sub arachnoid hemorrhage (sah)

Sub-Arachnoid Hemorrhage(Stabilization and referral in case of SAH, Raised ICP focus on SAH)

Sunil Kumar Daha

Janakpur, Nepal

Intracranial Pressure

• pressure inside the skull and thus in the brain tissue and cerebrospinal fluid (CSF).

• ICP is measured in millimeters of mercury (mmHg) and, at rest, is normally 7–15 mmHg for a supine adult

Causes of raised ICP

Epidemiology

• Womens are affected more commonly

• Usually present before the age of 65

• Immediate mortality of aneurysmal SAH is 30%

• Survivors have a recurrence rate of 40% in the 1st 4 wks and 3% annualythereafter

Etiology

1. 85%Berry aneurysma:

most common site : a. Anterior communicating artery (30%)

b. Posterior communicating artery (25%)

c. Middle cerebral artery (20%)

(Increased risk in case of first degree relatives of those with saccular aneurysm, patients with PKD and congenital connective tissue defects)

2. Non-aneurysmal haemorrhage ( Peri mesencephalic haemorrhage)

3. 5% Arteriovenous malformations and vertebral artery dissection

Clinical Features

1. Sudden, severe,thunder-clap’ headache lasting for hours or even days.

2. Thunder-clap headache accompanied by

-vomiting

- Raised blood pressure

-Neck stiffness or Pain

( commonly occurs on physical exertion, straining and sexual excitement)

On examination

• Loss of consciousness

•Distressed and irritable with photophobia

•Neck stiffness due to subarachnoid blood

• Focal hemisphere signs

Investigations

Management

• Nimodipine (30-60 mg IV for 5-14 daysfollowed by 360 mg for further 7 days.

• Insertion of platinum coils into an aneurysm (via endovascular procedure)

or, Surgical clipping of the aneurysm neck reduces the risk of both early and late recurrence.

Complications

1. Obstructive hydrocephalus

2. Delayed cerebral ischaemia due to vasospasm

3. Hyponatremia and

4. Systemic complications associated with immobility, chest infection and venous thrombosis

ICP following Subarachnoid haemorrhage

• sudden introduction of blood into the subarachnoid space results in CSF outflow resistance

• Increased ICP and a resultant decrease in cerebral perfusion play a principal role in the development of cortical damage

• The continuous monitoring of ICP aids in the early detection of secondary cerebral insults and guides therapeutic interventions by providing real-time, physiological feedback.

• Intracranial pressure control affords the opportunity for surgical treatment and postoperative intensive care to effect a favorable outcome in patients suffering from aneurysmal SAH

Severity of SAH

Recent Updates…

• Aneurysmal subarachnoid hemorrhage (SAH) is often a devastating event. Approximately 10 percent of patients with aneurysmal SAH die prior to reaching the hospital, 25 percent die within 24 hours of SAH onset, and about 45 percent die within 30 days; only one-third of patients will have a good outcome after treatment

• The most important predictive factors for acute prognosis after SAH include

• Level of consciousness and neurologic grade on admission

• Patient age (inverse correlation)

• Amount of blood on initial head computed tomography (CT) scan (inverse correlation

• early mortality is caused by the common complications of aneurysmal SAH, which include rebleeding, vasospasm and delayed cerebral ischemia, hydrocephalus, increased intracranial pressure, seizures, and cardiac complications

• A patient presenting with aneurysmal subarachnoid hemorrhage (SAH) is admitted to an intensive care setting for constant hemodynamic and neurologic monitoring . Patients with SAH are at risk for hemodynamic instability and neurologic deterioration. In one study, neurologic worsening occurred in 35 percent of patients within the first 24 hours of admission and heralded the onset of complications and poor outcomes . Pulmonary edema and cardiac arrhythmias complicate 23 and 35 percent of SAH cases respectively

Acute medical care• Indications for endotracheal intubation include a GCS ≤8 , elevated ICP,

poor oxygenation or hypoventilation, hemodynamic instability and requirement for heavy sedation or paralysis.

• Deep venous thrombosis (DVT) prophylaxis with pneumatic compression stockings is started prior to aneurysm treatment . Subcutaneous unfractionated heparin 5000 units three times daily can be added for DVT prophylaxis once the aneurysm is treated.

• Intravenous fluid administration should target euvolemia and normal electrolyte balance. Hyponatremia, in particular, is common; sodium levels should be checked at least daily (See 'Intravenous fluids' below and 'Hyponatremia' below.)

• Intravenous fluid administration should target euvolemia and normal electrolyte balance. Hyponatremia, in particular, is common; sodium levels should be checked at least daily

• A cohort study of 413 patients identified four variables that were independently associated with increased risk of death or disability three months after SAH

-Hypoxemia (arterio-alveolar gradient >125 mmHg)

-Metabolic acidosis (serum bicarbonate <20 mmol/L

-Hyperglycemia (serum glucose >180 mg/dL [10 mmol/L])

-Blood pressure instability (MAP of <70 or >130 mmHg

References

• Davidson’s Princples and practice of Medicine