SAH and ICH Flashcards
Define Subarachnoid hemorrhage
is the leakage of blood into the subarachnoid space and classically presents as a sudden, severe headache.
About 75% of atraumatic subarachnoid hemorrhages are caused by a ________________
ruptured aneurysm
In about 20% of cases a cause is___________
not identified
The remaining causes (5%) are related to a variety of miscellaneous conditions,
including arteriovenous malformations, sympathomimetic drugs, and other less common causes
__________________are focal arterial pouches typically located in areas of bifurcation of the circle of Willis.
Cerebral aneurysms
larger aneurysms of what size are more likely to rupture than smaller aneurysms?
> 5 to 10 mm
Patients with subarachnoid hemorrhage classically present to the ED with________________________
a severe headache of acute onset (termed a “thunderclap” headache) that reaches maximal intensity within seconds.
True or false
Even if a patient is not experiencing the “worst headache of their life,” a headache that is different in intensity or quality from past headaches should raise concern for subarachnoid hemorrhage
True
Subarachnoid hemorrhage can be ruled out with 100% sensitivity with implementation of the______________________________ for headache evaluation.
Ottawa Subarachnoid Hemorrhage Rule
subarachnoid hemorrhage may be excluded in patients
under 40 years of age
without neck pain or stiffness
without a witnessed loss of consciousness
without onset during exertion
without a thunderclap headache
without limited neck flexion
Give risk factors for SAH
• Hypertension
• Smoking
• Excessive alcohol consumption
• Polycystic kidney disease
• Family history of subarachnoid hemorrhage
• Coarctation of the aorta
• Marfan’s syndrome
• Ehlers-Danlos syndrome type IV
• α1-Antitrypsin deficiency
Differential Diagnosis of Subarachnoid Hemorrhage
• Vascular pathology (other intracranial hemorrhage, ischemic stroke or transient isch-
emic attack, arterial dissection, venous thrombosis)
• Drug toxicity
• Infection (meningitis, encephalitis)
• Intracranial tumor
• Intracranial hypotension
• Metabolic derangements
• Primary headache syndromes (benign thunderclap headache, migraine, cluster headache)
• Hypertensive disorders
The initial diagnostic modality of choice when subarachnoid hemorrhage is suspected is a
noncontrast CT of the head
The sensitivity of CT in diagnosing subarachnoid hemorrhage is highest shortly after symptoms begin and is estimated to be 98% within_____________ of symptom onset
6 to 12 hours
In patients who are neurologically intact who present with a thunderclap headache, a normal head CT within_________ of headache onset is extremely sensitive in ruling out aneurysmal subarachnoid hemorrhage
6 hours
Sensitivity of CT scan decreases to about 91% to 93% at 24 hours and continues to decline rapidly thereafter, reaching______ at 1 week.
50%
Most authorities recommend__________________ when a patient with suspected subarachnoid hemorrhage has a normal head CT.
cerebrospinal fluid (CSF) analysis
The_______________ in the ____________ tube of CSF is commonly used to identify subarachnoid hemorrhage.
RBC count in the third or fourth
Xanthochromia is a yellow appearance of the CSF due to the
enzymatic breakdown of blood releasing bilirubin
Limitation of Xanthochromia test
it takes approximately 12 hours from hemorrhage onset for xanthochromia to develop in CSF
True or false
normal head CT result with a positive finding of xanthochromia or elevated RBC count in tube 4 should be considered diagnostic of subarachnoid hemorrhage
True
The risk of rebleeding is greatest in the first _________ and can be reduced by adequate blood pressure control.
2 to 12 hours
While target pressures have not yet been established, a decrease in systolic blood pressure to a range of______________ is reasonable
120 to 160 mm Hg
Avoid__________________ because they increase cerebral blood volume and intracranial pressure.
nitroprusside and nitroglycerin
