FMGE cheat sheet

Brachial plexus: roots C5-T1; Erb palsy (C5-C6) gives waiter's tip; Klumpke palsy (C8-T1) gives claw hand with Horner syndrome.

Coronary arteries arise from aortic sinuses; left anterior descending supplies anterior two-thirds of interventricular septum; AV node is supplied by RCA in ~90% of people.

Nephron: filtration at glomerulus, ~125 mL/min GFR; proximal tubule reabsorbs ~65% of filtered Na+ and water; glucose reabsorption via SGLT2 in early proximal tubule.

Cardiac output = heart rate x stroke volume; Fick principle: CO = oxygen consumption / arteriovenous oxygen difference.

Enzyme kinetics: Km is substrate concentration at half-Vmax; competitive inhibitors raise Km with unchanged Vmax; non-competitive inhibitors lower Vmax.

Glycolysis yields net 2 ATP and 2 NADH per glucose; full oxidation gives ~30-32 ATP; rate-limiting enzymes: phosphofructokinase-1, isocitrate dehydrogenase, citrate synthase.

Oxygen dissociation curve shifts right (decreased affinity) with increased 2,3-BPG, CO2, H+, and temperature; fetal hemoglobin has higher affinity due to less 2,3-BPG binding.

Urea cycle occurs in liver mitochondria and cytosol; rate-limiting enzyme carbamoyl phosphate synthetase I; deficiency causes hyperammonemia with respiratory alkalosis.

Cell injury: reversible swelling and fatty change; irreversible injury marked by mitochondrial membrane damage and membrane rupture; necrosis is accompanied by inflammation, apoptosis is not.

Virchow's triad for thrombosis: endothelial injury, abnormal blood flow (stasis/turbulence), hypercoagulability.

Tumor suppressor genes require biallelic loss (Knudson two-hit hypothesis), e.g., RB, APC, BRCA1/2; oncogenes require single activating mutation, e.g., RAS, MYC.

Tumor markers: AFP (hepatocellular carcinoma, yolk sac tumor), CA-125 (ovarian), CEA (colorectal), calcitonin (medullary thyroid carcinoma), hCG (trophoblastic tumors).

Atherosclerosis begins with endothelial dysfunction and LDL retention; foam cells are lipid-laden macrophages; complicated plaque shows ulceration, thrombosis, calcification.

Nephrotic syndrome: proteinuria >3.5 g/day, hypoalbuminemia, edema, hyperlipidemia; nephritic syndrome: hematuria, RBC casts, hypertension, oliguria.

Granulomas are collections of activated macrophages (epithelioid cells) with giant cells; caseating in tuberculosis, non-caseating in sarcoidosis and Crohn disease.

Anemia classification by MCV: microcytic (<80 fL) iron deficiency, thalassemia, anemia of chronic disease; macrocytic (>100 fL) B12/folate deficiency, alcohol, hypothyroidism.

First-order kinetics: constant fraction eliminated per unit time; zero-order (saturation) kinetics with phenytoin, ethanol, aspirin at high dose - constant amount eliminated.

Volume of distribution Vd = dose / plasma concentration; loading dose = Vd x target concentration / bioavailability; maintenance dose = clearance x target concentration / bioavailability.

Cytochrome P450 inducers: rifampicin, phenytoin, carbamazepine, phenobarbital, rifabutin, St John's wort; inhibitors: ketoconazole, erythromycin, cimetidine, ritonavir, grapefruit.

Organophosphate poisoning: irreversible acetylcholinesterase inhibition - SLUDGE plus bradycardia; treat with atropine plus pralidoxime.

Aminoglycosides bind 30S ribosomal subunit, are bactericidal, cause ototoxicity and nephrotoxicity, and are contraindicated in myasthenia gravis.

Warfarin inhibits vitamin K epoxide reductase (factors II, VII, IX, X); heparin potentiates antithrombin III; protamine sulfate reverses heparin, vitamin K reverses warfarin.

Antihypertensive first-line in pregnancy: labetalol, nifedipine, methyldopa; ACE inhibitors and ARBs are contraindicated (fetotoxicity).

Beta-blockers: non-selective drugs contraindicated in asthma; cardioselective agents (atenolol, metoprolol) preferred when needed; esmolol is ultra-short acting.

Gram-positive cocci in clusters with coagulase positivity = Staphylococcus aureus; catalase-positive; novobiocin resistance identifies S. saprophyticus.

Gram-negative diplococci in neutrophils = Neisseria; N. meningitidis ferments glucose and maltose; N. gonorrhoeae ferments glucose only.

Tuberculosis: acid-fast bacilli on Ziehl-Neelsen stain; Lowenstein-Jensen medium; treatment with isoniazid, rifampicin, pyrazinamide, ethambutol in intensive phase.

Hepatitis B serology: HBsAg indicates infection; anti-HBs indicates immunity; HBeAg indicates high infectivity; anti-HBc IgM indicates acute infection.

HIV: p24 antigen detectable early, antibody by ELISA confirmed by Western blot; CD4 count <200 cells/microL defines AIDS; Pneumocystis jirovecii prophylaxis with cotrimoxazole.

Sterilization: autoclave 121 degrees C at 15 psi for 15-20 minutes; hot air oven 160 degrees C for 2 hours; ethylene oxide for heat-sensitive items.

Bacterial growth curve phases: lag, exponential (log), stationary, decline; generation time varies; spores are formed in stationary phase by Bacillus and Clostridium.

Dengue: Aedes aegypti vector; NS1 antigen within first 5 days, IgM after day 5; thrombocytopenia and hemoconcentration indicate plasma leakage.

Rigor mortis begins in small muscles (face, neck) 1-2 hours after death, spreads downward, and resolves in 24-36 hours; used to estimate postmortem interval.

Livor mortis begins 2-4 hours after death and fixes by 8-12 hours; position-dependent, blanchable early, non-blanchable later.

Carbon monoxide poisoning: cherry-red lividity, carboxyhemoglobin levels; treat with 100% oxygen, hyperbaric oxygen for severe cases.

Organophosphate poisoning: miosis, salivation, lacrimation, diarrhea, bradycardia, bronchorrhea; atropine until secretions dry plus pralidoxime.

Methanol poisoning: metabolic acidosis with high anion and osmolal gap, visual loss; treat with fomepizole or ethanol plus hemodialysis.

Lead poisoning: Burton line on gums, wrist drop, basophilic stippling, anemia; chelation with calcium disodium EDTA or dimercaprol.

Age estimation from teeth: first permanent molar at 6 years, second at 12 years, third molar at 18 years; ossification centers of wrist used in children.

Informed consent requires capacity, adequate information, and voluntariness; documentation is essential; emergency treatment may proceed under implied consent.

Incidence measures new cases over a period; prevalence measures existing cases at a point; prevalence = incidence x average duration of disease.

Sensitivity = true positives / (true positives + false negatives); specificity = true negatives / (true negatives + false positives); screening favors high sensitivity.

Infant mortality rate = infant deaths under 1 year per 1000 live births; neonatal mortality is deaths in first 28 days; major contributor is low birth weight.

Maternal mortality ratio = maternal deaths per 100,000 live births; leading causes are hemorrhage, sepsis, hypertensive disorders, obstructed labor.

Herd immunity threshold depends on basic reproduction number R0; for measles R0 is high, requiring ~95% coverage; polio requires ~80-85%.

Epidemiological study designs: cohort measures incidence and relative risk; case-control measures odds ratio; randomized controlled trial is best for causality.

Cold chain: vaccines stored at 2-8 degrees C; OPV and measles vaccine are heat-sensitive; freeze-sensitive vaccines include DPT, hepatitis B, and tetanus toxoid.

Screening test validity: positive predictive value depends on prevalence; low prevalence lowers PPV even with high sensitivity and specificity.

Acute myocardial infarction: ST elevation in contiguous leads; troponin rises 3-6 hours, peaks 12-24 hours; aspirin plus clopidogrel and primary PCI if within 12 hours.

Diabetic ketoacidosis: hyperglycemia, ketonemia, high anion gap metabolic acidosis; treat with IV fluids, insulin infusion, potassium replacement.

Hyperthyroidism: low TSH with high free T4/T3; Graves disease shows diffuse goiter, ophthalmopathy, TSH receptor antibodies.

Chronic kidney disease staging by eGFR: stage 1 >=90, stage 2 60-89, stage 3 30-59, stage 4 15-29, stage 5 <15 mL/min/1.73 m2.

Anemia of chronic disease: low serum iron, low TIBC, normal or high ferritin; iron deficiency: low ferritin, high TIBC.

Stroke: thrombolysis with alteplase within 4.5 hours of ischemic stroke onset after excluding hemorrhage on CT; blood pressure control avoids hemorrhagic transformation.

Rheumatoid arthritis: symmetric small joint involvement, morning stiffness >1 hour, anti-CCP and rheumatoid factor positive; treat with methotrexate.

Asthma: reversible airflow obstruction with FEV1/FVC <0.7 improving with bronchodilator; stepwise therapy with inhaled corticosteroids as controller.

Acute appendicitis: periumbilical pain migrating to right iliac fossa, McBurney point tenderness, Rovsing and psoas signs; treat with appendectomy or antibiotics in selected cases.

Shock classification: hypovolemic, cardiogenic, distributive (septic, anaphylactic, neurogenic), obstructive (tension pneumothorax, tamponade, pulmonary embolism).

Burns: Parkland formula for fluid = 4 mL x body weight (kg) x %TBSA burned in 24 hours, half in first 8 hours; use Ringer lactate.

Intestinal obstruction: colicky pain, vomiting, distension, absolute constipation; auscultation shows high-pitched bowel sounds early, absent later.

Hernia: indirect inguinal hernia passes through deep inguinal ring lateral to inferior epigastric vessels; direct hernia medial to them.

Thyroid surgery complications: recurrent laryngeal nerve injury (hoarseness), external branch of superior laryngeal nerve injury (voice fatigue), hypocalcemia from parathyroid injury.

Acute pancreatitis: elevated lipase more specific than amylase; Ranson criteria and modified Glasgow score for severity; treat with fluids and analgesia.

Breast cancer: sentinel lymph node biopsy for axillary staging; triple assessment = clinical examination, imaging, and tissue diagnosis.

Estimated date of delivery: Naegele rule - first day of last menstrual period plus 7 days minus 3 months, adjusted for cycle length.

Normal labor stages: first stage from onset to full dilatation; second stage from full dilatation to delivery; third stage from delivery to placental expulsion.

Preeclampsia: hypertension after 20 weeks with proteinuria or end-organ dysfunction; severe features include BP >=160/110, thrombocytopenia, elevated liver enzymes.

Postpartum hemorrhage: leading cause uterine atony; management includes uterine massage, oxytocin, ergometrine, carboprost, and surgical measures.

Contraception: combined oral pills contraindicated in smokers over 35, migraine with aura, and history of venous thromboembolism.

Ovarian cycle: follicular phase with FSH, ovulation triggered by LH surge around day 14, luteal phase with progesterone from corpus luteum.

Gestational diabetes screening with 75 g oral glucose tolerance test at 24-28 weeks; targets fasting <95 mg/dL and 2-hour <120 mg/dL.

Ectopic pregnancy: triad of amenorrhea, abdominal pain, vaginal bleeding; transvaginal ultrasound showing empty uterus with positive beta-hCG; treat with methotrexate or surgery.

Neonatal resuscitation: initial steps warmth, drying, stimulation; if apnea or heart rate <100, provide positive pressure ventilation; chest compressions if heart rate <60 after ventilation.

Birth weight categories: low birth weight <2500 g, very low <1500 g, extremely low <1000 g; preterm is <37 weeks gestation.

Breastfeeding: exclusive for first 6 months; colostrum rich in IgA; complementary feeding starts at 6 months with continued breastfeeding to 2 years.

Growth monitoring: weight doubles by 5 months, triples by 1 year; birth length increases 50% by 1 year; head circumference 35 cm at birth.

Kangaroo mother care: skin-to-skin contact, exclusive breastfeeding, and early discharge reduces mortality in low birth weight infants.

Measles vaccine: first dose at 9 months in high-burden settings, second dose later; vitamin A supplementation reduces measles mortality.

Neonatal jaundice: physiologic peak day 3-5 in term infants; pathological if within 24 hours, bilirubin rising >5 mg/dL/day, or direct hyperbilirubinemia.

Acute gastroenteritis: oral rehydration solution with zinc supplementation for 14 days reduces duration and severity of diarrhea.