What is the diagnosis and treatment for a patient with a positive Trousseau's sign?

Diagnosis and Treatment of Hypocalcemia with Positive Trousseau's Sign

The diagnosis for a patient with a positive Trousseau's sign is hypocalcemia, which requires immediate treatment with calcium supplementation to prevent life-threatening complications.

Diagnosis

A positive Trousseau's sign is a highly specific indicator of hypocalcemia, characterized by carpopedal spasm induced by inflating a blood pressure cuff above systolic pressure for 3 minutes. This clinical finding warrants immediate evaluation and treatment.

Clinical Manifestations of Hypocalcemia:

• Neuromuscular irritability
• Paresthesias (tingling around mouth, fingers)
• Positive Chvostek's sign (facial muscle spasm when tapping facial nerve)
• Positive Trousseau's sign
• Bronchospasm
• Laryngospasm
• Tetany
• Seizures
• In severe cases: speechlessness, hoarseness 1

Laboratory Assessment:

1. Serum calcium level (total and ionized if available)
2. Albumin level - essential for calcium correction
   • Corrected calcium (mg/dL) = Total calcium (mg/dL) + 0.8 × [4 - Serum albumin (g/dL)] 2
3. Serum magnesium - hypomagnesemia can cause or worsen hypocalcemia
4. Serum phosphorus - often elevated in hypocalcemia
5. Intact PTH level - to determine if primary or secondary hypocalcemia
6. Vitamin D levels (25-OH and 1,25-OH if available)
7. Renal function tests
8. Arterial blood gases - to assess for metabolic alkalosis

Treatment Algorithm

Immediate Management for Symptomatic Hypocalcemia:

1. For severe symptoms (tetany, seizures, laryngospasm):

   • Administer IV calcium gluconate 10% solution: 10-20 mL (1-2 ampules) over 10-20 minutes
   • Monitor cardiac function during administration (risk of arrhythmias)
   • Follow with continuous calcium infusion: 1-2 mg/kg/hr elemental calcium 2

2. For moderate symptoms:

   • IV calcium gluconate 10%: 10 mL over 10 minutes
   • Repeat as needed based on symptoms and calcium levels

Maintenance Therapy:

1. Oral calcium supplementation:

   • Calcium carbonate (40% elemental calcium): 1,000-1,500 mg elemental calcium daily
   • Divide into 2-3 doses for better absorption
   • Total elemental calcium intake should not exceed 2,000 mg/day 2

2. Vitamin D supplementation (if deficient):

   • Cholecalciferol (vitamin D3): 1,000-2,000 IU daily
   • For severe deficiency: consider higher doses under medical supervision
   • In hypoparathyroidism: calcitriol (active vitamin D) 0.25-1 μg daily

3. Magnesium replacement (if hypomagnesemic):

   • Oral magnesium oxide or magnesium citrate: 400-800 mg daily
   • For severe deficiency: IV magnesium sulfate

Monitoring:

• Check serum calcium levels every 4-6 hours initially for symptomatic patients
• Once stable, monitor every 1-2 days until normalized
• Long-term monitoring every 3 months 2
• Target calcium levels in normal range (8.4-9.5 mg/dL)

Underlying Causes of Hypocalcemia

Identifying and treating the underlying cause is crucial:

1. Hypoparathyroidism:

   • Post-surgical (most common)
   • Autoimmune
   • Genetic disorders

2. Vitamin D deficiency or resistance:

   • Nutritional deficiency
   • Malabsorption syndromes
   • Renal or hepatic disease

3. Magnesium disorders:

   • Hypomagnesemia can cause functional hypoparathyroidism

4. Renal disorders:

   • Chronic kidney disease
   • Acute kidney injury

5. Other causes:

   • Medication-induced (bisphosphonates, denosumab)
   • Tumor lysis syndrome
   • Pancreatitis
   • Rhabdomyolysis 1

Special Considerations

• Hypomagnesemia must be corrected before calcium replacement will be effective 2
• Avoid rapid correction of severe chronic hypocalcemia to prevent neurological complications
• Monitor phosphate levels and maintain calcium-phosphorus product <55 mg²/dL² to prevent tissue calcification, especially in CKD patients 2
• Consider rare causes such as Gitelman's syndrome which can present with hypocalcemic tetany despite typically being associated with normal calcium levels 3
• Beware of hypokalemia-induced tetany which can present with positive Trousseau's sign even in the absence of alkalosis 4

Hypocalcemia with positive Trousseau's sign represents a significant electrolyte disturbance that requires prompt diagnosis and treatment to prevent serious complications including life-threatening laryngospasm and seizures.