Neuropathy & Its detection
Diabetic neuropathy is the most common complication of diabetes mellitus (DM), affecting as many as 50% of patients with type 1 and type 2 DM. Diabetic peripheral neuropathy involves the presence of symptoms or signs of peripheral nerve dysfunction in people with diabetes after other possible causes have been excluded.
Signs and symptoms
In type 1 DM, distal polyneuropathy typically becomes symptomatic after many years of chronic prolonged hyperglycemia, whereas in type 2, it may be apparent after only a few years of known poor glycemic control or even at diagnosis. Symptoms include the following:
- Sensory – Negative or positive, diffuse or focal; usually insidious in onset and showing a stocking-and-glove distribution in the distal extremities
- Motor – Distal, proximal, or more focal weakness, sometimes occurring along with sensory neuropathy (sensorimotor neuropathy)
- Autonomic – Neuropathy that may involve the cardiovascular, gastrointestinal, and genitourinary systems and the sweat glands
Physical examination should include the following assessments:
- Peripheral neuropathy testing – Gross light touch and pinprick sensation; vibratory sense; deep tendon reflexes; strength testing and muscle atrophy; dorsal pedal and posterior tibial pulses; skin assessment; Tinel testing; cranial nerve testing
- Autonomic neuropathy testing – Objective evaluation of cardiovagal, adrenergic, and sudomotor function in a specialized autonomic laboratory; may be preceded by bedside screening to assess supine and upright blood pressure and heart rate, with measurement of sinus arrhythmia ratio
Some of the commonest tests to diagnose are
- Monofilament test: Sensitivity to touch may be tested using a soft nylon fiber called a monofilament. A 10gm Monofilament is used to touch at many points in the foot to rule out the loss of protective touch sensation.
- Digital Biothesiometry: A more advanced, simple and reliable diagnostic quality instrument which is used to measure the loss of vibration perception threshold quantitatively.
- Nerve conduction studies. This test measures how quickly the nerves in your arms and legs conduct electrical signals. It's often used to diagnose carpal tunnel syndrome.
- Electromyography (EMG). Often performed along with nerve conduction studies, electromyography measures the electrical discharges produced in your muscles.
- Quantitative sensory testing. This noninvasive test is used to assess how your nerves respond to changes in temperature both HOT & COLD.
- Autonomic testing. If you have symptoms of autonomic neuropathy, your doctor may request special tests to look at your blood pressure in different positions and assess your ability to sweat.