Correspondence
Clinical Problem-Solving: A Balancing Act
N Engl J Med 1999; 341:129-130July 8, 1999
- Article
To the Editor:
In the commentary of their Clinical Problem-Solving article “A Balancing Act” (Feb. 4 issue),1 Saha and colleagues emphasize the importance of clinical examination in assessing the safety of lumbar puncture. In particular, the presence of papilledema and focal neurologic signs are mentioned as indicators of increased intracranial pressure. Another valuable clinical marker is an assessment for retinal venous pulsation. Its presence has been demonstrated to signify that intracranial pressure is normal. Levin2 showed that although patients with normal intracranial pressure may not have venous pulsation, no patient with increased intracranial pressure had venous pulsation, despite the fact that only one third had evidence of papilledema. This simple clinical assessment would identify patients at increased risk from lumbar puncture and, hence, those who may benefit from brain imaging.
2 ReferencesTimothy B.L. Ho, M.R.C.P.
St. George's Hospital, London SW17 0QT, United KingdomHeather J. Jefferson, M.R.C.P.
King's College Hospital, London SE5 9RS, United Kingdom1
Saha S ,Saint S ,Tierney LM Jr . A balancing act. N Engl J Med 1999;340:374-378
Full Text | Web of Science | Medline2
Levin BE . The clinical significance of spontaneous pulsations of the retinal vein. Arch Neurol 1978;35:37-40
Web of Science | Medline
To the Editor:
Though the possibility of a brain abscess was not explicitly mentioned by the discussant in the Clinical Problem-Solving article or in the commentary, it may have been included in the differential diagnosis under the term “intracranial mass lesion.” The patient had an important feature that sometimes points to this diagnosis: a meningeal syndrome with polymorphonuclear pleocytosis suggestive of bacterial meningitis but negative Gram's staining and culture of cerebrospinal fluid. My colleagues and I have recently treated two patients with such features.
The first patient was a 37-year-old woman who presented with a headache, fever, photophobia, and nuchal rigidity, without focal neurologic deficit. Meningitis was suspected, and a lumbar puncture revealed 1754 leukocytes per cubic millimeter (65 percent polymorphonuclear cells) and hypoglycorrhachia (glucose level, 1.8 mmol per liter — 31 percent of the blood glucose level). Gram's staining of cerebrospinal fluid was negative. Treatment with ceftriaxone was followed by rapid defervescence and resolution of signs and symptoms. A computed tomographic (CT) scan obtained 13 days later revealed a small temporo-occipital abscess. After another three weeks of antibiotic treatment without neurosurgical intervention, the CT scan showed complete resolution of the lesion.
The second patient was a 73-year-old man with diabetes who was hospitalized for headache, slight fever (temperature, 37.2°C), and dizziness accompanied by falls. On admission he was fully oriented, with no focal neurologic deficits but with severe nuchal rigidity. Lumbar puncture revealed 1304 leukocytes per cubic millimeter (80 percent polymorphonuclear cells) and hypoglycorrhachia (glucose level, 0.6 mmol per liter — 7 percent of the blood glucose level). Gram's staining was negative. Treatment with ceftriaxone and amoxicillin was started. The patient's condition improved over the next three days. A CT scan showed an abscess in the right frontal region with blockade of the foramen of Monro. Neurosurgical drainage was necessary, and culture of abscess fluid revealed nocardia.
In patients who have signs, symptoms, and cerebrospinal fluid findings typical of bacterial meningitis but in whom no organisms are found in cerebrospinal fluid, follow-up CT scans should be obtained, even if clinical improvement occurs, because such patients may have a brain abscess, necessitating neurosurgical intervention.
Sigmund Rüttimann, M.D.
Kantonsspital Schaffhausen, CH-8208 Schaffhausen, SwitzerlandAuthor/Editor Response
The authors reply:
To the Editor: We agree with Drs. Ho and Jefferson that assessment for retinal venous pulsation, if there was a reliable method, might also be useful in determining the safety of lumbar puncture. We disagree, however, that this test “would identify patients at increased risk from lumbar puncture and, hence, those who may benefit from brain imaging.” As Drs. Ho and Jefferson point out, Levin found that the absence of retinal venous pulsations was a sensitive but nonspecific marker of elevated intracranial pressure.1 In other words, the presence of pulsations (a negative test) reliably indicates that the intracranial pressure is normal (less than 180 to 190 mm of water), but the absence of pulsations (a positive test) does not reliably indicate that intracranial pressure is elevated. Most patients with no pulsations are likely to have normal or mildly elevated intracranial pressure and are therefore unlikely to be at increased risk for brain herniation, which is usually associated with very high intracranial pressure (>500 mm of water2). Brain imaging would not be routinely indicated for these patients. If Levin's results are reproducible, however, the presence of retinal venous pulsations would be a useful and inexpensive way of identifying patients with normal intracranial pressure, thereby reassuring clinicians of the relative safety of lumbar puncture.
Dr. Rüttimann's case reports highlight the importance of considering brain abscess and other parameningeal infections when a patient is thought to have bacterial meningitis but analysis of cerebrospinal fluid reveals no organisms. Given the potentially dire consequences of undiagnosed brain abscess, we agree that brain imaging is indicated in such patients, though perhaps not in those with obvious reasons for having sterile cerebrospinal fluid, such as recent use of antibiotics.
2 ReferencesSomnath Saha, M.D., M.P.H.
Portland Veterans Affairs Medical Center, Portland, OR 97207Sanjay Saint, M.D., M.P.H.
University of Michigan, Ann Arbor, MI 48109Lawrence M. Tierney, M.D.
University of California, San Francisco, San Francisco, CA 941431
Levin BE . The clinical significance of spontaneous pulsations of the retinal vein. Arch Neurol 1978;35:37-40
Web of Science | Medline2
Durand ML ,Calderwood SB ,Weber DJ , et al. Acute bacterial meningitis in adults -- a review of 493 episodes. N Engl J Med 1993;328:21-28
Full Text | Web of Science | Medline
