Monday, September 27, 2010

Sjogren's Pearls

J. Birnbaum. Peripheral nervous system manifestations of Sjogren syndrome: clinical patterns, diagnostic paradigms, etiopathogenesis, and therapeutic strategies. The Neurologist 2010; 16:5:287 -- 297 .

1.Syndromes that can cause sicca symptoms and which should be typically excluded, include hepatitis B or hepatitis C, HIV, sarcoidosis, and a history of radiation to either the header the neck.

2. 30% to 50% of patients have negative auto antibodies and require a lip biopsy for diagnosis.

3.  Sensory ganglionapathy : aka sensory  neuronopathy is dramatic with isolated or disproportionate impairment of kinesthetic awareness, with profound handicap of proprioception, even affecting the larger joints. Sensory deafferentation can cause patients to become wheelchair-bound, or have pseudoathetoid movements which may be misdiagnosed as a movement disorder. The most common presentation is distal dysesthesias.  Differential diagnosis includes paraneoplastic syndromes, Bickerstaff brainstem encephalitis, and effect of drugs for example, cisplatin and pyridoxine. Nerve conduction studies typically absent sensory nerve action potential(snaps) and preserved compound motor action potentials (cmap). T2 hyper intensities in the dorsal spinal cord are described. Response to I VIG is inconsistent.

4.  Small fiber neuropathy: the cardinal feature can be excruciating burning pain. There is disproportionate or selective impairment in pinprick and temperature with preserved vibratory sense and proprioception. The onset is subacute or chronic usually. The differential diagnosis includes diabetes, amyloidosis, chemotherapy and other medications, genetic syndromes (i.e. Fabry's) and complications from HIV treatment.

5.  Patients with findings of small fiber dysfunction disproportionally affecting the proximal extremities, torso or face in unorthodox patterns may have Sjogren's. Patients may also have classic length dependent symptoms.

6.   Sjogrens and vasculitis: patients with mononeuritis multiplex should be evaluated for cryoglobulinemia especially with high titer rheumatoid factor, with disproportionate C-4 hypo-complementemia, or normal C-3. Small vessel vasculitis and low levels of C-4 complement in Sjogren's space placed the patient at 6 to 40.  fold risk for non-Hodgkin's lymphoma. Therefore the development of systemic features such as fever or weight loss merit close scrutiny. Nerve or muscle biopsy showing vasculitis more likely responds to immunosuppressive therapy. Mori described patients with axonal MMN who also had cranial neuropathies. The most common is trigeminal neuropathy  which may be indolent, progressive, or bilateral. The unifying feature may be ganglionapathy.  Facial nerve also may be affected. Acute cranial neuropathy plus rapid multiple mono neuropathies may prompt concern for vasculitis.

7. Demyelinating neuropathies are rare but may be noted subclinically. EMG may know isolated prolonged F. waves.
8. Autonomic features are seen in 50% of Sjogren's patients. Inquire about urinary frequency or hesitancy, erectile dysfunction, increased or decreased sweating, orthostatic or temperature intolerance, constipation or increased bowel movements. Adie's pupil , space orthostatic hypotension, and abnormal sweating occurs in 57, 40, and 70% of patients with sensory neuronopathy respectively.

9. Anti-nicotinic ganglionic receptor antibody role is under investigation in Sjogren's. This antibody differs from the anti-muscarinic receptor antibody seen in myasthenia gravis.

10. Inflammatory myopathies occur only in 1 to 2%. Myalgias  may be caused by autoimmune thyroid disease, vitamin D. deficiency, or fibromyalgia. Always assess vitamin D level. Vitamin D may be low due to malabsorption, bacterial deconjugation of bile acids due to gastric motility seen in autonomic neuropathies, type one renal tubular acidosis or coexisting celiac sprue.

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