endocrine and metabolic disorders
Hypocalcemia
Symptoms and Signs of Hypocalcemia
Hypocalcemia is frequently asymptomatic. The presence of hypoparathyroidism may be suggested by the clinical manifestations of the underlying disorder (eg, short stature, round facies, intellectual disability, basal ganglia calcification in type Ia pseudohypoparathyroidism; vitiligo with autoimmune hypoparathyroidism). Major clinical manifestations of hypocalcemia are due to disturbances in cellular membrane potential, resulting in neuromuscular irritability. Muscle cramps involving the back and legs are common. Insidious hypocalcemia may cause mild, diffuse encephalopathy and should be suspected in patients with unexplained dementia, depression, or psychosis. Papilledema occasionally occurs. Severe hypocalcemia with serum calcium<7 mg/dL (<1.75 mmol/L) may cause hyperreflexia, tetany, laryngospasm, or generalized seizures. Tetanycharacteristically results from severe hypocalcemia but can result from reduction in the ionized fraction of serum calcium without marked hypocalcemia, as occurs in severe alkalosis. Tetany is characterized by the following: Sensory symptoms consisting of paresthesias of the lips, tongue, fingers, and feet Carpopedal spasm, which may be prolonged and painful Generalized muscle aching Spasm of facial musculature Tetany may be overt with spontaneous symptoms or latent and requiring provocative tests to elicit. Latent tetany generally occurs at less severely decreased serum calcium concentrations: 7 to 8 mg/dL (1.75 to 2.20 mmol/L). Chvostek and Trousseau signs are easily elicited at the bedside to identify latent tetany. Chvostek signis an involuntary twitching of the facial muscles elicited by a light tapping of the facial nerve just anterior to the exterior auditory meatus. It is present in≤10% of healthy people and in most people with acute hypocalcemia but is often absent in chronic hypocalcemia. Trousseau signis the precipitation of carpal spasm by reduction of the blood supply to the hand with a tourniquet or blood pressure cuff inflated to 20 mm Hg above systolic blood pressure applied to the forearm for 3 minutes. Trousseau sign also occurs in alkalosis, hypomagnesemia, hypokalemia, and hyperkalemia and in about 6% of people with no identifiable electrolyte disturbance. Many other abnormalities may occur in patients with chronic hypocalcemia, such as dry and scaly skin, brittle nails, and coarse hair.Candidainfections occasionally occur in hypocalcemia but most commonly occur in patients with idiopathic hypoparathyroidism. Cataracts occasionally occur with long-standing hypocalcemia and are not reversible by correction of serum calcium. 