Palestinian Board Part I cheat sheet

Acute coronary syndrome: ST-elevation MI is diagnosed with ≥1 mm ST elevation in two contiguous limb leads or ≥2 mm in two contiguous precordial leads (or new LBBB); dual antiplatelet therapy plus urgent reperfusion is standard.

Heart failure with reduced ejection fraction (EF ≤40%): four pillars improve mortality - ACE inhibitor/ARB or ARNI, beta-blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor.

Diabetic ketoacidosis: glucose >250 mg/dL, pH <7.3, bicarbonate <18 mEq/L, anion gap >10-12, and ketonemia/ketonuria; treat with isotonic saline, insulin infusion, and potassium replacement once K <5.2 mEq/L.

Hyperkalemia ECG progression: peaked T waves → PR prolongation → loss of P waves → QRS widening → sine wave; give IV calcium gluconate for cardiac membrane stabilization first.

Community-acquired pneumonia severity: CURB-65 scores confusion, urea >7 mmol/L, respiratory rate ≥30, low blood pressure, and age ≥65; score ≥2 suggests inpatient care.

Nephrotic syndrome: proteinuria >3.5 g/day, hypoalbuminemia, edema, hyperlipidemia; minimal change disease is the commonest cause in children, membranous nephropathy in older adults.

Thyroid function: primary hypothyroidism shows high TSH with low free T4; subclinical hypothyroidism shows high TSH with normal free T4; central hypothyroidism shows low TSH with low free T4.

Cirrhosis complications: ascites is managed with spironolactone plus furosemide and sodium restriction; spontaneous bacterial peritonitis is diagnosed by ascitic neutrophil count ≥250/mm³.

Acute appendicitis: migratory right lower quadrant pain, anorexia, McBurney point tenderness; Alvarado score ≥7 supports operative management.

Small bowel obstruction: colicky pain, vomiting, distension, absolute constipation; upright film shows multiple air-fluid levels; initial management is nasogastric decompression and IV fluids, with surgery for strangulation signs.

Trauma primary survey follows ABCDE: catastrophic hemorrhage control, airway with cervical spine protection, breathing, circulation, disability, exposure.

Burns: Parkland formula gives 4 mL/kg/% total body surface area of crystalloid in 24 hours, half in the first 8 hours from injury; use the Rule of Nines for adult surface area.

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

Acute cholecystitis: right upper quadrant pain, Murphy sign, fever, leukocytosis; ultrasound shows wall thickening >3 mm and pericholecystic fluid; treat with antibiotics and early laparoscopic cholecystectomy.

Postoperative fever timing: within 48 hours consider atelectasis; days 3-5 consider urinary or wound infection; days 5-7 consider intra-abdominal abscess or anastomotic leak; after day 7 consider deep vein thrombosis.

Breast cancer staging uses tumor size, nodal involvement, and metastases; sentinel lymph node biopsy is standard for clinically node-negative axilla.

Neonatal resuscitation: warm, dry, stimulate; if heart rate <100/min or apnea, give positive pressure ventilation; chest compressions at 3:1 ratio if heart rate <60/min after effective ventilation.

Apgar score assesses heart rate, respiratory effort, muscle tone, reflex irritability, and color at 1 and 5 minutes; score 0-3 indicates need for immediate resuscitation.

Pediatric maintenance fluids by Holliday-Segar: 100 mL/kg/day for first 10 kg, 50 mL/kg/day for next 10 kg, 20 mL/kg/day thereafter.

Kawasaki disease: fever ≥5 days plus four of five criteria (rash, conjunctivitis, oral changes, extremity changes, cervical lymphadenopathy); treat with IV immunoglobulin and aspirin to prevent coronary aneurysm.

Intussusception: infant with episodic colicky pain, drawing up legs, red currant jelly stool, sausage-shaped mass; ultrasound shows target sign; air enema is diagnostic and therapeutic.

Pyloric stenosis: 3-6 week old infant with projectile nonbilious vomiting and visible peristalsis; hypochloremic hypokalemic metabolic alkalosis; correct electrolytes before pyloromyotomy.

Croup versus epiglottitis: croup has barking cough and inspiratory stridor with steeple sign; epiglottitis has drooling, tripod posture, and thumb sign; avoid throat examination in epiglottitis.

Vaccination schedule basics: BCG and hepatitis B at birth; DTP and oral polio at 2, 4, and 6 months; measles-mumps-rubella at 9 and 15 months in many regional schedules.

Estimated date of delivery by Naegele rule: first day of last menstrual period plus 7 days minus 3 months, or add 280 days.

Preeclampsia: blood pressure ≥140/90 mmHg after 20 weeks with proteinuria ≥300 mg/24 h or organ dysfunction; severe features include ≥160/110, platelets <100,000, liver enzymes doubled, or pulmonary edema.

Ectopic pregnancy: amenorrhea, abdominal pain, vaginal bleeding; transvaginal ultrasound shows empty uterus with beta-hCG above discriminatory zone (1500-3500 mIU/mL); treat with methotrexate if stable and unruptured.

Postpartum hemorrhage: uterine atony is the commonest cause; management sequence is uterine massage, oxytocin, then ergometrine, carboprost, or misoprostol, then balloon tamponade or surgery.

Fetal heart rate monitoring: late decelerations indicate uteroplacental insufficiency; variable decelerations indicate cord compression; prolonged bradycardia needs immediate delivery.

Ovarian torsion: sudden severe unilateral pelvic pain with nausea and vomiting; Doppler may be normal; diagnosis is clinical and surgical detorsion preserves the ovary.

Cervical cancer screening: Pap smear from age 21 or 25; co-testing with HPV DNA every 5 years from age 30; HPV 16 and 18 cause most cases.

Gestational diabetes screening: 75 g oral glucose tolerance test at 24-28 weeks; diagnostic thresholds are fasting ≥92, 1-hour ≥180, 2-hour ≥153 mg/dL (one value sufficient).

Anatomy: the brachial plexus derives from C5-T1 roots; injury at Erb point (C5-C6) causes waiter tip deformity; Klumpke injury (C8-T1) causes claw hand.

Physiology: cardiac output = heart rate × stroke volume; mean arterial pressure ≈ diastolic pressure + one third of pulse pressure.

Physiology: oxygen-hemoglobin dissociation curve shifts right with increased CO2, decreased pH, increased temperature, and increased 2,3-DPG, reducing affinity.

Biochemistry: glycolysis yields net 2 ATP and 2 NADH per glucose; the citric acid cycle yields 3 NADH, 1 FADH2, and 1 GTP per acetyl-CoA; oxidative phosphorylation yields about 30-32 ATP per glucose.

Biochemistry: vitamin B12 deficiency causes megaloblastic anemia with neurologic signs; folate deficiency causes megaloblastic anemia without neurologic signs.

Pathology: reversible cell injury shows swelling and fatty change; irreversible injury shows membrane rupture, mitochondrial damage, and nuclear changes (pyknosis, karyorrhexis, karyolysis).

Pharmacology: first-order kinetics eliminates a constant fraction per unit time; zero-order kinetics eliminates a constant amount per unit time (phenytoin, ethanol, aspirin at high dose).

Microbiology: Gram-positive cocci in clusters are Staphylococcus; in chains are Streptococcus; Gram-negative diplococci are Neisseria; acid-fast bacilli are Mycobacterium.

Levels of prevention: primary prevents disease before onset (immunization); secondary detects early disease (screening); tertiary limits disability (rehabilitation).

Sensitivity = true positives / (true positives + false negatives); specificity = true negatives / (true negatives + false positives); both are intrinsic to the test and independent of prevalence.

Positive predictive value depends on prevalence: it rises as prevalence rises, while negative predictive value falls.

Herd immunity threshold = 1 - 1/R0; for measles with R0 around 12-18, roughly 92-95% coverage is needed to interrupt transmission.

Incidence measures new cases per population at risk per time; prevalence measures all existing cases at a point or period; prevalence ≈ incidence × duration.

Maternal mortality ratio = maternal deaths per 100,000 live births; infant mortality rate = deaths under age 1 per 1,000 live births.

Screening criteria: the disease must be important, have a detectable latent stage, have an acceptable test, and have effective early treatment.

Case-control studies estimate odds ratios and are efficient for rare diseases; cohort studies estimate relative risk and can establish temporality.

Relative risk = incidence in exposed / incidence in unexposed; odds ratio = (a×d)/(b×c) in a 2×2 table; odds ratio approximates relative risk only when the disease is rare.

Attributable risk = incidence in exposed - incidence in unexposed; it estimates the excess disease burden due to exposure.

Confounding is a third variable associated with both exposure and outcome that distorts the observed association; randomization, restriction, matching, and stratification control it.

Bias types: selection bias from non-representative sampling; recall bias in retrospective studies; information bias from measurement error; lead-time bias from earlier detection without longer survival.

Randomized controlled trial minimizes confounding; intention-to-treat analysis preserves randomization but may dilute effect estimates.

Statistical significance: p <0.05 means the result is unlikely under the null hypothesis; it does not measure effect size or clinical importance.

Normal distribution: about 68% of values lie within 1 standard deviation of the mean, 95% within 2, and 99.7% within 3.

Error types: type I error (alpha) is rejecting a true null hypothesis; type II error (beta) is failing to reject a false null; power = 1 - beta.

Informed consent requires capacity, adequate disclosure of risks and benefits, comprehension, and voluntariness; a competent adult may refuse treatment even if the decision risks death.

Autonomy, beneficence, nonmaleficence, and justice are the four principles of biomedical ethics; autonomy generally prevails in conflicts involving competent adults.

Confidentiality may be breached only where law requires reporting, such as certain communicable diseases, gunshot wounds, or suspected child abuse.

Capacity assessment: the patient must understand the information, appreciate the consequences, reason about options, and communicate a choice.

Minors: consent is generally given by a parent or guardian; emancipated minors and those seeking care for sexually transmitted infections, contraception, or prenatal care may consent independently under many jurisdictions.

Breaking bad news: the SPIKES framework covers setting, perception, invitation, knowledge, empathy, and strategy/summary.

Grief stages as described by Kübler-Ross are denial, anger, bargaining, depression, and acceptance; they are not strictly sequential.

Placebo effect is a measurable improvement attributable to expectation rather than active treatment; it does not justify deceiving patients in clinical care.

Adult basic life support: compressions at 100-120/min, depth 5-6 cm, full recoil, ratio 30:2 with ventilation, and early defibrillation for shockable rhythms (ventricular fibrillation, pulseless ventricular tachycardia).

Anaphylaxis: intramuscular adrenaline 0.5 mg (1:1000) into the anterolateral thigh, repeated every 5 minutes as needed; antihistamines and steroids are adjuncts, not first-line.

Sepsis: give broad-spectrum antibiotics within 1 hour and 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L; norepinephrine is the first-line vasopressor for septic shock.

Tension pneumothorax: tracheal deviation, distended neck veins, absent breath sounds; treat with immediate needle decompression before imaging.

Opioid overdose: pinpoint pupils, respiratory depression, and coma; give naloxone and support ventilation.

Status epilepticus: give a benzodiazepine first (lorazepam or midazolam), then a second-line agent such as phenytoin or levetiracetam if seizures persist beyond 20 minutes.

Acute upper airway obstruction: stridor indicates inspiratory obstruction; a patient with severe obstruction who can speak has a partial obstruction and should be allowed to cough.

Glasgow Coma Scale: eye 1-4, verbal 1-5, motor 1-6; score ≤8 generally indicates need for airway protection.

Adrenal crisis: hypotension, hyponatremia, hyperkalemia, and hypoglycemia; treat immediately with IV hydrocortisone and saline before confirming the diagnosis.

SIADH: euvolemic hyponatremia with low serum osmolality, high urine osmolality, and urine sodium >40 mEq/L; treat with fluid restriction and, if severe, hypertonic saline.

Acute kidney injury staging (KDIGO): stage 1 is creatinine rise ≥0.3 mg/dL or 1.5-1.9 times baseline; stage 2 is 2.0-2.9 times; stage 3 is ≥3.0 times or need for dialysis.

Hypercalcemia: corrected calcium = measured calcium + 0.8 × (4 - albumin g/dL); primary hyperparathyroidism causes high calcium with high or inappropriately normal PTH.

Hypothyroidism treatment: levothyroxine is started at full dose in healthy young adults but at low dose (12.5-25 mcg) in elderly patients or those with coronary disease.

Metabolic acidosis: calculate the anion gap as sodium minus chloride minus bicarbonate; a normal gap with hyperchloremia suggests diarrhea or renal tubular acidosis.

Cushing syndrome: elevated late-night salivary cortisol, 24-hour urine free cortisol, or overnight dexamethasone suppression test; pituitary adenoma is the commonest cause.

Pheochromocytoma: episodic headache, sweating, and palpitations; diagnose with plasma free metanephrines; do not biopsy before alpha blockade.

Preoperative fasting: clear fluids up to 2 hours and light meals up to 6 hours before elective surgery in most guidelines; prolonged fasting offers no benefit.

Wound classification: clean, clean-contaminated, contaminated, and dirty; prophylactic antibiotics are indicated for clean-contaminated and contaminated wounds.

Surgical site infection: diagnosed within 30 days of surgery (or 90 days with implants) with purulent drainage, positive culture, or wound dehiscence.

Hemorrhagic shock classes: class I up to 15% blood loss; class II 15-30% with tachycardia; class III 30-40% with hypotension; class IV >40% with marked hypotension and lethargy.

Abdominal compartment syndrome: bladder pressure >20 mmHg with new organ dysfunction; treat with decompressive laparotomy.

Acute mesenteric ischemia: pain out of proportion to examination, metabolic acidosis, and elevated lactate; early CT angiography and surgical revascularization are required.

Thyroidectomy complications: recurrent laryngeal nerve injury causes hoarseness; external branch of superior laryngeal nerve injury causes voice fatigue; hypocalcemia from parathyroid injury occurs 24-48 hours later.

Postoperative deep vein thrombosis prophylaxis: low molecular weight heparin or unfractionated heparin plus mechanical compression for moderate- and high-risk patients.

Neonatal jaundice: assess with total serum bilirubin plotted on hour-specific nomograms; phototherapy thresholds depend on gestational age and risk factors; exchange transfusion for severe hemolytic disease.

Neonatal sepsis: group B Streptococcus and Escherichia coli are common pathogens; empiric ampicillin plus gentamicin is standard.

Respiratory distress syndrome: surfactant deficiency in premature infants; chest radiograph shows ground-glass opacity and air bronchograms; treat with exogenous surfactant and CPAP.

Failure to thrive: weight below the 3rd-5th percentile or crossing two major percentile lines; evaluate for organic causes and psychosocial factors.

Nephrotic syndrome in children: minimal change disease is commonest; treat with corticosteroids; biopsy is reserved for steroid resistance or atypical features.

Pediatric dehydration: mild <5% weight loss, moderate 5-10%, severe >10%; oral rehydration solution is preferred for mild to moderate cases.

Measles: Koplik spots precede a maculopapular rash that starts on the face and spreads downward; vitamin A reduces mortality in deficient children.

Febrile seizures: simple seizures are generalized, last under 15 minutes, and occur once in 24 hours; they do not require long-term anticonvulsants.

Antenatal visits: in an uncomplicated pregnancy, visits are typically scheduled monthly until 28 weeks, every 2 weeks until 36 weeks, then weekly until delivery.

Folic acid: 400 mcg daily before conception and through the first trimester reduces neural tube defects; 4-5 mg is used for women with a previous affected pregnancy.

Rhesus prophylaxis: give anti-D immunoglobulin at 28 weeks and within 72 hours of delivery of an Rh-positive infant to an Rh-negative unsensitized mother.

Labor stages: first stage from onset to full dilatation; second stage from full dilatation to delivery (up to 3 hours in nulliparas with epidural); third stage from delivery to placental expulsion.

Shoulder dystocia: call for help, perform McRoberts maneuver and suprapubic pressure; avoid fundal pressure and excessive traction.

Preterm labor: give antenatal corticosteroids (betamethasone) between 24 and 34 weeks and magnesium sulfate before 32 weeks for neuroprotection.

Placenta previa: painless vaginal bleeding in late pregnancy; confirm with ultrasound; avoid digital vaginal examination.

Puerperal sepsis: fever ≥38°C after delivery with uterine tenderness; treat with broad-spectrum antibiotics and uterine evacuation if retained products are present.

Abnormal uterine bleeding: classify by PALM-COEIN - polyp, adenomyosis, leiomyoma, malignancy/hyperplasia; coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, not otherwise classified.

Polycystic ovary syndrome: Rotterdam criteria require two of three - oligo/anovulation, clinical or biochemical hyperandrogenism, and polycystic ovaries on ultrasound.

Endometriosis: cyclic pelvic pain and dyspareunia; laparoscopy is the diagnostic gold standard; treat with hormonal suppression or surgical excision.

Menopause: clinical diagnosis after 12 months of amenorrhea; hormone therapy is the most effective treatment for vasomotor symptoms.

Cervical intraepithelial neoplasia: CIN1 often regresses; CIN2-3 is treated with excision or ablation; HPV vaccination prevents types 16 and 18.

Ectopic pregnancy risk factors: previous ectopic, tubal surgery, pelvic inflammatory disease, intrauterine device in situ, and smoking.

Ovarian cancer: CA-125 is a marker but is not diagnostic; epithelial tumors are commonest; BRCA1 and BRCA2 mutations increase risk.

Contraception: combined oral contraceptives are contraindicated in migraine with aura, uncontrolled hypertension, and a history of venous thromboembolism.

Coronary arteries: the left anterior descending supplies the anterior wall and septum; the right coronary artery supplies the inferior wall and the sinoatrial node in most people.

Cranial nerves: the facial nerve (VII) controls muscles of facial expression; the trigeminal nerve (V) provides facial sensation; the vagus (X) provides parasympathetic supply to the thorax and abdomen.

Renal physiology: the proximal tubule reabsorbs about 65% of filtered sodium and water; the loop of Henle creates the medullary concentration gradient.

Respiratory physiology: functional residual capacity = expiratory reserve volume + residual volume; vital capacity = inspiratory reserve + tidal volume + expiratory reserve.

Acid-base: the Henderson-Hasselbalch equation is pH = 6.1 + log([HCO3-]/(0.03 × PaCO2)); a rise in PaCO2 lowers pH.

Muscle physiology: the sliding filament theory holds that actin filaments slide over myosin during contraction; calcium binds troponin C to expose myosin binding sites.

Endocrine feedback: the hypothalamic-pituitary-thyroid axis is a negative feedback loop where thyroid hormones suppress TSH and TRH release.

Cardiac cycle: the first heart sound is closure of mitral and tricuspid valves; the second sound is closure of aortic and pulmonary valves.

Enzyme kinetics: Michaelis-Menten Km is the substrate concentration at half maximal velocity; a low Km indicates high affinity; Vmax reflects enzyme amount.

Inborn errors: phenylketonuria results from phenylalanine hydroxylase deficiency; galactosemia from GALT deficiency; both cause intellectual disability if untreated.

Nucleotide metabolism: gout results from uric acid deposition; treat acute attacks with NSAIDs, colchicine, or steroids, and use allopurinol for prevention.

Tumor markers: alpha-fetoprotein for hepatocellular carcinoma and yolk sac tumors; CA-125 for ovarian cancer; carcinoembryonic antigen for colorectal cancer monitoring.

Apoptosis pathways: the intrinsic pathway is mitochondrial and caspase-9 dependent; the extrinsic pathway is death receptor mediated and caspase-8 dependent.

Inflammation: acute inflammation shows vasodilation, increased permeability, and neutrophil infiltration; chronic inflammation shows lymphocytes, plasma cells, and fibrosis.

Neoplasia: benign tumors are well circumscribed and non-invasive; malignant tumors invade and metastasize; grading describes differentiation, staging describes spread.

Anemia classification: microcytic (iron deficiency, thalassemia), normocytic (chronic disease, hemolysis), macrocytic (B12, folate, alcohol).

Beta-lactam antibiotics inhibit cell wall synthesis by binding penicillin-binding proteins; resistance occurs through beta-lactamases, altered binding proteins, or efflux.

Aminoglycosides inhibit the 30S ribosomal subunit; they are nephrotoxic and ototoxic and require monitoring of levels and renal function.

Warfarin inhibits vitamin K epoxide reductase; monitor with INR; reverse with vitamin K and prothrombin complex concentrate in major bleeding.

Heparin acts via antithrombin; monitor with aPTT; reverse with protamine sulfate.

Cytochrome P450: inhibitors include erythromycin, ketoconazole, and grapefruit; inducers include rifampin, carbamazepine, and phenytoin.

Sterilization versus disinfection: sterilization kills all microorganisms including spores; disinfection reduces pathogens but may not kill spores.

Bacterial growth phases: lag, exponential (log), stationary, and decline; antibiotics are most effective during exponential growth.

Viral structure: DNA viruses replicate in the nucleus except poxviruses; RNA viruses replicate in the cytoplasm except influenza and retroviruses.

Social determinants of health include income, education, housing, nutrition, and access to health services; they explain much of the variation in health outcomes.

Primary health care principles: accessibility, community participation, intersectoral collaboration, appropriate technology, and equity.

Epidemiologic transition: as countries develop, communicable disease mortality falls and noncommunicable disease mortality rises.

Screening program success depends on high coverage, follow-up of positive results, and effective treatment; without these, screening does not reduce mortality.

Maternal and child health programs: antenatal care, skilled birth attendance, and postnatal care are the main interventions that reduce maternal and neonatal mortality.

Water and sanitation: safe drinking water and adequate sanitation are among the most effective public health interventions for reducing diarrheal disease.

Occupational health: pre-employment and periodic medical examinations detect work-related disease; personal protective equipment reduces exposure.

Health education is most effective when it targets a defined behavior, uses multiple channels, and is reinforced over time.

Study designs: cross-sectional measures prevalence; case-control compares past exposure between cases and controls; cohort follows exposed and unexposed groups forward.

Randomization balances known and unknown confounders between groups; blinding reduces measurement and observer bias.

Sample size increases with greater variability, smaller effect size, higher confidence level, and greater power.

Confidence interval interpretation: a 95% confidence interval means that if the study were repeated many times, 95% of such intervals would contain the true parameter.

Chi-square test compares observed and expected frequencies in categorical data; the t-test compares means; ANOVA compares three or more means.

Standard deviation measures spread of individual values; standard error of the mean measures precision of the sample mean and decreases with larger samples.

Screening test validity: a highly sensitive test is useful to rule out disease when negative; a highly specific test is useful to rule in disease when positive.

Survival analysis: the Kaplan-Meier method estimates survival probability over time; the log-rank test compares survival curves between groups.

Medical error disclosure: patients should be told about harmful errors, including what happened, why, and what will be done; disclosure reduces litigation risk.

Negligence requires four elements: a duty of care, a breach of that duty, causation, and damages.

Advance directives: a living will records treatment preferences; a durable power of attorney for health care appoints a surrogate decision-maker.

Surrogate decision-making should follow substituted judgment (what the patient would have wanted), then best interests if the patient's wishes are unknown.

Research ethics: the Declaration of Helsinki and Belmont Report principles require informed consent, risk minimization, and equitable subject selection.

Doctor-patient communication: open-ended questions, reflective listening, and summarizing improve disclosure and adherence.

Substance use: the CAGE questionnaire asks about cutting down, annoyance, guilt, and eye-opener use; two or more positive answers suggest problematic alcohol use.

Stages of change: precontemplation, contemplation, preparation, action, maintenance, and relapse; interventions should match the patient's stage.

Poisoning: activated charcoal is most useful within 1 hour of ingestion and is contraindicated in unprotected airway, caustic ingestion, and ileus.

Organophosphate poisoning: SLUDGE and DUMBELS symptoms from acetylcholinesterase inhibition; treat with atropine until secretions dry and pralidoxime.

Carbon monoxide poisoning: carboxyhemoglobin causes falsely normal pulse oximetry; treat with high-flow oxygen and hyperbaric oxygen for severe cases.

Tricyclic antidepressant overdose: sodium channel blockade causes QRS widening and arrhythmia; treat with sodium bicarbonate.

Paracetamol overdose: N-acetylcysteine is most effective within 8 hours; use the Rumack-Matthew nomogram to guide treatment.

Defibrillation: biphasic shocks of 120-200 J are used for ventricular fibrillation; resume compressions immediately after the shock.

Post-cardiac arrest care: target temperature management and avoidance of hyperthermia; treat the underlying cause and maintain adequate perfusion.

Rapid sequence intubation: preoxygenate, give an induction agent and a paralytic, and confirm tube placement with waveform capnography.

Malaria: Plasmodium falciparum causes severe disease with high parasitemia, cerebral involvement, and hypoglycemia; treat severe cases with IV artesunate.

Tuberculosis: latent infection is treated with isoniazid for 6-9 months or rifampin for 4 months; active disease requires multidrug therapy.

HIV: antiretroviral therapy is recommended for all people living with HIV regardless of CD4 count; monitor viral load and CD4 response.

Iron deficiency anemia: low ferritin is the most specific test; treat with oral iron and investigate the source of blood loss in adults.

Sickle cell disease: painful vaso-occlusive crises are treated with hydration, analgesia, and oxygen if hypoxic; acute chest syndrome is a medical emergency.

Thrombocytopenia: spontaneous bleeding is uncommon above 20,000-30,000 platelets/µL; immune thrombocytopenia is treated with steroids or IV immunoglobulin.

Neutropenic fever: give empiric broad-spectrum antibiotics within 1 hour; antipseudomonal beta-lactam is standard.

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

Acute pancreatitis: diagnose with two of three - characteristic pain, lipase or amylase >3 times upper limit, and imaging findings; treat with fluids and analgesia.

Peptic ulcer perforation: sudden severe epigastric pain with board-like rigidity and free air under the diaphragm on upright film; treat with surgery and antibiotics.

Upper gastrointestinal bleeding: variceal bleeding is treated with octreotide and endoscopic band ligation; non-variceal bleeding with proton pump inhibitor and endoscopic hemostasis.

Colorectal cancer: right-sided tumors present with anemia and weight loss; left-sided tumors present with obstruction and change in bowel habit.

Acute limb ischemia: the six Ps are pain, pallor, pulselessness, paresthesia, paralysis, and poikilothermia; treat with heparin and urgent revascularization.

Bowel obstruction: strangulation signs include fever, tachycardia, localized tenderness, and leukocytosis; these require urgent surgery.

Inguinal hernia repair: mesh repair has lower recurrence than tissue repair; complications include chronic pain and recurrence.

Liver abscess: fever, right upper quadrant pain, and elevated alkaline phosphatase; treat with antibiotics and drainage.

Growth charts: weight doubles by 5 months and triples by 1 year; birth length increases by 50% by 1 year.

Developmental milestones: social smile at 6 weeks, head control at 3 months, sitting without support at 6-8 months, walking at 12-15 months.

Language milestones: babbling at 6 months, first words at 12 months, two-word phrases at 24 months; lack of these warrants assessment.

Vision and hearing: red reflex should be present at birth; hearing screening is done in the newborn period; early intervention improves outcomes.

Breastfeeding: exclusive breastfeeding is recommended for the first 6 months; complementary feeding starts at 6 months with continued breastfeeding to 2 years.

Immunization schedule: BCG and hepatitis B at birth; DTP and OPV at 2, 4, and 6 months; measles at 9 months and MMR at 15 months in many schedules.

Autism spectrum disorder: impaired social communication and restricted repetitive behaviors; screen at 18 and 24 months with a validated tool.

Adolescent development: puberty in girls begins with breast budding around 8-13 years; in boys with testicular enlargement around 9-14 years.

Gestational hypertension: new hypertension after 20 weeks without proteinuria or organ dysfunction; preeclampsia adds proteinuria or organ dysfunction.

HELLP syndrome: hemolysis, elevated liver enzymes, and low platelets; delivery is the definitive treatment.

Placental abruption: painful vaginal bleeding with a tender, rigid uterus; fetal distress is common; management depends on maternal and fetal status.

Multiple pregnancy: monochorionic twins have higher risk of twin-to-twin transfusion syndrome; monitor with ultrasound every 2 weeks.

Preterm premature rupture of membranes: confirm with speculum examination and pooling; give antibiotics and corticosteroids; avoid digital examination.

Gestational diabetes: first-line treatment is medical nutrition therapy and exercise; insulin is added if glucose targets are not met.

Postpartum hemorrhage: uterine atony is the commonest cause; give oxytocin, then tranexamic acid within 3 hours, and escalate to surgery if needed.

Preeclampsia prevention: low-dose aspirin (75-150 mg) started before 16 weeks reduces risk in high-risk women.

Health system building blocks: service delivery, health workforce, health information, medical products, financing, and leadership/governance.

Universal health coverage means access to needed health services without financial hardship; it is measured by service coverage and catastrophic spending indicators.

Quality of care domains: safety, effectiveness, patient-centeredness, timeliness, efficiency, and equity.

Primary care attributes: first contact, continuity, comprehensiveness, and coordination; strong primary care is associated with better outcomes and lower costs.

Health financing: out-of-pocket payments are the least equitable; pooling and prepayment spread risk across the population.

Human resources for health: shortages and maldistribution are key barriers; task shifting to community health workers can expand access.

Health information systems: accurate vital registration and disease surveillance are essential for planning and outbreak response.

Patient safety: hand hygiene, surgical safety checklists, and medication reconciliation reduce adverse events.

Outbreak investigation steps: verify the diagnosis, confirm the outbreak, define cases, describe by time/place/person, generate hypotheses, and implement control measures.

Epidemic curve: a point-source outbreak has a single peak within one incubation period; a propagated outbreak has successive peaks.

Attack rate = new cases / population at risk during the outbreak; it is used for point-source outbreaks.

Screening program evaluation: measure sensitivity, specificity, positive predictive value, and cost-effectiveness; confirm positive results with a diagnostic test.

Lead-time bias occurs when screening detects disease earlier without changing the time of death; survival appears longer but mortality is unchanged.

Length bias: screening preferentially detects slower-growing disease, which appears to improve survival.

Randomized controlled trials are the best design for evaluating screening programs because they avoid lead-time and length bias.

Biostatistics: the number needed to treat = 1 / absolute risk reduction; a smaller number indicates greater benefit.

Depression: two weeks of depressed mood or anhedonia plus four or more symptoms such as sleep, appetite, energy, concentration, and suicidal ideation.

Suicide risk assessment: ask directly about suicidal thoughts, plans, means, and intent; a prior attempt is the strongest risk factor.

Schizophrenia: positive symptoms include delusions and hallucinations; negative symptoms include flat affect and social withdrawal; treat with antipsychotics.

Bipolar disorder: mania requires elevated or irritable mood with increased energy lasting at least 1 week; treat acute mania with mood stabilizers or antipsychotics.

Substance withdrawal: alcohol withdrawal can cause seizures and delirium tremens; treat with benzodiazepines and thiamine.

Involuntary admission: requires mental disorder, risk to self or others, and lack of capacity or less restrictive alternatives; periodic review is required.

Confidentiality and duty to warn: where a patient poses a serious threat to an identifiable person, disclosure may be justified to protect that person.

Capacity versus competence: capacity is a clinical assessment; competence is a legal determination made by a court.

Acute pulmonary edema: sit the patient upright, give oxygen, nitrates, and a loop diuretic; noninvasive ventilation reduces intubation in severe cases.

Acute severe asthma: give oxygen, inhaled salbutamol, ipratropium, and systemic corticosteroids; magnesium sulfate may be used for refractory cases.

Chronic obstructive pulmonary disease exacerbation: controlled oxygen to target saturation 88-92%, bronchodilators, steroids, and antibiotics if purulent sputum.

Pulmonary embolism: use the Wells score and D-dimer; CT pulmonary angiography is diagnostic; anticoagulation is the mainstay.

Aortic dissection: sudden tearing chest pain radiating to the back; give beta-blockers to reduce heart rate and blood pressure before imaging.

Hypertensive emergency: end-organ damage such as encephalopathy or aortic dissection; lower blood pressure gradually except in dissection.

Cardiogenic shock: hypotension with signs of hypoperfusion; treat with vasopressors and inotropes and consider revascularization.

Ventilator basics: tidal volume 6-8 mL/kg of predicted body weight reduces ventilator-induced lung injury.

Inflammatory bowel disease: ulcerative colitis involves the colon continuously from the rectum; Crohn disease is transmural and can affect any part of the gastrointestinal tract.

Cirrhosis: Child-Pugh and MELD scores predict prognosis; variceal screening with endoscopy is recommended at diagnosis.

Stroke: thrombolysis with alteplase is given within 4.5 hours of onset; thrombectomy is considered for large vessel occlusion within 6-24 hours in selected patients.

Transient ischemic attack: rapid assessment with the ABCD2 score; urgent evaluation reduces stroke risk.

Multiple sclerosis: relapsing-remitting course with demyelinating lesions; MRI shows periventricular and juxtacortical lesions; treat relapses with steroids.

Meningitis: bacterial meningitis requires immediate empiric antibiotics and dexamethasone; do not delay antibiotics for lumbar puncture.

Epilepsy: first-line treatment for focal seizures includes carbamazepine or levetiracetam; for generalized tonic-clonic seizures, valproate is effective but teratogenic.

Hepatic encephalopathy: precipitating factors include infection, bleeding, constipation, and electrolyte imbalance; treat with lactulose and rifaximin.

Renal colic: sudden severe flank pain radiating to the groin; CT without contrast is the diagnostic test of choice; treat with analgesia and hydration.

Urinary retention: painful inability to void with a palpable bladder; catheterize and investigate the cause, especially in men with prostatic enlargement.

Testicular torsion: sudden severe testicular pain with high-riding testis and absent cremasteric reflex; surgical exploration is required within 6 hours.

Prostate cancer: screen with PSA and digital rectal examination; confirm with biopsy; Gleason score determines grade.

Fracture management: the principles are reduction, immobilization, and rehabilitation; open fractures need antibiotics and urgent debridement.

Compartment syndrome: pain out of proportion, tense compartment, and pain on passive stretch; fasciotomy is required urgently.

Hip fracture: elderly patients with shortened, externally rotated leg; early surgery reduces mortality and complications.

Osteomyelitis: fever, bone pain, and elevated inflammatory markers; MRI is sensitive; treat with prolonged antibiotics and sometimes surgical debridement.

Bronchiolitis: respiratory syncytial virus is the commonest cause; treat with supportive care including oxygen and hydration; bronchodilators are not routinely recommended.

Asthma in children: stepwise management with inhaled corticosteroids as controller therapy and short-acting beta-agonists for rescue; use a spacer.

Congenital heart disease: cyanotic lesions include tetralogy of Fallot, transposition of the great arteries, and tricuspid atresia; acyanotic lesions include ventricular septal defect and patent ductus arteriosus.

Tetralogy of Fallot: four features are ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy, and overriding aorta; squatting increases systemic vascular resistance.

Kawasaki disease: coronary artery aneurysm is the major complication; IV immunoglobulin reduces risk when given within 10 days of fever onset.

Acute rheumatic fever: Jones criteria include carditis, arthritis, chorea, erythema marginatum, and subcutaneous nodules; treat with penicillin.

Cystic fibrosis: autosomal recessive defect in the CFTR chloride channel; presents with meconium ileus, steatorrhea, and recurrent respiratory infections.

Foreign body aspiration: sudden choking in a child with unilateral wheeze; chest radiograph may be normal; bronchoscopy is diagnostic and therapeutic.

Menstrual cycle: the follicular phase is dominated by estrogen; ovulation occurs around day 14 in a 28-day cycle; the luteal phase is dominated by progesterone.

Ovulation prediction: a midcycle luteinizing hormone surge precedes ovulation by about 24-36 hours; basal body temperature rises after ovulation.

Infertility: defined as failure to conceive after 12 months of unprotected intercourse; evaluate both partners; tubal patency and semen analysis are initial tests.

Polycystic ovary syndrome: first-line treatment for anovulatory infertility is letrozole or clomiphene citrate; metformin may be added in insulin resistance.

Endometrial hyperplasia: unopposed estrogen is the main risk factor; atypical hyperplasia carries a high risk of progression to cancer.

Hormone therapy: estrogen alone is used in women without a uterus; combined estrogen-progestogen is used in women with a uterus to protect the endometrium.

Contraceptive efficacy: the etonogestrel implant and intrauterine devices have failure rates below 1% per year; barrier methods have higher failure rates.

Menopause: vasomotor symptoms are treated with hormone therapy; vaginal dryness responds to topical estrogen.

Immunoglobulins: IgG crosses the placenta and provides neonatal immunity; IgM is the first antibody in primary infection; IgA is secreted in mucosa.

Hypersensitivity types: type I is IgE mediated (anaphylaxis); type II is antibody mediated (hemolysis); type III is immune complex mediated; type IV is T-cell mediated (contact dermatitis).

Complement: the classical pathway is activated by IgG or IgM; the alternative pathway is activated by microbial surfaces; both form the membrane attack complex.

Inheritance patterns: autosomal dominant affects every generation; autosomal recessive affects siblings; X-linked recessive affects males.

Genetic testing: karyotype detects aneuploidy and large structural changes; fluorescence in situ hybridization detects specific microdeletions; sequencing detects point mutations.

Trisomy 21: risk increases with maternal age; features include hypotonia, flat facies, and congenital heart defects such as ventricular septal defect.

Sickle cell disease: autosomal recessive point mutation in the beta-globin gene; heterozygotes have protection against falciparum malaria.

Major histocompatibility complex: class I presents to CD8 T cells; class II presents to CD4 T cells.

Air pollution: particulate matter under 2.5 micrometers penetrates deep into the lungs and is associated with cardiovascular and respiratory disease.

Water quality: chlorination is the most effective method for disinfecting drinking water; residual chlorine should be maintained in distribution systems.

Food safety: the main causes of foodborne illness are inadequate cooking, cross-contamination, and improper storage temperature.

Occupational exposure limits: threshold limit values are set for workplace exposure; monitoring and control measures reduce risk.

Lead poisoning: affects the nervous system and kidneys; children are more vulnerable; remove the source and chelate in severe cases.

Radiation protection: the principles are time, distance, and shielding; occupational dose limits are set by international guidelines.

Vector control: eliminating standing water reduces mosquito breeding; insecticide-treated nets reduce malaria transmission.

Climate and health: heat waves increase cardiovascular and respiratory mortality; vulnerable groups include the elderly and those with chronic disease.

Basic reproduction number R0 is the average number of secondary cases from one infectious case in a fully susceptible population; an epidemic grows when R0 >1.

Effective reproduction number Rt changes with immunity and interventions; control measures aim to reduce Rt below 1.

Incubation period is the time from exposure to symptom onset; it determines quarantine duration and outbreak curve shape.

Case fatality rate = deaths / confirmed cases; it can overestimate severity if mild cases are not detected.

Contact tracing: identify contacts, quarantine, and test; it is most effective when transmission occurs before symptoms.

Vaccine efficacy = (attack rate in unvaccinated - attack rate in vaccinated) / attack rate in unvaccinated × 100%.

Herd immunity: high coverage reduces transmission to those who cannot be vaccinated; the threshold depends on R0.

Surveillance types: passive surveillance relies on routine reporting; active surveillance seeks cases; sentinel surveillance uses selected sites.

Team communication: SBAR (situation, background, assessment, recommendation) structures handover and reduces error.

Handover: use a standardized format and include allergies, medications, and pending results to prevent information loss.

Patient safety culture: reporting systems should be non-punitive to encourage disclosure of errors and near misses.

Root cause analysis: identify system failures rather than individual blame; implement changes to prevent recurrence.

Checklists: the WHO surgical safety checklist reduces complications and mortality when used correctly.

Medication reconciliation: compare the patient's medication list at admission, transfer, and discharge to prevent discrepancies.

Infection control: hand hygiene is the single most effective measure to prevent healthcare-associated infection.

Consent for procedures: the clinician performing the procedure should obtain consent and discuss risks, benefits, and alternatives.

Trauma: the primary survey is ABCDE; the secondary survey is a head-to-toe examination after stabilization.

Head injury: Glasgow Coma Scale ≤8 requires intubation; signs of raised intracranial pressure include unequal pupils and hypertension with bradycardia.

Spinal cord injury: immobilize the cervical spine until cleared; neurogenic shock causes hypotension with bradycardia.

Burns: estimate surface area with the Rule of Nines; give fluids by the Parkland formula; escharotomy for circumferential burns with compartment compromise.

Hypothermia: rewarm gradually; use active external and internal rewarming for severe cases; avoid rough handling of the patient.

Heat stroke: core temperature above 40°C with altered mental status; cool rapidly with ice water immersion or evaporation.

Drowning: the priority is rescue breathing and ventilation; cervical spine injury is uncommon unless a diving mechanism is reported.

Snake envenomation: immobilize the limb and give antivenom for systemic or severe local signs; avoid tourniquets and incision.

Rheumatoid arthritis: symmetric small joint involvement with morning stiffness; anti-cyclic citrullinated peptide is specific; treat early with methotrexate.

Systemic lupus erythematosus: malar rash, photosensitivity, arthritis, and renal involvement; antinuclear antibody is sensitive; anti-double-stranded DNA is specific.

Gout: monosodium urate crystals are needle-shaped and negatively birefringent; pseudogout has rhomboid positively birefringent calcium pyrophosphate crystals.

Ankylosing spondylitis: inflammatory back pain and sacroiliitis; HLA-B27 is associated; treat with NSAIDs and TNF inhibitors.

Psoriasis: well-demarcated plaques with silvery scale on extensor surfaces; treat with topical steroids, phototherapy, or biologics.

Cellulitis: acute spreading erythema and warmth; treat with antibiotics covering streptococci and staphylococci; mark the border to monitor progression.

Stevens-Johnson syndrome: severe mucocutaneous reaction with epidermal detachment; stop the offending drug and treat in a burn unit.

Osteoporosis: diagnose with dual-energy X-ray absorptiometry T-score ≤-2.5; treat with bisphosphonates and calcium and vitamin D.

Pediatric basic life support: compressions at 100-120/min, depth one third of chest diameter, ratio 30:2 for one rescuer and 15:2 for two rescuers.

Croup: barking cough and inspiratory stridor; treat with dexamethasone and nebulized adrenaline for severe cases.

Epiglottitis: drooling, tripod position, and high fever; do not examine the throat; secure the airway in the operating room.

Anaphylaxis in children: intramuscular adrenaline 0.01 mg/kg (max 0.5 mg) into the thigh; repeat every 5 minutes as needed.

Dehydration: assess with weight loss, capillary refill, and mucous membranes; give oral rehydration solution for mild to moderate cases and IV fluids for severe cases.

Febrile seizure: most are benign; investigate the source of fever; give antipyretics for comfort, not to prevent seizures.

Poisoning: call the poison center; activated charcoal is limited to recent ingestion with a protected airway; antidotes depend on the toxin.

Sudden infant death syndrome: put infants to sleep on their back, on a firm surface, without soft bedding or bed sharing.