Merck Manual

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Some Causes of Peripheral Nerve Disorders

Some Causes of Peripheral Nerve Disorders

Type

Examples

Motor neuron diseases

Hereditary

Acquired diseases that begin suddenly

Polio, infections due to coxsackievirus or other enteroviruses (rare), and West Nile virus infection

Acquired diseases that are chronic

Nerve root disorders

Hereditary

Neurofibromas (soft, fleshy growths of nerve tissue)

Acquired

A herniated disk, infections, injuries, and metastatic cancer

Plexus disorders

Acquired

Acute brachial neuritis, autoimmune disorders, damage during delivery in newborns, diabetes mellitus, a hematoma (a pocket of blood), severe injuries (such as those due to high-speed motor vehicle accidents), metastatic cancer, neurofibromatosis (rare), and nerve tumors

Peripheral nerve disorders

Hereditary

Hereditary neuropathies (such as Charcot-Marie-Tooth disease)

Infectious

In developing countries, diphtheria, leprosy, and parasite infections

Inflammatory

Ischemic (due to blockage of the blood supply)

Vasculitis (inflammation of blood vessels)

Metabolic

Amyloidosis, diabetes mellitus, vitamin B deficiencies, undernutrition due to chronic excess consumption of alcohol, and kidney failure

Pressure-related (called nerve entrapment syndromes)

Toxins

Arsenic, lead, and mercury

Neuromuscular junction disorders

Various

Botulism in infants, Eaton-Lambert syndrome, myasthenia gravis, and dysfunction caused by exposure to insecticides or nerve gas (such as sarin) or by use of certain drugs

Muscle disorders*

Hereditary

Endocrine

Acromegaly (excessive growth due to overproduction of growth hormone), Cushing syndrome, diabetes mellitus, hyperthyroidism (an overactive thyroid gland), and hypothyroidism (an underactive thyroid gland)

Inflammatory

Infections (usually viral) and polymyositis and dermatomyositis

Metabolic

Lipid and glycogen storage diseases, alcoholism, and hypokalemia (low potassium levels)

*Disorders that affect muscle rather than nerves cause muscle weakness, as can peripheral nerve disorders. Doctors do tests to determine whether the cause of weakness is a muscle or a nerve disorder.