What are the symptoms and treatment of hypocalcemia?

Symptoms of Hypocalcemia

Hypocalcemia presents with neuromuscular irritability as its hallmark feature, ranging from mild paresthesias to life-threatening tetany, seizures, and cardiac arrhythmias. 1

Neuromuscular Symptoms

The most common manifestations involve increased neuronal excitability:

• Paresthesias (tingling/numbness) affecting the hands, feet, and perioral region are classic early symptoms 1
• Muscle cramps and spasms occur frequently and can progress to painful tonic contractions 1
• Tetany represents severe neuromuscular irritability with focal or generalized tonic muscle cramps 2
• Laryngospasm can occur in severe cases, representing a medical emergency 2
• Seizures may be the first presenting sign, particularly in patients with pre-existing seizure disorders 1

Neuropsychiatric Manifestations

Calcium deficiency affects central nervous system function:

• Irritability and emotional changes are common neurological symptoms 1
• Confusion or altered mental status develops in severe hypocalcemia 1
• Behavioral changes including anxiety or depression can occur and may be confused with primary psychiatric conditions 1
• Movement disorders including dystonia, myoclonus, tremors, motor tics, and parkinsonism-like symptoms can develop, particularly affecting the basal ganglia 3

Cardiovascular Symptoms

Cardiac manifestations require immediate attention:

• Prolonged QT interval on electrocardiogram is a common finding 1, 2
• Cardiac arrhythmias including ventricular tachycardia and fibrillation can occur 1
• Myocardial dysfunction may develop in severe cases 2
• Cardiomyopathy is a rare but serious complication 1

High-Risk Periods and Precipitating Factors

Symptoms are more likely to manifest during:

• Biological stress including surgery, childbirth, infection, fractures, or injuries 1, 3
• Perioperative periods, acute illness, puberty, and pregnancy 1
• Decreased oral intake or consumption of alcohol and carbonated beverages (especially colas) 1, 3

Clinical Pitfalls to Avoid

• Psychiatric misdiagnosis: Symptoms may be mistaken for primary depression or anxiety disorders 1
• Special populations: Patients with 22q11.2 deletion syndrome have an 80% lifetime prevalence of hypocalcemia and are at particularly high risk for movement disorders 1, 3
• Severity assessment: Even mild symptoms warrant evaluation, as hypocalcemic tetany can rapidly progress to life-threatening complications 4, 2

Diagnostic Approach

When hypocalcemia is suspected:

• Measure pH-corrected ionized calcium (most accurate diagnostic test) 1, 3
• Check parathyroid hormone (PTH) levels to determine if hypoparathyroidism is present 1
• Assess magnesium levels, as hypomagnesemia can cause or worsen hypocalcemia 1, 2
• Monitor thyroid function and renal function (creatinine) 1
• Obtain ECG to evaluate for QT prolongation and arrhythmias 1

Treatment Based on Severity

Acute Symptomatic Hypocalcemia

• Administer 10% calcium chloride (270 mg elemental calcium per 10 mL) or calcium gluconate 100-200 mg elemental calcium intravenously 1, 2
• Monitor cardiac rhythm during rapid calcium administration due to arrhythmia risk 1, 5
• Central venous access is preferred for severe cases to avoid extravasation complications 6

Chronic Hypocalcemia Management

• Daily calcium and vitamin D supplementation forms the cornerstone of chronic management 1, 4
• Calcitriol dosing: Start with 0.5 μg daily in patients >12 months old, or 20-30 ng/kg body weight daily 1
• Magnesium supplementation if hypomagnesemia is present (magnesium must be corrected before calcium will normalize) 1, 2
• Monitor calciuria levels to keep within normal range and prevent nephrocalcinosis 1

Critical Monitoring Points

• Avoid overcorrection: Hypercalcemia can lead to renal calculi and renal failure 1, 3
• Target low-normal calcium range in hypoparathyroidism to minimize hypercalciuria 4
• Increased surveillance during vulnerable periods (surgery, pregnancy, acute illness) 1