Step 1 Basics (USMLE‪)‬ Sam Smith

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.

5.12 Anxiety Related Disorders
Psychiatry review for the USMLE Step 1 Exam
Anxiety is a normal response to threats or stressors in the environment Anxiety disorders occur when anxiety causes significant distress or impairment in functioning Generalized Anxiety Disorder (GAD) involves persistent and excessive worry about various aspects of daily life for at least 6 months, accompanied by physical symptoms Treatment for GAD typically involves a combination of cognitive-behavioral therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) Panic Disorder is diagnosed in individuals who experience spontaneous panic attacks and fear future attacks Panic attacks are acute episodes of intense anxiety and physical symptoms Treatment for Panic Disorder involves CBT and SSRIs, with SSRIs being the first-line medication Agoraphobia is the fear of being in public places where escape may be difficult and often follows a traumatic event CBT and SSRIs are the recommended treatment for Agoraphobia Social Anxiety Disorder (Social Phobia) involves fear of scrutiny or embarrassment in social situations Public speaking can be a significant trigger for individuals with social anxiety disorder Beta blockers can be used to treat social anxiety disorder by reducing physical symptoms Treatment for social anxiety disorder usually involves CBT, SSRIs, or beta blockers.