Long term high blood glucose (sugar) levels can cause damage to the nerve fibers and give rise to various manifestations of diabetic neuropathy.
The diabetic neuropathies are heterogeneous with diverse clinical manifestations.
They may be focal or diffuse.
Most common among the neuropathies are chronic sensorimotor distal symmetric polyneuropathy and autonomic neuropathy.
Why is it necessary to undergo evaluation for diabetic neuropathy?
1) Nondiabetic neuropathies may be present in patients with diabetes and may be treatable.
2) A number of treatment options exist for symptomatic diabetic neuropathy.
3) Up to 50% of DPN may be asymptomatic and patients are at risk for insensate injury to their feet.
4) Autonomic neuropathy and particularly cardiovascular autonomic neuropathy is associated with substantial morbidity and even mortality.
Diabetic Peripheral Neuropathy
The areas of the body most commonly affected by diabetic peripheral neuropathy are the feet and legs. Nerve damage in the feet can result in a loss of foot sensation, increasing the risk of foot problems. Injuries and sores on the feet may go unrecognized due to lack of sensation. Hands and upper limbs can also get affected in later stages.
Symptoms of diabetic peripheral neuropathy may include:
- Numbness (severe or long-term numbness can become permanent)
- Burning (especially in the evening)
In most cases, early symptoms of diabetic peripheral neuropathy will become less when blood sugar is under control. Medications can be taken to help control the discomfort if needed.
Diabetic autonomic neuropathy
Major clinical manifestations of diabetic autonomic neuropathy include resting tachycardia (incresed heart rate>100/min), exercise intolerance, orthostatic hypotension (lowering of blood pressure on standing), constipation, gastroparesis (delayed gastric emptying), erectile dysfunction, sudomotor dysfunction (dry or moist skin), impaired neurovascular function, and potentially autonomic failure in response to hypoglycemia.
Cardiovascular autonomic neuropathy (CAN), may be indicated by resting tachycardia (>100 bpm) or orthostasis (a fall in SBP >20 mmHg upon standing without an appropriate heart rate response); it is also associated with increased cardiac event rates.
Gastrointestinal neuropathies (e.g., esophageal enteropathy, gastroparesis, constipation, diarrhea, fecal incontinence) are common, and any section of the gastrointestinal tract may be affected. Gastroparesis should be suspected in individuals with erratic glucose control or with upper gastrointestinal symptoms without other identified cause. Constipation is the most common lower-gastrointestinal symptom but can alternate with episodes of diarrhea.
Diabetic autonomic neuropathy is also associated with genitourinary tract disturbances. In men, diabetic autonomic neuropathy may cause erectile dysfunction and/or retrograde ejaculation. Evaluation of bladder dysfunction should be performed for individuals with diabetes who have recurrent urinary tract infections, pyelonephritis, incontinence, or a palpable bladder.