Mononeuropathies

Mononeuropathies (neuritis and neuralgia) are isolated lesions of individual neural trunks.

Etiology. At the heart of the disease is a direct trauma, compression of the nerve trunk. Predisposing factors are the superficial location of the nerve on the bone or its passage in the canals formed by osseous ligament and muscle elements. In similar anatomical conditions, the corresponding parts of the nerve trunks are particularly sensitive to chronic professional or sports trauma, limb compression during deep sleep, etc. (tunnel, or trapped, syndromes). Atherosclerosis, diabetes mellitus, nodular periarteritis of menoneuropathy are caused by ischemia (ischemic neuropathies). Direct infection of individual nerves is very rare (characteristic only for leprosy). In a considerable number of cases, the etiology of neuropathy is unknown.

Pathogenesis - see Polyneuropathies.

Symptoms, course. The defeat of the main nerve trunk leads to the loss of all its functions. More distal foci cause only partial disturbances. The clinical picture depends on the degree of damage to nerve fibers. Below, only the syndromes of the complete break of the main nerves of the extremities in their proximal parts are described, as well as the clinical course of the most frequent cranial mononeuropathies.

Neuritis of the ulnar nerve, impossibility of flexion of the IV and V fingers of the hand and its deformation as a "clawed paw"; The last two fingers are in the withdrawal state; Anesthesia of the ulnar surface of the hand, as well as IV and V fingers. Most often the nerve is squeezed in the cubital canal near the inner condyle of the humerus.

Neuritis of the radial nerve: impossibility of extension in the ulnar and radiocarpal joints ("hanging brush"); Loss of reflex with m. Triceps; Anesthesia of the posterior surface of the shoulder, forearm and 1 finger. Most often the nerve is damaged on the shoulder, where it spirals around the humerus.

Neuritis of the median nerve: impossibility of pronation of the hand and flexion of the first three fingers; Anesthesia of the lateral surface of the palm, I-III fingers and lateral surface of the IV finger. Most often, the nerve is damaged in the carpal tunnel (the most frequent tunnel syndrome).

Neuritis of the femoral nerve: impossibility of extension in the knee joint; Abaissement of the knee reflex; Anesthesia of the anterior surface of the thigh and the medial surface of the shin.

Neuritis of the sciatic nerve: impossibility of flexion in the knee joint, paralysis of the foot; Abaissement of the Achilles reflex; Anesthesia of the lower leg (except for its medial surface) and feet.

Neuritis of tibial Nera: impossibility of plantar flexion of the foot and fingers; Abaissement of Achilles reflex (walking on fingers is impossible); Anesthesia of the plantar surface of the foot. The distal nerve can be compressed in the tarsal canal near the inner ankle.

Neuritis of the peroneal nerve: the inability of the back folding of the foot (the foot hangs down and inside); Anesthesia of the external surface of the lower leg and the rear of the foot.

The differential diagnosis of mononeuropathies with root syndromes and plexus lesions is based on a careful analysis of the clinical picture, which is often difficult to distinguish from radiculopathy (hence the unjustified frequency of diagnosis of femoral and sciatic nerves neuritis). In favor of discogenic radiculopathy is indicated, in particular, vertebral syndrome (antalgic scoliosis, etc.), as well as frequent increase in protein in the cerebrospinal fluid.

Treatment. Vasodilators and decongestants, B vitamins, massage, physiotherapy exercises, physiotherapy: in the absence of effect in many cases, surgery for decompression and neurology is indicated.