Greetings @deholt, the patient of the present case was not able to perform lumbar puncture, in view of the country situation, however, the study of brain abscess falls within the protocol, the frequent thing we observe in this case is hypoglycorrhagia, proteinorrhagia, isolation of some germ in the culture. With respect to the contraindication to this procedure it would be that the patient presents signs and symptoms of endocranial hypertension, prolongation of coagulation times, infected lesions at the LP site, among others. Another thing to keep in mind is that you can have a sterile liquid in those patients who have received antibiotic therapy for several days prior to diagnosis.