Diabetes mellitus results from the dysfunction of pancreatic beta cells or from insulin resistance. Compared with diabetic
people, diabetic cats seem to develop fewer long-term complications. The most common complication is simply an inability to
keep good control of blood glucose concentrations.
Hypoglycemia is the clinical term for blood glucose concentrations below the accepted reference range, and hyperglycemia is the term for blood glucose concentrations above the reference range. Serious complications can result from either condition
if not remedied in a timely fashion. Unregulated or fluctuating blood glucose concentrations can contribute to long-term complications
such as renal disease (diabetic nephropathy) or neuropathies and increase the acute risk of diabetic ketoacidosis or cataracts.
Maintaining well-regulated control of blood glucose concentrations helps to prevent these complications.
Here are the signs and common treatments for the chronic and acute complications that may develop so you can help catch them
early in your feline patients.
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The most common complication in cats that are chronically hyperglycemic is diabetic neuropathy—about 10 percent of cats are
affected. The progression to this condition may take several months, and, if properly treated, it can resolve within six to
12 months. The femoral nerve is most commonly affected.
An affected femoral nerve can lead to a plantigrade gait, which is walking on the whole sole of the foot (e.g., like rabbits, bears, and people). In cats, this gait takes the shape of walking on hocks (heels), and the tarsal joints
and nerves of the hind legs are progressively damaged, leading to pain, numbness, and weakness or paralysis. The first sign
of neuropathy in cats is often weak hind legs. As the condition progresses, the cat won't be able to stand on its toes. Jumping
will become increasingly difficult until it's impossible. Eventually, the cat's legs will seem to slip out from under it,
and the cat will be unable to walk. These are signs of motor and sensory nerve damage.
Fortunately, in the early stages, this damage is reversible by regulating blood glucose concentrations. Regulation alone is
the treatment of choice to reverse neuropathy in cats. However, some anecdotal evidence suggests that a specific form of vitamin
B12, methylcobalamin, may help these patients recover more quickly. Methylcobalamin is thought to promote nerve regrowth and
can be absorbed in the spinal fluid. It is not the same as the injectable B12 given to cats that have a true deficiency due
to gastrointestinal disease, and it is typically referred to as methyl-B12. A veterinarian should be consulted before using this product.
Again, the primary treatment is regulating blood glucose concentrations. There is no research to support the use of methylcobalamin
for treating peripheral neuritis in cats, but it may result in faster resolution and is relatively safe to use. The neuropathy
generally resolves once good glycemic control is achieved.