Subarachnoid Hemorrhage Nina T. Gentile, MD Associate Professor Division of Emergency Medicine Temple University School of Medicine Philadelphia, PA. Teaching Objectives. Emphasize the importance of early detection of both large and “sentinel” SAH
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Subarachnoid HemorrhageNina T. Gentile, MDAssociate ProfessorDivision of Emergency MedicineTemple University School of MedicinePhiladelphia, PA
Teaching Objectives • Emphasize the importance of early detection of both large and “sentinel” SAH • Understand the value and the limitations of CT and LP to diagnose the disease • Describe the therapies used to manage or prevent • The acute effects of the hemorrhage • Vasospasm and subsequent ischemic stroke
Aneurysmal Subarachnoid Hemorrhage: Introduction • 30,000 Americans suffer non-traumatic SAH each year • Overall mortality rates are 35 to 40% • Up to 12% of patients die before reaching medical attention • Another 25% die in subsequent 3 months • Morbidity among survivors is 50%
Case Example • 49 year old male with sudden onset of severe headache followed by a syncopal episode at work • Colleagues called EMS who found him awake but confused • No PMH and on no medications
Symptoms of Subarachnoid Hemorrhage • Sudden, unusually severe or “thunderclap” headache • Pain in neck, back, eye, or face • Loss of or change in consciousness • Nausea, vomiting, photophobia, or phonophobia
Signs of Subarachnoid Hemorrhage • Abnormal vital signs • Respiratory changes, hypertension, cardiac arrhythmias • Meningismus • Focal neurologic signs • III nerve palsy – IC/PCA aneurysm • Paraparesis – ACA aneurysm • Hemiparesis, aphasia – MCA aneurysm • Ocular hemorrhages
Symptoms and Signs of Subarachnoid Hemorrhage • Roughly half of all patients with SAH have “typical” presentations • However, patients presenting with less severe headache without a change in mentation, meningismus or a focal neurologic deficit are likely to be misdiagnosed
Warning or “Sentinel” Bleeds • Diagnosis of “sentinel” hemorrhage is often made retrospectively • Up to 50% of patients with SAH report having had a distinct, severe headache in the days to weeks before the index bleed • half will have seen a doctor • Screen patients with “sentinel” headaches before a full-blown hemorrhage occurs.
Misdiagnosis of SAH Outcome of Patients Initially Misdiagnosed and Correctly With SAH Outcome Misdiagnosis (n=45) Correct Diagnosis (n=75) Excellent/good 24 (53)* 68 (91)* Fair 5 (11) 4 (5) Poor/vegetative/dead 16 (36)* 3 (4)* Values are number (%) in each clinical grade category. • P<.001 Stroke 1996;27:1558-63
Suspected SAH Unenhanced CT CT (-) CT (+) LP (-) LP (+) Subspecialty Consultation No SAH
Computed Tomography • Sensitive for blood • day of the bleed 95% • within 12 hours of symptom onset as high as 98%. • Sensitivity drops when • symptoms are days in duration • amount of bleeding is small • study is difficult to interpret • Patients with small or “sentinel” bleeds are more likely to receive an incorrect clinical diagnosis and are more likely to have a false negative CT 85%
Computed Tomography Characteristic hemorrhage after aneurysmal rupture
Lumbar puncture and CSF Exam in SAH • CSF should be examined if the CT is negative, equivocal, or technically inadequate • LP early after symptom onset will show frank blood or red blood cells on microscopy. • Delayed CSF examination may show only xanthochromia or an inflammatory reaction
Cardiac Complications of Subarachnoid Hemorrhage • ECG abnormalities are common in SAH • ST segment elevation or depression and deep T waves are the most common. • Are usually benign • Cardiac damage can occur • CK-MB elevated in 20 to 50% • Echo shows LV abnormalities (especially with severe SAH)
Vasospasm • Appears after 3-4 days and peaks at 7-10 days • Caused by a release of factors at time of bleeding that induce vasoconstriction and decreased blood flow • New headache, seizures, or decreased alertness • New focal neurologic signs suggesting ischemia
Prevent Ischemic Complications of Vasospasm • Avoid Dehydration, Correct Hyponatremia and Hypotension • Manage High Intracranial Pressure (CPP=MAP-ICP) • Early Use of Calcium Channel Blocker • Nimodipine 60 mg q4 po or NG
Returning to our Case Example… • Patient’s CT scan showed SAH. • With neurosurgical input, oral nimodipine was started while in the ED. • Angiography revealed a ruptured right posterior communicating artery aneurysm. • He underwent aneurysm clipping and developed symptomatic vasospasm on post-op day 4. • After rehab, he was left with only a mild right hemiparesis.
Teaching Points • SAH is often misdiagnosed • CT is sensitive but not fool-proof • LP for patients with normal or equivocal CT • Early angiography and neurosurgical consultation to facilitate surgical intervention • Treat to: • Avoid aspiration, hypertension, and neurogenic cardiac injury • Control seizure and increased ICP • Prevent recurrent hemorrhage and ischemic stroke from vasospasm