Case Report

1. The Continued Relevance of Lumbar Puncture in the Early Diagnosis of Acute Subarachnoid Hemorrhage: A Case ReportDerek Orchard1, DO, Troy Pennington2, DO, Michael Neeki3, DO, MSDepartment of Emergency Medicine, Arrowhead Regional Medical Center, Colton CA Treatment Course Outcome Discussion/Conclusions Introduction According to McCormack et al, a CT followed by CTA can exclude SAH with greater than 99% posttest probability.[9] Therefore, performing a LP after CT/CTA puts the pretest risk of a missed aneurysmal SAH at less than 1%. This case suggests that the standard of a CT followed by LP may still be the best approach to diagnose the elusive SAH. Subsequent follow-up Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiography (MRA) showed a thrombosed one centimeter pedunculated aneurysm involving the left M-2 segment of the middle cerebral artery without flow. At one month follow up, patient complained of occasional memory loss and lightheadedness. She was ambulating with a walker. At the one year follow-up, the patient was back to baseline and only complained of a daily mild temporal headache. Subarachnoid hemorrhage (SAH) is a rare condition, accounting for less than 1% of the total headache presentations to the emergency department. Though rare, a SAH from an aneurysm carries a mortality rate between 25-50%.[9] Even if diagnosed and treated SAH leaves 1/3 of the surviving patients left with neurologic deficits affecting activities of daily living. Acute diagnosis of SAH is a challenging task. Over 25% of SAH are initially missed in the Emergency Department; however some new data suggest a much lower rate of 5.4%.[10 ] The traditional algorithm for the diagnosis of SAH includes a non-contrast computed tomography (CT) of the brain with subsequent lumbar puncture. Recent research suggests the possibility of forgoing the lumbar puncture with a negative brain CT if performed within 6 hours of symptom onset.[1] The subsequent work up resulted in no significant findings on the non-contrast brain CT yet, a hypochromic microcytic anemia with hemoglobin of 7.6 G/dL was noted. The lumbar puncture indicated a red blood cell count of 248,000/UL. A CT angiogram of the brain showed a 5 mm aneurysm at the left Middle Cerebral Artery at bifurcation with an active hemorrhagic component. The patient was admitted to the neurosurgical ICU where she underwent coiling of the aneurysm and was discharged without sustaining any significant neurological deficits. Discussion/Conclusions Non-contrast CT brain Aneurysmal SAH is a potentially devastating disease. The initial emergent diagnosis of SAH continues to be missed in 23% to 53% of patients [6,7] despite recent technological advances in CT imaging. CT without contrast has been reported to be the most sensitive imaging study in SAH. When obtained within 6 hours of headache onset, CT has 100% sensitivity and specificity[1]. Sensitivity is 93% within 24 hours of onset[8],80% at 3 days, and 50% at 1 week[1].Sensitivity is less on older second- or first-generation scanners, but most North American hospitals have been using third-generation scanners since the mid 1980s. Thin (3 mm) cuts are necessary to properly identify the presence of smaller hemorrhages. Patients who survive the initial event are at high risk of re-bleeding; which may result in death or permanent neurological deficits. Previous studies have shown that early detection significantly improves outcomes. Standard of care continues to be that patients suspected of SAH receive a non-contrast CT brain with subsequent LP. This case contradicts the recent recommendation by Perry et al to forego lumbar puncture if an inconclusive modern third generation CT is found within the first 6 hours of symptom onset. [1] Case Report References A 42 year-old right-handed hispanic female without significant medical history presented to the emergency department complaining of new onset headache. While coaching her daughter’s cheer team, the patient reported sudden onset sharp unremitting headache localized to the left frontal area with radiation to the posterior neck. The headache was associated with nausea and photophobia. She denies history of recent trauma, illness, migraines or family history of brain aneurysm. Patient denies tobacco or recreational drugs but admits to occasional alcohol and takes acetaminophen as needed. Physical examination was remarkable for moderate distress, mildly elevated blood pressure, normal eye exam, no meningeal signs, no evidence of trauma, no focal neurological deficits, and GCS 15. The patient reported improvement after a migraine cocktail, which included dexamethasone, diphenhydramine and metoclopramide. • Perry JJ, Stiell IG et al Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ 2011 Jul.;343(jul18 1):d4277–d4277. • Jeffrey J Perry, et al. High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: prospective cohort study. BMJ. 2010; 341: c5204. • Jeffrey J Perry, et al. An international study of emergency physicians' practice for acute headache management and the need for a clinical decision rule. CJEM. 2009 Nov;11(6):516-22. • A-M Landtblom A-M, et al. Sudden onset headache: a prospective study of features, incidence and causes. Cephalalgia 2002; 22:354-360. London. ISSN 0333-1024. • Ricardo J. Komotar, et al. Resuscitation and Critcal Care of Poor-Grade Subarachnoid Hemorrhage. Neurosurgery 64:397-411, 2009 • Edlow JA, Kalan LR. Primary care: Avoiding pitfalls in the diagnosis of subarachnoid hemorrhage. N Engl J Med 2000;341:29-36. • Kowalski RG, Claassen J, Kreiter KT, et al. Initial misdiagnosis and outcome after subarachnoid hemorrhage. JAMA 2004;291:866-9. • Suarez JI, Tarr RW, Selman WR. Aneurysmal subarachnoid hemorrhage. N Engl J Med. Jan 26 2006;354(4):387-96 • McCOrmack RF, Hutson A. Can Computed tomography angiography of the brain replace lumbar puncture in the evaluation of acute-onset headache after a negative noncontrast cranial computed tomography scan?. Acad Emerg Med 2010 Apr; 17(4):444-51. • Marian J. Vermeulen, Michael J. Schull. Missed Diagnosis of Subarachnoid Hemorrhage in the Emergency Department. Stroke. 2007;38:1216-1221 CT Angiogram (CTA) brain