Step 1 Basics (USMLE)

4.11 Antibody Review Rheumatology review for the USMLE Step 1 Exam. ANA Principles ANA (Anti-Nuclear Antibody): Non-specific antibody. Reacts against nuclear antigens, including proteins, DNA, RNA, and nucleic acid-protein complexes. Includes a group of antibodies such as anti-dsDNA, anti-histone, SSA/Ro, SSB/La, Scl-70, anti-aminoacyl-tRNA synthetase (Jo-1). Found in 20-30% of the general public without connective tissue disorder symptoms. ANA+ individuals may or may not have a rheumatologic disorder. Further workup is needed in ANA+ cases to determine the specific disorder. Antibodies by Disease Process Systemic Lupus Erythematosus (SLE) Anti-dsDNA antibody. Anti-Smith antibody. Drug-Induced Lupus Anti-histone antibody. Diffuse vs. Limited Scleroderma Diffuse: Anti-Scl-70 (anti-topoisomerase I). Limited: Anti-centromere (often called CREST syndrome, with CREST standing for centromere). Sjogren's Syndrome Anti-SSA (Ro). Anti-SSB (La), which usually occurs in the presence of SSA. SSA is considered the Sjogren-specific antibody, leading to the presence of SSB. Rheumatoid Arthritis (RA) Anti-CCP (Cyclic Citrullinated Peptide). RF (Rheumatoid Factor) is non-specific. Thanks for listening!

4.10 Gout and Pseudogout Rheumotology review for the USMLE Step 1 Exam. Gout Caused by uric acid crystal deposition due to purine metabolism. Triggers inflammation when crystals precipitate in cooler joint fluid. Presents with severe, red, and swollen monoarticular joints, often in the big toe. Diagnosis through synovial fluid analysis. Acute treatment: colchicine, NSAIDs, and glucocorticoids. Preventive treatment: allopurinol, febuxostat, probenecid, and lifestyle changes. Pseudogout Resulting from calcium pyrophosphate crystal deposition, often due to ATP breakdown. Manifests with painful, swollen joints, typically affecting multiple upper extremity joints, especially the knee. Diagnosis through synovial fluid analysis. Acute treatment resembles gout management. No direct preventive treatment to lower calcium pyrophosphate levels. Thanks for listening!

4.09 Rheumatologic Emergencies Rheumatology review for USMLE Step 1 Exam Giant Cell Arteritis (GCA) A large vessel vasculitis, mainly in older individuals. Symptoms: headache, jaw claudication, vision loss. Ischemia from granulomas in large vessels causes vision loss. Immediate high-dose corticosteroids are crucial. Scleroderma Renal Crisis A complication of scleroderma. Symptoms: finger edema, skin tightening, sudden hypertension, rising creatinine. Renal artery fibrosis leads to high blood pressure. Treat with IV ACE inhibitor, not steroids. Acute Transverse Myelitis in SLE Inflammation of the spinal cord in lupus. Symptoms: bilateral numbness, tingling, weakness. Treat with corticosteroids. Catastrophic Antiphospholipid Syndrome (CAPS) A rare, life-threatening form of APS. Symptoms: unexplained miscarriages, unexplained clots, multiorgan failure. Treat with anticoagulation followed by immune suppression

1.06 Systolic Heart Murmurs Cardiovascular system review for the USMLE STEP 1 Exam Heart murmurs are caused by turbulent blood flow in the heart There are 4 different types of systolic murmurs: ventricular septal defect (VSD), patent ductus arteriosus (PDA), aortic stenosis, and mitral or tricuspid regurgitation PDA produces a constant, machine-like murmur VSD produces a harsh holosystolic murmur Aortic stenosis produces a crescendo-decrescendo systolic ejection murmur Mitral and tricuspid regurgitation produce a holosystolic high pitched "blowing" murmur Mitral valve prolapse produces a mid-systolic click followed by a late systolic murmur Aortic regurgitation produces a decrescendo diastolic murmur Mitral stenosis produces a rumbling diastolic murmur  

5.13 OCD and Related Disorders Psych review for the USMLE Step 1 Exam Obsessive Compulsive Disorder (OCD): Unwanted thoughts (obsessions) and repetitive behaviors (compulsions). Treat with CBT + SSRIs/SNRIs. Tic Disorders: Tourette Syndrome involves multiple motor and at least one vocal tic. Treat with Habit Reversal Therapy. Body Dysmorphic Disorder: Preoccupation with minor flaws, treat with SSRIs and CBT. Trichotillomania: Hair pulling disorder, treat with Habit Reversal Training and sometimes SSRIs. PANDAS: Pediatric disorder after strep infection, sudden OCD-like symptoms. Treat with antibiotics, CBT, and SSRIs.