Medical: Hypocalcemia

abnormally low level of calcium in the blood; associated with hypoparathyroidism or kidney malfunction or vitamin D deficiency

hypocalcaemia is the presence of low serum calcium levels in the blood, usually taken as less than 2.2 mmol/L or 9mg/dl or an ionized calcium level of less than 1.1 mmol/L (4.5 mg/dL). It is a type of electrolyte disturbance. It mainly occurs due to a deficiency of parathyroid hormone, inefficient parathyroid hormone, or deficiency of Vitamin D. It may be seen alongside hypomagnesemia

DISTIBUTION OF CALCIUM IN THE BODY

A 70kg man has approx1000grams of calcium in his body, of this bone contains 99% of the total calcium1% in the extracellular and intracelluar fluid,only 1% of skeletal calcium is freely exchangable with extracellular fluid calcium

DISTRIBUTION OF CALCIUM IN THE SERUM

40% Is protein bound, 5-10% complexed to other substance e.g phosphate and sulphate and 50% is ionized

MAJOR HORMONES INVOLVED IN CALCIUM METABOLISM.

1)Parathairoid hormone.

2)Vitamin D

3)Calcitonin

FACTORS AFFECTING RENAL CALCIUM EXCREATION.

Renal calcium excretion  is increased by saline diuresis, Loop diuretics,and volume expansion, in contrast ,renal calcium excretion is decreased in volume depletion and other states associated with renal salt retension. 

Cause

• Absent parathyroid hormone (PTH)
• Hereditary hypoparathyroidism
• Acquired hypoparathyroidism(usually following tyroid or parathyroid surgery)
• Hypomagnesemia
• Ineffective PTH
• Chronic renal failure
• Absent active vitamin D
• Decreased dietary intake
• Decreased sun exposure
• Defective Vitamin D metabolism
• Anticonvulsant therapy
• Vitamin-D dependent rickets, type I
• Ineffective active vitamin D
• Intestinal malabsorption
• Vitamin-D dependent rickets, type II
• Pseudohypoparathyroidism
• Deficient PTH
• Severe acute hyperphosphatemia
• Tumor lysis syndrome
• Acute renal failure
• Rhabdomyolysis (initial stage)
• Osteitis fibrosa following parathyroidectomy
• Exposure to hydrofluoric acid ,medication such as protamine,heparin, and glucagons may cause transient hypocalcaemia

Signs and symptoms

Tetany and paraesthesia, alterd mental status(lethargic to coma)

Seizures. QT intaval prolongation on the ECG,increased intracranial pressure.

Lenticular

TROUSSEAU’S SIGN-a sphygmomanometer is placed on the arm and inflated to greater than systolic pressure, and let in place for at least 2 minutes,a posite response is carpal spasm of the ipsilateral arm .relaxation will take 5 to 10 seconds after the pressure s released.

CHEVOSTEK’S SIGN-tape the facial nerve between the corner of the mouth  an th zygomatic arch.a posive response is twiching of the ipsilateral facial muscle,especially the angle of the mouth.

TREATMENT

REPLACEMENT THERAPY. WITH VITAMIN D