Neurophysiological studies in malignant disease with particular reference to involvement of peripheral nerves

Abstract

Neurological and neuromuscular disorders are frequent complications in patients with neoplasms and may involve the neuromuscular system, including motor and sensory nerve cell bodies, axons, myelin, neuromuscular transmission and muscle alone or in combination. Electrophysiological studies are of value in delineating the type, degree and extent of involvement, and may be of assistance in pointing towards the underlying cause: paraneoplastic factors, treatment with chemotherapy or radiation or metastatic infiltration. Though some electrophysiological features may be characteristic of certain syndromes, they rarely can stand alone but require clinical, pathological, radiological, and laboratory studies to obtain a diagnosis. Even in cases where such studies are obtained, a final diagnosis may only be ascertained during follow up, since the neuromuscular disorders frequently occur before the neoplasm is detected.

Diagnosis of acute neuropathies

“…Nevertheless, in some cases no underlying disease can be found. In small cell lung cancer antibodies against neuronal nuclear antigens (ANNA1,anti-Hu) are present in the blood and the CSF [6,27,35,89,100]. In other types of cancer some patients have shown presence of anti-Purkinje cell antibodies (PCA-1, anti-Yo).…”

“…The prognosis is poor regarding the sensory neuropathy especially when the disease is caused by degeneration of dorsal root ganglion cells precluding recovery by regeneration. Although SSN is the most characteristic type of neuropathy in cancer, patients more frequently present with a mixed sensory and motor neuropathy, which may show axonal or demyelinating features [27,89], and paraneoplastic neuropathies usually take the form of a generalized neuropathy [36,37]. In paraneoplastic SSN, the patients may not have symptoms of the underlying malignancy at the time of presentation, and they may show additional signs of CNS involvement with encephalomyelitis or limbic encephalitis.…”

Paraneoplastic syndromes of the peripheral nerves

“…Though the classic electrophysiologic features of SSN are limited to small to absent sensory nerve action potentials [42], there may also be slowing of conduction velocities, reduced compound muscle action potential amplitudes, and absent or prolonged F waves [38,41 ].…”

Tiroid foliküler kanserine bağlı paraneoplastik polinöropati, Lambert-Eaton myastenik sendrom ve paraneoplastik serebellar dejenerasyon olgusu

“…It was first diagnosed by Denny-Brown in 1948 when degeneration in the dorsal root ganglion and neuronal loss were discovered in the autopsy of 2 patients with rapid progressive sensory neuropathy and ataxia (7). Pathologically, there might be involvement in the anterior horn motor neurons, sensory neurons in the dorsal root ganglia, in axons, or nerve terminals, in the neuromuscular junction, or in muscle or autonomic nervous systems (8,9). Initially, it is usually subacute.…”