What are the symptoms of hypocalcemia?

Symptoms of Hypocalcemia

Hypocalcemia manifests primarily through neuromuscular irritability, with paresthesias (tingling/numbness) of the hands, feet, and perioral region being the most common early symptoms, progressing to muscle cramps, tetany, seizures, and potentially life-threatening cardiac arrhythmias in severe cases. 1

Neuromuscular Manifestations

The neuromuscular system is most characteristically affected by low calcium levels:

• Paresthesias (tingling and numbness) affecting the hands, feet, and perioral (around the mouth) region are among the earliest and most common symptoms 1
• Muscle cramps and spasms occur frequently, particularly in the lower legs and feet 1, 2
• Tetany represents more severe neuromuscular irritability, clinically detectable through Trousseau sign (carpal spasm after blood pressure cuff inflation) or Chvostek sign (facial twitching with facial nerve tapping) 2
• Seizures may be the first presenting sign, especially in patients with pre-existing seizure disorders 1

Neuropsychiatric Symptoms

Calcium plays a critical role in neurotransmitter release, leading to diverse neurological manifestations:

• Irritability and emotional changes are common neurological symptoms 1
• Confusion or altered mental status can occur with severe hypocalcemia 1
• Behavioral changes including anxiety or depression may be associated with hypocalcemia and can be confused with primary psychiatric conditions 1
• Fatigue is a subtle early symptom 2
• Abnormal involuntary movements of any type may be confused with other neurologic conditions 2

Cardiovascular Manifestations

Cardiac involvement can be life-threatening and requires immediate recognition:

• Prolonged QT interval on electrocardiogram is a common and critical finding that predisposes to dangerous ventricular arrhythmias 1, 2
• Cardiac arrhythmias, including ventricular tachycardia and fibrillation, can occur 1
• Cardiomyopathy is a rare complication of chronic hypocalcemia 1
• Hypotension, bradycardia, and cardiac arrest can occur in severe cases 3

Special Population Considerations

Neonates

• Jitteriness and hypotonia in the first 24-48 hours may be early manifestations 2
• Most early neonatal hypocalcemia (first 24-48 hours) is asymptomatic and results from interrupted placental calcium transfer and delayed PTH surge 2
• Late-onset hypocalcemia (after 72 hours) is more likely to be symptomatic and related to excessive phosphate intake, maternal vitamin D deficiency, or hypomagnesemia 2

High-Risk Periods

The American College of Medical Genetics and Genomics emphasizes that hypocalcemia risk increases during biological stress 1:

• Surgery, childbirth, or infection 1
• Perioperative periods and acute illness 1
• Puberty and pregnancy 1
• Patients receiving large volume blood transfusions (citrate chelates calcium) 2

Important Clinical Pitfalls

• Symptoms may be confused with psychiatric conditions such as depression or anxiety, delaying appropriate diagnosis and treatment 1
• Measure pH-corrected ionized calcium (most accurate) rather than total calcium alone, as ionized calcium is the physiologically active fraction 1, 2
• Always check magnesium levels in hypocalcemic patients, as hypomagnesemia impairs PTH secretion and creates PTH resistance—hypocalcemia will not resolve until magnesium is corrected 2, 4
• Patients can have magnesium deficiency despite normal serum concentrations since less than 1% of total body magnesium is in extracellular fluids 4