Cardiology

Cardiology focuses on diseases and disorders of the heart and blood vessels.

• Aortic Aneurysm — abdominal and thoracic, Crawford classification, EVAR vs open repair
• Arrhythmia — irregular heartbeats, SVT, ventricular tachycardia
• Atrial Fibrillation — CHA₂DS₂-VASc scoring, rate vs rhythm control, ablation
• Cardiomyopathy — dilated, hypertrophic, restrictive, arrhythmogenic
• Cardiovascular Disease — atherosclerosis, risk factor management
• Coronary Artery Disease — angina, myocardial infarction, revascularization
• Endocarditis — infective endocarditis, Duke criteria, prophylaxis
• Heart Failure — HFrEF, HFpEF, NYHA classification
• Hypertension — primary and secondary, ACC/AHA staging
• Myocarditis — viral, autoimmune, Dallas criteria
• Peripheral Artery Disease — claudication, ABI, Fontaine/Rutherford staging
• Stroke — ischemic, hemorrhagic, TIA, thrombolysis
• Valvular Heart Disease — stenosis, regurgitation, ACC/AHA staging, TAVR

Dermatology

Dermatology addresses conditions affecting the skin, hair, and nails.

• Acne — comedonal, inflammatory, isotretinoin
• Eczema — atopic dermatitis, barrier dysfunction, biologics
• Fungal Infections — dermatophytes, candidiasis, antifungal therapy
• Psoriasis — plaque, guttate, biologic therapy
• Rosacea — erythematotelangiectatic, papulopustular, phymatous

Endocrinology

Endocrinology deals with hormone-related disorders and metabolic conditions.

• Addison's Disease — primary adrenal insufficiency, cortisol replacement
• Cushing's Syndrome — hypercortisolism, dexamethasone suppression test
• Diabetes Mellitus — Type 1, Type 2, insulin therapy, HbA1c targets
• Diabetes Insipidus — central vs nephrogenic, water deprivation test, desmopressin
• Hyperparathyroidism — primary/secondary/tertiary, calcium-PTH axis, calcimimetics
• Metabolic Syndrome — ATP III/IDF criteria, insulin resistance, cardiovascular risk
• Obesity — BMI classification, GLP-1 agonists, bariatric surgery
• Pheochromocytoma — catecholamine excess, metanephrines, alpha-blockade, MEN2/VHL
• Polycystic Ovary Syndrome — PCOS, Rotterdam criteria, hyperandrogenism
• Thyroid Disorders — hypothyroidism, hyperthyroidism, Graves', Hashimoto's

Gastroenterology

Gastroenterology focuses on the digestive system and related organs.

• Celiac Disease — autoimmune gluten sensitivity, Marsh classification, tTG-IgA
• Crohn's Disease — transmural inflammation, skip lesions, biologic therapy
• Diverticulitis — diverticulosis, Hinchey classification, complicated vs uncomplicated
• Gallbladder Disease — cholelithiasis, cholecystitis, Tokyo guidelines, HIDA scan
• GERD — Barrett's esophagus, PPI therapy
• Inflammatory Bowel Disease — Crohn's vs ulcerative colitis overview
• Irritable Bowel Syndrome — Rome IV criteria, IBS subtypes, low-FODMAP diet
• Pancreatitis — acute and chronic, Ranson criteria, Atlanta classification
• Peptic Ulcer Disease — H. pylori, triple therapy, Forrest classification
• Ulcerative Colitis — mucosal inflammation, aminosalicylates, colectomy

Hematology

Hematology studies diseases of the blood, bone marrow, and coagulation system.

• Anemia — iron deficiency, B12/folate, hemolytic, aplastic
• Deep Vein Thrombosis — Virchow's triad, anticoagulation, Wells score
• DIC — consumptive coagulopathy, ISTH scoring
• Hemochromatosis — iron overload, HFE mutations, phlebotomy
• Hemophilia — factor VIII/IX deficiency, emicizumab, gene therapy
• Polycythemia Vera — JAK2 V617F, myeloproliferative neoplasm, ruxolitinib
• Sickle Cell Disease — HbS, vaso-occlusive crises, hydroxyurea
• Thalassemia — alpha and beta, transfusion-dependent, iron chelation
• Thrombocytopenia — ITP, HIT, TTP, platelet transfusion thresholds
• Von Willebrand Disease — VWF subtypes, DDAVP, VWF replacement

Infectious Disease

Infectious disease focuses on illnesses caused by bacteria, viruses, fungi, and parasites.

• Cellulitis — skin and soft tissue infection, empiric antibiotics
• C. difficile Infection — toxin A/B, fidaxomicin, FMT, IDSA/SHEA guidelines
• Hepatitis — viral hepatitis overview
• Hepatitis B — HBV serologic markers, tenofovir
• Hepatitis C — direct-acting antivirals, SVR, cure
• HIV/AIDS — CD4 staging, ART regimens, PrEP, opportunistic infections
• Lyme Disease — Borrelia burgdorferi, erythema migrans, doxycycline
• Malaria — Plasmodium species, artemisinin-based therapy
• Meningitis — bacterial and viral, CSF analysis, empiric antibiotics
• Sepsis — Sepsis-3 criteria, SOFA/qSOFA, Surviving Sepsis Campaign
• Tuberculosis — RIPE therapy, latent TB management

Parasites

Parasitic disease covers infections caused by protozoa and free-living amoebae found in water and soil.

• Acanthamoeba — free-living amoeba in water and soil, keratitis, GAE
• Acanthamoeba Keratitis — the contact-lens eye infection, corneal scrapings, biguanides

Nephrology & Hepatology

This specialty addresses diseases of the kidneys and liver.

• Acute Kidney Injury — KDIGO staging, prerenal/intrinsic/postrenal, dialysis indications
• Cirrhosis — Child-Pugh/MELD scoring, portal hypertension, transplant
• Glomerulonephritis — nephritic vs nephrotic, IgA nephropathy, ANCA vasculitis
• Kidney Disease — CKD stages, GFR estimation, renal replacement therapy
• Liver Disease — hepatic disorders, liver function tests
• Nephrotic Syndrome — proteinuria, minimal change, FSGS, membranous nephropathy
• NAFLD/NASH — fatty liver, FIB-4 score, resmetirom

Neurology

Neurology focuses on disorders of the brain, spinal cord, and nervous system.

• Alzheimer's Disease — amyloid plaques, tau tangles, cholinesterase inhibitors
• Epilepsy — seizure classification, antiepileptic drugs
• Multiple Sclerosis — demyelination, McDonald criteria, DMTs
• Parkinson's Disease — dopamine depletion, levodopa, DBS

Oncology

Oncology is dedicated to the diagnosis and treatment of cancer.

• Cancer — overview, staging, prevention, screening
• Leukemia — ALL, AML, CLL, CML, chemotherapy
• Lymphoma — Hodgkin, non-Hodgkin, Ann Arbor staging
• Metastatic Cancers — spread patterns, systemic therapy
• Multiple Myeloma — plasma cell neoplasm, CRAB criteria
• Sarcoma — bone and soft tissue tumors

Pain & Allergy

This field focuses on chronic pain conditions and immune-mediated allergic disorders.

• Allergies — IgE-mediated, anaphylaxis, immunotherapy
• Chronic Pain — nociceptive, neuropathic, multimodal management
• Food Intolerance — lactose, histamine, elimination diets
• Migraine — aura, triptans, CGRP antagonists, prevention

Pediatrics

Pediatrics covers diseases and developmental conditions primarily affecting infants, children, and adolescents.

• ADHD — inattention, hyperactivity-impulsivity, stimulant therapy, behavioral interventions
• Autism Spectrum Disorder — social communication deficits, DSM-5 levels, ABA, early intervention
• Biliary Atresia — neonatal cholestasis, Kasai portoenterostomy, liver transplant
• Bronchiolitis — RSV, wheezing in infants, supportive care
• Cerebral Palsy — non-progressive motor disorder, GMFCS classification, spasticity management
• Congenital Heart Disease — structural cardiac defects, VSD, ASD, surgical repair
• Congenital Hypothyroidism — newborn screening, levothyroxine, intellectual disability prevention
• Croup — laryngotracheobronchitis, barking cough, stridor, dexamethasone
• Cystic Fibrosis — CFTR mutations, CFTR modulators, pulmonary and pancreatic involvement
• Febrile Seizures — simple vs complex, HHV-6, lumbar puncture criteria
• Galactosemia — GALT deficiency, neonatal liver failure, galactose-free diet
• Henoch-Schönlein Purpura — IgA vasculitis, palpable purpura, arthritis, nephritis
• Hirschsprung's Disease — aganglionic megacolon, neonatal obstruction, pull-through surgery
• Intussusception — telescoping bowel obstruction, target sign on ultrasound, air enema
• Juvenile Idiopathic Arthritis — childhood arthritis, oligoarticular/polyarticular/systemic, biologics
• Kawasaki Disease — vasculitis, coronary artery aneurysm, IVIG, aspirin
• Neonatal Jaundice — physiologic hyperbilirubinemia, phototherapy, kernicterus prevention
• Pertussis — whooping cough, Bordetella pertussis, macrolide therapy, Tdap vaccination
• Pyloric Stenosis — projectile vomiting, olive mass, pyloromyotomy
• Rotavirus — infantile gastroenteritis, vaccine-preventable, oral rehydration
• RSV Bronchiolitis — respiratory syncytial virus, nirsevimab prophylaxis, wheezing in infants

Psychiatry

Psychiatry addresses mental health disorders and behavioral conditions.

• ADHD — attention deficit hyperactivity disorder, stimulant therapy
• Anxiety — GAD, panic disorder, SSRIs, CBT
• Autism — autism spectrum disorder, early intervention
• Bipolar Disorder — mania, depression, mood stabilizers
• Dementia — cognitive decline, vascular, Lewy body
• Depression — major depressive disorder, SSRIs, psychotherapy
• Schizophrenia — psychosis, antipsychotics, negative symptoms

Pulmonology

Pulmonology focuses on diseases of the lungs and respiratory system.

• ARDS — Berlin criteria, lung-protective ventilation, prone positioning
• Asthma — airway hyperresponsiveness, GINA stepwise therapy
• COPD — GOLD classification, bronchodilators, exacerbations
• Cystic Fibrosis — CFTR mutations, modulators, pancreatic insufficiency
• Influenza — seasonal flu, antiviral therapy
• Interstitial Lung Disease — IPF, antifibrotic therapy, HRCT patterns
• Obstructive Sleep Apnea — AHI scoring, CPAP
• Pleural Effusion — Light's criteria, thoracentesis
• Pneumonia — CAP, HAP, VAP, empiric antibiotics
• Pulmonary Embolism — Wells criteria, CT angiography, anticoagulation
• Pulmonary Hypertension — WHO groups I-V, right heart catheterization
• Sarcoidosis — non-caseating granulomas, bilateral hilar lymphadenopathy

Reproductive Medicine

Reproductive medicine deals with reproductive health, fertility, and pregnancy-related conditions.

• Endometriosis — ectopic endometrial tissue, dysmenorrhea, laparoscopy
• Gestational Diabetes — IADPSG criteria, glucose screening, insulin management
• Infertility — male and female factors, IVF, assisted reproduction
• Ovarian Cysts — functional vs pathological, IOTA criteria, O-RADS
• Preeclampsia — hypertensive pregnancy disorder, HELLP, magnesium sulfate
• Uterine Fibroids — FIGO classification, UAE, myomectomy

Rheumatology

Rheumatology focuses on autoimmune and inflammatory diseases affecting joints and connective tissues.

• Arthritis — osteoarthritis, rheumatoid, DMARDs
• Lupus — SLE, ANA, multi-organ involvement
• Osteoporosis — DEXA scanning, bisphosphonates, fracture risk

Urology

Urology focuses on diseases of the urinary tract and the male reproductive system.

• Benign Prostatic Hyperplasia — IPSS scoring, alpha-blockers, 5-ARIs, TURP
• Bladder Cancer — urothelial carcinoma, TNM staging, BCG immunotherapy
• Erectile Dysfunction — PDE5 inhibitors, vascular and neurogenic causes
• Interstitial Cystitis — bladder pain syndrome, Hunner lesions
• Kidney Stones — calcium oxalate, uric acid, struvite, cystine
• Prostate Conditions — prostatitis, prostate cancer screening, PSA
• Urinary Tract Infections — cystitis, pyelonephritis, recurrent UTIs

Ear, Nose & Throat (ENT)

ENT covers conditions affecting the ears, nose, throat, and related structures.

• Sinusitis — acute and chronic, bacterial vs viral
• Tinnitus — ringing in the ears, management strategies

Ophthalmology

Ophthalmology addresses diseases and conditions of the eye and visual system.

• Cataracts — lens opacity, phacoemulsification, IOL implantation
• Glaucoma — intraocular pressure, optic nerve damage
• Macular Degeneration — AMD, anti-VEGF therapy

Symptoms

Common symptoms that point to underlying disease — descriptions, causes, evaluation, and research.

• Abdominal Pain or Discomfort — visceral, parietal, and referred pain by region
• Dark Urine — bilirubin, blood, myoglobin, and other causes
• Fatigue — acute, subacute, and chronic exhaustion
• Jaundice — pre-hepatic, hepatic, and obstructive yellowing
• Joint Pain — mechanical, inflammatory, crystal, and infectious arthritis
• Loss of Appetite — anorexia, cachexia, and the cytokine link
• Nausea and Vomiting — the vomiting reflex and antiemetic targets
• Pale Stool — acholic stool and biliary obstruction

Orthopedics

Orthopedics focuses on musculoskeletal disorders and injuries.

• Fibromyalgia — widespread pain, central sensitization
• Herniated Disc — radiculopathy, spinal stenosis
• Tendinitis — overuse injury, tendon inflammation

Genetics

Genetics covers inherited and de novo disorders — chromosomal, single-gene, and mitochondrial.

• Down Syndrome — trisomy 21, intellectual disability, congenital heart defects
• Marfan Syndrome — FBN1 fibrillin-1, aortic root dilation, tall stature
• Fragile X Syndrome — most common inherited intellectual disability, FMR1
• Ehlers-Danlos Syndrome — connective tissue disorder, hypermobility, skin fragility
• Turner Syndrome (45,X) — ovarian dysgenesis, short stature
• Phenylketonuria (PKU) — newborn screening, low-phenylalanine diet
• Neurofibromatosis Type 1 — café-au-lait spots, neurofibromas
• Osteogenesis Imperfecta — brittle bones, blue sclerae, bisphosphonates
• Tay-Sachs Disease — GM2 gangliosidosis, cherry-red spot
• Prader-Willi Syndrome — hyperphagia, obesity, hypotonia

Immunology

Immunology covers primary immunodeficiency diseases — inherited defects in immune defense, clearance, and regulation.

• Common Variable Immunodeficiency — most common symptomatic antibody deficiency in adults
• IgA Deficiency — most common primary immunodeficiency overall
• Severe Combined Immunodeficiency — profound T/B-cell failure, stem cell transplant
• Hereditary Angioedema — C1-inhibitor deficiency, laryngeal edema
• Mast Cell Activation Syndrome — multisystem mast-cell symptoms, POTS/EDS overlap
• Chronic Granulomatous Disease — NADPH oxidase defect, recurrent infections
• DiGeorge Syndrome (22q11.2) — thymic hypoplasia, T-cell lymphopenia
• Wiskott-Aldrich Syndrome — eczema, thrombocytopenia, immunodeficiency
• X-Linked Agammaglobulinemia — BTK mutation, B cells virtually absent

Bacteria

Profiles of major human bacterial pathogens — their biology, the diseases they cause, and treatment.

• Escherichia coli — foodborne illness, UTIs, Shiga-toxin strains
• Staphylococcus aureus — skin and soft-tissue infections, MRSA
• Helicobacter pylori — peptic ulcers, gastric cancer risk
• Streptococcus pyogenes — strep throat, rheumatic fever
• Clostridioides difficile — antibiotic-associated colitis
• Mycobacterium tuberculosis — tuberculosis, RIPE therapy
• Borrelia burgdorferi — Lyme disease
• Salmonella — foodborne gastroenteritis