The aim of this study is to describe the cerebrospinal fluid’s (CSF) characteristics in transplanted patients without a primary neurologic disease and describe patients’ clinical and pharmacological variables at the moment of the procedure.

Normal CSF values are standardized for adult population. Transplanted patients have unique characteristics due to immunosuppression and polypharmacy, that can alter CSF without a pathological value.

Observational, retrospective, and descriptive study. We reviewed clinical records and CSF reports of transplanted patients without a primary neurological inflammatory disease, between 2017 and 2019.

N=97. Median age 57 y.o. (IQR 33,5-63), female 39,2%.

Opening pressure 16 cm H2O (SD 9,4), white blood cell count 1/mm3 (IQR 0-2), CSF glucose 74,7 mg/dl (SD 23,5), CSF/blood glucose ratio 0,56 (SD 0,13), CSF proteins 0,43g/l (IQR 0,28-0,76).

Renal transplant was the most frequently performed (37,1%).

Comorbidities: 20,6% had diabetes; 11,3% hypothyroidism; 28% had history of neurological disease and 12,4% had cancer without compromise of the nervous system.

Polypharmacy was a feature common to all the patients, being immunosuppressants (100%) and antibiotics (60.8%) the most frequently prescribed drugs. On average, patients were under treatment with 1.9 immunosuppressants and 2.5 antibiotics.

During hospital stay, 60,8% developed sepsis, 22,7% seizures and 13,4% non-convulsive status epilepticus. Mortality was 17,5%.

When analyzing the CSF values included in the interquartile range, all of them, except for white blood cell count, exceed what is established as normal for adults.

Several systemic factors have been described that could influence the CSF’s characteristics (hypothyroidism, diabetes, polypharmacy, autoimmune disorders, systemic inflammation). Baring these findings in mind, it would be important to always contextualize the clinical finding and suspected diagnosis based on the CSF findings, in order to avoid asking for unnecessary ancillary tests and starting empirical treatment.