Going Green in the CSF

By Joseph F. John, MD, Associate Chief of Staff for Education, Ralph H. Johnson Veterans Administration Medical Center; Professor of Medicine, Medical University of South Carolina, Charleston, is Associate Editor for Infectious Disease Alert.

Dr. John reports no financial relationship to this field of study.

Synopsis: Pigment production by P. aeruginosa made the cerebral spinal fluid green.

Sources: Escota G, Como J, Kessler H. The green cerebrospinal fluid. Am J Med 2011;124:411-413.

A 52-year-old woman had systemic symptoms including nausea and vomiting. Seven months prior to admission she had a subarachnoid hemorrhage and needed multiple ventriculo-pleural shunts. The newest shunt was 2 months old at the time of the patient's admission. She was alert on admission, but had a left pleural effusion. The shunt was externalized and the external ventricular drain provided. Cerebral spinal fluid (CSF) then was sampled and sent daily for chemistries and culture. The initial CSF formula included 10,000 RBCs and 40 WBCs, of which 58% were monos. CSF glucose and protein were normal. The daily CSF sample was a light green color, had Gram-negative rods on microscopic examination, and consistently grew Pseudomonas aeruginosa.

The patient was treated with cefipime 2 g Q 8 hours, but the organism was only intermediately susceptible. The spinal fluid persisted to be green. Cefepime was stopped and meropenem 2 g Q 12 hours was begun. The CSF remained green. Intrathecal amikacin 20 mg/day was initiated. After 1 day, the CSF cleared and the patient eventually had a complete recovery.


The group from Rush Medical School's Infectious Disease Section headed by Dr. Harold Kessler brought this case to light. The article brings up many experiences by us older ID clinicians that in the treatment of Gram-negative CNS infections still pertain to modern care. About 20 years ago in the midst of a rash of CNS infections with Gram-negative bacilli, a study commenced to determine the efficacy of intrathecal amikacin. I remember the massive consent form, itself a challenge to enrolling these unusual patients.1

Yet the clinical trial provided experience with intrathecal dosing and use of aminoglycoside, which impacts still today as evidenced by this patient's eventual happy outcome. The authors discuss the process of choosing antibiotics for Gram-negative meningitis, a process that may end in use of intrathecal antibiotics. New studies suggest the cure rate for Gram-negative meningitis may only be slightly more than 50% and P. aeruginosa still causes 35% of the cases.2

The novelty of this report was the green color (due to the pyoverdin and pyocyanin pigments produced by P. aeruginosa) of what should otherwise be a crystal clear CSF. The CSF remains one of the few areas of modern life where we would choose not to "go green."


  1. Rodriguez K, Dickinson GM, Greenman RL. Successful treatment of gram-negative bacillary meningitis with imipenem/cilastatin. South Med J1985;78:731-732.
  2. Hammad OM, Hifnawy TM, Omran DA, et al. Gram-negative bacillary meningitis in Egypt. J Egypt Public Health Assoc 2011;86:16-20.