USMLE/COMLEX 2 - Hypokalemia Management

Here are key facts for USMLE Step 2 & COMLEX-USA Level 2 from the Hypokalemia 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.

• --

1. K+ < 3.5 mEq/L. 2. Severity classification guides management approach:

• Mild/Moderate: K+ 3.0-3.4 mEq/L
• Severe/Symptomatic: K+ < 3 mEq/L

1. Muscle manifestations: Cramps, weakness, rhabdomyolysis 2. Cardiac complications: Premature beats, arrhythmias 3. Diagnostic ECG findings: U waves, flattened T waves 1. IV replacement therapy: 20 to 60 mEq KCl in saline 2. Critical administration rate: Not exceeding 10-20 mEq/hr to prevent peripheral vein irritation 3. Monitoring protocol: Close monitoring with ECG if arrhythmias present

• --

1. Oral replacement regimen: K+ supplements – 10-20 mEq, 2-4× daily (maximum 80 mEq/day) 2. Nutritional intervention: Increase intake of K+-rich foods 1. Identification of underlying etiology:

• Address gastrointestinal losses
• Manage diuretic therapy
• Consider renal function during replacement

2. Therapeutic goals:

• Maintain K+ between 3.5-5 mEq/L
• Carefully adjust treatment to avoid hyperkalemia and arrhythmias

3. Advanced management considerations:

• Evaluate and correct magnesium deficiency
• Consider potassium-sparing diuretics (e.g., amiloride) in renal losses
• Personalize treatment based on comorbidities and clinical status

• --

Below is clinical information essential for USMLE Step 2 CK beyond what's explicitly contained in the tutorial. 1. History and physical: Focus on medications, GI symptoms, and blood pressure 2. Laboratory workup: Assess acid-base status, magnesium, and calcium levels 3. Urinary potassium: Helps differentiate renal from non-renal causes (TTKG calculation) 4. ECG interpretation: Serial ECGs to monitor for QT prolongation and arrhythmias 1. Diuretic management: Protocol for monitoring K+ in patients on chronic diuretic therapy 2. Perioperative concerns: Risks of hypokalemia during anesthesia and surgery 3. Emergency presentations: Management of hypokalemic periodic paralysis 4. Special populations: Considerations in renal failure, heart failure, and liver disease 1. Rebound hyperkalemia: Risk factors and prevention strategies 2. IV infiltration: Management of extravasation of potassium solutions 3. Enteric-coated preparations: GI complications and alternative formulations 4. Drug interactions: ACE inhibitors, ARBs, and NSAIDs effects on potassium levels 1. Prophylactic supplementation: Indications in high-risk patients 2. Patient education: Dietary counseling and medication adherence 3. Monitoring protocols: Frequency of laboratory testing based on risk factors 4. Combination therapy: Role of potassium-sparing with potassium-wasting diuretics