Your path to the USMLE

• •Systolic: aortic stenosis (ejection, radiates to carotids), mitral regurgitation (blowing, to axilla).
• •Diastolic: aortic regurgitation (early, decrescendo), mitral stenosis (mid-diastolic rumble).
• •Left-sided murmurs are louder on expiration; right-sided on inspiration.

• •Obstructive (asthma, COPD): FEV1/FVC reduced (< 0.7).
• •Restrictive (fibrosis): FEV1/FVC normal or high, but low volumes.
• •A flattened flow-volume loop points to obstruction.

• •Check pH, then CO₂ (respiratory) and HCO₃ (metabolic).
• •Anion-gap metabolic acidosis: MUDPILES (e.g. DKA, lactate, toxins).
• •Vomiting → metabolic alkalosis; hyperventilation → respiratory alkalosis.

• •Type 1: autoimmune beta-cell loss, young, ketosis-prone, needs insulin.
• •Type 2: insulin resistance, older/obese, HHS more than DKA.
• •Diagnosis: HbA1c ≥ 6.5%, fasting glucose ≥ 126 mg/dL.

• •MCA: contralateral face/arm weakness, aphasia (dominant hemisphere).
• •ACA: contralateral leg weakness. PCA: homonymous hemianopia.
• •Time is brain — urgent CT to exclude bleed before thrombolysis.

• •Microcytic (low MCV): iron deficiency, thalassemia.
• •Macrocytic (high MCV): B12/folate deficiency.
• •Normocytic: acute blood loss, chronic disease, hemolysis.

• •Type I: IgE, immediate (anaphylaxis). Type II: antibody, cytotoxic.
• •Type III: immune complexes (SLE). Type IV: T-cell, delayed (TB test).
• •Mnemonic ACID: Anaphylactic, Cytotoxic, Immune-complex, Delayed.

• •Muscarinic agonists → SLUDGE; blockers (atropine) → dry, dilated, hot.
• •Beta-1 raises heart rate/contractility; beta-2 dilates airways.
• •Alpha-1 agonists vasoconstrict (raise BP).

• •Pre-hepatic: unconjugated (hemolysis).
• •Hepatic: mixed (hepatitis, cirrhosis).
• •Post-hepatic: conjugated, pale stools and dark urine (obstruction).

• •Sensitivity rules OUT (SnNout); specificity rules IN (SpPin).
• •PPV and NPV depend on disease prevalence.
• •Number needed to treat = 1 / absolute risk reduction.

• •FSH grows the follicle; the LH surge triggers ovulation (~day 14).
• •Estrogen dominates the follicular phase; progesterone the luteal phase.
• •No pregnancy → corpus luteum regresses → progesterone falls → menstruation.

• •Autosomal dominant: every generation affected (e.g. Huntington's, Marfan).
• •Autosomal recessive: skips generations, carriers (e.g. cystic fibrosis).
• •X-linked recessive: males affected, no male-to-male transmission (e.g. hemophilia).

• •Cushing = too much cortisol: weight gain, moon face, striae, high glucose and BP.
• •Addison = too little cortisol/aldosterone: fatigue, low BP, low sodium, high potassium, pigmentation.
• •Screen Cushing with dexamethasone suppression; Addison with a short Synacthen test.

• •Congenital infections crossing the placenta: Toxoplasma, Other (syphilis), Rubella, CMV, Herpes.
• •Clues: rash, deafness, cataracts, hepatosplenomegaly, brain calcification.
• •CMV is the commonest congenital infection.

• •Inducers lower drug levels: rifampicin, phenytoin, carbamazepine, chronic alcohol.
• •Inhibitors raise levels/toxicity: macrolides, azoles, grapefruit, valproate.
• •Matters most for narrow-therapeutic-index drugs (warfarin, the pill).

• •Dorsal columns: fine touch, vibration, proprioception (cross in the medulla).
• •Spinothalamic: pain and temperature (cross at the level of entry).
• •Corticospinal: voluntary motor (cross in the medullary pyramids).

• •PT/INR tests the extrinsic pathway — monitors warfarin.
• •APTT tests the intrinsic pathway — monitors heparin.
• •Both prolonged → a common-pathway or liver problem.

• •Valid consent is informed, voluntary, and by someone with capacity.
• •Capacity = understand, retain, weigh, and communicate the decision.
• •A competent adult may refuse treatment, even if it seems unwise.

Step 1

Tests: Basic sciences — anatomy, physiology, biochemistry, pathology, pharmacology, microbiology, immunology and behavioral science — organized by system and process.

Format: One 8-hour day: fourteen 30-minute blocks of up to 20 items each, up to ~280 items in total, plus 55 minutes of break time and a 5-minute optional tutorial (format in force since 14 May 2026).

Scoring: Pass / Fail only (since January 2022).

When (India): Usually after the pre- and para-clinical years, once the basic sciences are covered — commonly around 2nd–3rd year of MBBS. Not realistically after just first year.

Step 2 CK

Tests: Clinical knowledge — diagnosis and management across medicine, surgery, pediatrics, obstetrics & gynecology, psychiatry and more.

Format: One 9-hour day: sixteen 30-minute blocks of up to 20 items each, plus 55 minutes of break time and a 5-minute optional tutorial (format in force since 7 May 2026; previously eight 60-minute blocks).

Scoring: A 3-digit numeric score — the score most residency programs now weigh heavily.

When (India): During the clinical years or internship, after solid clinical exposure.

Step 3

Tests: Applying knowledge for unsupervised practice — patient management, plus computer-based case simulations (CCS).

Format: Two days: multiple-choice blocks, then more questions with interactive CCS cases.

Scoring: A 3-digit numeric score.

When (India): After ECFMG Certification — usually taken during or after the first year of US residency.