Assessment and Diagnosis
Assessment and Diagnosis is the domain that asks how you think, not just what you know. Items present a patient, then test whether you prioritize the right data, generate a safe differential, choose the next best action, and document the reasoning. Emergency settings reward speed plus calibration.
A structured approach
- Physiology first: vital signs, shock index (HR ÷ systolic BP), mental status, and lactate before pattern-matching to a chief complaint.
- Primary survey (airway, breathing, circulation, disability, exposure) precedes the detailed history when the patient looks unwell.
- Triage acuity matters: under-triage of an Emergency Severity Index level 3 patient is the classic safety failure - a normotensive GI bleed on a beta blocker can look deceptively stable.
- Build a differential that includes the can't-miss diagnoses, then choose tests that will change management rather than tests that are merely available.
- Use validated risk tools where they exist (HEART for chest pain, Wells or PERC for pulmonary embolism, NIHSS for stroke, PECARN for pediatric head injury) and state their limits.
Atypical presentations
- Acute coronary syndrome in women, older adults, and people with diabetes may present as dyspnea, nausea, syncope, or "indigestion" without chest pain.
- Sepsis in older adults may show only delirium, tachypnea, or a fall; fever is often absent.
- Mesenteric ischemia and appendicitis in patients over 65 may lack fever and classic exam findings - pain out of proportion to exam is a red flag.
Worked example
A 68-year-old with type 2 diabetes reports two hours of dyspnea and "indigestion," no chest pain. HR 104, BP 148/86, RR 24, SpO2 94% on room air. Reasoning: dyspnea with nausea in a diabetic is an ACS-equivalent presentation, so a 12-lead ECG goes on within 10 minutes, the patient goes on the monitor, and serial high-sensitivity troponins are ordered while heart failure and pulmonary embolism are worked up in parallel. A single early troponin is not exclusionary at two hours of symptoms.
Traps that cost marks
- Premature closure after the first plausible diagnosis.
- Treating one negative test as definitive exclusion regardless of timing.
- Attributing symptoms to anxiety or "drug-seeking" before organic causes are addressed.
- Failing to reassess after an intervention; the trend is the finding.
- Documenting a diagnosis without documenting the reasoning that ruled out the dangerous alternative.