Hypocalcemia: Causes and Clinical Features

00:01 Let's go through the causes of hypocalcemia.

00:04 Parathyroid surgery and the hungry bone syndrome are classic causes of low serum calcium.

00:12 Patient's who've had neck irradiation, likewise may have damage to their parathyroid gland, also immune damamge to the thyroid gland as well, infiltrative diseases of the thyroid gland as one may rarely see in cases of sarcoidosis or lymphomas, hemochromatosis or Wilson's disease, pseudohypercalcemia caused by low albumin state, patients with malignancies undergoing plasmapheresis, those individuals with vitamin D deficiency or low magnesium, as well as patients with pancreatitis who can have saponification of calcium within the gland due to extreme exacerbations that lead to a low serum calcium.

00:54 Rhabdomyolysis is another classical example as is most causes of kidney injury and finally, the tumor lysis syndrome.

01:03 The clinical features of hypercalcemia are also based on the level of calcium obtained.

01:11 There really are minimal symptoms when the level lies in the range of 7.5 to 8.9 mg/dL Most patients report symptoms of intermittent paresthesias of the hands or feet or perioral numbness.

01:27 Hypocalcemia due to chronic hypoparathyroidism can also be associated with cataract formation, basal ganglia calcification, papilledema and dental enamel hyperplasia.

01:40 As the calcium level decreases further, patients may present with neuromuscular symptoms and signs.

01:46 Carpopedal spasms is the classic example.

01:50 Here there is flexion at the metacarpophalangeal joints and extension at the interphalangeal joints.

01:56 Spontaneous or triggered by transient distal limb ischemia during blood pressure assesment can cause this carpopedal spasm, and this is classically known as Trousseau's sign.

02:08 Facial nerve hyperirritability and muscle spasm demonstrated by percussion of the facial nerve just anterior to the ear is known as Chovstek's sign.

02:20 Laryngospasm, seizures and even myocardial dysfunction which may cause sudden cardiac death due to severe hypocalcemia usually occur in ranges of calcium lower than 7.5 mg/dL