Polyneuropathy: an important hint for early diagnosis of amyloidosis?

Amyloidosis is a rare multisystemic disease caused by a deposition of immunoglobulin light chain fragments in a variety of tissues. Clinical signs of amyloidosis are vague and include neuropathy, fatigue, myopathy and cardiac or renal failure. The most common neuropathy associated with systemic amyloidosis is a small-fiber axonal polyneuropathy that is characterized by amyloid deposits in the epi-, peri-, and endoneurium of the peripheral nerves.

Here, we report of a 75-year-old woman who was initially admitted to the department of internal medicine with symptoms of fatigue, hypotension, diarrhoea and a reduced general condition. In order to stabilize the clinical situation, intermittent dialysis and catecholamine administration became necessary. A coronary angiography showed no significant stenosis of the coronary arteries. However, the ECG recording revealed a low voltage.

With reduced consciousness and signs of increasing autonomous dysregulation, the patient was then transferred to the department of neurology. The cMRI as well as the neurological work up including a lumbar puncture, and Doppler-ultrasound were normal. Whereas a detailed electrophysiological testing showed a severe axonal polyneuropathia the histological examination of the nerves revealed no pathological findings. Monoclonal light chains lambda and kappa were detected in the serum and the diagnosis of amyloidosis became supposable. Before further diagnostics such as fat aspiration and bone marrow biopsy could be done the patient showed a rapid progressive decline with increasing autonomic dysregulation as the prominent symptom. The patient finally died and the diagnosis of amyloidosis was proven by autopsy.

In summary, the clinical diagnosis of amyloidosis is often difficult but necessary prior to therapy with chemotherapy or autologous stem cell transplantation. Late diagnosis of amyloidosis is associated with a bad prognosis and high mortality. As we show here, amyloidosis should be considered as differential diagnosis in patients presented with autonomic polyneuropathy and therefore a complete work up including biopsy seems to be necessary in such patients.