Emergency and Acute Medicine: Vomiting (Pediatric)




Pediatric vomiting is a forceful, coordinated expulsion of gastric contents through the mouth, involving the phases of nausea, retching, and emesis. During vomiting, there is sustained contraction of the abdominal muscles and diaphragm, while the pylorus and antrum contract simultaneously. Unlike adults, vomiting in children—especially neonates and infants—requires a high index of suspicion for serious pathology, as it may be the first sign of life-threatening disease.


The etiology of pediatric vomiting is broad and age-dependent, encompassing gastrointestinal, metabolic, neurologic, infectious, and feeding-related causes. Gastrointestinal causes include conditions such as Hypertrophic pyloric stenosis, Intussusception, and Midgut volvulus, all of which may lead to obstruction and require urgent intervention. Metabolic causes include inborn errors of metabolism and diabetic ketoacidosis, while neurologic causes include intracranial hemorrhage, tumors, or hydrocephalus. Infectious etiologies such as gastroenteritis, urinary tract infections, pneumonia, and sepsis are also common. Feeding-related issues, including overfeeding or milk allergy, are particularly relevant in infants.


Clinical presentation varies depending on the underlying cause, but assessment of vomiting characteristics is critical. Nonbilious vomiting suggests obstruction proximal to the pylorus, whereas bilious (green) vomiting indicates obstruction distal to the ampulla of Vater and is a surgical emergency until proven otherwise. Bloody vomiting may indicate upper gastrointestinal bleeding, while “coffee-ground” emesis reflects digested blood. A feculent odor suggests distal bowel obstruction or peritonitis. Projectile vomiting in a 2–6 week old infant is classic for hypertrophic pyloric stenosis, while sudden onset vomiting with abdominal distention and systemic illness may suggest volvulus or intussusception.


On physical examination, clinicians should assess hydration status, vital signs, and overall appearance, as children can deteriorate rapidly. Signs such as tachycardia, poor perfusion, altered mental status, or shock indicate severe illness. Abdominal examination may reveal distention, tenderness, masses, or peritoneal signs suggesting obstruction or perforation. Additional examination should include evaluation of the genitourinary system (e.g., testicular torsion) and neurologic status.


The diagnostic workup is guided by clinical suspicion and aimed at excluding life-threatening causes. Laboratory studies may include glucose, electrolytes, and infection markers (CBC, cultures). Imaging plays a key role: abdominal radiographs can identify obstruction or perforation, while ultrasound is particularly useful for diagnosing pyloric stenosis and intussusception. CT scans may be required for complex cases such as appendicitis or masses. In some cases, nasogastric tube placement can aid in diagnosis and management by assessing gastric contents.


Management begins with initial stabilization, including airway, breathing, and circulation assessment. Fluid resuscitation with isotonic saline (0.9% NS) is essential, especially in dehydrated or hypovolemic children, while cautiously considering conditions such as increased intracranial pressure. Bedside glucose testing is important to detect hypoglycemia. Gastric decompression with a nasogastric or orogastric tube may be required in cases of obstruction or persistent vomiting. Treatment then focuses on identifying and addressing the underlying cause, with early surgical consultation when an acute abdomen is suspected. Antibiotics should be initiated if infection or peritonitis is present.


Antiemetic therapy may be used once serious causes have been excluded or addressed. First-line therapy includes Ondansetron, given at 0.1 mg/kg per dose (typically 4–8 mg) IV or PO every 6 hours. Second-line options include Metoclopramide at 0.1 mg/kg per dose PO every 6 hours, Prochlorperazine at 0.1 mg/kg per dose IV, IM, or PR every 6 hours, and Promethazine at 0.25 mg/kg per dose PO, PR, or IM every 6 hours. These medications should be used cautiously due to potential side effects, especially in younger children.


Disposition depends on the child’s clinical status and underlying cause. Admission is required for unstable vital signs, dehydration, inability to tolerate oral intake, or suspected serious pathology. Children may be discharged if they are stable, able to tolerate fluids, and serious causes have been excluded, with clear instructions given to caregivers regarding warning signs such as persistent vomiting, abdominal distention, decreased urine output, fever, lethargy, or behavioral changes.


A critical clinical pearl is that bilious vomiting in neonates is an emergency and should be assumed to represent intestinal obstruction (e.g., malrotation with volvulus) until proven otherwise. Additionally, clinicians must always consider non-gastrointestinal causes of vomiting, including neurologic, metabolic, and toxicologic etiologies, to avoid missing potentially life-threatening conditions.

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Emergency and Acute Medicine: Venous Insufficiency




Chronic venous insufficiency is a condition in which dysfunctional venous valves impair normal one-way blood flow from the lower extremities back to the heart. This leads to venous hypertension, causing edema, skin changes, and eventually ulcer formation. It is a chronic vascular disorder most commonly affecting the lower limbs.


Normally, venous blood flows from superficial to deep veins with the aid of muscle contraction and competent valves. When these valves are damaged—commonly after Deep vein thrombosis—they fail to prevent backward flow (reflux). This results in increased venous pressure, vein dilation, and separation of valve leaflets, further worsening the condition. Over time, elevated pressure in the dermal microcirculation leads to leakage of proteins and red blood cells, triggering inflammation, skin damage, and poor wound healing.


The most common cause is primary valve incompetence, although secondary causes such as prior DVT are important. Risk factors include advanced age, obesity, sedentary lifestyle, smoking, pregnancy, family history, and lower extremity trauma.


Patients may initially be asymptomatic or present with mild venous dilation such as telangiectasias or small varicosities. As the disease progresses, symptoms include leg swelling (especially at the ankle and calf), varicose veins, dull aching pain, burning sensation, pruritus, and night cramps. Symptoms typically worsen with prolonged standing and improve with leg elevation. Chronic changes include skin hyperpigmentation (brownish discoloration), stasis dermatitis, lipodermatosclerosis (skin thickening and fibrosis), and venous ulcers—most commonly located near the medial malleolus.


On examination, findings include dependent edema, visible varicose veins, skin discoloration, and ulceration. It is critical to confirm the presence of intact peripheral pulses, as absence suggests arterial insufficiency rather than venous disease. Signs of infection such as cellulitis, purulent drainage, or fever should also be assessed.


Diagnosis is primarily clinical, but imaging is useful when the diagnosis is uncertain or complications are suspected. Duplex ultrasonography is the preferred modality, as it evaluates venous anatomy, detects reflux, and helps rule out DVT. Additional tests such as Doppler studies or ankle–brachial index may be used to differentiate venous from arterial disease.


Management in the emergency setting focuses on symptom control and prevention of complications. Key measures include leg elevation above heart level, use of compression stockings, and proper wound care for ulcers. Barrier creams and dressings help protect the skin and promote healing. Antibiotics are indicated if there is evidence of infection such as cellulitis or infected ulcers. Anticoagulation is required if DVT is confirmed. Aspirin may aid ulcer healing, and topical steroids or antihistamines can be used for dermatitis and pruritus.


Patients should be admitted if there is concern for arterial insufficiency, severe infection (e.g., cellulitis, lymphangitis, osteomyelitis), or complicated DVT. Most patients can be managed as outpatients if pulses are intact, infection is controlled, and appropriate follow-up is arranged. Referral to primary care or vascular surgery is recommended for ongoing management. Definitive treatments such as vein stripping, ligation, sclerotherapy, or endovenous ablation may be considered in refractory cases but are not emergent.


A key clinical point is to exclude arterial insufficiency before initiating compression therapy, as compression is contraindicated in patients with significant peripheral arterial disease.

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Emergency and Acute Medicine: Visual Loss


Visual Loss refers to any decrease in visual function, including reduced visual acuity, visual field defects, or blurred vision. It is a high-stakes emergency presentation because causes range from benign refractive errors to immediately vision-threatening or life-threatening conditions such as stroke or vascular occlusion. The etiology is broad and includes ophthalmologic (corneal, retinal, optic nerve), traumatic, neurologic, cardiovascular, infectious, immunologic, endocrine, and toxic causes.


A key step in evaluation is categorizing the visual loss based on time course, pain, and laterality. Transient visual loss lasting minutes is often due to ischemia, such as amaurosis fugax (a form of transient ischemic attack), while episodes lasting hours may suggest migraine or hemodynamic instability. Persistent visual loss can be painless—seen in retinal detachment, vascular occlusion, or optic neuritis—or painful, as in acute angle-closure glaucoma, corneal injury, or uveitis. Monocular vision loss typically indicates pathology anterior to the optic chiasm (eye or optic nerve), whereas binocular loss suggests lesions posterior to the chiasm, such as occipital stroke or mass lesions.


Clinical evaluation requires a thorough history and focused eye examination. Important historical features include onset (sudden vs gradual), presence of pain, trauma, associated neurologic symptoms, and visual phenomena such as floaters or flashing lights. Physical examination must include visual acuity (always documented), pupillary responses (looking for afferent pupillary defect), visual fields, extraocular movements, intraocular pressure measurement, and fundoscopic exam. Systemic examination may reveal clues such as carotid bruits (embolic source) or temporal artery tenderness suggestive of Giant Cell Arteritis.


Three conditions require immediate recognition and treatment within minutes to prevent permanent vision loss. Central Retinal Artery Occlusion presents with sudden, painless monocular vision loss and a classic “cherry-red spot” on fundus exam. Management includes urgent ophthalmology consultation, ocular massage, and reduction of intraocular pressure (e.g., acetazolamide) to dislodge the embolus. Chemical eye burns demand immediate and copious irrigation (at least 30 minutes) to normalize ocular pH—this should begin even before full evaluation. Acute Angle-Closure Glaucoma presents with painful vision loss, a red eye, mid-dilated pupil, and elevated intraocular pressure; treatment involves rapid pressure reduction using topical and systemic agents (e.g., beta-blockers, acetazolamide, pilocarpine).


Additional investigations depend on suspected etiology. Laboratory testing (e.g., ESR) is crucial when giant cell arteritis is suspected, while imaging such as CT, MRI, or vascular studies (carotid ultrasound) may be required for neurologic or embolic causes. A dilated fundus examination is essential for evaluating posterior segment pathology. In cases of suspected embolic disease, cardiac and carotid evaluation is necessary to prevent future strokes.


Management is directed at the underlying cause, with early ophthalmology consultation for any uncertain or severe case. Admission is required for serious conditions such as orbital cellulitis, cavernous sinus thrombosis, ruptured globe, or associated neurologic or vascular disease. Patients may be discharged only if the diagnosis is clear, stable, and not progressive, with appropriate follow-up arranged.


A critical principle in emergency care is that visual acuity must be documented in every patient with eye complaints, and any sudden vision loss should be treated as an emergency until proven otherwise. Missing time-sensitive diagnoses like retinal artery occlusion or glaucoma can result in irreversible blindness, making rapid recognition and intervention essential.

Emergency and Acute Medicine: Management of Violence 




Management of Violence in Emergency Department is a critical component of emergency medicine, as EDs are high-risk environments for aggressive and violent behavior. Contributing factors include overcrowding, prolonged waiting times, substance intoxication, psychiatric illness, and patients arriving in police custody. Individuals with a prior history of violence, poor impulse control, or intoxication are at particularly high risk. Importantly, violence may stem not only from psychiatric conditions such as psychosis or mania but also from underlying medical issues like hypoglycemia, hypoxia, infections, intoxication, withdrawal states, or neurologic disorders.


Early recognition of escalating behavior is essential for prevention. Initial warning signs include loud speech, agitation, pacing, and clenched fists, while more concerning features include threatening language, irrational behavior, and invasion of personal space. A thorough assessment should include history of prior violence, substance use, medical and psychiatric conditions, and current triggers. Clinicians must remain vigilant for medical causes of agitation, especially in patients over 40 years old without a psychiatric history or those with abnormal vital signs or focal neurologic findings.


Management begins with ensuring safety for both staff and patients. Environmental strategies include visible security presence, controlled access, removal of potential weapons, and clear protocols. When approaching a potentially violent patient, clinicians should not act alone, maintain a safe distance, keep an open exit path, and use a calm, non-confrontational approach. Verbal de-escalation is always the first-line intervention—this involves acknowledging the patient’s concerns, setting clear boundaries, and offering choices to reduce agitation.


If de-escalation fails, escalation to seclusion or restraint may be necessary. Physical restraints should follow institutional protocols, with careful documentation of indications, prior attempts at de-escalation, and ongoing monitoring. Positioning is important—supine for evaluation or lateral if aspiration risk exists—and airway safety must always be maintained. Chemical restraint is often required in conjunction with physical restraint, using medications such as antipsychotics (e.g., haloperidol) and/or benzodiazepines (e.g., lorazepam). The choice depends on the underlying cause: benzodiazepines are preferred in hyperadrenergic states (e.g., stimulant intoxication), while antipsychotics are commonly used in primary psychiatric agitation. Combination therapy is frequently effective.


Ongoing monitoring is crucial after restraint, particularly for complications such as respiratory depression, QT prolongation, or neuroleptic malignant syndrome. Vulnerable populations—including the elderly and those with medical comorbidities—require lower medication doses and closer observation. A key principle is to treat the underlying cause whenever possible, rather than focusing solely on behavioral control.


Disposition depends on the etiology. Patients with medical causes require admission for further management, while those with psychiatric illness may need inpatient psychiatric care, including involuntary admission if they pose a risk to themselves or others. Safe discharge requires stabilization, reassessment (especially if intoxicated), and clear follow-up plans. Clinicians must also be aware of legal responsibilities, including duty to warn or protect others when credible threats are identified.


A critical clinical takeaway is that not all violent behavior is psychiatric in origin—failure to identify an underlying medical cause can lead to significant morbidity. Effective management requires a structured, stepwise approach prioritizing safety, de-escalation, appropriate restraint, and treatment of the root cause.

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Emergency and Acute Medicine: Vertigo




Vertigo is a specific type of dizziness characterized by the false sensation of movement—typically spinning—either of the patient or the surrounding environment. It accounts for a significant proportion of emergency department visits and can arise from dysfunction in any of the three systems responsible for balance: the visual, proprioceptive, and vestibular systems. Clinically, vertigo must be distinguished from other nonspecific dizziness symptoms such as lightheadedness or presyncope, as it more often reflects an underlying neurologic or vestibular disorder.


Vertigo is broadly classified into peripheral and central causes. Peripheral vertigo, which originates from the inner ear or vestibular nerve, tends to produce severe, episodic symptoms lasting seconds to minutes, often triggered by head movement. It is commonly associated with horizontal or torsional nystagmus that fatigues and improves with visual fixation. Common causes include Benign Paroxysmal Positional Vertigo, the most frequent etiology due to displaced otoliths in semicircular canals; Vestibular Neuritis, which presents as continuous vertigo without hearing loss; and Ménière Disease, characterized by episodic vertigo, hearing loss, and tinnitus. In contrast, central vertigo arises from pathology in the brainstem or cerebellum, such as Vertebrobasilar Insufficiency, stroke, multiple sclerosis, or tumors. Central causes often present with milder but continuous vertigo, non-fatigable or vertical nystagmus, and associated neurologic deficits.


The history is crucial in distinguishing etiologies. Sudden, brief episodes triggered by head movement strongly suggest BPPV, whereas continuous vertigo lasting days suggests vestibular neuritis. Recurrent episodes with auditory symptoms point toward Ménière disease. Red flags for central causes include neurologic symptoms such as diplopia, dysarthria, limb weakness, ataxia, or severe imbalance out of proportion to vertigo. Stroke risk factors, including older age and vascular disease, further increase suspicion for a central cause.


Physical examination focuses on eye movements and neurologic assessment. Evaluation of nystagmus provides key diagnostic clues: unidirectional horizontal nystagmus suggests peripheral vertigo, whereas vertical, bidirectional, or non-fatigable nystagmus suggests central pathology. The head impulse test helps identify vestibular dysfunction, while skew deviation testing can indicate central lesions. The Dix–Hallpike maneuver is used to diagnose posterior canal BPPV, and the supine roll test assesses lateral canal involvement. A full neurologic exam is essential to identify subtle deficits suggestive of central causes.


Management depends on the underlying etiology. Peripheral vertigo is typically treated symptomatically with antihistamines (e.g., meclizine), benzodiazepines, and antiemetics. Repositioning maneuvers such as the Epley or Semont maneuvers are highly effective for BPPV. In contrast, central vertigo requires urgent evaluation and management of the underlying cause, such as stroke or hemorrhage, often involving neuroimaging and specialist consultation. Admission is indicated for serious causes like cerebellar infarction, vertebrobasilar insufficiency, or intractable symptoms preventing ambulation or oral intake.


A key clinical pearl is that vertigo can be the sole presenting symptom of a posterior circulation stroke. Therefore, clinicians must maintain a high index of suspicion, especially when vertigo is accompanied by neurologic signs or occurs in patients with vascular risk factors.

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Emergency and Acute Medicine: Ventriculoperitoneal Shunts




Ventriculoperitoneal shunt (VP shunt) is a device used to treat Hydrocephalus by diverting cerebrospinal fluid (CSF) from the ventricles of the brain to the peritoneal cavity, where it can be absorbed. The system typically consists of a ventricular catheter, a valve mechanism, and distal tubing. Although life-saving, VP shunts are associated with significant complication rates, especially within the first year after placement.


The most common complication is shunt malfunction due to obstruction, which impairs CSF drainage and leads to increased intracranial pressure (ICP). The severity of symptoms depends on how rapidly ICP rises. Patients may present with headache, nausea, vomiting, irritability, and decreased level of consciousness. In children, especially infants with open fontanelles, symptoms may be more subtle and include drowsiness, feeding difficulties, or increasing head circumference. Neurologic signs such as seizures, decreased upward gaze, and autonomic instability may also occur.


Another important complication is overdrainage syndrome, in which excessive CSF outflow leads to low intracranial pressure. This typically causes postural headaches that worsen when the patient is upright and improve when lying down, often accompanied by nausea. In severe cases, rapid overdrainage can result in brainstem displacement and signs of herniation, including apnea, bradycardia, and decreased consciousness.


Shunt infection is a serious and potentially life-threatening complication because the device acts as a foreign body. The most common organisms are Staphylococcus species, particularly Staphylococcus epidermidis, although gram-negative organisms and resistant strains such as MRSA may also be involved. Infections usually occur within the first six months after placement. Clinical features include fever, meningeal signs, altered mental status, and local signs such as redness, swelling, or tenderness along the shunt tract. Peritonitis may also occur if infection spreads distally.


A less common but important complication is slit ventricle syndrome, which occurs after prolonged overdrainage. The ventricles become chronically small, and patients develop intermittent symptoms of increased ICP due to episodic obstruction. These patients often have recurrent headaches with alternating periods of normal and altered mental status.


Evaluation of a suspected VP shunt complication begins with a careful history, including the timing of shunt placement and any recent revisions or manipulations. Physical examination should assess mental status, focal neurologic deficits, and signs of infection along the shunt tract. In suspected malfunction, bedside assessment of the shunt reservoir may be attempted; failure to compress or refill appropriately may suggest obstruction, although this test is not fully reliable.


Imaging plays a central role in diagnosis. A noncontrast CT scan of the head is used to assess ventricular size and catheter position, with enlargement suggesting obstruction and small ventricles suggesting overdrainage. A shunt series, consisting of radiographs of the skull, chest, and abdomen, helps identify disconnection, kinking, or malposition of the tubing. In children with open fontanelles, ultrasound may be used to evaluate ventricular size. If infection is suspected, cerebrospinal fluid may be obtained from the shunt reservoir for analysis and culture, typically in consultation with a neurosurgeon.


Management depends on the underlying complication but always begins with stabilization. Patients with signs of increased ICP or impending herniation require urgent airway management and measures to reduce ICP, such as head elevation, controlled ventilation, and administration of osmotic agents like mannitol. In some cases, careful manipulation or tapping of the shunt may temporarily relieve pressure, but this should be done cautiously and ideally with specialist input.


Definitive management requires early neurosurgical consultation. Shunt malfunction often necessitates surgical revision, while infections typically require removal of the shunt and initiation of broad-spectrum intravenous antibiotics, such as vancomycin combined with a third-generation cephalosporin or an aminoglycoside. Overdrainage is managed by placing the patient in a supine position and correcting volume depletion.


Most patients with suspected VP shunt complications require hospital admission, often to a monitored or intensive care setting. Prompt recognition and management are essential to prevent serious complications such as permanent neurologic damage or death. Importantly, clinicians should avoid attributing all symptoms to the shunt and must consider alternative diagnoses, as conditions such as metabolic disturbances or infections can mimic shunt malfunction.

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Emergency and Acute Medicine: Ventricular Fibrillation




Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia characterized by completely disorganized electrical activity in the ventricles, resulting in ineffective myocardial contraction and absence of cardiac output. On cardiac monitoring, VF appears as chaotic, irregular oscillations without identifiable QRS complexes or T waves. Without immediate treatment, it rapidly leads to death.


The underlying mechanism of VF typically involves re-entrant electrical circuits within damaged myocardium. The most common cause is acute myocardial ischemia, particularly during ST-elevation myocardial infarction, where a significant proportion of cases occur within the first 24 hours. Other cardiac causes include cardiomyopathies, such as dilated or hypertrophic cardiomyopathy, which predispose patients to malignant arrhythmias. Nonischemic causes include drug toxicity (e.g., tricyclic antidepressants or digoxin), electrolyte abnormalities, acid–base disturbances, and inherited channelopathies such as long QT syndrome or Brugada syndrome. Additional triggers include hypoxia, hypothermia, electrocution, and blunt chest trauma.


Clinically, VF presents abruptly with loss of consciousness due to cessation of cerebral perfusion. Patients may exhibit brief seizure-like activity or gasping respirations before progressing to apnea. On examination, there is no palpable pulse or heart sounds, and the condition represents a form of cardiac arrest. If untreated, VF is fatal within minutes, making it one of the most critical emergencies in medicine.


Diagnosis is made immediately using a cardiac monitor or automated external defibrillator (AED), which identifies VF as a shockable rhythm. Differentiation from asystole is important, as fine VF may mimic a flatline; checking multiple leads can help detect subtle fibrillatory activity. Laboratory investigations are not useful during active resuscitation but become important after return of spontaneous circulation (ROSC) to identify reversible causes.


Management of VF is centered on rapid defibrillation and high-quality cardiopulmonary resuscitation (CPR). Early defibrillation is the single most important determinant of survival, with each minute of delay reducing survival by approximately 7–10%. Treatment follows advanced cardiac life support principles, beginning with immediate unsynchronized defibrillation using biphasic energy (typically 120–200 J), followed by uninterrupted CPR for 2 minutes. This cycle of shock and CPR continues until a perfusing rhythm is restored or resuscitation is terminated.


Pharmacologic therapy is used in refractory VF. Epinephrine is administered after the second shock and repeated every 3–5 minutes to improve coronary perfusion pressure. If VF persists after the third shock, antiarrhythmic drugs such as Amiodarone are recommended, with Lidocaine as an alternative. Magnesium sulfate may be given in cases of torsades de pointes. Establishing intravenous or intraosseous access and managing the airway are important but should never delay defibrillation or CPR.


After ROSC, management focuses on identifying and treating the underlying cause, most commonly acute coronary occlusion, which may require urgent reperfusion therapy such as percutaneous coronary intervention. Supportive care includes maintaining adequate oxygenation, blood pressure, and ventilation, as well as targeted temperature management to reduce neurologic injury. Monitoring includes ECG, cardiac biomarkers, and imaging such as echocardiography.


All patients who survive a VF arrest require admission to an intensive care unit for close monitoring and further management. Long-term considerations may include evaluation for implantable cardioverter-defibrillator placement, especially in patients at high risk of recurrence. Prevention strategies include correcting electrolyte abnormalities and maintaining adequate potassium levels, particularly in patients with myocardial infarction.


In summary, ventricular fibrillation is a rapidly fatal arrhythmia that demands immediate recognition and treatment. Prompt defibrillation, effective CPR, and systematic post-resuscitation care are essential to improving survival outcomes.

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Emergency and Acute Medicine: Ventilator Management




Mechanical ventilation is the use of positive pressure to deliver gas into the lungs, replacing or assisting normal breathing. Unlike normal respiration, which relies on negative pressure, mechanical ventilation forces air into the lungs, helping maintain oxygenation and carbon dioxide removal in patients who cannot do so adequately on their own. It is a critical intervention in emergency and intensive care settings, particularly for patients with respiratory failure, shock, or decreased consciousness.


The fundamental principles of ventilator management revolve around two key goals: ventilation and oxygenation. Ventilation refers to the removal of carbon dioxide and is determined by minute ventilation, which is the product of tidal volume and respiratory rate. Oxygenation, on the other hand, is controlled primarily by the fraction of inspired oxygen (FiO₂) and positive end-expiratory pressure (PEEP), which helps keep alveoli open and improves gas exchange. Understanding this distinction is essential because adjustments in ventilator settings must target the specific physiologic problem.


Lung mechanics play an important role in interpreting ventilator parameters. Compliance reflects how easily the lungs expand and is reduced in conditions such as Acute respiratory distress syndrome or pulmonary edema. Resistance reflects airflow obstruction and is increased in conditions like asthma or when there are issues with the endotracheal tube. These concepts are clinically assessed using pressures on the ventilator: plateau pressure reflects lung compliance and should be kept below 30 cmH₂O to avoid lung injury, while peak pressure reflects both compliance and airway resistance and should generally remain below 40 cmH₂O.


Mechanical ventilation is indicated when patients fail to oxygenate, fail to ventilate, or require airway protection. Failure to oxygenate can occur in diseases such as pneumonia or pulmonary edema, while failure to ventilate may result from central nervous system depression, neuromuscular weakness, or severe metabolic acidosis requiring compensatory hyperventilation. In some cases, ventilation is initiated preemptively when a patient is expected to deteriorate clinically.


Initial ventilator settings are typically standardized but must be individualized based on the patient’s condition. A common starting approach includes assist-control mode, a respiratory rate of 12–20 breaths per minute, tidal volume of 6–8 mL/kg of ideal body weight, FiO₂ initially set at 100% and then rapidly reduced, and PEEP of 5–10 cmH₂O. These settings are then adjusted according to arterial blood gas results and the patient’s clinical response.


Different ventilator modes determine how breaths are delivered. Assist-control mode is most commonly used initially because it ensures full ventilatory support while allowing patient-triggered breaths. Synchronized intermittent mandatory ventilation allows spontaneous breathing between machine-delivered breaths, while pressure support ventilation assists spontaneous breaths and is commonly used during weaning. Continuous mandatory ventilation provides fully controlled breaths without patient interaction and is less commonly used in modern practice.


Ventilator strategies must be tailored to specific disease states. In patients with Acute respiratory distress syndrome, a lung-protective strategy using low tidal volumes and higher PEEP is essential to prevent ventilator-induced lung injury. In obstructive diseases such as asthma, it is crucial to allow sufficient time for exhalation to avoid air trapping and breath stacking. In metabolic acidosis, increasing minute ventilation helps compensate for acidemia, while in pulmonary edema, improving oxygenation through PEEP is often the priority.


Monitoring is essential after initiating mechanical ventilation. Arterial blood gas analysis should be performed within 15 to 30 minutes to assess adequacy of ventilation and oxygenation. End-tidal carbon dioxide monitoring provides continuous information about ventilation and can help confirm endotracheal tube placement, assess response to therapy, and evaluate conditions such as bronchospasm or poor perfusion.


Mechanical ventilation carries significant risks. These include ventilator-induced lung injury from excessive pressures or volumes, barotrauma such as pneumothorax, decreased cardiac output due to increased intrathoracic pressure, and oxygen toxicity. Additional risks include infections due to loss of natural airway defenses, complications from sedation such as delirium, and long-term muscle weakness due to immobility.


Sedation and analgesia are important components of ventilator management and should aim for the lowest effective level. Commonly used medications include Propofol, which provides rapid sedation but may cause hypotension; Dexmedetomidine, which has minimal respiratory depression; Fentanyl for pain control; and Ketamine, which is useful in hemodynamically unstable patients. Careful titration is necessary to avoid oversedation and its complications.


In clinical practice, understanding ventilator physiology is essential for troubleshooting. An isolated increase in peak pressure suggests increased airway resistance, such as bronchospasm or secretions, whereas increases in both peak and plateau pressures indicate decreased lung compliance, as seen in conditions like ARDS or pulmonary edema. Recognizing these patterns allows for rapid identification and correction of underlying problems.


Overall, successful ventilator management requires a clear understanding of respiratory physiology, careful adjustment of settings based on the patient’s condition, and vigilant monitoring for complications.

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Emergency and Acute Medicine: Vitreous Hemorrhage




Vitreous Hemorrhage is the presence of blood within the vitreous cavity of the eye and is considered a secondary diagnosis, meaning that identifying the underlying cause is essential for proper management. It most commonly results from retinal vessel disruption due to vitreous separation, trauma, or spontaneous bleeding from neovascularization, particularly in patients with diabetes mellitus.


The causes of vitreous hemorrhage are varied and include both traumatic and nontraumatic conditions. Trauma may be blunt or penetrating, leading to direct vessel rupture. Nontraumatic causes include proliferative retinopathies (especially diabetic retinopathy), retinal tears or detachments, retinal vein occlusion, sickle cell disease, and age-related macular degeneration. Less common causes include intraocular tumors and intracranial hemorrhage such as Terson syndrome. In pediatric patients, important considerations include prematurity, congenital retinal disorders, and nonaccidental trauma such as shaken-baby syndrome.


Clinically, patients typically present with sudden, painless, unilateral visual disturbance, ranging from mild blurring to significant vision loss. They often describe floaters, cobwebs, or a hazy visual field, sometimes accompanied by flashing lights if there is associated retinal traction. On examination, a key finding is loss of the red reflex and inability to visualize the fundus, which strongly suggests vitreous hemorrhage. A mild afferent pupillary defect may also be present depending on severity.


Evaluation requires a thorough ocular examination, including slit-lamp assessment, tonometry, and dilated fundoscopic examination. When the fundus cannot be visualized, B-scan ultrasonography is essential to assess for serious underlying pathology such as retinal detachment or intraocular tumor. Additional laboratory tests, such as complete blood count and coagulation studies, may be performed if a systemic cause is suspected. Imaging like CT may be necessary in cases of trauma to exclude intraocular foreign bodies.


Management in the emergency setting is primarily supportive. Patients should be advised to rest with the head of the bed elevated to allow blood to settle inferiorly and improve vision. Activities that increase intraocular pressure, such as heavy lifting or straining (Valsalva), should be avoided. Medications that impair clotting, such as NSAIDs and anticoagulants, should also be avoided unless medically necessary. There are no specific emergency medications required for vitreous hemorrhage itself; treatment is directed at the underlying cause.


Definitive management is guided by ophthalmology and may include laser photocoagulation or cryotherapy for proliferative vascular disease, surgical repair for retinal detachment, or vitrectomy if the hemorrhage does not resolve or is associated with complications such as neovascularization or glaucoma. Urgent ophthalmologic consultation within 24–48 hours is essential, even in seemingly mild cases, to prevent missed vision-threatening conditions.


A critical point is that vitreous hemorrhage may mimic or coexist with other serious conditions such as retinal detachment or vascular occlusions. Therefore, prompt evaluation and follow-up are necessary to prevent permanent visual impairment.

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Emergency and Acute Medicine: Volvulus




Volvulus is an axial twisting of a segment of the gastrointestinal tract around its mesentery, resulting in partial or complete bowel obstruction. This twisting can compromise venous outflow and eventually arterial inflow, leading to bowel ischemia, gangrene, and possible perforation. It is a life-threatening surgical emergency, particularly when vascular compromise is present. Volvulus accounts for approximately 10–15% of colonic obstructions and is most commonly seen in the cecum and sigmoid colon. Cecal volvulus typically affects younger adults due to congenital mobility of the cecum, whereas sigmoid volvulus is more common in elderly, institutionalized patients with chronic constipation, neurologic disease, or psychiatric illness. In children, especially neonates, midgut volvulus occurs due to congenital malrotation and often presents early with bilious vomiting.


The clinical presentation varies depending on the location and severity but generally reflects bowel obstruction. Patients commonly report colicky abdominal pain, abdominal distention, obstipation, nausea, and vomiting. The onset may be acute or more insidious, particularly in sigmoid volvulus, where symptoms may recur intermittently over weeks or months. In contrast, midgut volvulus in infants presents abruptly with bilious vomiting and abdominal pain. Signs of bowel ischemia or gangrene include fever, tachycardia, hypotension, peritoneal signs (guarding, rebound), hematochezia, and shock, indicating advanced disease and the need for immediate surgical intervention.


Diagnosis relies on clinical suspicion supported by imaging. Plain abdominal radiographs may demonstrate characteristic findings such as the “coffee bean” sign in sigmoid volvulus or a displaced, dilated cecum. However, CT imaging is the preferred modality in adults and may reveal the classic “whirl sign” of twisted mesenteric vessels. In pediatric patients, an upper gastrointestinal contrast study is the most sensitive initial test and may show a “corkscrew” appearance of the twisted bowel. A barium enema may demonstrate a “bird’s beak” deformity, though it must be used cautiously due to the risk of perforation.


Initial management focuses on rapid stabilization. Patients should be kept nil per os (NPO), and aggressive fluid resuscitation should be initiated with isotonic fluids such as 0.9% saline (2 L bolus in adults or 20 mL/kg in children). A nasogastric tube should be inserted for decompression, and electrolyte abnormalities should be corrected. Early consultation with surgery and gastroenterology is essential. Definitive management depends on the type of volvulus and the patient’s condition. In stable patients with sigmoid volvulus, endoscopic decompression may be attempted and is often successful, although recurrence is common and elective surgical resection is usually required. In unstable patients or those with cecal volvulus, urgent surgical intervention with bowel resection is necessary. In children with midgut volvulus, emergency surgery (Ladd procedure) must be performed promptly to prevent bowel necrosis.


Medication management is supportive and aimed at preventing or treating complications such as infection, ischemia, or perforation. Broad-spectrum intravenous antibiotics should be administered when there is concern for sepsis or bowel compromise. Options include Ampicillin-sulbactam at a dose of 3 g IV every 6 hours (pediatric: 100–200 mg/kg/day divided every 6 hours), or Cefoxitin at 2 g IV every 6 hours (pediatric: 80–160 mg/kg/day divided every 6 hours). Another commonly used regimen is Ceftriaxone 1–2 g IV every 12–24 hours combined with Metronidazole 500 mg IV every 8 hours (pediatric metronidazole: 30 mg/kg/day divided every 6 hours). Alternatively, Piperacillin-tazobactam may be used at 3.375–4 g IV every 4–6 hours (pediatric: 200–300 mg/kg/day of the piperacillin component divided every 6–8 hours). These regimens provide essential coverage against gram-negative and anaerobic organisms commonly involved in bowel infections.


All patients with suspected volvulus require hospital admission and urgent surgical evaluation, as there are no safe discharge criteria. Delayed diagnosis significantly increases morbidity and mortality, particularly if bowel ischemia develops. Early recognition, aggressive resuscitation, appropriate antibiotic therapy, and timely surgical intervention are critical to improving outcomes and preventing life-threatening complications.

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