Pruritus in familial Creutzfeldt-Jakob disease: a common symptom associated with central nervous system pathology.

Pruritus, a common feature of animal prion diseases such as scrapie, is rarely reported in humans with Creutzfeldt-Jakob disease (CJD), and its anatomical background is not well defined. The present study was undertaken to carry out a methodical prospective search for the prevalence of pruritus in CJD patients and investigate its anatomical substrate by MRI. The study group included consecutive familial and sporadic CJD patients carrying the E200K PRNP mutation followed up in a longitudinal prospective study between the years 2005 and 2008. Pruritus was prospectively screened for and diffusion-weighted imaging (DWI) was used to correlate brain diffusion abnormalities with pruritus in CJD patients. Pruritus was present in 6/31 (19.35%) patients with familial disease (fCJD) and in none of the patients with sporadic disease (sCJD). Pruritus was a presenting symptom in one patient and evolved during the course of the disease in the other five patients. The pruritus was generalized in three patients, regional in two and localized in one patient. It was transient in one patient and continued throughout the disease in five patients. DWI showed that pruritus was significantly associated with reduced diffusion in the several areas known to be affected by CJD, but most significantly in the midbrain periaqueductal grey matter. Pruritus is relatively common in patients with familial CJD carrying the E200K mutation. Our findings point to a central origin that involves damage to the inhibitory gating mechanism for itch in the periaqueductal grey matter.