Psychobehavioral Disorders
Core approach
Psychobehavioral emergencies require safety, medical screening, and respectful de-escalation. Core topics include agitation, psychosis, depression and suicide risk, anxiety and panic, substance intoxication and withdrawal, delirium, neuroleptic malignant syndrome, serotonin syndrome, and capacity assessment. First exclude reversible medical causes: hypoglycemia, hypoxia, head injury, infection, withdrawal, and anticholinergic toxicity. Use verbal de-escalation and offer choices before physical restraint; if medication is needed, choose based on the likely cause and comorbidity.
Traps
Delirium is a medical emergency and is often mistaken for psychosis; fluctuating attention and altered consciousness are clues. Suicide risk assessment must be documented, but asking about suicide does not implant the idea. Do not miss withdrawal states, especially alcohol and benzodiazepine withdrawal, which can be fatal. Neuroleptic malignant syndrome causes rigidity, hyperthermia, and autonomic instability; serotonin syndrome causes clonus and hyperreflexia. Restraints require monitoring and airway assessment.
Worked example
An agitated patient has dilated pupils, dry skin, urinary retention, and mumbling speech after an overdose. This suggests anticholinergic toxicity, not schizophrenia. Provide supportive care, monitor for arrhythmia, and use benzodiazepines cautiously for agitation. Rule of thumb: new agitation in a previously calm patient is a medical symptom until proven otherwise.
Key concepts
Treat reversible causes before sedating. Alcohol withdrawal can progress to seizures and delirium tremens. Capacity is decision-specific.
Renal, Urogenital, Endocrine, Hematologic, and Other Emergent Conditions
Core approach
This domain spans high-yield emergencies in renal, urologic, endocrine, and hematologic systems. Know acute kidney injury, hyperkalemia, dialysis indications, renal colic, testicular torsion, DKA and hyperosmolar hyperglycemic state, thyroid storm, myxedema coma, adrenal crisis, anemia, thrombocytopenia, TTP, hemophilia, sickle cell crisis, and transfusion reactions. For hyperkalemia with ECG changes, give intravenous calcium first to stabilize the myocardium, then shift potassium intracellularly and remove it. DKA treatment requires fluids, insulin, and potassium replacement; total-body potassium is depleted even when serum potassium is normal or high.
Traps
A normal serum potassium does not exclude dangerous total-body depletion in DKA; check and replace potassium before insulin if it is low. Testicular torsion is a time-critical surgical emergency; do not wait for ultrasound if suspicion is high. Adrenal crisis can present with hypotension and hyponatremia, and steroids should not be delayed in unstable suspected cases. TTP presents with microangiopathic hemolytic anemia and thrombocytopenia; platelet transfusion may worsen it unless there is life-threatening bleeding. Hyperkalemia can cause sine-wave ECG changes and cardiac arrest.
Worked example
A dialysis patient has weakness and a potassium of 7.2 mmol/L with peaked T waves. Give IV calcium gluconate or chloride immediately, then insulin with glucose, a beta-agonist, and arrange urgent dialysis. Rule of thumb: in hyperkalemia with ECG changes, stabilize the myocardium with calcium before shifting potassium.
Key concepts
Torsion is a clinical emergency; detorsion should not be delayed for imaging. DKA potassium can fall rapidly with insulin. Adrenal crisis requires prompt glucocorticoids.