Magnesium Deficiency in Cats

A magnesium deficiency is a relatively rare occurrence in cats referred to as “hypomagnesemia”. Because magnesium is key for the absorption of such things as sodium, calcium, potassium and vitamins C and E, when magnesium is scarce in the body none of these other vitamins and minerals are absorbed properly. Hypomagnesemia can also lead to serious cardiovascular problems. Left unchecked, a magnesium deficiency has the potential to become life threatening, so veterinary attention is required.

Magnesium is the body’s second most abundant nutrient. It is a vital mineral for the function of many different body parts. Magnesium helps the body on a cellular level and assists in the secretion of hormones. It also is responsible for enzyme function and the building of both bones and teeth. When a cat becomes deficient in this necessary substance, the entire body suffers.

As magnesium directly affects so many parts of the body, a deficiency will also affect multiple organs, muscles and bones. Sometimes the underlying cause of the deficiency will show severe symptoms in addition to any typical hypomagnesemia symptoms. Symptoms are as follows:

• Muscle trembling or twitching
• Lack of coordination 
• Severe pain
• Stunted growth
• Convulsions
• Weakness
• Depression
• Sudden lameness
• Irregular heartbeat
• Overextended carpal joints
• Urinary tract stone development

There are multiple possibilities for the cause of magnesium deficiency in cats. It is important to understand the exact cause for your cat’s deficiency so that you can later eradicate the exacerbation if possible. Known causes include:

• Diet (especially from low-quality cat food)
• Malnutrition
• Genetic abnormalities that interfere with the cat’s nutrient absorption process
• Intestinal disease
• Diabetes
• Failing kidneys
• Hyperthyroidism
• Hypoparathyroidism (decreased parathyroid production)
• Diuretics or drugs that may damage the kidneys

This issue is generally easy to diagnose, although the vet may need some time to pinpoint the exact cause of the deficiency. Your veterinarian will need a full medical history on the cat and will ask you about the cat’s diet and current urination frequency. A complete physical examination will be performed during which the vet will look for any cardiac abnormalities. They may also ask about any medications that the cat is taking.

Blood work will be done for a more detailed picture of the cat’s health. The vet will look for low levels of magnesium, and will also note the levels of calcium that are present in the blood. The vet may also choose to check PTH (parathyroid hormone) levels in the blood. A urinalysis will be performed to evaluate the condition of the kidneys. An ECG (electrocardiogram) test may be done to monitor heart beat patterns for irregularities. An ACTH (adrenocorticotropic hormone) test may be requested to assess how well adrenal glands are functioning. A free T4 test will be required if thyroid disease is suspected. 

While magnesium deficiency can become life threatening, it is easy to reverse by restoring magnesium levels in the body. Veterinary clinics and animal hospitals have the capabilities to carry out these treatments.

Magnesium Infusion 

If the cat is in a dire condition, generally from severe malnutrition, magnesium will be administered intravenously. The veterinarian will monitor this process to ensure heart rates stay steady throughout. This is a very effective way to restore magnesium levels to appropriate amounts. 

Supplement Prescription 

If the deficiency is caught in its earlier stages, a daily supplement may be advised to get levels back to the norm. A supplement that dissolves under the tongue is suggested as the body has a difficult time absorbing magnesium through the digestive process.

Underlying Conditions

The underlying cause of the deficiency may also require treatment, as in the case of urinary tract stones or thyroid disease. Treatment will depend on the exact cause and the severity of the condition. Sometimes these treatments can involve surgery or a lifelong treatment involving medications.

A magnesium deficiency in itself is an easy problem to rectify with a good prognosis. Certain secondary problems, such as kidney failure, can have a more guarded prognosis due to more complicated treatments. If your cat does end up needing surgery to rectify an underlying cause, be sure to take all precautions in administering post-surgical, at-home care. The less stress a cat has to face during this period of time, the greater chance for healing.

To decrease the possibility of a magnesium deficiency developing again, make sure your cat is given a nutrient rich cat food and continue administering daily supplements. Terminate the use of medications that have a poor effect on the kidneys. Visit your veterinarian regularly to monitor magnesium levels and to spot early signs of recurrence.