ACUTE REVERSIBLE NEUROPATHY

ACUTE REVERSIBLE NEUROPATHY

            Pain, discomfort numbness in legs i.e. feet feel dead are the symptoms of diabetic neuropathy. Pain in lower limbs of diabetic patients

1. Because of sensory neuropathy a) Acute sensory & b) Chronic sensory motor
2. Entraptment neuropathy – Meralgia Parasthesia
3. Proximal motor neuropathy – Amyotrophy
4. Peripheral Arterial Disease a) Intermittent claudication & b) Rest pain

Examination of DN:

            Dry skin suggests coexisting sympathetic dysfunction, look for ulcers deformities charcot changes

1. Pressure sensation (10g monofilament)
2. Pinprick sensation
3. Light touch
4. Vibration (128Hz tuning fork at the apex of the hallux )
5. Ankle refluxes

Pathogenic mechanisms for neuropathy

1. Hyperglycemia
2. Nonenzymatic glycation
3. Oxidative stress
4. Ischemic or hypoxic factors
5. Nerve growth factor abnormalities
6. Polyol pathway activation
7. Immunological abnormalities

Risk factors are

1. Age
2. Duration of diabetes
3. Glycemic control
4. Cholestrol / triglycerides level
5. Hypertension
6. Other micro vascular complication
7. Smoking

Sensory Neuropathy

            Distal sensory neuropathy (DSN) chronic sensiromotor variety. Symptoms are burning discomfort, pain of an electrical nature, stabbing, prickling, pricking, shooting or stabbing pains symmetrically in the feet and lower limbs. Pins and needles and other dysesthetic symptoms are also common. All these symptoms are prone to nocturnal exacerabration with characteristic bed cloth hyperthesia. Patient with nocturnal symptoms may benefit from getting up and walking around occasionally immerse their legs in cold water to relieve the burning discomfort.

            Chronic sensorimotor neuropathy is the most common variety of diabetic neuropathy and is of insidious onset with symptoms that wax and wane. Signs are both sensory and motor with small muscle wasting and absent reflexes hence sensorimotor neuropathy. Symptoms of “a burning and unremitting character” last for years but gradually tend to improve with progressive sensori loss, leaving the patient at a risk of insensitive foot injuries.

            To determine the small fiber function, protective sensation in the feet temperature discrimination threshold and skin integrity. For large myelinated fibers, VPT vibration perception threshold using biosthesiometer is the good predictor of foot ulceration. Wasting, weakness and ankle reflexes indicate alterations  in motor nerve function. For detecting sensory nerve dysfunction, vibration using tuning fork, sensitiveness to semmens – Weinstein 10g monofilamend and pinprick should be useful.

            To diagnose diabetic neuropathy to quantitative sensory testing done. Activating cutaneous sensory receptors by measurable physical stimuli and studying the evoked potentials gives quantitative somato sensory function.  The vibration perception threshold (VPT) is measured by a biosthesiometer. A VPT more than 25 volt at the foot is associated with increased risk of foot ulceration.

            The thermal perception threshold (TPT) signifies the function of c fibres. Pressure perception cutaneous threshold (PPCT) is easily measured by a Semmen-Weinstein Monofilament. Absence of sensation with a 10g filament is associated with risk of foot ulceration.

            Single fiber electromyography (EM) and macro EM has applied to demonstrate deficient innervation in diabetic neuropathy DN. A skin punch biopsy with immuno staining with special anti bodies to human protein gene product 9.5 substance P and calcitonin gene product peptide is a new technique.

            For autonomic testing

1. Beat to Beat variation, heart beat variation during deep breathing.
2. Lying to standing and val salva maneuver
3. BP response to standing

            Hyperglycemia speeds up the programmed cell death of both nerve cells and cells of their protective covering i.e. schwann cell. The neurotropin, IGF-1 protect neurons, nerve cells, schawann cells even in presence of high blood glucose or sugar.

Meralgia Parathesia. Entrapment of lateral cutaneous nerve of thigh can give rise to localized neuropathy symptoms in its area of innervation, the lateral area of mid thigh. The pain is localized and usually unilateral.

Amyotrophy:

            Proximal Motor Neuropathy is typically affects older male type II diabetes with neuropathic pain in thigh region together with proximal motor weakness.

The Management of Neuropathy:

1. Tricyclics antidepressant a) Amtriptyline  & b) Imipramine
2. Anticonvulsants a) Gabapentin, 900-3600 mg/day, b) Phenytoin, c)Lomotrigine & d) Carbomazepine
3. Antiarrhythmics a) Mexilitine 10mg/kg
4. Other opiods a) Tramadol
5. Tropical application a) Capsaicin

            The new drugs gamma as linolenic and alpha lipoic acid and methyl cobolamin.

CONCLUSION:

            Any patient found on clinical examination to have reduced sensation to modalities such as vibration, touch or pain must be considered to be at risk of insensitive injury.

REFERENCE:

            Therapy for DM and Related Disorders, ADA