Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) associated to hereditary neuropathy with liability to pressure palsies (HNPP) and revealed after influenza AH1N1 vaccination.

Neurological complications of AH1N1 vaccination such as Guillain-Barré syndrome were described in the previous years. Several reports suggest that hereditary neuropathies may be a predisposing factor for immune-mediated neuropathies. We report the case of a 54-year-old female who developed chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) 5 weeks after AH1N1 vaccination. She had no previous neurological history, but neurophysiological features led us to suspect an underlying hereditary neuropathy. PMP22 gene analysis showed a typical deletion, confirming the diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP). We observed a significant clinical and neurophysiological improvement of the neuropathy after intravenous immunoglobulin treatment. This is, to our knowledge, the first reported case of CIDP potentially triggered by AH1N1 vaccination. This and previous observations suggest that genetic-determined neuropathies could predispose to the occurrence of immune-mediated neuropathies. One must recall the possibility of a superimposed hereditary neuropathy like HNPP in patients with a clinical presentation of CIDP, especially when positive family history or unexpected neurophysiological features are present.