Cerebral Aneurysm, Emergency Medicine

Basics

Description

Abnormal, localized dilation or outpouching of cerebral artery wall:
- Occurs in 5-10% of population
Rupture of saccular aneurysms account for 5-15% of strokes
Of those that rupture:
- 40% occur at anterior communicating artery (ACA)
- 30% at internal carotid (IC)
- 20% in middle cerebral artery (MCA)
- 5-10% in vertebrobasilar artery (VBA) system

Etiology

Asymptomatic in 3.2% of population
"Congenital,"¯ saccular, or berry aneurysms most common (90%):
- Develop at weak points in arterial wall and bifurcations of major cerebral arteries
- Incidence increases with age
- Multiple in 20-30%
- Increased incidence:
  - Polycystic kidney disease
  - Cerebral arteriovenous malformation
  - Type III collagen deficiency
  - Fibromuscular dysplasia
  - Ehlers-Danlos syndrome
  - Marfan syndrome
  - Pseudoxanthoma elasticum
  - Neurofibromatosis
  - Moyamoya syndrome
  - Coarctation of the aorta
  - Tuberous sclerosis
  - Sickle cell disease
  - Osler-Weber-Rendu syndrome
  - Ī±1-Antitrypsin deficiency
  - Systemic lupus erythematosus
  - Glucocorticoid remediable hyperaldosteronism
Arteriosclerotic, fusiform, or dolichoectatic (7%):
- More common in peripheral arteries
Inflammatory (mycotic):
- 10% of patients with bacterial endocarditis
Traumatic, associated with severe closed head injury
Neoplastic, embolized tumor fragments
Familial correlation: 1st-degree relative with history of aneurysm essentially doubles lifetime risk

Although rare in children, more likely to be giant (>25 mm)
Occur in the posterior circulation

Diagnosis

Signs and Symptoms

Commonly asymptomatic before rupture
Sentinel headaches occur in 30-60% of patients before rupture:
- Can be unilateral
Seizures, syncope, or altered level of consciousness

History

Onset of headache
Family history
Altered mental status
Focal neurologic deficits
Rupture results in subarachnoid hemorrhage:
- Headache: Severe ("worst headache ever"¯) with sudden onset ("thunderclap"¯)
  - Different from prior headaches
  - Classically without focal deficits
- Nuchal rigidity (most common sign) secondary to blood in CSF

Physical Exam
Compression of adjacent structures may cause neurologic symptoms:

ACA aneurysms:
- Optic tract: Altitudinal field cut or homonymous hemianopsia
- Optic chiasm: Bitemporal hemianopsia
- Optic nerve: Unilateral amblyopia
Aneurysms at IC-posterior communicating artery junction:
- Oculomotor nerve: Fixed and dilated pupil, ptosis, diplopia, and temporal deviation of eye with inability to turn eye upward, inward, or downward
Aneurysms in cerebral cortex may produce focal deficits including:
- Hemiparesis
- Hemisensory loss
- Visual disturbances
- Aphasia
- Seizures

Essential Workup

Complete neurologic examination
Emergent noncontrast head CT scan will diagnose 90-95% of subarachnoid hemorrhages
Lumbar puncture with CSF analysis if CT scan is negative

Diagnosis Tests & Interpretation

Lab

Coagulation studies
Baseline CBC with platelets and differential
Electrolytes
Renal and liver function tests
Arterial blood gas

Imaging

CXR for pulmonary edema
4-vessel cerebral angiography remains gold standard
MRA
Helical CT scanning may be useful in detecting aneurysms >3 mm
Transcranial Doppler US may be useful in detecting vasospasm.

Diagnostic Procedures/Surgery
Lumbar puncture if suspect aneurysmal leak or rupture with normal head CT

Differential Diagnosis

Neoplasm
Arteriovenous malformation
Optic neuritis
Migraine
Meningitis
Encephalitis
Hypertensive encephalopathy
Hyperglycemia or hypoglycemia
Temporal arteritis
Acute glaucoma
Subdural hematoma
Epidural hematoma
Intracerebral hemorrhage
Thromboembolic stroke
Air embolism
Sinusitis

Treatment

Pre-Hospital

Cautions:
- Neurologic examination in the field can be extremely helpful
- Assess:
  - Level of consciousness
  - Glasgow coma scale score
  - Gross motor deficits
  - Speech abnormalities
  - Gait disturbance
  - Facial asymmetry
  - Other focal deficits
Patients with subarachnoid hemorrhage may need emergent intubation for rapidly deteriorating level of consciousness
Patients must be transported to a hospital with emergent CT scanning and intensive care unit (ICU)-level treatment

Initial Stabilization/Therapy

ABCs:
- Supplemental oxygen
- Rapid-sequence intubation may be required for airway protection or for controlled ventilation
- Continuous cardiac monitoring and pulse oximetry
For altered mental status:
- Check blood glucose immediately, give D50 (if glucose is low)
- Naloxone
- Thiamine
Reversal of anticoagulation
Prevention of acute increases in intracranial pressure from vomiting should be accomplished with antiemetics
Seizures should be managed acutely with IV benzodiazepines and fosphenytoin/phenytoin
Seizure prophylaxis is controversial and not recommended

Ed Treatment/Procedures

Following initial stabilization, the major goals of early treatment of ruptured or leaking aneurysms are to prevent re-rupture, cerebral vasospasm, and hydrocephalus (see "Subarachnoid Hemorrhage"¯).

Surgery/Other Procedures

Optimal timing for angiography and surgery remain controversial, but trend is toward early surgery to decrease incidence of rebleeding and cerebral vasospasm
Early placement of ventriculostomy in appropriate patients may allow for direct intracranial pressure monitoring and often decreases systemic hypertension

Aneurysms in children have a high rate of hemorrhage and should be repaired early

Medication

First Line

Labetalol: 20-30 mg/min IV bolus, then 40-80 mg q10min max. 300 mg; follow with continuous infusion 0.5-2 mg/min
Nimodipine: 60 mg PO/nasogastric q4h
Ondansetron: 4 mg PO/SL/IV q4h PRN (peds: 0.1 mg/kg IV; max. 4 mg/dose)
Prochlorperazine: 5-10 g IV/IM q6-8h (peds: 0.2 mg/kg/d IM in 3 or 4 div. doses); max. 40 mg/d

Second Line

Diazepam: 5-10 mg IV q10-15min max., 30 mg (peds: 0.2-0.3 mg/kg q5-10min max. 10 mg)
Docusate sodium: 100 mg PO BID
Fosphenytoin: 15-20 mg/kg phenytoin equivalents (PE) at rate of 100-150 mg/min IV/IM
Hydralazine: 10-20 mg IV q30min
Lorazepam: 2-4 mg IV q15min PRN (peds: 0.03-0.05 mg/kg/dose; max. 4 mg/dose)
Nicardipine: 5 mg/h IV infusion, increase by 2.5 mg/h q5-15min max. 15 mg/h (peds: Dosing unavailable)
Phenytoin: 15-20 mg/kg IV load at max. 50 mg/min; max. 1.5 g (adult and peds); maintenance 4-6 mg/kg/d IV/IM

Follow-Up

Disposition

Admission Criteria

Any patient with acute aneurysmal subarachnoid hemorrhage should be admitted, preferably to ICU
Any patient with symptomatic unruptured aneurysm should receive admission and urgent neurosurgical consultation, given high rate of rupture

Discharge Criteria

Patients with incidentally discovered asymptomatic intracranial aneurysms may be discharged with close neurosurgical follow-up
Note that overall risk of rupture is 1-2%/yr and that critical size at which risk for rupture outweighs risk for surgery is controversial (classically 10 mm, but probably in the 4-8-mm range).

Follow-Up Recommendations

Neurosurgery
Neurology
Primary care

Pearls and Pitfalls

CT scan alone is not sufficient to exclude subarachnoid hemorrhage
Vasospasm is typically seen on day 3 after bleed or surgery
Nimodipine can prevent or treat vasospasm but should never be administered IV
Nitroprusside and nitroglycerine should be avoided due to tendency to increase cerebral blood volume and thereby intracranial pressure

Additional Reading

Backes D, Rinkel GJ, Kemperman H, et al. Time-dependent test characteristics of head computed tomography in patients suspected of nontraumatic subarachnoid hemorrhage. Stroke. 2012;43:2115-2119.
Bederson JB, Connolly ES Jr, Batjer HH, et al. Guidelines for management of aneurysmal subarachnoid hemorrhage: A statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke. 2009;40:994-1025.
Menke J, Larsen J, Kallenberg K. Diagnosing cerebral aneurysms by computed tomographic angiography: Meta-analysis. Ann Neurol. 2011;69:646-654.
Naval NS, Stevens RD, Mirski MA, et al. Controversies in the management of aneurysmal subarachnoid hemorrhage. Crit Care Med. 2006;34:511-524.
Raymond J, Guillemin F, Proust F, et al. Unruptured intracranial aneurysms: A critical review of the International Study of Unruptured Aneurysms (ISUIA) and of appropriate methods to address the clinical problem. Interv Neuroradiol. 2008;14:85-96.
Seibert B, Tummala RP, Chow R, et al. Intracranial aneurysms: Review of current treatment options and outcomes. Front Neurol. 2011;2:45.
Swadron SP. Pitfalls in the management of headache in the emergency department. Emerg Med Clin North Am. 2010;28:127-147.
Vlak MH, Rinkel GJ, Greebe P, et al. Trigger factors for rupture of intracranial aneurysms in relation to patient and aneurysm characteristics. J Neurol. 2012;259:1298-1302.

Codes

ICD9

430 Subarachnoid hemorrhage
437.3 Cerebral aneurysm, nonruptured
747.81 Anomalies of cerebrovascular system

ICD10

I60.7 Nontraumatic subarachnoid hemorrhage from unspecified intracranial artery
I67.1 Cerebral aneurysm, nonruptured
Q28.3 Other malformations of cerebral vessels

SNOMED

128609009 Intracranial aneurysm (disorder)
233983001 Ruptured cerebral aneurysm
590005 Congenital aneurysm of anterior communicating artery (disorder)
277196008 Berry aneurysm
128608001 cerebral arterial aneurysm (disorder)
42994005 Nonruptured cerebral aneurysm

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