USMLE/COMLEX 2 - Hypocalcemia Management

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

VITAL FOR USMLE/COMLEX 2

Clinical Definition and Classification

1. Definition: Serum Ca < 8.5 mg/dL 2. Clinical categories:

Chronic/Mildly Symptomatic: Ca > 7.5 mg/dL
Acute/Symptomatic: Ca ≤ 7.5 mg/dL

Management of Acute Hypocalcemia

1. IV calcium replacement: IV bolus 1-2 g calcium gluconate 2. Continuous infusion: Followed by 1000 ml infusion of 1 mg/ml elemental calcium at 50mg/hr 3. Daily monitoring: Measure serum calcium levels daily

Management of Chronic Hypocalcemia

1. Oral supplementation: 1-2 g of calcium gluconate daily, divided doses 2. Regular monitoring: Monitor serum calcium weekly

Clinical Manifestations

1. Neuromuscular symptoms: Muscle spasms, tingling, lethargy, seizures 2. Cardiac manifestations: QT interval prolongation

HIGH YIELD

Etiology

1. Parathyroid disorders: Hypoparathyroidism 2. Nutritional deficiencies: Vitamin D deficiency 3. Renal disorders: Chronic kidney disease

Treatment Principles

1. Post-stabilization care: Switch to oral calcium after IV stabilization 2. Specialized treatment: Initiate calcitriol with oral calcium for hypoparathyroidism 3. Associated electrolyte correction: Correct hypomagnesemia

Management Pearls

1. Route selection: IV for acute/symptomatic (Ca ≤ 7.5 mg/dL), oral for chronic/mild (Ca > 7.5 mg/dL) 2. Dosing strategy: Divided doses for oral calcium supplementation 3. Special considerations: Different management approaches based on etiology (hypoparathyroidism vs. other causes)

Beyond the Tutorial

Below is information not explicitly contained within the tutorial but important for USMLE & COMLEX 2.

Diagnostic Approach

1. Physical examination: Assess for Chvostek's and Trousseau's signs 2. Laboratory workup: Measure ionized calcium, PTH, vitamin D, magnesium, phosphate 3. ECG evaluation: Assess for QT prolongation and other cardiac abnormalities

Cause-Specific Management

1. Post-surgical hypoparathyroidism: Long-term calcium and vitamin D supplementation 2. Vitamin D deficiency: High-dose vitamin D replacement (50,000 IU weekly for 8 weeks) 3. CKD-related hypocalcemia: Phosphate binders, vitamin D analogs, calcimimetics

Complications Management

1. Hypocalcemic seizures: Immediate IV calcium and anticonvulsant therapy 2. Laryngospasm: Emergency airway management and rapid calcium correction 3. Cardiac arrhythmias: Cardiac monitoring during correction

Special Populations

1. Pregnant patients: Higher calcium requirements, risk of neonatal complications 2. Elderly patients: Increased risk of vitamin D deficiency, careful dosing to avoid hypercalcemia 3. Critical illness: More frequent monitoring, potential for calcium-medication interactions