Lower Risk of Missed Subarachnoid Hemorrhage

Missed cases of subarachnoid hemorrhage "are devastating to everyone involved," says Andrew Garlisi, MD, MPH, MBA, VAQSF, medical director for Geauga County EMS and co-director of University Hospitals Geauga Medical Center's Chest Pain Center in Chardon, OH.

Misdiagnosis of aneurysmal subarachnoid hemorrhage in the ED has been reported to occur in a significant proportion of cases, due in part to a wide spectrum of presentations and subtle initial signs.1,2

Legal pitfalls for the ED physician include failure to take a careful history including rapidity of onset, intensity and character of the headache pain, or failure to inquire about personal or family history of cerebral aneurysm or intracranial bleed.

Other potential problems, says Garlisi, involve minimizing the patient's complaint or judging the patient as a drug-seeker, and unfamiliarity with performing a high-quality, atraumatic lumbar puncture. Physicians may also have the perception that the lumbar puncture, if done, will consume too much time in a busy ED.

Reliance on a negative head CT to rule out subarachnoid hemorrhage is a dangerous practice, warns Garlisi. "A CT scan can miss a sentinel bleed which is swept away by the cerebrospinal fluid, only to be found on analysis of the spinal fluid," he explains.

For patients with sudden severe headaches, or headaches clearly of different pattern than the typical migraine usually experienced, Garlisi says that "it behooves the emergency physician to explain to the patient and family why a lumbar puncture is indicated" If the patient refuses, a Refusal of Procedure form should be signed, with risks of undiagnosed subarachnoid hemorrhage explained.

Garlisi says that a colleague once complained that he was experiencing trouble performing the lumbar puncture procedure. "He had several 'traumatic' taps, especially on patients who required three or four needle sticks to obtain the specimen," says Garlisi. "He complained that the patients could not remain still during the procedure. He also had trouble performing lumbar punctures on obese patients." Garlisi gives these recommendations:

• Take a couple of minutes to reassure the patient. "Let the patient know how important it is to remain still and in good position to maximize the likelihood of a successful tap," says Garlisi. "Tell the patient you will provide light sedation."

• Sedate the patient after obtaining consent. "A small dose of Versed with a narcotic makes the procedure more humane and tolerable. It virtually guarantees that the patient will not jump or squirm while the needle is introduced," says Garlisi.

• Sit the patient up, leaning over a bedside table with pillow. "I find this creates an incredible alignment of hips and shoulders, and makes it easier for the patient to arch the back, making palpation of landmarks easier," says Garlisi.

Recognize Risk

Sandra Schneider, MD, professor of emergency medicine at University of Rochester (NY) Medical Center, says that the first issue is the recognition of a patient at risk. "These are generally young healthy patients who present with a headache," she says. "Sorting through all the headaches for the one subarachnoid hemorrhage can be difficult. Subarachnoid hemorrhages have been reported to improve with analgesia, even Compazine," notes Schneider.

Have a low index of suspicion, and remember that CT does not rule out all subarachnoid hemorrhages. "About 10% will have a normal CT," says Schneider. "Even a perfusion CT is not conclusive, as again a small number will not have a documented aneurysm." If the patient refuses an lumbar puncture, it should be carefully documented including they were warned of potential rebleed.

Most often, ED physicians are sued for sending the patient home and the patient then rebleeds with devastating neurologic deficits. Lawsuits may involve a scenario where the patients' workup is delayed, "but most, if not all, are for discharging the patient," says Schneider.

Patients with a sudden onset of severe headache should be worked up for subarachnoid hemorrhage, says Schneider, and patients who have a negative CT for subarachnoid hemorrhage should have a lumbar puncture. "If possible, headaches should be treated with alternatives to narcotics, such as Compazine," says Schneider.

Jesse M. Pines, MD, MBA, MSCE, associate professor of emergency medicine and health policy at George Washington University in Washington, DC, says that while emergency physician might think that the most dangerous practice is not getting a lumbar puncture after a negative CT, according to the literature, the most dangerous practice is not getting a CT.3 "The message here is that if you are at all concerned about subarachnoid hemorrhage, get a CT," says Pines.

Pines says that unfortunately, there are no clinical decision rules that effectively differentiate patients who have subarachnoid hemorrhage from those who don't. While the best way to reduce liability is to test more, this will also increase costs.

"From a patient perspective, it is not clear whether this will improve outcomes. But increased testing will certainly increase the amount of radiation delivered, and the numbers of painful lumbar punctures, of which a third get post-dural headaches," says Pines. "These can debilitate patients for more than a week."


  1. Vermeulen MJ, Schull MJ. Missed diagnosis of subarachnoid hemorrhage in the emergency department. Stroke 2007; 38:1216-1221.
  2. Edlow JA, Rothman RE, Barsan WG. What do we really know about neurological misdiagnosis in the emergency department? Mayo Clin Proc 2008; 83:253-254.
  3. Kowalski RG, Claassen J, Kreiter KT, et al. Initial misdiagnosis and outcome after subarachnoid hemorrhage. JAMA 2004 18;291:866-869.