Ruptured Brain Aneurysm and Critical Care

Introduction

Aneurysms occur anywhere in the brain and have an increased risk of rupture and bleeding. It is commonly found in women between the age of 35 to 60 years. Patients with ruptured aneurysms have an increased risk of mortality and disability due to subarachnoid hemorrhage. The complications and severity of the condition are assessed and managed in the intensive care unit with mechanical ventilation. In addition, critical care survivors require rehabilitation therapy to cope with long-term disabilities and cognitive and behavioral impairments.

What Is a Ruptured Brain Aneurysm?

An aneurysm is a bulging area in the walls of the blood vessels. When an aneurysm grows, it pressures adjacent structures and becomes thin and weak. As a result, it may rupture, releasing blood into the subarachnoid space (space between the brain and the skull), called a subarachnoid hemorrhage. The blood in this area may cause damage to the lining of the brain and brain cells.

What Are the Types of Aneurysms?

The following are the different types of aneurysms.

1. Saccular - The aneurysm bulging from the artery wall on one side, also called berry.

2. Fusiform - The aneurysm bulges or balloons out on all sides of the blood vessel.

3. Dissecting - Tear in the artery's inner wall due to traumatic injury allowing blood to pool.

What Are the Causes and Risk Factors Associated With Rupture of Brain Aneurysms?

Causes: The following are the causes associated with the formation of brain aneurysms.

• Hypertension.

• Smoking.

• Chronic alcohol use.

• Family history of aneurysms.

• Polycystic kidney disease.

• Marfan syndrome.

• Ehler-Danlos syndrome.

• Fibromuscular dysplasia.

• Neurofibromatosis type 1.

Risk Factors: All the aneurysms do not rupture. The risk factors responsible for the rupture of the brain aneurysms include the following.

• Family history of aneurysm rupture.

• Multiple aneurysms in the brain.

• Giant aneurysms, which are more prominent, may burst easily.

• High blood pressure damages the blood vessels making them more vulnerable to rupture.

• Aneurysms on the communicating arteries (anterior and posterior) are more susceptible to rupture.

What Are the Characteristic Features of a Ruptured Brain Aneurysm?

Most brain aneurysms do not show symptoms unless they rupture. The common symptoms associated with a ruptured brain aneurysm include the following.

• Sudden and intense headache.

• Nausea and vomiting.

• Loss of consciousness.

• Seizures.

• Hazy vision or double eyesight and drooping eyelids.

• Weakness and confusion.

• Neck stiffness.

• Nerve palsy.

• Bilateral lower limb weakness.

• Facial and orbital pain.

What Are the Complications of Ruptured Brain Aneurysm?

The complications of a ruptured brain aneurysm in the early and delayed phase include the following.

• When an aneurysm rupture, the blood is released into the subarachnoid space (space between the brain and the skull), which is previously filled with cerebrospinal fluid (CSF) that act as the cushion for the brain. When the blood spreads, fills the space, and clots, it causes damage to the brain cells. Early brain injury (EBI) occurs within the first 72 hours of rupture due to the bleeding of the subarachnoid space and transient ischemia.

• Excessive catecholamine release and sympathetic hyperactivity due to the rupture of aneurysms cause cardiopulmonary complications.

• Stroke may occur due to deprivation of oxygenated blood in the brain areas previously supplied by ruptured blood vessels.

• Blood clots inside the skull increase the pressure causing the brain to shift and crush against the bones. Thus the CSF circulation is blocked, causing hydrocephalus (enlarged ventricles), resulting in loss of consciousness.

• After 5 to 10 days of rupture, the walls of the arteries are narrowed, causing vasospasm resulting in delayed cerebral ischemia (DCI).

How to Manage Ruptured Brain Aneurysm in a Critical Care Unit?

The complications of the ruptured brain aneurysm are treated as early as possible to provide improved health outcomes.

Management Strategies: The management strategies to decrease mortality include the following.

• Transfer of patients to a high-volume center.

• Neurological support in a neurological intensive care unit.

• Repair of aneurysms as early as possible.

• Multimodal neuromonitoring.

• Management of intracranial pressure.

• Prevention and treatment of delayed cerebral ischemia.

• Prevention and treatment of other medical complications.

Treatment Procedure: The treatment procedures in the intensive care unit include the following.

1. Initial Management:

• Initial management of patients with a ruptured brain aneurysm and subarachnoid hemorrhage includes medical stabilization, prevention of re-bleeding, and control of intracranial pressure.

• Non-stop bleeding may cause the death of patients if left untreated. So the initial management focuses on preventing re-bleeding in patients who survived initial hemorrhage.

• Surgical clipping, endovascular coiling, and aneurysm occlusion are performed within 72 hours of rupture to prevent re-bleeding after subarachnoid hemorrhage.

• The increased intracranial pressure (ICP) is reduced by elevating the head of the patient's bed (approximately 30 to 45 degrees), use of drugs such as sedatives, analgesics, hyperosmolar agents (mannitol and hypertonic saline), and barbiturates, hypothermia, and decompressive craniectomy.

• Cerebrospinal fluid drainage is vital in the management of intracranial pressure. Therefore, an external ventricular drain is inserted to drain the cerebrospinal fluid in cases of hydrocephalus.

2. Prevention and Treatment of Delayed Cerebral Ischemia:

• Delayed cerebral ischemia occurs after 72 hours of subarachnoid hemorrhage. It is reversible and preventable with appropriate management.

• Triple-H therapy(hypervolemia, hypertension, and haemodilution) is essential in managing delayed cerebral ischemia.

3. Multimodal Neuromonitoring - Intracranial and cerebral perfusion pressure is monitored in comatose patients with brain injury. Continuous electroencephalography monitoring in patients with subarachnoid hemorrhage predicts and diagnoses vasospasm and delayed cerebral ischemia. Monitoring brain tissue's partial pressure of oxygen helps detect early changes in cerebral tissue oxygenation that causes ischemic damage.

4. Pharmacological Prophylaxis - Nimodipine (L-type dihydropyridine calcium channel antagonist) decreases vasospasm and the influx of calcium after delayed cerebral ischemia. Statins are prescribed to prevent delayed cerebral ischemia.

5. Dysnatremia Management - Hyponatremia and hypernatremia occur in the ICU management of subarachnoid hemorrhage patients. An effective protocol is not available, and additional studies are required.

6. Rehabilitation - After discharge from critical care, rehabilitative therapy, including physical, occupational, and speech therapy, is recommended for patients to overcome the comorbidities associated with an ICU stay.

Conclusion

Ruptured brain aneurysms and subarachnoid hemorrhages are complex neurovascular diseases requiring multidisciplinary specialized care. Many controversies are associated with the ICU management of ruptured brain aneurysms. So, more attention should be paid to sympathetic activity, hemodynamic management, glycemic management, and intensive care duration to improve outcomes.