Medical Care
Care of patients with paraneoplastic autonomic neuropathy depends on severity of autonomic dysfunction and status of associated malignancy.
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Malignancy
The most important aspect of medical care in a patient with paraneoplastic autonomic dysfunction is treatment of the underlying malignancy. If the malignancy can be cured, progression of autonomic dysfunction may cease and potentially even reverse. If a cure is not possible and chemotherapy is a consideration, then a non-neurotoxic immunosuppressive regimen such as cyclophosphamide and doxorubicin (Adriamycin) is theoretically appealing. However, no data show superiority of any particular regimen, as long as the tumor is controlled.
In exceptional cases, patients presenting with typical encephalomyeloneuropathy, including autonomic failure and positive antineuronal antibody titers, may be considered for chemotherapy even in the absence of a tissue diagnosis. The risk of an occult malignancy in this specific situation is very high.
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Autoimmune process: In general, immunosuppressive or immunomodulation treatments directed against the paraneoplastic antibodies (eg, plasmapheresis, IVIG, steroids, immunoadsorption) have been disappointing. However, for some specific types of paraneoplastic disorders, such as LEMS, stiff-person syndrome, anti-NMDA receptor encephalitis, and gastric dysmotility disorders, some reports have shown benefits of immunotherapy. [43, 22, 44, 16, 33]
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No therapy directed at suppressing the immune system has been shown to be reliably effective; however, successful treatment of the associated malignancy by resection and/or chemotherapy may slow or stop the progression of the neurologic syndrome.
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Autonomic failure
Nonpharmacologic measures are useful for all patients with autonomic dysfunction:
Discontinue antihypertensive medications and other medications known to lower blood pressure, if feasible.
Increase fluid and salt intake.
Equipment aids may be helpful; these include tight support stockings, abdominal binders or antigravity suits for symptomatic hypotension, and bladder catheterization for urinary retention.
Dietary fiber and enemas may help improve bowel motility and decrease straining during defecation.
Patients with decreased sweating should limit their physical activity, particularly in hot weather. Sponging with water during activity may help prevent overheating.
Large meals may exacerbate hypotension and should be avoided.
Positional changes, such as standing, should be performed slowly and gradually.
Elevate the head of the bed and avoid prolonged recumbency.
Many pharmacological interventions directed against symptoms of autonomic failure are helpful; please see the article on Idiopathic Orthostatic Hypotension and Other Autonomic Failure Syndromes for a discussion.
Surgical Care
Temporary pacing of unstable cardiac rhythms has been found to be helpful in certain cases of NMDA receptor antibody encephalitis. [23, 24]
Consultations
If no known underlying cancer is present, consider seeking consultation from a pulmonary medicine specialist. A pulmonologist can help in finding an obscure small-cell lung cancer or other lung tumor. A medical oncology specialist can be of diagnostic help, in addition to assisting in the treatment of the associated malignancy.
Gastroenterology and urology consultation may be needed if intestinal dysmotility and urinary incontinence are part of the clinical manifestations.
Diet
High fluid and salt intake is of potential value for orthostatic hypotension. A fiber-rich diet can help some gastric dysmotility symptoms.
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Paraneoplastic autonomic neuropathy. Histopathology of peripheral nerve and sympathetic ganglion from a patient with autonomic failure, oat-cell carcinoma of the lung, and positive anti-HU antibody titer. (a) Peripheral nerve in longitudinal section stained with Luxol fast blue-periodic acid-Schiff (PAS) showing scattered wallerian degeneration (arrowheads). (b) Low-power view of a paravertebral sympathetic ganglion stained with hematoxylin and eosin (H&E). Arrowhead indicates perivascular mononuclear infiltrates. (c) High-power view of the same sympathetic ganglion showing degenerating neurons (single arrowheads) and mononuclear infiltrates (double arrowhead). Magnification bars in a and b indicate 100 mm; c is 50 mm.
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Paraneoplastic autonomic neuropathy. Hematoxylin and eosin (H&E)–stained sections from dorsal root ganglion showing the hallmark histopathology of anti-HU disease; a and c are from a healthy patient; b and d are from a patient with autonomic failure, oat-cell carcinoma of the lung, and positive titer of anti-HU antibodies. The arrowheads in b and d indicate degenerating sensory neurons. Also note the interstitial hypercellularity and decreased numbers of neurons in b and d. Magnification bar in b indicates 100 mm and applies also to a. Similarly, the magnification bar in d indicates 50 mm, which also applies to c.
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Paraneoplastic autonomic neuropathy. Central nervous system sections from a patient with autonomic failure, oat-cell carcinoma of the lung, and positive titer of anti-HU antibodies stained with hematoxylin and eosin (H&E). (a) Inferior olive showing a cluster of mononuclear cells (arrowhead); (b) hippocampus showing perivascular mononuclear infiltrate (arrowhead); (c) midbrain section showing a vessel encased in a mononuclear infiltrate; (d) ventral horn of the thoracic spinal cord showing clusters of mononuclear cells around degenerating motor neurons (arrowheads). Magnification bars indicate 100 mm. The bar in b applies also to a and the bar in d also applies to c.
