Clinical Pearls & Morning Reports
The combination of proximal sensory symptoms and sensory loss with ataxia, with preserved strength, is the archetypal sensory ganglionopathy syndrome. Read the NEJM Review Article here.
Q: Describe a major difference between sensory ganglionopathy and diabetic polyneuropathy.
A: Most common polyneuropathies (e.g., those due to diabetes) result from axonal damage, which leads to degeneration in the distal parts of the longest nerves and symptoms that begin in the toes, ascend the legs, and only later appear in the fingers and proximal parts of the body. In contrast, sensory ganglionopathies are not dependent on the length of axons, and sensory features can start in any or all territories innervated by sensory neurons, particularly in the face, scalp, oral mucosa, trunk, and proximal limbs.
Q: What is the most common malignant process associated with sensory ganglionopathy?
A: The most common malignant process associated with sensory ganglionopathy is small-cell lung carcinoma, but the syndrome has also been associated with breast, ovarian, prostate, colon, and gastric cancers, lymphoma, neuroendocrine tumors, and other cancers.
A: Polyneuropathies occur in 5 to 15% of patients with Sjögren’s syndrome, of which approximately 40% are large-fiber sensory ganglionopathies and 20% are small-fiber sensory neuropathies or ganglionopathies. Symptoms may involve the arms more than the legs and may be asymmetric at the start but usually become generalized. Facial and perioral numbness from involvement of the trigeminal ganglia is common. Cisplatin, carboplatin, and oxaliplatin in large cumulative doses cause sensory ganglionopathy, with ataxia, pseudoathetoid movements, and Lhermitte’s sign. Symptoms may begin to appear as many as 8 weeks after the drug has been stopped and may progress for up to 6 months. Pyridoxine (vitamin B6) in high doses (usually at doses > 2 g per day but possibly with doses as low as 116 mg per day; recommended daily allowance is 2 to 4 mg) has been associated with dysesthesias and sensory ataxia. Studies in animals have shown loss of dorsal root ganglion cells and degeneration of the posterior column tracts. Many, but not all, patients have improvement after discontinuation of the pyridoxine. Immune checkpoint inhibitors may induce an autoimmune attack against sensory ganglia. Approximately half of all cases of sensory ganglionopathy are idiopathic.
A: A variety of immunotherapies (e.g., glucocorticoids, immunosuppressive agents, plasma exchange, intravenous immune globulin, and rituximab) have been tried in different forms of paraneoplastic and other immune-mediated sensory ganglionopathies but usually with little success. Treating an underlying cancer usually fails to lead to remission of the ganglionopathy, but exceptions occur. It is likely that improvement with treatment is limited by destruction of the cell body of the sensory neuron. However, immunotherapy occasionally halts disease progression, and some form of immunotherapy may be undertaken if the neurologic syndrome is progressive and has a duration of days or weeks.