Diabetic neuropathy is damage to the peripheral and central nervous system caused by metabolic disorders and vasculopathy in diabetes mellitus. Its complication rate was statistically considered to be about 5% in the past. However, electromyography, nerve conduction velocity and brain evoked potential examination found that the incidence of early and mild neurological changes can be as high as 92%-96%.
I. Main etiology
The pathogenesis has not been fully elucidated, but now it is thought that it is mainly related to the metabolic disorders of sugar, fat and phospholipids caused by diabetes and vascular disorders such as atherosclerosis, outer and outer membrane hypertrophy, vitreous degeneration and even occlusion of the trophoblastic vessels of peripheral nerves. This leads to segmental demyelination of nerve fibers, swelling degeneration of axons, fibrosis and motor end plate tumors. The lesions are mainly seen in peripheral nerves and posterior roots, but also in the posterior cords of the excitatory medulla and muscles.
Main symptoms
In addition to the clinical manifestations of diabetes mellitus such as excessive drinking, polyphagia, polyuria, lethargy, fatigue, elevated blood glucose and glycosuria, the neurological system can manifest as follows
1. Peripheral neuropathy. Polyneuritis is the most common, with symmetrical sensory disorders, motor disorders and ataxia on both sides. Cranial nerve involvement is less common, there may be one or both sides of the abducens nerve, motoneuritis, retinitis and optic nerve atrophy. The vegetative nerves are often involved, manifesting as gastrointestinal dysfunction, diarrhea, bladder disorders, impotence, postural hypotension, abnormal sweating and vasodilatory instability. Electromyography shows neurogenic changes and slowed nerve conduction velocity.
2, spinal cord damage symptoms. It can be manifested as anterior horn cell damage similar to chronic poliomyelitis, spinal cord consumption-like (called pseudospinal consumption) posterior root and posterior column damage, and posterior and lateral cord degeneration similar to subacute joint spinal cord degeneration. These changes are mostly thought to be caused by persistent spinal cord blood supply deficiency caused by diabetic vascularity.
3. Symptoms of brain damage. There are many causes of encephalopathy in diabetes mellitus, which can be caused by high blood sugar, headache, weakness, physical and mental fatigue, excitement, emotional instability, etc. Long-term without proper treatment can lead to memory loss and mental decline, and hypertonic coma, ketotoxic coma and hypoglycemic coma can also occur. In addition, diabetic vasculopathy can also be complicated by cerebral thrombosis, especially multiple lacunar cerebral infarction and dementia.
4. Muscle damage. It can be manifested as muscle atrophy in the pelvic girdle, scapular girdle and proximal extremities. Hypokalemic paralysis may be present in diabetes mellitus with hypokalemia.
III. Current examination
Diagnosis can be made based on clinical manifestations, blood glucose, urine glucose, urine ketone bodies and other tests and electromyography and nerve conduction velocity measurement.
IV. How to treat
First of all, diet should be controlled, blood sugar should be controlled, and metabolic disorders in the body should be corrected, which is the most fundamental measure for the treatment and prevention of diabetic neuropathy.
Secondly, high-dose B vitamins and niacin can be used to promote the recovery of nerve function.
For diabetic cerebrovascular disease can be treated as cerebrovascular disease.
For hyperosmolar coma, ketosis coma and hypoglycemic coma, resuscitation should be actively carried out.
V. How to detect diabetic neuropathy?
The diagnosis of diabetic neuropathy is based on the patient’s medical history and the results of physical examination. Diabetic neuropathy is mostly peripheral neuropathy and autonomic neuropathy. In 1992, a group of experts from the Rochester Neuropathy Center in the United States established the diagnostic criteria for diabetic neuropathy, which means that diabetic neuropathy can be diagnosed when two or more of the following criteria are present: (1) symptoms of diabetic neuropathy are present. (ii) Abnormal results of nerve defect examination. (iii) Abnormal results of nerve conduction velocity examination. (iv) Abnormal results of quantitative sensory examination. ⑤ Abnormal results of quantitative autonomic nerve examination. For the early diagnosis of diabetic neuropathy, scholars from various countries have proposed many examination methods, but there is no good uniform standard yet. The following highlights several examination methods for diabetic complications of peripheral neuropathy.
1. Nerve conduction function test: This test can assess the ability of the patient’s peripheral nerves to transmit electrical signals, and usually includes the examination of the motor and sensory functions of the median nerve, ulnar nerve, common peroneal nerve, and tibial nerve. The results of these tests can clarify whether a diabetic patient has peripheral neuropathy, as well as the distribution and extent of peripheral neuropathy.
Motor nerve conduction velocity test: This test can reflect the damage of motor nerve and the degree of muscle atrophy. Diabetic patients with peripheral neuropathy may have a light systolic peak voltage significantly higher than normal during electromyography.
3. Quantitative sensory examination: This examination is a quantitative determination of the patient’s sensation by using psychophysical techniques. Commonly used quantitative sensory examination methods include: quantitative temperature sensation, quantitative vibration sensation and light touch sensation examination.
Autonomic nerve function examination: Autonomic nerve is also called visceral nerve or vegetative nerve, including sympathetic nerve and parasympathetic nerve. Autonomic nerves can innervate visceral, cardiovascular and glandular activities, and their functional parameters are closely related to patients’ anxiety, depression and other psychological disorders. The autonomic nerve examination mainly includes: ① Heart rate during deep breathing. ②Heart rate at rest. ③Fist clenching test. ④Heart rate variability spectrum analysis. ⑤ 24-hour ambulatory blood pressure.
5. Omnilux diagnostic paste: German diabetic experts have introduced a new type of early diagnostic paste for diabetic complications of foot neuropathy, Omnilux diagnostic paste, taking advantage of the disorder of sweat metabolism in the feet of diabetic patients. Diabetic patients can put the paste on the ball-shaped area under the left and right big toes, and after 10 minutes, observe the color change of the paste. If all of the paste turns pink, it means that the patient’s foot nerves are not involved; if only part of the paste turns pink, it means that the patient has the precursor of foot neuropathy; if the paste always maintains its original color (blue), it means that the patient’s foot has obvious neuropathy. This new diagnostic paste has a high sensitivity in the detection of diabetic neuropathy.