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HYPOCALCAEMIA What is hypocalcaemia? Hypocalcaemia means low circulating blood calcium.
It is most commonly observed in eclampsia, or so-called milk fever, which
may occur in bitches at any time during lactation or sometimes immediately
before they whelp. However
hypocalcaemia can occur due to other causes. Why is calcium important? Calcium is of major importance in the transmission of nerve impulses
across the neuoromuscular junction and in muscle
contraction. It is also one of the
most important minerals in bone. How is low blood calcium diagnosed? A simple blood test is all that is necessary which will reveal the total amount of circulating calcium. In the normal animal this should be between 2-3 nmol/l. About 40% of this is described as ionised or free calcium whereas the other half is bound with circulating proteins, mainly albumen, and thus cannot diffuse through cells and is therefore unavailable for use by the body. What causes hypocalcaemia? There are several causes of low blood calcium: 1. Low circulating albumen. This is usually without symptoms (asymptomatic) provided the free calcium is unaffected. In some conditions where low blood albumen (hypoalbuminaemia) is due to actual albumin loss as occurs in certain kidney diseases (nephrotic syndrome) and bowel problems (protein losing enteropathy) a symptomatic hypocalcaemia may be evident. 2. Chronic renal failure. This involves a complicated process involving both phosphate and calcium. 3. Reduced intestinal absorption of calcium due to the lack of Vitamin D or inadequate dietary intake. 4. Some dogs with acute pancreatitis develop hypocalcaemia as a secondary complication. 5. By far the most common cause occurs during lactation when milk production may make such demands on circulating blood calcium that it falls to dangerously low level and eclampsia develops. This involves muscle trembling and twitching, a stiff gait, panting and ultimately convulsions and death . This is an emergency situation and immediate treatment is required with intravenous calcium borogluconate. |