USMLE/COMLEX 2 - Hyponatremia Management

undefined Here are key facts for USMLE Step 2 & COMLEX-USA Level 2 from the Acute Hyponatremia Management 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. Timeline classification: From the document, hyponatremia is categorized as acute when developed within last 48 hours, and chronic when longer than 48 hours. 2. Neurological manifestations: From the tutorial's key symptoms section, acute hyponatremia presents with cognitive symptoms (confusion, seizures, and coma), motor symptoms (ataxia or tremor), and GI symptoms (nausea or vomiting). 3. Physical examination: From the key physical exam findings section, look for peripheral edema from volume overload and cerebral edema which can manifest with neurological signs of coma. 4. Severity stratification: From the severity section, classify as severe (<120 mEq/L), moderate (120-130 mEq/L), or mild (130-135 mEq/L). 1. Treatment threshold: From the treatment indication section, acute hyponatremia should be treated when sodium is <130 mEq/L. 2. Correction rate goal: From the general goal section, aim for 5 mEq/L increase over the first few hours but avoid over-correction over 24 hours. 3. Symptomatic emergency treatment: From the symptomatic section, give rapid 100 mL 3% hypertonic saline infusion (over 10 minutes) to any acutely symptomatic patient due to risk of cerebral edema. 4. Monitoring frequency: From the general goal section, monitoring should be close (hourly) to avoid complications of treatment.

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1. Common acute causes: From the common acute causes section, identify IV fluid overload in surgery and water intoxication (marathon runners, psychotic polydipsia). 2. Medication causes: From the additional management section, look for medications that could be contributing, specifically thiazide diuretics. 3. SIADH triggers: From the additional management section, consider recent surgery, pain, and certain medications as possible causes of SIADH. 1. Asymptomatic management: From the asymptomatic section, for patients without acute symptoms, use 50 mL of 3% saline, check sodium hourly, and repeat bolus if needed. 2. Autocorrection monitoring: From the autocorrecting section, if hyponatremia is already autocorrecting from water diuresis, NO saline bolus is needed - just monitor hourly targeting a 5 mEq/L increase. 3. Fluid management: From the additional management section, stop other IV fluids to avoid worsening the hyponatremia. 4. Water restriction: From the additional management section, restrict any electrolyte-free water intake. 5. Prevention of complications: From the general goal section, the key principle is to "treat rapidly, early, monitor closely (hourly) and then level off to give the brain a chance to adapt and avoid osmotic demyelination." 6. SIADH management: From the additional management section, in SIADH, consider additional treatments including salt tablets and loop diuretics. 1. Underlying cause investigation: From the additional management section, look for any underlying causes including medications and conditions that can cause SIADH. 2. Hourly monitoring: From multiple sections, sodium levels should be checked hourly during acute correction.

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Below is information not explicitly contained within the tutorial but important for USMLE & COMLEX 2. 1. Osmotic demyelination prevention: When correcting chronic hyponatremia or in high-risk patients (alcoholics, malnourished), slower correction rates may be needed. 2. Overcorrection management: If overcorrection occurs, consider DDAVP and hypotonic fluids to re-lower sodium levels. 3. Risk stratification: Patients with liver disease, alcoholism, malnutrition, or hypokalemia have higher risk for osmotic demyelination with rapid correction. 1. Volume status assessment: Aids in differentiating between hypovolemic, euvolemic, and hypervolemic hyponatremia. 2. When to consult nephrology: For refractory cases, complex electrolyte disorders, or when dialysis might be needed. 3. Follow-up monitoring: After initial correction, continued monitoring needed with frequency based on clinical response.