Polyneuropathy

Definition:

Poly:  many or much

Neuro: nerve

Pathy: suffering

Ethiology (causes):

Genetic

Inflammatory/infectious

Immunologic

Metabolic or nutritional

Paraneoplastic (with different types of tumors)

Toxic

Classification:

Sensory: pain, numbness, hypoesthesia

Motor: muscle weakness

Sensorimotor: the combination of motor and sensory symptoms

Autonomic: breathing difficulties, cardiac arrhythmia, pupil size abnormality, neurogenic bladder or bowel dysfunction

Pathologic conditions:

Axonal neuropathy

Demyelinating neuropathy

Neuronopathy

Genetic polyneuropathy:

HMSN (CMT): hereditary sensorimotor neuropathy (Charcot Marie Tooth)

Many subtypes

Some groups affect the white matter (myelin), and some groups affect the gray matter (axon) dominantly.

The most common form is CMT or HSMN Type 1A (affects the white matter/substance)

CMT (HMSN) type 1A:

Most common forms

It affects white matter dominantly 

Related gene mutation: PMP22 (chromosome 17)

Slow progress

Inflammatory/immunologic:

Acute type: GBS: Guillain-Barres syndrome

Chronic type: CIDP: Chronic inflammatory demyelinating polyneuropathy

Certain causes of inflammatory/infectious polyneuropathy:

Rheumathologic diseases

Sarcoidosis

Neuroborreliosis

Viral infections (HIV)

Metabolic/nutritional:

Diabetes mellitus

B Vitamin deficiency

E Vitamin deficiency

Alcoholism 

Renal failure

Hypothyroidism

Hyperthyroidism

Toxic:

Cisplatin

Amiodarone (Cordarone)

Vincristine (Oncuvin)

B6 Vitamin

Paraneoplastic:

Lung cancer

Thymoma

Breast cancer

Ovarian cancer

Symptoms:

Muscle weakness

Numbness

Hypoesthesia

Pain

Tremor

Muscle atrophy

Breathing difficulties (in severe types of polyneuropathy)

Speech difficulties (in severe types of polyneuropathy)

Dysphagia (in severe types of polyneuropathy)

Slow (absent) pupil reflex against the light (or against autonomic reactions as fear)

Diagnosis:

Anamnesis (positive family history of polyneuropathy) 

Clinical examination

Neurography

Electromyography

Nerve biopsy

Blod test (genetic, biochemical, or metabolic tests)

Treatment:

There is no curative treatment for hereditary or genetic forms

Treatment with IVIg (intravenous immunoglobulins/antibodies), corticosteroid, or cytostatics/cytotoxics for inflammatory forms

Treatment of underlying disease in metabolic polyneuropathies

Prognosis:

Inflammatory polyneuropathies usually have good predictions if treatment is given in good time. Treatment must be started as soon as possible!

The varying prognosis for metabolic forms, due to underlying disease.

There is not good prognosis for hereditary forms, but they usually give mild symptoms and have slow progress.