Clinical Cases & Differential Diagnosis
Structured patient presentations, diagnostic differentials, investigation checklists, and emergency management protocols.
Clinical Reasoning & Simulation Engine
Mastering patient encounters requires structured diagnostic thinking: exploring the history of present illness (SOCRATES), targeted physical examination, rational test ordering, and evidence-based treatment prioritization.
- Cardiology
Acute Coronary Syndrome (STEMI / NSTEMI)
Presentation: 58-year-old male with crushing substernal chest pain radiating to left jaw, diaphoresis, and nausea.
Top Differentials
Acute Myocardial Infarction · Aortic Dissection · Pulmonary Embolism · Gastroesophageal Reflux Disease
Diagnostic Workup
12-lead ECG within 10 min, Serial Troponin I/T, CXR, CBC, CMP, Coagulation profile.
Management Strategy
MONA protocol (Morphine, Oxygen, Nitrates, Aspirin 300mg), Dual antiplatelet therapy, Urgent Coronary Angiography/PCI within 90 min.
- Pulmonology
Community-Acquired Pneumonia (CAP)
Presentation: 64-year-old female with productive cough (rusty sputum), high-grade fever, chills, pleuritic chest pain, and tachypnea.
Top Differentials
Streptococcus pneumoniae Pneumonia · Pulmonary Tuberculosis · Acute Bronchitis · Pulmonary Infarction
Diagnostic Workup
Chest X-Ray (lobar consolidation), Sputum Gram stain & culture, Blood cultures, CURB-65 scoring, ABG.
Management Strategy
Empiric antibiotics (Amoxicillin-Clavulanate + Macrolide or Respiratory Fluoroquinolone), Oxygen therapy, IV hydration.
- General Surgery
Acute Appendicitis (Acute Abdomen)
Presentation: 21-year-old male with periumbilical pain migrating to right lower quadrant (McBurney point), anorexia, low-grade fever, and rebound tenderness.
Top Differentials
Acute Appendicitis · Mesenteric Adenitis · Meckel Diverticulitis · Urolithiasis · Testicular Torsion
Diagnostic Workup
CBC (leukocytosis with left shift), CRP, Abdominal Ultrasound/CT abdomen, Urinalysis, Alvarado score.
Management Strategy
NPO, IV fluids, IV broad-spectrum antibiotics (Ceftriaxone + Metronidazole), Emergency Laparoscopic Appendectomy.
- Endocrinology & Emergency
Diabetic Ketoacidosis (DKA)
Presentation: 19-year-old with Type 1 Diabetes presenting with nausea, vomiting, abdominal pain, Kussmaul breathing (fruity breath), and altered sensorium.
Top Differentials
Diabetic Ketoacidosis · Hyperosmolar Hyperglycemic State (HHS) · Alcoholic Ketoacidosis · Sepsis
Diagnostic Workup
Capillary blood glucose (>250 mg/dL), Serum ketones (beta-hydroxybutyrate), ABG (metabolic acidosis with anion gap >12), Serum electrolytes (K+, Na+), Urinalysis.
Management Strategy
IV isotonic saline resuscitation, IV regular insulin infusion (0.1 units/kg/hr), Potassium replacement (maintain K 4-5 mEq/L), Bicarbonate only if pH < 6.9.
- Neurology & Infectious Diseases
Acute Bacterial Meningitis
Presentation: 26-year-old with triad of severe headache, neck stiffness (nuchal rigidity), high fever, photophobia, positive Kernig & Brudzinski signs.
Top Differentials
Bacterial Meningitis (N. meningitidis, S. pneumoniae) · Viral Meningoencephalitis · Subarachnoid Hemorrhage · Tuberculous Meningitis
Diagnostic Workup
Urgent Blood Cultures, Cranial CT (if focal signs/papilledema before LP), Lumbar Puncture (CSF analysis: high protein, low glucose <40% serum, elevated opening pressure, neutrophilic pleocytosis).
Management Strategy
Immediate IV Dexamethasone + IV Ceftriaxone (2g q12h) + IV Vancomycin (do not delay for CT/LP). Droplet precautions.
- Cardiology & Emergency
Acute Pulmonary Embolism (PE)
Presentation: 45-year-old female post-orthopedic surgery with sudden onset dyspnea, pleuritic chest pain, hemoptysis, tachycardia (HR 120), and unilateral calf swelling.
Top Differentials
Pulmonary Embolism · Acute Coronary Syndrome · Pneumothorax · Pneumonia
Diagnostic Workup
Wells Criteria score, D-dimer (high sensitivity), CT Pulmonary Angiography (CTPA - gold standard), Lower limb Doppler Ultrasound, ECG (S1Q3T3 pattern / sinus tachycardia).
Management Strategy
Oxygen, Hemodynamic support, Low-Molecular-Weight Heparin (Enoxaparin) or DOAC (Apixaban/Rivaroxaban), Systemic Thrombolysis (Alteplase) for massive hemodynamically unstable PE.
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