Cerebral spinal fluid (CSF) is normally colorless and clear. Analysis provides clues to infectious diseases (meningitis, encephalitis, abscess) and noninfectious diseases (subarachnoid hemorrhage, Guillain-Barré syndrome, transverse myelitis, idiopathic intracranial hypertension, vasculitis, carcinomatosis, multiple sclerosis, paraneoplastic syndromes). The presence of xanthochromia (see Fig. 25.58) in the context of recent onset of severe headache suggests a spontaneous subarachnoid hemorrhage. Turbid fluid (see Fig. 25.59) obtained from a patient with headache and neck stiffness suggests meningitis.
Cerebral Spinal Fluid—Xanthochromia. Observed in this image is a sample of CSF with xanthochromia in a patient with subarachnoid hemorrhage. (Photo contributor: Shawna D. Bellew, MD.)
Cerebral Spinal Fluid—Meningitis. Cloudy CSF in a patient confirmed to have bacterial meningitis as a result of Streptococcus pneumoniae. (Photo contributor: Scott H. Witt, MD.)
Management and Disposition
A patient with suspected subarachnoid hemorrhage requires blood pressure control and neurosurgery consultation for ICU admission. If obtunded, the patient should be intubated. Patients with suspected meningitis should be started on intravenous antibiotics tailored to the suspected pathogen and admitted to the hospital.
Xanthochromia is present in 90% of patient with a subarachnoid hemorrhage within 12 hours after the onset of bleeding.
As few as 200 white blood cells/mm3 and 400 red blood cells/mm3 will give CSF a turbid appearance.
Normal CSF production rate is 20 mL/h.
Lumbar punctures should not be performed with a platelet count of less than 50,000/mm3 or an INR of greater than 1.4 due to risk of developing a spinal hematoma.
Newer oral anticoagulants should be held for 48 hours prior to lumbar puncture.
Serum bilirubin greater than 15 mg/dL can cause CSF xanthochromia.