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Infectious Disease and Microbiology – Bell’s Palsy
Bell’s palsy is defined as an acute, idiopathic, unilateral paralysis of the facial nerve (cranial nerve VII). Approximately half of all facial nerve palsies are classified as Bell’s palsy. Bilateral involvement is rare, occurring in about 0.3% of cases. Although termed “idiopathic,” viral etiologies are strongly suspected, particularly herpes simplex virus. Other infectious associations include herpes zoster (including herpes zoster oticus). Rarely, Bell’s palsy has been reported as an adverse event following immunization.
The incidence in the United States ranges from 13 to 34 cases per 100,000 persons annually. The condition most commonly affects individuals aged 20–35 years and those over 70 years of age. Males and females are equally affected. Bell’s palsy is the most common cause of seventh nerve palsy in children. Risk factors include pregnancy, diabetes mellitus, and hypertension in individuals older than 40 years. Currently, there is no known preventive measure.
Clinically, Bell’s palsy presents with acute onset over one to two days and rapid progression to partial or complete unilateral facial paralysis. Patients may experience decreased tear and saliva production on the affected side, hyperacusis (increased sensitivity to sound), dysgeusia (altered taste), and retroauricular pain. The diagnosis is primarily clinical.
The differential diagnosis is broad and includes infectious causes such as Lyme disease, HIV infection (particularly during seroconversion), otitis media, mastoiditis, tuberculosis, syphilis, infectious meningitis, rubella, tetanus, Mycoplasma infection, and enteroviral infections. Noninfectious causes include sarcoidosis, Sjögren’s syndrome, systemic lupus erythematosus, tumors (parotid gland tumors, melanoma, meningioma), cerebral aneurysm, Guillain-Barré syndrome, trauma, iatrogenic injury, and others. In cases of bilateral facial paralysis, Lyme disease and sarcoidosis should be strongly considered.
Electrodiagnostic studies such as electromyography (EMG) or electroneurography may be useful in selected cases, particularly if recovery is incomplete. Patients with a typical presentation and early recovery usually do not require further testing. Imaging with CT or MRI is indicated if the presentation is atypical, if symptoms progress slowly, or if there is no improvement within six months, to exclude intracranial or middle ear pathology. Recent evidence suggests that ultrasound measurement of the distal facial nerve diameter may help predict recovery at three months.
Early treatment significantly improves outcomes. Prednisolone should be initiated within three days of symptom onset, at a dose of 60–80 mg daily for one week, as it increases the likelihood of complete recovery at three and nine months. Antiviral therapy may be added in severe cases of facial palsy. Eye protection is essential, including artificial tears during the day and lubricating ointment at night, to prevent corneal injury. The role of surgical decompression remains controversial.
Ongoing care focuses on eye protection and psychological support. Complications include incomplete recovery in approximately one-third of patients, keratitis, corneal abrasions, and recurrence in 7–15% of cases.
Bell’s palsy is defined as an acute, idiopathic, unilateral paralysis of the facial nerve (cranial nerve VII). Approximately half of all facial nerve palsies are classified as Bell’s palsy. Bilateral involvement is rare, occurring in about 0.3% of cases. Although termed “idiopathic,” viral etiologies are strongly suspected, particularly herpes simplex virus. Other infectious associations include herpes zoster (including herpes zoster oticus). Rarely, Bell’s palsy has been reported as an adverse event following immunization.
The incidence in the United States ranges from 13 to 34 cases per 100,000 persons annually. The condition most commonly affects individuals aged 20–35 years and those over 70 years of age. Males and females are equally affected. Bell’s palsy is the most common cause of seventh nerve palsy in children. Risk factors include pregnancy, diabetes mellitus, and hypertension in individuals older than 40 years. Currently, there is no known preventive measure.
Clinically, Bell’s palsy presents with acute onset over one to two days and rapid progression to partial or complete unilateral facial paralysis. Patients may experience decreased tear and saliva production on the affected side, hyperacusis (increased sensitivity to sound), dysgeusia (altered taste), and retroauricular pain. The diagnosis is primarily clinical.
The differential diagnosis is broad and includes infectious causes such as Lyme disease, HIV infection (particularly during seroconversion), otitis media, mastoiditis, tuberculosis, syphilis, infectious meningitis, rubella, tetanus, Mycoplasma infection, and enteroviral infections. Noninfectious causes include sarcoidosis, Sjögren’s syndrome, systemic lupus erythematosus, tumors (parotid gland tumors, melanoma, meningioma), cerebral aneurysm, Guillain-Barré syndrome, trauma, iatrogenic injury, and others. In cases of bilateral facial paralysis, Lyme disease and sarcoidosis should be strongly considered.
Electrodiagnostic studies such as electromyography (EMG) or electroneurography may be useful in selected cases, particularly if recovery is incomplete. Patients with a typical presentation and early recovery usually do not require further testing. Imaging with CT or MRI is indicated if the presentation is atypical, if symptoms progress slowly, or if there is no improvement within six months, to exclude intracranial or middle ear pathology. Recent evidence suggests that ultrasound measurement of the distal facial nerve diameter may help predict recovery at three months.
Early treatment significantly improves outcomes. Prednisolone should be initiated within three days of symptom onset, at a dose of 60–80 mg daily for one week, as it increases the likelihood of complete recovery at three and nine months. Antiviral therapy may be added in severe cases of facial palsy. Eye protection is essential, including artificial tears during the day and lubricating ointment at night, to prevent corneal injury. The role of surgical decompression remains controversial.
Ongoing care focuses on eye protection and psychological support. Complications include incomplete recovery in approximately one-third of patients, keratitis, corneal abrasions, and recurrence in 7–15% of cases.
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Infectious Disease and Microbiology – Bartonellosis (Oroya Fever/Verruga Peruana)
Bartonellosis is an infection caused by Bartonella bacilliformis, transmitted by sandflies of the genus Phlebotomus. It occurs in endemic areas and presents in two distinct clinical forms. Nonimmune individuals typically develop an acute febrile illness known as Oroya fever, characterized by profound hemolytic anemia. After recovery from the acute phase, a chronic cutaneous form called verruga peruana may develop, featuring angioproliferative skin lesions that resemble those seen in bacillary angiomatosis caused by other Bartonella species.
The disease is endemic to the Andean river valleys at altitudes between 600 and 2,500 meters in Peru, Ecuador, and Colombia. Oroya fever most commonly affects tourists or visitors who lack prior immunity, whereas verruga peruana is more frequently seen in the native population. Rare imported cases have been reported outside endemic regions. Risk factors include residence in or travel to endemic areas and exposure to the sandfly vector. Prevention focuses on vector control measures such as indoor and outdoor insecticide spraying, use of insect repellents, and bed nets.
Pathophysiologically, B. bacilliformis invades erythrocytes and endothelial cells. The bacteria multiply within intracellular vacuoles inside red blood cells, which are subsequently destroyed by the reticuloendothelial system, resulting in severe hemolytic anemia. The organism is a small, gram-negative bacillus closely related to Bartonella quintana.
The incubation period of Oroya fever averages about three weeks but can extend up to 100 days. The acute illness may begin gradually with low-grade fever, malaise, headache, and anorexia, or abruptly with high fever, chills, diaphoresis, altered mental status, and rapidly progressive anemia. Patients may experience dyspnea, chest discomfort, myalgias, arthralgias, and in severe cases, delirium or coma. Anasarca indicates a poor prognosis. During the convalescent phase, fever subsides and anemia improves.
Physical examination in Oroya fever reveals high fever, signs of profound anemia, generalized nontender lymphadenopathy, and occasionally thrombocytopenic purpura. Splenomegaly is uncommon and may suggest concurrent infection.
Verruga peruana develops weeks to months after recovery from the acute phase. Lesions appear in crops and may be miliary (1–4 mm papular erythematous lesions), nodular, or larger “mular” lesions exceeding 5 mm in diameter. They are typically bright red, bleed easily, and may involve skin, mucous membranes, or internal organs. Lesions are generally nontender unless secondarily infected and may be present at different stages simultaneously.
Diagnosis in the acute phase is made by identifying numerous bacteria attached to red blood cells on Giemsa- or Wright-stained peripheral blood smears or by positive blood or bone marrow cultures. Peripheral smear may also reveal macrocytosis, poikilocytosis, Howell–Jolly bodies, nucleated red blood cells, and immature myeloid cells. Profound anemia with a negative Coombs’ test is typical. In subacute cases, smears may initially be negative, and blood cultures are required. In the chronic phase, organisms can be demonstrated in cultures from skin lesions or bone marrow. Serologic tests such as ELISA or indirect immunofluorescence can support the diagnosis. Skin biopsy may show increased angiogenesis and characteristic endothelial inclusions (Rocha-Lima inclusions).
The acute phase must be differentiated from other endemic febrile illnesses such as malaria, typhoid fever, and leptospirosis. Verruga lesions resemble bacillary angiomatosis, Kaposi’s sarcoma, and certain neoplasms; epidemiologic context is a key diagnostic clue.
Treatment of Oroya fever consists of chloramphenicol (500 mg orally or intravenously every 6 hours) combined with a second antimicrobial, preferably a beta-lactam such as penicillin, for 14 days. Chloramphenicol also provides coverage against salmonellosis, a common secondary infection. Doxycycline is an alternative agent, while fluoroquinolones are generally not recommended due to resistance. Verruga peruana is treated with rifampin (10 mg/kg daily, maximum 600 mg daily) for 10–14 days. Streptomycin is a second-line option. Supportive care, including blood transfusion for severe anemia, is essential in the acute phase. Large or secondarily infected skin lesions may require surgical excision.
Patients with Oroya fever typically require inpatient management, whereas those with verruga peruana can often be managed as outpatients. Monitoring during the acute phase should include hydration status, complete blood counts, and surveillance for secondary infections such as salmonellosis, malaria, or tuberculosis.
Untreated Oroya fever carries a mortality rate of 50–88%. With appropriate therapy, fever usually resolves within 24 hours, though bacteremia may persist longer. Complications include secondary bacterial infections during convalescence and ulceration or bleeding of verruga lesions.
Bartonellosis is an infection caused by Bartonella bacilliformis, transmitted by sandflies of the genus Phlebotomus. It occurs in endemic areas and presents in two distinct clinical forms. Nonimmune individuals typically develop an acute febrile illness known as Oroya fever, characterized by profound hemolytic anemia. After recovery from the acute phase, a chronic cutaneous form called verruga peruana may develop, featuring angioproliferative skin lesions that resemble those seen in bacillary angiomatosis caused by other Bartonella species.
The disease is endemic to the Andean river valleys at altitudes between 600 and 2,500 meters in Peru, Ecuador, and Colombia. Oroya fever most commonly affects tourists or visitors who lack prior immunity, whereas verruga peruana is more frequently seen in the native population. Rare imported cases have been reported outside endemic regions. Risk factors include residence in or travel to endemic areas and exposure to the sandfly vector. Prevention focuses on vector control measures such as indoor and outdoor insecticide spraying, use of insect repellents, and bed nets.
Pathophysiologically, B. bacilliformis invades erythrocytes and endothelial cells. The bacteria multiply within intracellular vacuoles inside red blood cells, which are subsequently destroyed by the reticuloendothelial system, resulting in severe hemolytic anemia. The organism is a small, gram-negative bacillus closely related to Bartonella quintana.
The incubation period of Oroya fever averages about three weeks but can extend up to 100 days. The acute illness may begin gradually with low-grade fever, malaise, headache, and anorexia, or abruptly with high fever, chills, diaphoresis, altered mental status, and rapidly progressive anemia. Patients may experience dyspnea, chest discomfort, myalgias, arthralgias, and in severe cases, delirium or coma. Anasarca indicates a poor prognosis. During the convalescent phase, fever subsides and anemia improves.
Physical examination in Oroya fever reveals high fever, signs of profound anemia, generalized nontender lymphadenopathy, and occasionally thrombocytopenic purpura. Splenomegaly is uncommon and may suggest concurrent infection.
Verruga peruana develops weeks to months after recovery from the acute phase. Lesions appear in crops and may be miliary (1–4 mm papular erythematous lesions), nodular, or larger “mular” lesions exceeding 5 mm in diameter. They are typically bright red, bleed easily, and may involve skin, mucous membranes, or internal organs. Lesions are generally nontender unless secondarily infected and may be present at different stages simultaneously.
Diagnosis in the acute phase is made by identifying numerous bacteria attached to red blood cells on Giemsa- or Wright-stained peripheral blood smears or by positive blood or bone marrow cultures. Peripheral smear may also reveal macrocytosis, poikilocytosis, Howell–Jolly bodies, nucleated red blood cells, and immature myeloid cells. Profound anemia with a negative Coombs’ test is typical. In subacute cases, smears may initially be negative, and blood cultures are required. In the chronic phase, organisms can be demonstrated in cultures from skin lesions or bone marrow. Serologic tests such as ELISA or indirect immunofluorescence can support the diagnosis. Skin biopsy may show increased angiogenesis and characteristic endothelial inclusions (Rocha-Lima inclusions).
The acute phase must be differentiated from other endemic febrile illnesses such as malaria, typhoid fever, and leptospirosis. Verruga lesions resemble bacillary angiomatosis, Kaposi’s sarcoma, and certain neoplasms; epidemiologic context is a key diagnostic clue.
Treatment of Oroya fever consists of chloramphenicol (500 mg orally or intravenously every 6 hours) combined with a second antimicrobial, preferably a beta-lactam such as penicillin, for 14 days. Chloramphenicol also provides coverage against salmonellosis, a common secondary infection. Doxycycline is an alternative agent, while fluoroquinolones are generally not recommended due to resistance. Verruga peruana is treated with rifampin (10 mg/kg daily, maximum 600 mg daily) for 10–14 days. Streptomycin is a second-line option. Supportive care, including blood transfusion for severe anemia, is essential in the acute phase. Large or secondarily infected skin lesions may require surgical excision.
Patients with Oroya fever typically require inpatient management, whereas those with verruga peruana can often be managed as outpatients. Monitoring during the acute phase should include hydration status, complete blood counts, and surveillance for secondary infections such as salmonellosis, malaria, or tuberculosis.
Untreated Oroya fever carries a mortality rate of 50–88%. With appropriate therapy, fever usually resolves within 24 hours, though bacteremia may persist longer. Complications include secondary bacterial infections during convalescence and ulceration or bleeding of verruga lesions.
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Infectious Disease and Microbiology – Balanitis
Balanitis refers to inflammation and/or infection of the glans penis, while balanoposthitis involves both the glans and the foreskin. Infectious causes are common and may result from fungal, bacterial, viral, or parasitic pathogens. Sexual exposure plays an important role in transmission, particularly in men whose partners have Candida vaginitis. In young boys, balanitis may occur in association with diaper dermatitis.
Risk factors include being uncircumcised, diabetes mellitus (especially newly diagnosed diabetes), immunodeficiency, poor hygiene, use of broad-spectrum antibiotics, and increasing age in the case of Candida colonization. Circumcision and proper genital hygiene significantly reduce the risk. Treatment of sexual partners is important when Candida or Trichomonas infection is identified.
Infectious etiologies include Candida species (most common), Trichomonas species, anaerobic bacteria such as Bacteroides and Gardnerella vaginalis, Chlamydia, Neisseria gonorrhoeae, human papillomavirus (HPV), herpes simplex virus (HSV), Treponema pallidum, Mycoplasma, Mycobacterium (including Bacillus Calmette–Guérin), group A and B streptococci, Staphylococcus aureus, Borrelia burgdorferi, and Entamoeba histolytica.
Patients typically present with pain, tenderness, erythema, pruritus, edema, erosions, and sometimes pustules on the glans penis. Anaerobic infections may produce a characteristic foul odor.
Diagnosis is largely clinical but may be supported by laboratory testing. Fungal preparations often reveal Candida. Direct impression onto CHROMagar Candida medium has been shown to provide a higher yield than swab sampling. Wet mount examination may detect Trichomonas or Gardnerella. Urethral discharge should be tested for sexually transmitted infections. Serologic or culture testing for HIV, HPV, and HSV may be indicated based on risk factors. Blood glucose testing is recommended to evaluate for underlying diabetes mellitus.
The differential diagnosis includes numerous noninfectious conditions such as irritant dermatitis, trauma, contact dermatitis, lichen sclerosus, lichen planus, Zoon’s balanitis, erythroplasia of Queyrat, pemphigus, pemphigoid, Bowen’s disease, leukoplakia, fixed drug eruption, psoriasis (particularly inverse psoriasis), Paget’s disease, nummular eczema, scabies, and squamous cell carcinoma.
Management begins with good hygiene, including gentle washing of the glans after foreskin retraction. Candida balanitis is typically treated with topical imidazole antifungal agents, and 1% hydrocortisone cream may be added for symptomatic relief. Severe cases may require oral fluconazole. Trichomonas infection responds to metronidazole, and sexual partners should be treated simultaneously. Anaerobic infections may be managed with oral metronidazole, oral amoxicillin–clavulanate, or topical clindamycin cream.
Patients should be monitored for recurrence and evaluated for underlying diabetes if not previously diagnosed. Complications include phimosis, paraphimosis, fissuring of the prepuce, and scarring.
Balanitis refers to inflammation and/or infection of the glans penis, while balanoposthitis involves both the glans and the foreskin. Infectious causes are common and may result from fungal, bacterial, viral, or parasitic pathogens. Sexual exposure plays an important role in transmission, particularly in men whose partners have Candida vaginitis. In young boys, balanitis may occur in association with diaper dermatitis.
Risk factors include being uncircumcised, diabetes mellitus (especially newly diagnosed diabetes), immunodeficiency, poor hygiene, use of broad-spectrum antibiotics, and increasing age in the case of Candida colonization. Circumcision and proper genital hygiene significantly reduce the risk. Treatment of sexual partners is important when Candida or Trichomonas infection is identified.
Infectious etiologies include Candida species (most common), Trichomonas species, anaerobic bacteria such as Bacteroides and Gardnerella vaginalis, Chlamydia, Neisseria gonorrhoeae, human papillomavirus (HPV), herpes simplex virus (HSV), Treponema pallidum, Mycoplasma, Mycobacterium (including Bacillus Calmette–Guérin), group A and B streptococci, Staphylococcus aureus, Borrelia burgdorferi, and Entamoeba histolytica.
Patients typically present with pain, tenderness, erythema, pruritus, edema, erosions, and sometimes pustules on the glans penis. Anaerobic infections may produce a characteristic foul odor.
Diagnosis is largely clinical but may be supported by laboratory testing. Fungal preparations often reveal Candida. Direct impression onto CHROMagar Candida medium has been shown to provide a higher yield than swab sampling. Wet mount examination may detect Trichomonas or Gardnerella. Urethral discharge should be tested for sexually transmitted infections. Serologic or culture testing for HIV, HPV, and HSV may be indicated based on risk factors. Blood glucose testing is recommended to evaluate for underlying diabetes mellitus.
The differential diagnosis includes numerous noninfectious conditions such as irritant dermatitis, trauma, contact dermatitis, lichen sclerosus, lichen planus, Zoon’s balanitis, erythroplasia of Queyrat, pemphigus, pemphigoid, Bowen’s disease, leukoplakia, fixed drug eruption, psoriasis (particularly inverse psoriasis), Paget’s disease, nummular eczema, scabies, and squamous cell carcinoma.
Management begins with good hygiene, including gentle washing of the glans after foreskin retraction. Candida balanitis is typically treated with topical imidazole antifungal agents, and 1% hydrocortisone cream may be added for symptomatic relief. Severe cases may require oral fluconazole. Trichomonas infection responds to metronidazole, and sexual partners should be treated simultaneously. Anaerobic infections may be managed with oral metronidazole, oral amoxicillin–clavulanate, or topical clindamycin cream.
Patients should be monitored for recurrence and evaluated for underlying diabetes if not previously diagnosed. Complications include phimosis, paraphimosis, fissuring of the prepuce, and scarring.
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Emergency And Acute Medicine – Pneumonia in Pediatric Patients
Pneumonia in children is an infection of the lung parenchyma most commonly resulting from oropharyngeal aspiration, although hematogenous spread may occur. The radiographic distribution often depends on the organism involved: interstitial patterns are typically seen with viral infections and Mycoplasma pneumoniae, lobar consolidation with Streptococcus pneumoniae, abscess formation with Staphylococcus aureus, and diffuse disease with Pneumocystis jirovecii. Clinical presentation and likely pathogens vary significantly with age.
In neonates younger than 2 weeks, common pathogens include group B Streptococcus, enteric gram-negative organisms, respiratory syncytial virus (RSV), herpes simplex virus, and S. aureus. Between 2 weeks and 3 months, pathogens include Chlamydia trachomatis, parainfluenza virus, RSV, S. pneumoniae, S. aureus, Haemophilus influenzae, and Bordetella pertussis. From 3 months to 8 years, viral etiologies predominate (RSV, parainfluenza, influenza, adenovirus), along with S. pneumoniae, H. influenzae in unimmunized children, group A streptococcus, S. aureus, and B. pertussis. In children older than 8 years, Mycoplasma pneumoniae is most common, followed by viral pathogens and S. pneumoniae. Recent immigrants may be at risk for Mycobacterium tuberculosis. Immunocompromised children are susceptible to organisms such as Pneumocystis jirovecii, Mycobacterium avium complex, M. tuberculosis, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Less common causes include fungal infections and rickettsial organisms.
Common symptoms across all pediatric age groups include cough, fever, tachypnea, tachycardia, hypoxia, rales, and signs of respiratory distress such as retractions or grunting. A maculopapular rash may occur in up to 10% of cases. Infants younger than 6 months may present atypically with irritability, lethargy, apnea (especially RSV in premature infants), cyanosis, poor feeding, temperature instability, vomiting with coughing, nasal congestion, nasal flaring, or wheezing. A staccato cough in infants suggests Chlamydia trachomatis. Older children, particularly those over 5 years, are more likely to report pleuritic chest pain, productive cough, rigors, and chills. A thorough history should include immunization status, immune function, exposures, and progression of symptoms.
Pulse oximetry is essential in all suspected cases. Chest radiography remains the gold standard for diagnosis and should be obtained in children with signs of lower respiratory tract infection and in those younger than 36 months with marked leukocytosis (WBC >15,000 or absolute neutrophil count >9,000). Viral and Mycoplasma infections often produce interstitial, perihilar, or peribronchial infiltrates, whereas bacterial infections may demonstrate focal lobar consolidation, alveolar infiltrates, pleural effusion, or pneumatocele. Round pneumonia is considered pathognomonic for S. pneumoniae. Lateral decubitus films can help identify pleural effusions.
Laboratory studies may include a complete blood count, although sensitivity and specificity are limited. Marked leukocytosis (WBC ≥20,000 or ANC >9,000) increases the risk of pneumococcal bacteremia. Bordetella pertussis typically presents with leukocytosis and lymphocytosis. Blood cultures are recommended in children younger than 36 months and in toxic-appearing or hospitalized patients, though yield is low. Arterial blood gas analysis may be necessary in critically ill patients to assess respiratory insufficiency. Electrolytes should be checked in hypotensive children or when syndrome of inappropriate antidiuretic hormone secretion is suspected. Sputum cultures may be obtained in older children, and nasopharyngeal testing can identify RSV, C. trachomatis, and B. pertussis.
Initial management focuses on airway, breathing, and circulation. Children with moderate to severe illness may require aggressive airway management and intubation. High-flow oxygen should be administered for hypoxia. Intravenous fluid resuscitation with 0.9% normal saline (20 mL/kg bolus) is indicated for hypovolemia or shock. Bedside glucose should be checked in severely ill infants and toddlers, with prompt treatment of hypoglycemia. Ongoing monitoring with pulse oximetry is essential.
Empiric antibiotic therapy depends on age and clinical severity. Most well-appearing children aged 6 months and older can be treated as outpatients with oral antibiotics. For children aged 3 months to 5 years, amoxicillin is first-line therapy, with alternatives including amoxicillin–clavulanate or macrolides when atypical pathogens are suspected. For children aged 5 to 18 years, macrolides such as azithromycin or clarithromycin are commonly used for suspected Mycoplasma pneumoniae. Neonates requiring hospitalization should receive ampicillin plus cefotaxime or gentamicin, with azithromycin added if Chlamydia trachomatis or Bordetella pertussis is suspected. Infants 1–2 months old should receive ampicillin plus cefotaxime. Children older than 3 months requiring admission may receive cefotaxime, cefuroxime, or ceftriaxone, with vancomycin added for suspected penicillin-resistant S. pneumoniae, macrolides for atypical pathogens, and clindamycin for suspected group A streptococcal infection. Bronchodilators such as albuterol may be beneficial in children with concurrent reactive airway disease. Thoracentesis is indicated for significant pleural effusion.
Admission is warranted for toxic appearance, respiratory distress or failure, dehydration, apnea, infants younger than 2 months, infants younger than 6 months with lobar pneumonia, hypoxia (oxygen saturation <92% on room air at sea level), pleural effusion, poor outpatient response, immunocompromised status, or concerns about caregiver reliability. most mild cases can be discharged if there is no hypoxia, significant work of breathing, dehydration, vomiting, compliance concern, with follow-up ensured within 1–2 days.< />pan>
Early recognition and aggressive airway management are critical in children with severe sepsis or septic shock. Delays in antibiotic therapy should be avoided. Knowledge of local antimicrobial resistance patterns is essential to guide empiric therapy. Clear discharge instructions, reliable follow-up, and caregiver education are vital to ensure safe outpatient management.
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Emergency And Acute Medicine – Pleural Effusion
Pleural effusion is the abnormal accumulation of fluid within the pleural space. Under normal conditions, the pleural cavity contains approximately 0.1–0.2 mL/kg of clear, low-protein fluid that facilitates lung movement within the thorax. Fluid balance is governed by hydrostatic and oncotic forces, with formation primarily from the parietal pleura and reabsorption through the visceral pleura and lymphatics. Disruption of these forces or lymphatic drainage results in fluid accumulation.
Effusions are classified as transudative or exudative. Transudative effusions are low in protein and cells and result from increased hydrostatic pressure or decreased oncotic pressure without primary pleural disease. Common causes include congestive heart failure, cirrhosis with ascites, nephrotic syndrome, peritoneal dialysis, pulmonary embolism, and hypoalbuminemia. Exudative effusions contain higher protein and cellular content and result from pleural inflammation or impaired lymphatic drainage. Causes include pneumonia, tuberculosis, malignancy, mesothelioma, metastatic disease, pulmonary embolism, pancreatitis, subdiaphragmatic abscess, esophageal rupture, rheumatologic disease, trauma, hemothorax, chylothorax, and certain medications.
Small effusions are often asymptomatic. Larger effusions may cause dyspnea, pleuritic chest pain, cough, tachypnea, and hypoxia. Physical examination may reveal decreased breath sounds, decreased tactile fremitus, dullness to percussion, increased egophony above the fluid level, and occasionally a pleural friction rub. Evaluation should also focus on identifying the underlying cause such as heart failure, infection, or malignancy.
Initial workup includes cardiac monitoring, pulse oximetry, laboratory studies including complete blood count and metabolic panel, and chest imaging. Upright chest radiography typically shows blunting of the costophrenic angle and requires approximately 200–250 mL of fluid for detection. Lateral decubitus films or bedside ultrasound can detect as little as 5–10 mL of fluid and help differentiate free-flowing from loculated effusions. Ultrasound improves safety and reduces pneumothorax risk during thoracentesis. CT of the chest with intravenous contrast is the most sensitive imaging modality and is useful for identifying loculated collections and underlying pulmonary or pleural pathology. Pulmonary embolism should always be considered in cases of unexplained effusion.
Thoracentesis is indicated for new effusions in ill patients or for symptomatic relief of dyspnea due to large effusions. Fluid analysis distinguishes transudative from exudative effusions using Light criteria. An effusion is exudative if one or more of the following are present: pleural fluid protein to serum protein ratio greater than 0.5, pleural fluid LDH to serum LDH ratio greater than 0.6, or pleural fluid LDH greater than two-thirds the upper limit of normal serum LDH. Exudative effusions require further analysis including cell count, Gram stain, culture, cytology, pH, glucose, and other tests guided by clinical suspicion. A pleural fluid hematocrit greater than half of serum hematocrit defines hemothorax. A pH less than 7 or glucose less than 60 mg/dL suggests complicated parapneumonic effusion or empyema.
Therapeutic thoracentesis should avoid removal of more than 1,500 mL to reduce the risk of re-expansion pulmonary edema. Indications for tube thoracostomy include empyema, complicated parapneumonic effusion with low pH or glucose, positive Gram stain or culture, loculated effusion, or hemothorax. Post-procedure chest radiography is recommended to evaluate for pneumothorax.
Emergency management includes airway, breathing, and circulation stabilization with supplemental oxygen and intravenous access. Emergent thoracentesis is required for significant respiratory compromise. Treatment is directed at the underlying cause. Heart failure–related effusions require diuresis. Parapneumonic effusions require antibiotics. Pulmonary embolism requires anticoagulation, and the presence of bloody effusion is not a contraindication. Rheumatologic effusions may respond to anti-inflammatory therapy. Loculated effusions may require intrapleural fibrinolytics or surgical intervention.
Admission is indicated for respiratory compromise, unknown etiology, empyema, suspected parapneumonic effusion, or complications of thoracentesis. Intensive care is required for severe respiratory or hemodynamic instability. Discharge may be considered when the cause is identified, respiratory status is stable, and appropriate follow-up is arranged.
The most common causes of pleural effusion are congestive heart failure, pneumonia, and malignancy. Failure to recognize life-threatening causes such as pulmonary embolism, esophageal rupture, or hemothorax can result in significant morbidity and mortality. Bedside ultrasound is invaluable in diagnosis and procedural guidance and should be used whenever available.
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Emergency And Acute Medicine – Plant Poisoning
Plant exposure is one of the most common reasons for contacting a poison center, and the majority of cases involve unintentional ingestion in children younger than 6 years. Accurate identification of the ingested plant is critical whenever possible, as toxicity varies widely depending on species and toxin class. Plants may produce toxicity through anticholinergic compounds, cardiac glycosides, nicotine-like alkaloids, cyanogenic compounds, calcium oxalate crystals, pyrrolizidine alkaloids, sodium channel activators, or toxalbumins.
Plants with anticholinergic properties such as jimson weed and deadly nightshade act as competitive antagonists at muscarinic receptors and produce the classic toxidrome of dry, warm, flushed skin, urinary retention, absent bowel sounds, and agitated delirium. Plants containing cardiac glycosides such as foxglove and oleander inhibit the sodium–potassium ATPase pump and cause digoxin-like toxicity, including gastrointestinal symptoms, bradycardia, tachydysrhythmias, and hyperkalemia. Nicotine-like alkaloid–containing plants such as tobacco and poison hemlock stimulate nicotinic receptors, leading to hypertension and tachycardia early, followed by bradycardia, muscle weakness, and respiratory failure in severe cases.
Cyanogenic plants such as apricot, cherry, and cassava are metabolized to cyanide and interfere with cellular respiration, causing abdominal pain, altered mental status, lactic acidosis, seizures, cardiovascular collapse, and multiorgan failure. Calcium oxalate–containing plants such as dumb cane and philodendron release microscopic crystals that cause immediate burning pain, oral swelling, and potential airway compromise; ocular exposure results in keratoconjunctivitis. Pyrrolizidine alkaloid–containing plants may cause acute hepatitis and, with chronic exposure, hepatic veno-occlusive disease. Sodium channel–activating plants such as aconite and rhododendron may produce gastrointestinal symptoms, bradycardia with atrioventricular block, tachydysrhythmias, seizures, and cardiovascular instability. Toxalbumin-containing plants such as castor bean interfere with ribosomal function and can cause severe systemic toxicity depending on route and dose.
In pediatric patients, lip, tongue, and oropharyngeal irritation is common, especially with calcium oxalate plants, and airway compromise is a concern. Children often ingest concentrated plant parts such as seeds or berries, which increases toxicity risk. Even small amounts of certain plants, such as yellow oleander leaves or jimson weed seeds, may be life-threatening.
Diagnosis is primarily clinical and depends on history, plant identification, and toxidrome recognition. Laboratory evaluation may include electrolytes, renal function, glucose, liver function tests, and blood gas analysis for acid–base status. Digoxin levels should be obtained in suspected cardiac glycoside poisoning. Lactate measurement is useful in suspected cyanogenic toxicity. Electrocardiography is essential in patients with suspected cardiotoxic plant ingestion.
Prehospital care focuses on airway, breathing, and circulation. Syrup of ipecac is not recommended. Plant material should be collected in a paper bag for identification.
Emergency department management is largely supportive. Airway protection and cardiac monitoring are priorities. Intravenous fluids should be administered for dehydration or hypotension, with vasopressors initiated if fluid resuscitation fails. Anticholinergic agitation is treated with benzodiazepines, and physostigmine may be considered for severe delirium. Cardiac glycoside toxicity with significant bradycardia, tachydysrhythmias, or hyperkalemia warrants digoxin-specific antibody fragments. Cyanogenic toxicity with severe lactic acidosis or hemodynamic instability should be treated with hydroxocobalamin or a cyanide antidote kit. Atropine is indicated for bradycardia associated with sodium channel–active plant toxins. Calcium oxalate exposures are managed with irrigation, analgesia, and airway monitoring. Toxalbumin and pyrrolizidine alkaloid exposures require supportive care and specialist consultation.
Patients require admission if they develop dysrhythmias, refractory hypotension, altered mental status, intractable vomiting, metabolic acidosis, or evidence of end-organ damage. Children should be admitted with a lower threshold due to smaller lethal doses and less specific symptoms. Patients may be discharged if they return to baseline mental status, tolerate oral intake, demonstrate stable cardiac function, and have no anticipated delayed toxicity.
Death from unintentional plant ingestion is rare, but intentional ingestion, misuse of herbal preparations, or consumption of highly toxic species can be fatal. Early recognition of toxidromes and consultation with poison control or a medical toxicologist are essential to optimize outcomes.
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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.
