What is the role of lumbar puncture and biopsy in the evaluation of autonomic failure syndromes?

Updated: Oct 21, 2018
  • Author: Mohini Gurme, MD; Chief Editor: Selim R Benbadis, MD  more...
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Answer

See the list below:

  • Because of the frequency of autonomic dysfunction in AIDP, acute onset of autonomic abnormalities must prompt consideration of AIDP in the differential diagnosis.

    • A lumbar puncture is indicated for CSF studies.

    • Patients with AIDP typically develop elevated protein levels but no elevation of the cell counts (ie, albuminocytologic dissociation).

    • Highly cellular CSF suggests alternate diagnoses, such as infection or inflammation.

  • Sural nerve biopsy may be indicated if the clinical presentation suggests amyloidosis or if an unexplained axonal neuropathy is present on NCS or EMG testing.

    • If the clinical suspicion for amyloidosis is high, biopsy of the abdominal fat pad or a rectal biopsy should be performed to look for amyloid deposits. Patients with amyloid neuropathy, may have patchy deposition of the abnormal proteins in nerve, but sural nerve biopsy may still be helpful, especially if the findings on fat pad and rectal biopsy are normal.

    • Nerve biopsy is unnecessary if NCS reveals clear evidence of focal demyelination, or if the course of disease and clinical findings are otherwise consistent with AAN.

  • Skin biopsy has been studied in the evaluation of small fiber neuropathy as well as demyelinating neuropathies with autonomic symptoms. [10] In patients with either acute or chronic demyelinating neuropathies, the subgroups with autonomic symptoms have lower intraepidermal nerve-fiber densities.


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