Background
Neuropathy is present in approximately half of all individuals with diabetes mellitus (DM), with diabetic peripheral neuropathy (DPN) as the most common cause. However, it is important to be aware of other causes of neuropathy, which may be readily treatable.
Case
A 33 year old male with DM diagnosed four months prior presented with intractable postprandial nausea and vomiting, and progressive lower limb peripheral neuropathy over five months. Severe gastroparesis was confirmed on a gastric emptying study. Symptoms were not responsive to prokinetics. Nutritional, viral, autoimmune and vasculitic screens for neuropathy were negative. Magnetic resonance imaging of the brain was normal. Cerebrospinal fluid analysis revealed an elevated protein level. Nerve conduction studies revealed a sensory motor axonal and demyelinating polyneuropathy. A probable diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) was made and the patient was treated with a five-day course of intravenous immuonoglobulin (IVIg) with rapid resolution of his gastroparetic symptoms.
Discussion
CIDP is a heterogenous immune-mediated disorder of the peripheral nervous system, seen in ~ 8 per 100,000 persons. The classical form is characterised by symmetrical proximal and distal muscle weakness and sensory loss. Autonomic dysfunction may occur, though is rare. Several studies report an increased prevalence of CIDP in individuals with DM, and after DPN, it is one of the most common causes of neuropathy in those with DM. Patients with DM and CIDP tend to have more extensive axonal loss and more severe neuropathy, however respond equally well to immunotherapies as CIDP patients without DM.
Conclusion
It is important consider CIDP when assessing patients with symptoms not typical of DPN, as in contrast to the latter, it is often responsive to immunomodulatory treatment.