To measure, and seek clinical correlates with, levels of substance P (SP) in the cerebrospinal fluid (CSF) of fibromyalgia syndrome (FMS) patients.
CSF from 32 FMS patients and 30 normal control subjects was tested for SP by radioimmunoassay. Clinical measures included tender point examination and standardized questionnaires.
CSF SP levels were 3-fold higher in FMS patients than in normal controls (P < 0.001), but they correlated only weakly with tenderness found on examination.
SP is significantly elevated in FMS CSF, but other abnormalities must exist in FMS to more fully explain the symptoms.