POLYNEURITIS
(Peripheral neuritis, Multiple symmetrical peripheral neuritis, Polyneuropathy)
DEFINITION
POLYNEURITIS is a syndrome characterised by disturbances of the functions of peripheral nerves due to varied aetiology.
AETIOLOGY
Infective
(i) Leprosy
(ii) Diphtheria
(iii) Typhoid
(iv) Dysentery
(v) AIDS and HIV infection.
(vi) Tetanus
Viral
Acute infective polyneuritis, mumps, measles, influenza, small pox, etc.
Toxic
Alcohol, Arsenic, Lead, Gold, Mercury, Triorthocresyl phosphate, INH, Nitrofurantoin, Organic chloride compound, Vincristine, Chlorambucil, Dapsone, Cisplatin, Amphotericin, Procarbazine. Phenytoin, Chloramphenicol, Disulfiram, Carbon disulphide and various others.
Deficiency diseases
Beri-Beri, B12 neuropathy, pellagra, folic acid deficiency, nutritional neuropathy.
Metabolic diseases
Diabetes, pregnancy, uraemia, porphyria, myxoedema, gout, dysproteinaemias, hepatic disorders, amyloidosis.
Collagen and allied disorders
Disseminated lupus erythematosus, Polyarteritis nodosa, Sarcoidosis, Rheumatoid arthritis, Giant cell arteritis (Sjogren’s syndrome).
Genetic and hereditary diseases
(i) Familial polyneuritis.
(ii) Refsum’s syndrome.
(iii) Dejerine-Sottas disease.
(iv) Peroneal muscular atrophy.
(v) Charcot-Marie-Tooth disease
(vi) Friedreich’s ataxia.
Malignancy
(i) Malignant or carcinomatous neuropathy.
(ii) POEMS Syndrome.
Idiopathic
Sensorimotor neuropathy.
CLINICAL FEATURES OF POLYNEURITIS
Onset is usually insidious, rarely acute.
Sensory symptoms
These symptoms start earlier. Patient complains of pins and needles sensation, tingling, numbness and sometimes burning sensation first in the stocking, gloves area, ultimately involving the whole body. Lower limb is affected first. Gradually loss of touch, pain and temperature sensations may be seen which is followed by easy traumatisation, ulceration, burning etc. Afterwards sensory ataxia may develop.
Motor symptoms
These start later. There may be weakness of fingers and toes leading to difficulty in holding objects, weakness in the grip and in course of time complete loss of motor power. Muscles will undergo wasting and gradually wrist drop, foot drop and claw like deformity of hand and feet may develop. Patient is unable to walk in late stages.
Autonomic symptoms
Flushing of skin coldness of the limbs, sweating . pigmentation , difficulty in micturition and defaecation, postural syncope, loss of erection of penis, etc. may develop.
On examination
Higher functions
Usually normal but may be altered due to the underlying causes as in alcoholism, uraemia, etc.
Cranial nerves
In some cases there may be paralysis of cranial nerves, e.g., palatal palsy in diphtheria, oculomotor and 7th nerve palsy in acute infective polyneuritis, 7th nerve palsy in leprosy, etc.
Motor functions
Nutrition is poor in the affected muscles; hands and feet may assume claw like deformity as mentioned above. Motor power is weak and gradually lost. Wrist drop and foot drop may develop. Tone is diminished, Co-ordination test is abnormal. Involuntary muscular movement may be present in the form of tremulousness in the affected muscles.
Reflexes
Plantar and abdominal reflexes may be normal if elicitable. Deep reflexes may be brisk in the very early stages but lost in well-developed cases. Sphincteric reflexes may show variable disturbances in some cases.
Sensory changes
In the early stages there may be hyperaesthesia, hyperalgesia and excessive thermal sensations but gradually all these sensations are lost. Tenderness may be elicited on squeezing the calf muscles which is an important clinical sign. Vibration sense is lost. Joint sense and muscle sense are also lost.
Trophic changes
There may be trophic ulcer, oedema, cyanosis, pigmentation and Charcot’s joints.
Gait
Due to foot drop there may be high stepping or steppage gait. Patient stands on a broad base and raises the lower limb to a very high level due to foot drop and during stepping toes touch the ground first as if the patient is crossing a brooklet cautiously.
MANAGEMENT
1. Rest in bed is advisable.
2. Treatment of the underlying cause should be done as far as practicable.
3. Bi, B, and B12 in proper doses may be given parenterally. B-complex vitamins as a whole may also be given. Sometimes ordinary analgesic drugs are to reduce pain. To relieve stabbing pain phenytoin, gabapentine carbamazepine may be helpful.
4. Appropriate splinting to prevent foot drop and wrist drop may be done.
5. Physiotherapy may also help.
6. Steroids may be given in selected cases.
7. For postural hypotension elastic stokings and sleeping suits are beneficial. Neuropathic heart trouble may get benefit by the use parasympathetic drugs. Inpotence and diarrhea are difficult to treat.