Diabetic neuropathy is one of the symptoms of prolonged hyperglycemia. It causes numbness and weakness in the legs, particularly in cats.
In diabetic neuropathy, nerves in the legs are progressively damaged, leading to tingliness, pain, numbness, and weakness or paralysis. In cats, this often shows first as weak hind legs, progressing until the cat cannot stand on his toes as usual, and walks on his hocks (heels) or sits down more often. This condition is known as plantigrade stance or posture. This article contains a photo of the posture.
Jumping becomes difficult, then impossible. Eventually the cats' legs seem to slip out from under them and they become unable to walk. These symptoms are the result of damage to the motor and sensory nerves, but they can usually be reversed with better control of blood sugar and certain dietary supplements.
The symptoms are less common in dogs, but do occur. Many dogs have hind leg weakness when they are first diagnosed with diabetes. This is sometimes the symptom which brings the pet to the vet's office. It's often falsely attributed to "getting older" by the caregiver. What is also known as "diabetic neuropathy" most often affects both rear legs and will progress symmetrically. With treatment and regulation, most dogs also have reversal of neuropathy.
This 1983 JAVMA abstractindicates that both the neuropathy and low blood pressure returned to normal following the control of the diabetes with insulin.
Reversal with Methyl-B12 and RegulationEdit
Fortunately, in early stages this damage is reversible. A combination of reducing the attacks on the nerve cells (by regulating blood glucose levels), and Methylcobalamin supplements that promote nerve regrowth, is effective in many cats in just a few weeks.
Effective regulation alone has been known to reverse neuropathy in cats, though perhaps not as quickly as with the Methyl-B12 supplements. Methyl-B12 (aka Methylcobalamin) is a special form of vitamin B12 that can be absorbed in the spinal fluid, and is not the same as regular B12. (Some people quote studies showing that "Vitamin B supplements don't work", which is quite true if they're not the Methyl form. Get specific.) Supplements alone don't help (or not much) if blood glucose remains high.
You can pill the animal or crush the pill into the pet's wet food. Some caregivers give their cats 3mg a day; some less. If you can only find 5mg pills, that's ok too-- the vitamin is water-soluble and the excess will be urinated away. Many pills come with small amounts of glucose or fructose as flavoring, but diabetic cat owners have not noticed significant blood sugar changes as a result of these small amounts.
A reliable source in the US of Methyl-B12 supplement is Zobaline - made specifically for diabetic cats, not to be confused with Xobaline for humans. In Australia Methyl-B12 can be compounded at the pharamcy with perscription from a veterinarian and injected in the same manner as insulin shots once per week.
Mechanics of diabetic neuropathyEdit
In humans, the excess glucose oxidizes the tiny capillaries that nourish nerve cells, and the resulting constriction starves the nerve cells. (See Wikipedia:Diabetic Neuropathy link below.) In dogs and cats the mechanism seems different: the nerve axons dwindle and atrophy, and the spaces between them become clogged with glycogen deposits.
Understanding how this works, means some learning about nerve cells, impulses and their relationship to muscles. An Atlantic Coast Veterinary Conference (ACVC) 2001 presentation of feline neurological diseases has a section dealing with diabetes-mediated neuropathy. The basic problems regarding nerves, muscles and neuropathy apply to all those with diabetes, so let's take it apart:
The most common neuropathy noted in the feline is diabetic neuropathy (secondary to diabetes mellitus). Clinical signs occur most commonly in the middle to older aged feline and present as lower neuron signs (plantigrade stance-below) in the hind limbs. Patellar (of the knee) reflexes may be diminished, although flexor reflexes and pain sensation are usually intact.
Muscles and nerves can't communicate properlyEdit
The etiology and pathogenesis of diabetic neuropathy involves primary and secondary axonal (nerve fiber) degeneration due to slowing of axon transport (Neuron impulses move along axons very much like electricity through a wire. Flaws in this communication system between nerves and muscles are the basis for neuropathy and other nerve-related disorders, such as Muscular Distrophy, etc.) secondary to hyperglycemia, alteration of macromolecular transport, interference with axon maintenance and repair by the neuronal cell body, and neural hypoxia (Insufficient oxygen--in this case to the neuron).
A gradual stateEdit
Progression to this state may occur over several months. Diagnosis and treatment is through the establishment of underlying disease (diabetes mellitus) and characteristic neurologic exam findings, and in most cases will resolve in 6 to 12 months if the DM is treated appropriately. Those who have a disease or diseases of the endocrine system (medical catch-all term is Endocrinopathy) are more prone to neuropathic problems than anyone who has no endocrine conditions.
Peripheral and other neuropathiesEdit
There is a form of neuropathy which has been known to doctors treating people with diabetes since the advent of insulin therapy. The name given to it is insulin neuritis, as it often occurs shortly after starting insulin. The problem is that even though it's been around about as long as insulin treatment, the phenomenon is currently not considered common. Insulin neuritis can follow the rapid improvement of diabetic control, but its mechanisms are still elusive. As you see from this link, one theory is that insulin neuritis is caused by the regeneration of the nerve axons.
- Excellent summary on Neuropathy and Methyl-B12
- Using Methyl-B12 for neuropathy (Laurie and Jasper)
- Methylcobalamin and diabetic neuropathy by Fujiya et al.
- Neuropathy Associated With Transient Diabetes in Two Cats Modern Veterinary Practice 1984
- Neurological Complications Associated with Spontaneously Occurring Feline Diabetes Mellitus-Journal of Neuropathology & Experimental Neurology-2002
- FDMB discussion on more recent sources and forms of Methyl-B12
- Feline Neuromuscular Disorders-WSAVA 2003
- Perineurial Abnormalities in the Spontaneously Diabetic Dog-Acta Neuropathologica-1999
- Electrodiagnostic Analysis of Peripheral Neuropathy in Dogs with Diabetes Mellitus-American Journal of Veterinary Research-1981
Study with long-time diabetic dogs has findings similar to those of humans--that long-term diabetes tends to mean some neuropathy.
- More from Delano on Methyl-B12 in diabetic pets
- Peripheral Neuropathy--Diabetes and Non-Diabetes Related
- Dorlands Medical Dictionary-Definition of Perineurium
- Dog ear infection
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- Ivermectin for dogs
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- Purina dog chow coupons
- ↑ Long Beach Animal Hospital--Diabetes
- ↑ Southpaws.com-Diabetic Neuropathy
- ↑ Peripheral Neuropathy & Hypotension in a Diabetic Dog
- ↑ Neuropathy Associated with Diabetes Mellitus in the Cat-Journal of the American Veterinary Association-1984
- ↑ Wikipedia:Diabetic neuropathy
- ↑ Diabetic Neuropathy in Dogs & Cats-1989 Tierartzlichen Praxis (Veterinary Practice)
- ↑ ACVC 2001-Feline Neurologic Disease
- ↑ Biology Pages: Neuron
- ↑ Plantigrade Stance-Drs. Foster & Smith Pet Education Library
- ↑ Biology Pages: Muscle Spindles
- ↑ Biology Pages: Muscle Spindles
- ↑ Biology Pages: Neurons
- ↑ Biology Pages: Neuromuscular Junction
- ↑ Biology Pages: Excitable Cells
- ↑ Biology Pages: Fueling Muscle Contraction
- ↑ Biology Pages: Muscles
- ↑ Southpaws.com-Peripheral Neuropathy
- ↑ Peripheral Neuropathy: National Diabetes Information Clearinghouse (NDIC)
- ↑ Southpaws.com-Fall, 1999-Peripheral Neuropathy
- ↑ National Diabetes Information Clearinghouse (NDIC)-Neuropathy Affects Nerves Throughout the Body
- ↑ Southpaws.com-Diabetic Neuropathy
- ↑ Endotext.com-Diabetic Neuropathies
- ↑ Under-recognised Paradox of Neuropathy from Rapid Glycemic Control-Postgraduate Medical Journal-2004 Register Free to Read
- ↑ Management of Diabetic Neuropathic Pain-Insulin Neuritis-Page 2
- ↑ Arterio-venous Shunting and Proliferating New Vessels in Acute Painful Neuropathy of Rapid Glycemic Control (Insulin Neuritis)-CAT.INIST.FR (French National Center for Scientific Research)-English Abstract
- ↑ Acute Glucose DeprivationLeads to Apotosis in a Cell Culture Model of Acute Painful Diabetic Neuropathy
- ↑ Diabetic Peripheral Neuropathy-1998-Insulin Neuritis-Page 5
- ↑ Neuromuscular Junction
- ↑ Acute Painful Diabetic Neuropathy Precipitated by Strict Glycemic Control-Acta Neuropathica-1986
- ↑ American Diabetes Association-Chat Transcript-2005
- ↑ Royal College of Nursing-Starting Insulin Treatment for Type 2 Patients-Page 22