Reference

Illness scripts

Compact disease representations in one fixed frame, because diagnosis is matching the patient's story against these. The frame is the point: who, tempo, symptoms, findings, investigations, differentiators.

Heart failure with reduced ejection fraction

Cardiology

Who?: Older adults with prior infarction, hypertension, or cardiomyopathy.
Time course?: Chronic with acute decompensations over days.
Key symptoms?: Exertional dyspnea, orthopnea, PND, edema, fatigue.
Key findings?: Raised JVP, displaced apex, S3, crackles, peripheral edema.
Key investigations?: Echo shows EF below 40 percent; NT-proBNP elevated; CXR congestion.
What differentiates it?: The S3 and displaced apex point at a dilated, failing pump; preserved-EF disease shares the congestion but not the systolic signature.

See it in action

CompareHFrEF vs HFpEF

Heart failure with preserved ejection fraction

Cardiology

Who?: Older, often hypertensive patients, frequently with obesity, diabetes, or AF.
Time course?: Chronic; exertional intolerance dominant, decompensating with volume or AF.
Key symptoms?: Exertional dyspnea and intolerance; edema; symptoms flare with tachycardia.
Key findings?: Hypertension, S4 more than S3, congestion without a displaced apex.
Key investigations?: Echo: EF at or above 50 percent with diastolic dysfunction and atrial enlargement; NT-proBNP raised (less than HFrEF, and blunted by obesity).
What differentiates it?: Same congestion, stiff rather than weak ventricle; diagnosis leans on echo indices and the company it keeps (age, hypertension, AF).

See it in action

CompareHFrEF vs HFpEF

Nephritic syndrome

Nephrology

Who?: Any age; post-infectious in the young, vasculitis and IgA across adults.
Time course?: Days to weeks.
Key symptoms?: Dark (tea or cola) urine, edema, headache from hypertension, oliguria.
Key findings?: Hypertension, edema, hematuria.
Key investigations?: Dysmorphic red cells and red cell casts; subnephrotic proteinuria; complement pattern and serologies steer the cause.
What differentiates it?: Inflammation leaks cells: blood and casts dominate over protein. The nephrotic pattern is the mirror image.

See it in action

UrineRead the sediment

Nephrotic syndrome

Nephrology

Who?: Children (minimal change) through older adults (membranous, diabetes, amyloid).
Time course?: Weeks to months, often insidious.
Key symptoms?: Progressive edema, frothy urine, weight gain.
Key findings?: Marked edema, sometimes periorbital; blood pressure variable.
Key investigations?: Proteinuria above 3.5 g/day, hypoalbuminemia, hyperlipidemia; bland sediment.
What differentiates it?: A podocyte leak, not inflammation: protein without cells. Companions include thrombosis (renal vein), infection, and lipiduria.

See it in action

CompareNephritic vs nephrotic

Diabetic ketoacidosis

Endocrinology

Who?: Type 1 diabetes (new or established); increasingly type 2 under stress or SGLT2 inhibitors.
Time course?: Hours to two days.
Key symptoms?: Thirst, polyuria, vomiting, abdominal pain, air hunger.
Key findings?: Kussmaul respiration, dehydration, ketotic breath, tachycardia.
Key investigations?: Glucose high (or near-normal in euglycemic DKA), ketones, high anion gap metabolic acidosis.
What differentiates it?: The gap acidosis plus ketones is the identity; HHS shares the sugar but not the acid.

See it in action

Blood gasThe DKA gas

Pulmonary embolism

Respirology

Who?: Immobilization, surgery, malignancy, estrogen, prior VTE; often nobody obvious.
Time course?: Sudden to hours.
Key symptoms?: Pleuritic chest pain, dyspnea out of proportion, syncope in large emboli, hemoptysis occasionally.
Key findings?: Tachycardia, tachypnea, clear lungs despite hypoxia; unilateral leg swelling sometimes.
Key investigations?: Wells score gates D-dimer versus CTPA; ECG shows sinus tachycardia most often, S1Q3T3 rarely.
What differentiates it?: Hypoxia with a clear chest film and a clear chest exam is the classic dissonance.

See it in action

CalculatorWells score

Anaphylaxis

Allergy & Clinical Immunology

Who?: Any age; foods, stings, drugs (antibiotics, contrast), latex; sometimes no identified trigger.
Time course?: Minutes; biphasic recurrence hours later in a minority.
Key symptoms?: Urticaria and flushing with airway (throat tightness, stridor), respiratory (wheeze), GI (cramping, vomiting), or circulatory (presyncope) involvement.
Key findings?: Hives, angioedema, hypotension, wheeze; skin findings absent in up to a fifth.
Key investigations?: Clinical diagnosis; serum tryptase drawn early supports it retrospectively.
What differentiates it?: Two or more organ systems after a plausible exposure. Epinephrine early is both treatment and, in effect, the diagnostic commitment; there is no lab to wait for.

See it in action

drugSteroids' supporting role

Delirium

Geriatric Medicine

Who?: Older, frail, cognitively vulnerable, or acutely ill inpatients; postoperative and ICU settings.
Time course?: Hours to days, fluctuating through the day; worse at night.
Key symptoms?: Acute inattention with disorganized thinking; hyperactive, hypoactive (most missed), or mixed.
Key findings?: Failure of attention tasks (months backwards); altered arousal; a cause elsewhere: infection, retention, impaction, drugs, pain, metabolic upset.
Key investigations?: Directed by the suspected driver: glucose, electrolytes, cultures with a symptom anchor, medication review always.
What differentiates it?: Acuity and fluctuation separate it from dementia; attention is the axis. Delirium is a syndrome pointing at a cause list, never a stopping point.

See it in action

ApproachApproach to confusion

Febrile neutropenia

Medical Oncology

Who?: Patients on cytotoxic chemotherapy, typically 7 to 14 days after a cycle.
Time course?: Hours; can collapse quickly despite looking well early.
Key symptoms?: Fever, sometimes nothing else: neutropenia mutes every localizing sign.
Key findings?: Often unremarkable; examine lines, perineum (no rectal exams), mouth, skin. Absence of findings excludes nothing.
Key investigations?: CBC with differential (the defining count), cultures from every lumen before antibiotics, directed imaging.
What differentiates it?: Fever plus an absolute neutrophil count below 0.5: empiric broad antibiotics within the hour, no waiting for localization. The classic oncologic emergency of omission.

See it in action

CaseThe sepsis clock, same rules

Hypercalcemia of malignancy

Medical Oncology

Who?: Known or occult malignancy: lung, breast, myeloma, renal cell.
Time course?: Days to weeks; faster and higher than primary hyperparathyroidism.
Key symptoms?: Polyuria and thirst, constipation, nausea, lethargy through confusion ('groans, stones, moans').
Key findings?: Volume depletion, altered mentation at higher levels; short QT on ECG.
Key investigations?: Corrected calcium, PTH (suppressed), PTHrP and vitamin D metabolites by mechanism hunt.
What differentiates it?: A suppressed PTH divides it from primary hyperparathyroidism, the other common cause. Treatment starts with volume, then antiresorptives; the cancer is the diagnosis.

See it in action

CalculatorCorrected calcium

Acute gout

Rheumatology

Who?: Middle-aged and older adults; diuretics, alcohol, renal disease, metabolic syndrome.
Time course?: Hours; often overnight onset.
Key symptoms?: Abrupt monoarticular agony, classically first MTP; exquisite touch sensitivity.
Key findings?: A red, hot, swollen joint; tophi in chronic disease.
Key investigations?: Synovial fluid: needle-shaped, negatively birefringent crystals, inflammatory cell counts.
What differentiates it?: Only aspiration separates it definitively from its dangerous mimic, the septic joint, and the two can coexist.

See it in action

FluidThe crystal tap