Amyloid Neuropathy

Specialty Area: Peripheral Nerve

Disorders of peripheral nerves are the most common neurological complications of systemic amyloidosis; an illness where a protein called amyloid is deposited in tissues and organs. Amyloidosis can affect peripheral sensory, motor or autonomic nerves and deposition of amyloid lead to degeneration and dysfunction in these nerves.

Symptoms
The typical symptoms of amyloid neuropathy are due to sensory and autonomic dysfunction. Patients may experience painful paresthesias (unusual sensations), numbness and balance difficulties due to sensory dysfunction and persistent nausea, vomiting, diarrhea, constipation, incontinence, sweating abnormalities or sexual dysfunction due to autonomic nerve involvement.

Diagnosis Diagnosis of amyloid neuropathies is based on history, clinical examination and supporting laboratory investigations. These include electromyography with nerve conduction studies, skin biopsies to evaluate cutaneous nerve innervation, and nerve and muscle biopsies for histopathological evaluation. In cases of familial amyloidosis, genetic testing in the blood may be useful.

Treatment
Treatment of amyloid neuropathies is directed at both preventing further deposition of amyloid in peripheral nerves and treating painful symptoms. Depending on the type of amyloid protein, patients may benefit from liver or bone marrow transplant. Neuropathic pain due to amyloid neuropathy can be treated with anti-seizure medications such as gabapentin (Neurontin), pregabalin (Lyrica) and topiramate (Topamax), antidepressants such as amitriptyline (Elavil) and duloxetine (Cymbalta), or analgesics including opiate drugs. In severe painful conditions patients may be referred to the Blaustein Chronic Pain Clinic for a multidisciplinary approach to pain management.