensitivity may occur. Trismus is generally absent unless infection has spread to the muscles of mastication.
Imaging and laboratory studies are not routinely required for diagnosis. However, panoramic, periapical, or occlusal radiographs may help confirm the diagnosis and determine the extent of disease. Bedside ultrasound can assist in identifying fluid collections. CT imaging may be indicated if there is concern for extension into adjacent structures. Anaerobic cultures may be considered in complicated cases or in immunocompromised patients. Electric pulp testing, performed by a dental specialist during follow-up, helps assess tooth viability.
The differential diagnosis includes periapical abscess, maxillary sinusitis, aphthous ulcers, oral herpes, salivary gland tumors, mumps, sialadenitis, localized adenopathy, facial cellulitis, acute otitis media, and peritonsillar abscess. In children, periapical abscess is more likely. For asymptomatic parulis, fibroma, pyogenic granuloma, peripheral ossifying granuloma, or Kaposi sarcoma should be considered.
Prehospital management rarely involves airway emergencies. However, if signs of airway compromise are present, airway equipment should be available, the patient transported upright, and supplemental oxygen provided. Initial stabilization in the emergency setting includes assessment of airway patency and securing the airway if there is respiratory distress, inability to manage secretions, or significant oropharyngeal swelling.
Emergency department management focuses on analgesia and drainage. NSAIDs or opioids may be used for pain control. Incision and drainage are performed under local anesthesia, typically using 2% lidocaine with epinephrine. A small stab incision is made toward the alveolar bone, followed by blunt dissection and irrigation with saline. If the cavity is large, a small iodoform gauze or Penrose drain may be placed for 24–48 hours and secured to prevent aspiration.
Antibiotics are indicated when the abscess is extensive or when systemic signs are present. Penicillin VK is considered first-line therapy. For penicillin-allergic patients, azithromycin, erythromycin, or clindamycin may be used. Clindamycin is also appropriate for patients who fail penicillin therapy. Ampicillin/sulbactam may be required for severe infections. Warm salt water rinses are recommended hourly while awake for 24–48 hours.
Admission is required for severe infections, complications such as cavernous sinus thrombosis or osteomyelitis, airway compromise, Ludwig angina, systemic toxicity, immunocompromised patients, treatment failure, or inability to manage the condition at home. Uncomplicated cases may be discharged with close dental follow-up within 24–48 hours.
Dental follow-up is essential for definitive care, including assessment of tooth viability, possible extraction, root canal therapy, and removal of drains. Without proper dental evaluation, symptoms may recur and long-term tooth preservation may be compromised. Maxillary sinusitis may be misdiagnosed if a thorough oral examination is not performed, underscoring the importance of careful assessment and timely referral.
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KembaraXtra -Medicine- Emergency and Acute Medicine – Periorbital and Orbital Cellulitis
Periorbital (preseptal) cellulitis and orbital cellulitis are infections involving the tissues around the eye, distinguished by their anatomic relationship to the orbital septum. The orbital septum is a connective tissue extension of the orbital periosteum that separates superficial eyelid structures from the deeper orbital contents. Periorbital cellulitis is confined to tissues anterior to this septum, whereas orbital cellulitis involves structures deep to it. This distinction is critical because orbital cellulitis is a true medical emergency with risk of permanent vision loss and life-threatening complications.
Periorbital cellulitis most commonly occurs as a complication of upper respiratory tract infection or sinusitis, where inflammatory edema leads to vascular and lymphatic congestion. It may also arise from local eyelid infections such as blepharitis, hordeolum, or dacryocystitis, or from surrounding skin disruptions including insect bites, minor trauma, impetigo, or dermatologic conditions. The septum typically acts as a barrier to deeper spread, although it may be incomplete.
Orbital cellulitis usually results from extension of infection from adjacent structures, most commonly ethmoid sinusitis penetrating the thin lamina papyracea. Other causes include dental abscess, retained orbital foreign body, puncture wounds, orbital fractures, postoperative infections, and hematogenous spread through valveless orbital veins. Rarely, it results from direct progression of periorbital cellulitis. Common pathogens include Streptococcus pneumoniae, Streptococcus viridans, Streptococcus pyogenes, Streptococcus anginosus, and Staphylococcus aureus. Anaerobes, Bacteroides species, and gram-negative organisms may also be involved.
All forms of orbital cellulitis carry significant morbidity and mortality risk. Complications include permanent visual loss, subperiosteal abscess, cavernous sinus thrombosis, and central nervous system infections. Fungal orbital cellulitis, particularly cerebrorhino-orbital phycomycosis (CROP), is rare but highly lethal, especially in immunocompromised patients and those with diabetic ketoacidosis. It often begins in the paranasal sinuses and invades blood vessels, causing thrombosis and tissue necrosis. Bloody nasal discharge and necrosis of the palate or nasal mucosa may be present.
In children, routine Hib and pneumococcal vaccinations have reduced incidence, but infection still occurs. Periorbital cellulitis is approximately five times more common and usually affects children younger than five years, whereas orbital cellulitis is more common in children older than five.
Both conditions present with unilateral red, swollen eyelids, and swelling may be severe in either. The key differences lie in systemic toxicity and ocular involvement. Orbital cellulitis is often preceded by sinusitis (60–90% of cases), dental infection, trauma, or recent surgery. Patients may report eye pain, visual changes, decreased color vision, diplopia, restricted or painful extraocular movements, and headache. Fever above 39°C and a toxic appearance are common. On examination, findings may include proptosis, conjunctival injection, chemosis, afferent pupillary defect, decreased visual acuity, ophthalmoplegia, and signs of meningismus.
Periorbital cellulitis typically follows local skin injury or superficial infection and presents more subacutely with low-grade fever and minimal systemic symptoms. Visual acuity and extraocular movements remain normal, and there are no signs of deep orbital involvement.
A complete eye examination is essential in all cases. This includes assessment of visual acuity, extraocular movements, pupillary response, fundoscopic examination, intraocular pressure measurement, and a thorough neurologic exam.
Laboratory studies are supportive but not diagnostic. A white blood cell count below 15,000 is more typical of periorbital cellulitis, whereas higher counts may suggest orbital involvement. Blood cultures and cultures of purulent material may be obtained, particularly if bacteremia is suspected. When gonorrhea is considered, appropriate culture media should be used.
Contrast-enhanced CT of the orbits is indicated when there are central nervous system signs, visual disturbances, proptosis, painful or restricted extraocular movements, ophthalmoplegia, bilateral edema, lack of improvement within 24 hours, or clinical deterioration. CT helps define the extent of infection, detect sinusitis, orbital emphysema, subperiosteal abscess, foreign bodies, and cavernous sinus thrombosis. Lumbar puncture may be necessary in toxic patients with meningismus to exclude CNS involvement.
Treatment depends on severity and depth of infection. Periorbital cellulitis in stable patients typically responds to oral antibiotics such as amoxicillin-clavulanate, cephalexin, clindamycin, or dicloxacillin. Parenteral antibiotics are indicated for toxic appearance, suspected bacteremia, or inability to tolerate oral therapy. Close follow-up within 24–48 hours is essential.
Orbital cellulitis requires hospital admission and immediate intravenous antibiotics. Early ophthalmology consultation is mandatory, and ENT consultation should be considered when sinusitis is the source. Empiric therapy commonly includes IV ceftriaxone or other broad-spectrum coverage, with vancomycin added if MRSA is suspected. Metronidazole may be included when anaerobic infection is likely. Surgical intervention may be required for abscess drainage, sinus decompression, or optic nerve decompression. In suspected fungal infection, high-dose IV amphotericin B and urgent surgical debridement are required.
Patients with periorbital cellulitis may be discharged if they have no systemic toxicity, no orbital findings, can tolerate oral antibiotics, and have reliable follow-up. Admission is required for orbital cellulitis, systemic toxicity, visual impairment, inability to arrange follow-up, progression on oral therapy, or high-risk conditions.
Any patient presenting with a red, swollen eye must be carefully evaluated for orbital cellulitis. A detailed history should include recent sinusitis, trauma, dental infection, surgery, immunocompromised state, or recent diabetic ketoacidosis. Clinicians must carefully assess for systemic toxicity, visual changes, pain with eye movement, and neurologic symptoms to avoid missing this potentially vision- and life-threatening condition.
