Hypocalcaemia

What is Hypocalcaemia?

Low level of Calcium in the blood is called Hypocalcaemia. Normal blood Calcium is 8.5 – 10.2 mg/dl. In normal health blood calcium is maintained in this range and the normal mechanism is that most of the Calcium is bound to albumin (proteins) and hence before assessing the normal calcium levels , the albumin levels have to be known.

Why is it important for blood Calcium to be normal ?

Calcium is important for a variety of normal physiological activities like muscle contraction, nerve conduction, blood coagulation and release of enzymes & hormones. When the level of blood calcium falls theses activities can be affected

What are the symptoms/ signs of hypocalcaemia?

The symptoms of hypocalcaemia are as follows:

Nerve function

Mental status

Skin changes

Cardiac changes

Fatigue

Confusion

Dry skin & nails

Ventricular arrhythmias

Anxiety

Psychosis

Brittle nails

Prolonged QT interval

Muscle cramps

Atopic eczema

Torsadepointes

Polymyositis

Psoriasis

Paraesthesias

Enamel hypoplasia

The clinical signs of hypocalcaemia are:
1. Chovstek’s sign
is elicited by tapping over the facial nerve approximately 20 mm anterior to the ear lobe below the zygomatic arch.

2. Trosseau’s sign represents carpal spasm secondary to ischaemia of the ulnar and median nerves in response to inflation of sphygmomanometer to 20 mm of Hg over systolic blood pressure.

hypocalcaemia-sign2

CHOVSTEK’S SIGN hypocalcaemia TROUSSEAU’S SIGN


What are the causes of hypocalcaemia?

While there are many causes of low calcium, the most common is due to destruction to the parathyroid glands, either due to a developmental defect in the fetus or after neck surgery or irradiation. Antibodies to tissue components of the parathyroid gland can also develop, affecting the ability of the glands to make parathyroid hormone.

Other causes include

    • Vitamin D deficiency – nutritional lack, malabsorption, liver disease, receptor defects

    • Vitamin D resistance (rickets) – renal tubular dysfunction (Fanconi’s syndrome) or receptor defect

    • PTH resistance (pseudo hypoparathyroidism), hypomagnesaemia

    • Drugs – calcium chelators (citrate in blood transfusion)

    • Bone resorption inhibitors (bisphosphonates, calcitonin, plicamycin)

    • Drugs affecting vitamin D (phenytoin, ketaconazole), foscarnet

    • Others – acute pancreatitis, acute rhabdomyolysis, massive tumour breakdown, osteoblastic metastases, toxic shock syndrome, hyperventilation

What are the investigations necessary?

Fasting blood sample for

  1. S.calcium

  2. S.Phosphate

  3. Alkaline phosphate

  4. PTH

  5. S.Magnesium

  6. Vitamin D levels

  7. Liver function tests

  8. Renal function tests

What is the treatment of hypocalcaemia ?

Hypocalcaemia is an endocrine emergency. During the acute period IV calcium infusion is to be given. This can be followed later on by calcium and Vitamin D supplementations. During the acute period blood calcium will have to be checked very frequently, once stabilized, less frequent monitoring is sufficient. Once stable, calcium will have to be checked less frequently say once or twice a year. Once a dose change is made it is advisable to check calcium two to three weeks later.

Are there any risks of treatment?

The main risk of treatment with Vit.D/calcium supplementation is that the blood level of calcium can go up above normal. This should not happen if the medication has been started after the right diagnosis and if the monitoring is regular. Once there are symptoms of high blood calcium like thirst, increased urination, constipation etc. it is advisable to get a blood level checked immediately and adjust the calcium supplementation.