Hypoparathyroidism: Low PTH Symptoms Include Muscle Cramps, Tingling, Seizures, and Cataracts

Hypoparathyroidism = insufficient parathyroid hormone (PTH) → hypocalcemia + hyperphosphatemia.

Causes

• Post-surgical (thyroidectomy, parathyroidectomy) – most common.
• Autoimmune (isolated or polyglandular syndrome type 1).
• Genetic (CaSR mutations, DiGeorge syndrome).
• Magnesium deficiency (impairs PTH secretion).
• Infiltrative (hemochromatosis, Wilson's, metastases).

Symptoms (from hypocalcemia)

• Neuromuscular: paresthesias (perioral, fingertips), carpopedal spasm, tetany, seizures, laryngospasm.
• Neuropsychiatric: anxiety, depression, brain fog, memory issues.
• Ectodermal: brittle nails, coarse hair, dry skin, cataracts (chronic).
• Dental: enamel hypoplasia, root shortening.
• Cardiac: QT prolongation, arrhythmias, heart failure.

Management

• Calcium carbonate/citrate + active vitamin D (calcitriol) – lifelong.
• Monitor: serum calcium, phosphorus, magnesium, creatinine, 24-hr urine calcium.
• PTH replacement (palopegteriparatide) – emerging therapy.

Acute severe hypocalcemia (tetany, seizures) = IV calcium gluconate emergency.