History
In neonates, hypocalcemia is more likely to occur in infants born of diabetic or preeclamptic mothers. Hypocalcemia also may occur in infants born to mothers with hyperparathyroidism.
Clinically evident hypocalcemia generally presents in milder forms and is usually the result of a chronic disease state. In emergency department patients, chronic or subacute complaints secondary to mild or moderate hypocalcemia are more likely to be a chief complaint than severe symptomatic hypocalcemia.
Once laboratory results demonstrate hypocalcemia, the first question is whether the hypocalcemia is true—that is, whether it is representative of a decrease in ionized calcium. The presence of chronic diarrhea or intestinal disease (eg, Crohn disease, sprue, chronic pancreatitis) suggests the possibility of hypocalcemia due to malabsorption of calcium and/or vitamin D.
The patient's past medical history should be explored for pancreatitis, anxiety disorders, kidney or liver failure, gastrointestinal disorders, and hyperthyroidism or hyperparathyroidism. Previous neck surgery suggests hypoparathyroidism; a history of seizures suggests hypocalcemia secondary to anticonvulsants. The patient may have a recent history of thyroid, parathyroid, or bowel surgeries or recent neck trauma.
The length of time that a disorder is present is an important clue. Hypoparathyroidism and pseudohypoparathyroidism are lifelong disorders. Instead, acute transient hypocalcemia may be associated with acute gastrointestinal illness, nutritional deficiency, or acute or chronic renal failure.
In an elderly patient, a nutritional deficiency may be associated with a low intake of vitamin D. A history of alcoholism can help diagnose hypocalcemia due to magnesium deficiency, malabsorption, or chronic pancreatitis.
Inquire about recent use of drugs associated with hypocalcemia, including the following:
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Radiocontrast
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Estrogen
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Loop diuretics
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Bisphosphonates
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Calcium supplements
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Antibiotics
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Antiepileptic drugs
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Cinacalcet
Other considerations in the history include the following:
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Family history of hypocalcemia
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Low-calcium diet
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Lack of sun exposure
Acute hypocalcemia may lead to syncope, chronic heart failure (CHF), and angina due to the multiple cardiovascular effects. [38] Neuromuscular and neurologic symptoms may also occur. [39] Neuromuscular symptoms include the following [40] :
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Numbness and tingling sensations in the perioral area or in the fingers and toes
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Muscle cramps, particularly in the back and lower extremities; may progress to carpopedal spasm (ie, tetany)
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Wheezing; may develop from bronchospasm
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Dysphagia
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Voice changes (due to laryngospasm)
Neurologic symptoms of hypocalcemia include the following [41] :
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Irritability, impaired intellectual capacity, depression, and personality changes
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Fatigue
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Seizures (eg, grand mal, petit mal, focal)
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Other uncontrolled movements
Chronic hypocalcemia may produce the following dermatologic manifestations:
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Coarse hair
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Brittle nails
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Psoriasis
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Dry skin
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Chronic pruritus
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Poor dentition
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Cataracts
Physical Examination
Neuromuscular and cardiovascular findings predominate. Neural hyperexcitability due to acute hypocalcemia causes smooth and skeletal muscle contractions. In addition, patients may appear confused or disoriented and may exhibit signs of dementia or overt psychosis. Irritability, confusion, hallucinations, dementia, extrapyramidal manifestations, and seizures may occur.
On head and neck examination, the hair may appear coarse, and alopecia may be present. Signs of recent trauma or of surgery of the neck (eg, scars over the thyroid region) should be noted. Perioral anesthesia may be present, and adults with chronic (since childhood) hypocalcemia may be at an increased risk for dental caries and enamel hypoplasia. On eye examination, subcapsular cataracts or papilledema may be seen.
On respiratory examination, inspiratory or expiratory wheezes may be present. Smooth muscle contraction may lead to laryngeal stridor, dysphagia, and bronchospasm. On cardiac examination, bradycardia, tachycardia, S3, and signs of heart failure may be present. [42]
Dry skin or patches of psoriasis and eczema may be present, particularly in patients with chronic hypocalcemia. Excoriations as a result of pruritus may be noted. Test for Chvostek sign by tapping the skin over the facial nerve about 2 cm anterior to the external auditory meatus. Ipsilateral contraction of the facial muscles is a positive sign. Depending on the calcium level, a graded response will occur: twitching first at the angle of the mouth, then by the nose, the eye, and the facial muscles. Up to 10% of the population will have a positive Chvostek sign in the absence of hypocalcemia; thus, this test, while suggestive, is not diagnostic of hypocalcemia.
Test for the Trousseau sign by placing a blood pressure cuff on the patient’s arm and inflating to 20 mm Hg above systolic blood pressure for 3-5 minutes. This increases the irritability of the nerves, and a flexion of the wrist and metacarpal phalangeal joints can be observed with extension of the interphalangeal joints and adduction of the thumb (carpal spasm). The Trousseau sign is more specific than the Chvostek sign but has incomplete sensitivity.
Movement abnormalities associated with hypocalcemia include the following:
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Choreoathetosis [43]
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Dystonic spasm
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Parkinsonism
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Hemiballism
Peripheral nervous system findings include tetany, focal numbness, and muscle spasms. Smooth muscle contraction causes biliary colic, intestinal colic, and dysphagia. Seizures often occur in individuals with preexistent epileptic foci when the excitation threshold is lowered.
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Electrocardiogram (ECG) findings in severe hypocalcemia.
