Subarachnoid hemorrhage often misdiagnosed in ED

September 15, 2009

As many as 12% of subarachnoid hemorrhages are misdiagnosed at the ED, leading clinicians to look past the classic symptoms to CT scans and lumbar punctures for proof.

CT scan, lumbar puncture can back up classic headache symptom

An ED physician at Brackenridge Hospital in Austin, TX, was about to give a triptan to a 42-year-old woman with a severe headache and a history of migraines. However, the treatment plan changed dramatically, due to a piece of information shared by an ED nurse.

"While the nurse was talking to the patient, she told her that the pain was significantly different than her migraines and that this was worse," says Lauren Brandt, RN, MSN, CNRN, clinical director of Brackenridge's Neurosciences, Brain & Spine Center in Austin, TX. "The nurse brought that information to the physician, who then ordered a CT scan which showed a subarachnoid hemorrhage."

Subarachnoid hemorrhage is one of the most deadly neurological emergencies, but it is often misdiagnosed, as often as 12% of the time, according to updated guidelines from the American Heart Association.1 Misdiagnosed patients are four times as likely to die or become disabled.

Any patient with an acute, new onset headache needs to be seriously considered as having a diagnosis of a ruptured aneurysm, says Aman B. Patel, MD, one of the authors of the guidelines and an associate professor of neurosurgery and radiology and director of the Cerebrovascular Program at New York City-based Mount Sinai School of Medicine.

Brandt advises looking for the classic symptom: The "worst headache" of the patient's life. "These are usually described as a 'thunderclap' or very sudden onset, sometimes with a loss or change in consciousness," says Brandt. "Other signs and symptoms include cranial nerve defects. Photophobia and nuchal rigidity may occur later."

If the headache is misdiagnosed as a new migraine, says Brandt, "only pain medications are given, because there are no other real symptoms on presentation. The most common demographics are women between the ages of 40 and 60, which are also the most typical type of patient to have headaches from other causes."

Patel notes that although "the worst headache of my life" is a classic sign, somebody who doesn't have a history of headaches with a headache severe enough to bring them to the ED "should be concerning enough" for you to consider subarachnoid hemorrhage.

Patients who come in with sudden, severe headaches should get an immediate CT scan to look for evidence of hemorrhage, says Brandt.

"The CT scan is approximately 95% effective in detecting the presence of blood if done early," she says. "There is a high percentage of patients who are at risk of re-bleeding during the first 24 to 48 hours after the initial hemorrhage. If the aneurysm or cause of bleeding is not identified and secured, then the mortality from this significantly increases."

Patel says if you still are concerned after a negative head CT scan, a lumbar puncture can be done. "That should pick up the last of the subarachnoid hemorrhages," he says. "After the diagnosis has been made, the goal of the ED is preventing re-rupture until the aneurysm can be secured, before the patient is transferred to the neurosurgical intensive care unit or another center."

Keeping the blood pressure under control is very important, says Patel. Hypertension is a predisposing factor to having a second hemorrhage, and the mortality from a second hemorrhage is 70% or higher, he says. "The second therapeutic measure that needs to be instituted is the loading of dilantin or another antiepileptic agent to prevent a seizure, which has also been associated with a higher risk of re-rupture," says Patel.

Reference

1. Bederson JB, Connolly S, Batjer H, et al. Guidelines for the management of aneurysmal subarachnoid hemorrhage.

Stroke

2009; 40:994-1,025.

This story was adapted from one originally published by AHC Media LLC (800-688-2421).

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