USMLE/COMLEX 2 - Nausea, Vomiting, Diarrhea

Here are key facts for USMLE Step 2 & COMLEX-USA Level 2 from the Nausea, Vomiting, Diarrhea tutorial, as well as points of interest at the end of this document that are not directly addressed in this tutorial but should help you prepare for the boards. See the tutorial notes for further details and relevant links.

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1. Nausea and vomiting: Assess for dehydration, electrolyte imbalances, and potential complications like aspiration and esophageal tears 2. Diarrhea: Evaluate for malabsorption of nutrients, dehydration, and electrolyte abnormalities 1. Medication-induced: Antibiotics, opioids, antidepressants, vitamins and mineral supplements, NSAIDs, chemotherapy 2. Obstructive processes: Mechanical GI obstructions including adhesions, volvulus, foreign bodies, hernias, tumors 3. Neurological causes: Central nervous disorders (migraines, infections, increased intra-cranial pressure) 4. Systemic conditions: Early pregnancy hormonal changes, motion sickness 1. Malabsorptive disorders: Lactose intolerance, celiac disease, pancreatic insufficiency 2. Inflammatory conditions: Inflammatory bowel disease (Crohn's disease with mucous diarrhea, ulcerative colitis with bloody diarrhea), microscopic colitis 3. Neoplastic causes: Neuroendocrine tumors producing carcinoid syndrome 1. Infectious gastroenteritis: Key pathogens include norovirus, rotavirus, E. coli, Salmonella, Shigella, and Campylobacter 2. Vascular pathology: Intestinal ischemia from blocked mesenteric arteries 3. Functional disorders: Irritable bowel syndrome from disordered brain-gut communication 4. Endocrine disturbances: Thyroid disorders, adrenal insufficiency, and diabetes

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1. Esophageal achalasia: Presents with heartburn, chest pain, and regurgitation due to sustained lower esophageal sphincter contraction 2. Gastroparesis: Patients feel full after eating small amounts of food and experience heartburn and vomiting due to vagus nerve damage 3. Cyclical vomiting syndrome: Recurring severe episodes of vomiting triggered by stress, often beginning in childhood 1. Steatorrhea: Oily, foul smelling stools that are yellowish and float due to high fat content, characteristic of pancreatic insufficiency 2. Carcinoid syndrome: Presents with watery, loose stools, flushing, wheezing, and valvular heart disease in 30-40% of neuroendocrine tumor patients 3. IBD patterns: Differentiate between Crohn's disease (mucous diarrhea) and ulcerative colitis (bloody diarrhea) 1. Early pregnancy: "Morning sickness" can occur throughout the day due to first trimester hormonal changes 2. Motion sickness: Results from mismatch between expected and experienced sensory inputs 3. Intestinal ischemia: Can present with the triad of nausea, vomiting and bloody diarrhea when mesenteric arteries become blocked 1. Vomiting complications: Monitor for and prevent aspiration, dehydration, electrolyte imbalance, undernutrition, and esophageal tears 2. Diarrhea sequelae: Address malabsorption, dehydration, and electrolyte abnormalities

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Below is information not explicitly contained within the tutorial but important for USMLE & COMLEX 2. 1. History and physical examination: Key elements to differentiate organic from functional disorders 2. Laboratory evaluation: Targeted testing based on suspected etiology 3. Endoscopic procedures: Indications and findings in various conditions 1. Antiemetics: Pharmacologic approach to different causes of nausea and vomiting 2. Antidiarrheals: When to use and when to avoid 3. Disease-modifying therapies: Management of underlying conditions 1. Pediatric considerations: Dehydration assessment and management 2. Geriatric patients: Medication interactions and comorbidity management 3. Pregnancy: Safety considerations for diagnostic and therapeutic interventions 1. Guidelines: Current recommendations for acute and chronic management 2. Red flags: Indicators for urgent evaluation and intervention 3. Follow-up protocols: Monitoring for resolution or progression