Diagnosis

Subarachnoid hemorrhage

Etiology

Cause [za1]

• Traumatic

• Non-traumatic:

  • Rupture of aneurysm (85%)

  • AV-malformation (10%)

  • Intracranial arterial dissection

  • Other causes: Cocaine abuse, sickle cell anemia, anticoagulant therapy, bleeding disorders, pituitary apoplexy, cerebral amyloid angiopathy, cerebral venous thrombosis, moyamoya disease, cerebral vasculitis

Pathophysiology [za1]

1. Subarachnoid space:

   • Between the arachnoid membrane and the pia mater

   • Consists of the cerebrospinal fluid and the cerebral blood vessels

2. Hemodynamic stress --> inflammation --> formation of intracranial aneurysm

   • Arterial junctions

   • Bifurcations

   • Abrupt vascular angles

3. Large aneurysms may compress the adjacent structures --> neurological signs

4. Law of Laplace: wall stress = (Pressure x Radius) / (2 x wall thickness)

5. Rupture:

   • Elevated intracranial pressure --> reduced cerebral perfusion --> cerebral ischemia

   • Mechanical blockage of the CSF flow --> hydrocephalus

   • Cerebral vasospasm --> delayed cerebral ischemia

Risk factors [za1]

• Large aneurysm (>5 mm)

• Older age (>60 years)

• Atherosclerosis

• Hypertension

• Cigarette smoking

• Family history

• Alcohol

• Sympathomimetic drugs

• Estrogen deficiency

• Polycystic kidney disease

Complications [za1]

• Vasospasm (40-60%)

• Hydrocephalus (30%)

• Rebleeding (9-17%)

• Seizure

• Increased intracranial pressure

• Brain herniation

• Cerebral infarction

• Neurogenic pulmonary edema

• Death

Epidemiology

Incidence per 100.000 [w5s][tmd][7sd][cns][8od][za1]

Approach

• Blood test

• Blood gas

• Ophtalmoscopy

• CT angiography

• MR angiography

• Cerebral angiography: detecting vasospasm

• Transcranial Doppler: monitoring vasospasm

• Lumbar puncture

• Xanthochromia

• EEG: subclinical seizures or nonconvulsive status epilepticus

• ECG

Treatment

Goal of treatment: prevent rebleeding, hydrocephalus and vasospasm

1. Initial treatment: [za1]

   • Airway: Decreased consciousness --> Intubation

   • Breathing: Respiratory failure --> Oxygen or mechanical ventilation

   • Circulation: Blood pressure <160 mm Hg (prevention of rebleeding/vasospasm):

     • Labetalol 5-20 mg IV every 15 minutes

     • Hydralazine 20-40 mg every 30 to 60 minutes

     • Nicardipine 5-15 mg/hr continuous IV infusion

     • Clevidipine 1-2 mg/hr and repeated every 90 seconds

     • Nimodipine (oral) 60 mg every 4 hours

2. Supportive treatment: [za1]

   • Osmotic diuretics (Mannitol)

   • Antiepileptics

   • Antibiotics

   • Anticoagulants: discontinue all anti-thrombotic agents and reverse all anticoagulation until the aneurysm is definitively repaired

   • Pain control: Acetaminophen 1000 mg IV, opioid 2-4 mg IV every 1 to 2 hours

3. Interventional options: endovascular coiling

4. Surgery:

   • Clipping of the aneurysm

   • Intraventricular external drainage device to reduce the ICP/hydrocephalus

Differential diagnoses

Arteriovenous malformation, Brain tumor, Cerebral aneurysm, Epidural hematoma, Hydrocephalus, Intracerebral hemorrhage, Meningitis, Multiple sclerosis, Sarcoidosis, Stroke, Subdural hematoma, Syndrome of inappropriate antidiuretic hormone secretion, Toxoplasmosis