Isolated blood-cerebrospinal fluid barrier dysfunction: prevalence and associated diseases

An isolated dysfunction of the blood-CSF barrier is characterised by an abnormal elevation of the albumin CSF/serum concentration ratio (Q(alb)) without any other pathological CSF findings. Although common in routine CSF analysis, the clinical significance of an isolated barrier dysfunction frequently remains unclear. We examined neurological disorders associated with an isolated elevation of Q(alb) to identify possible determinants of blood-CSF barrier dysfunction.

367 patients (124 women, 243 men, median age 60. 0 years) out of 3,873 patients receiving diagnostic lumbar puncture at the University Hospital of Ulm (Germany) showed an isolated dysfunction of the blood-CSF barrier. Clinical data as well as MRI findings of these patients were analysed.

Isolated barrier dysfunction occurred most frequently (> 30%) in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), normal pressure hydrocephalus (NPH), lumbar spinal stenosis, and polyneuropathy (PNP). In patients who showed no other evidence of neurological disease, isolated barrier dysfunction was found in 14. 9% of cases. The extent of barrier dysfunction was most prominent in brain tumours, GBS, and CIDP. There was a significant correlation of Q(alb) with both weight and body mass index (BMI).

Although isolated barrier dysfunction may be found in a variety of neurological diseases, it is especially frequent in GBS, CIDP, NPH, spinal canal stenosis, and PNP. In these patients, disease-related mechanisms contributing to barrier dysfunction are likely. Moreover, barrier function seems to be influenced by disease-independent determinants like weight and BMI.