Neuro-Trauma

The use of steroids was associated with increased mortality in two weeks and these agents should no longer be used for the patient with traumatic brain injury

"Treatment in search of cure in the face of hopeless prognosis is a travesty of medical care and goes against the ethical principle of the physicians' obligation to act in the best interest of the patient and his family" - Dr Farhad Kapadia Consultant Physician and Intensivist PD Hinduja Hospital, Mumbai

Rehabilitation of TBI patients should begin in the ICU during the first few days after injury, with the consultation of a psychiatrist and passive range-of-motion exercises of the extremities

Traumatic Brain Injury (TBI) is a major cause of disability, death and economic cost to our society. All neurological damage from TBI does not occur at the moment of impact, but evolves during the ensuing hours or days and this secondary injury may be a major determinant of the patient's ultimate neurologic outcome. Serious Injury can be prevented by seat belt and air-bags for motorists, helmet for two wheelers with effective implementation of drunken driving laws.

Patho Physiology

Primary injury: Primary brain injury, which is the result of direct mechanical damage that occurs at the time of trauma, is divided into focal lesions.

Secondary injury: Secondary brain injury occurs after the initial trauma. Its damage to neurons is due to the systemic physiologic responses to the initial injury. Post-traumatic ischemia initiates a cascade of metabolic events that lead to the surplus production toxic metabolites that play a key role in neurodegeneration. Hypoxia, hypotension, hypercarbia, hyperthermia, seizures, hypoglycemia and low cerebral blood flow states aggravate secondary injury.

Role of Blood Pressure & Intracranial Pressure

Maintaining adequate cerebral blood flow is critical in all brain injury patients. Irreversible neuronal damage occurs if cerebral blood flow drops. Intra cranial hypertension and low blood pressure leads decrease in cerebral blood flow. Hence, blood pressure needs to be maintained. Hypertensive patients are more susceptible to ischemia keep higher BP in chronic hypertensive patients. Intracranial hypertension warrants immediate treatment.

Neurological Evaluation

Primary Trauma Survey: The first priority in any injured patient is to stabilise the cervical spine, establish an adequate airway by ensuring adequate ventilation to avoid hypoxia and hypercarbia. All patients with either blunt injury or penetrating injury with sufficient mechanism of injury to lead to a spinal injury should be considered to have a spinal injury, until proven otherwise. Whole spine immobilisation is required. Head should be in neutral position without traction. This can be achieved manually or with semi-rigid cervical collar. Maintain circulation and expose the victim to look for additional injuries. Chest trauma, abdominal trauma and long bone fractures can rapidly lead to shock. Perform thorough physical examination- do ultrasound or CT-scan for diagnosis. Fix the fracture.

Secondary Trauma Survey: Secondary survey is completed once the patient is relatively stable and includes a complete neurologic examination. The severity of the head injury is classified clinically by the Glasgow Coma Scale (GCS). A GCS score of 13 to 15 is classified as a mild head injury, as score of 9 to 12 as moderate, and a score of eight or less, as severe.

Management

Pre-hospital care: Care of the TBI victim always should begin with evaluating and securing a patent airway and restoring normal breathing and circulation with stabilisation of cervical spine. The acutely injured brain is vulnerable to further damage from systemic hypotension, hypoxemia & hypercarbia. Preventing these physiologic insults is crucial to limiting secondary brain injury.

Early hospital management: Early endotracheal incubation usually benefits comatose patients. Securing and maintaining an airway are essential to optimal oxygenation and ventilation, and early intubation has been found to reduce mortality after severe TBI. Rapid Sequence Induction (RSI) is recommended for rapid control of airway to avoid hypoxia, hypercapnia (high Co2), and rise in ICP with sedation, analgesia and muscle relaxant.

Imaging Techniques

The imaging evaluation of the patient with severe brain injury usually begins with a CT-scan as an emergency procedure. To identify intracranial lesions that may need surgical correction, Cerebro-Spinal Fluid (CSF) obstruction (hydrocephalus), severity of cerebral edema or the presence of brain shift and to evaluate prognosis. Marshall et al. developed (now a widely used system) that classifies head injuries according to the changes seen on CT scan, defining four categories of injury (diffuse injury I-IV). A normal initial CT scan does not exclude significant intracranial hypertension.

Magnetic resonance imaging is increasingly used to better appreciate the type of cerebral lesions, including posterior fossa lesions and detection of spinal ligament injury. In absence of CT scan cervical spine X-rays should be done to rule out any cervical spine instability.

ICU Aspects

If there is a focal neurologic deficit, GCS score 13, or an intracranial lesion on head CT, the patient should be admitted to an ICU or neurologic observation unit for frequent neurological monitoring, aggressive Intra Cranial Pressure (ICP) management, haemodynamic monitoring and support. If the patient cannot follow commands or patients with a GCS score of eight, ICP monitoring is recommended since intracranial hypertension in this population is more than 60 per cent. Intraventricular catheters are preferred when possible, as these allow for continuous measurement of ICP and for drainage of CSF to control raised ICP. Ventilator settings should be adjusted to maintain adequate oxygen level and normal carbon dioxide. Other issues taken care in ICU are glucose control, electrolyte imbalance, nutritional support and deep venous thrombosis prophylaxis.

For patients with transient loss of consciousness, amnesia, or a GCS score of 13 to 14, do immediate non-contrast CT-head. If finding is negative, patient can be discharged with instructions. Head-injured patients with no loss of consciousness, no amnesia, no palpable fractures, and a GCS score of 15 can be discharged home to a reliable caretaker without brain imaging. Written instructions on how to evaluate the patient at home should be given.

Neurosurgical Consultation

Neurological Consultation is critical to determining the severity of the brain injury and the appropriate treatment by CT findings combined with a reliable post-resuscitation GCS score and assessment of pupil size and reactivity. It helps in deciding whether to proceed directly with surgical evacuation or medical management. All acute traumatic extra-axial hematoma 1 cm in thickness warrant evacuation, a subdural or epidural hematoma 5 mm in thickness with an equivalent midline shift in a comatose patient (GCS score 8) should also be evacuated urgently. Surgical evacuation has been recommended in patients with intracerebral hematomas 20 ml with mass effect. Surgical repair is also required in patients with depressed, open and compound skull fractures. De-compression craniectomy is emerging as a useful technique in relieving raised ICP and may become a standard aspect of management.

Use of corticosteroids in acute traumatic brain injury: The CRASH trial namely Corticosteroid Randomisation After Significant Head Injury, investigated this widespread practice in a large, international, randomised placebo-controlled trial. The use of steroids was associated with increased mortality in two weeks and these agents should no longer be used for the patient with traumatic brain injury.

Physical Therapy & Rehabilitation

The primary goal of these programmes is to re-integrate patients into their communities by either restoring normal or near-normal ability to function or teaching them alternative strategies to function well despite their disabilities. Such programmes should involve a multi-disciplinary team of physical, occupational, and speech therapists, neurophysiologist and social workers, ideally co-ordinated by a physiatrist or a neurologist with special training in physical medicine and rehabilitation.

Rehabilitation of TBI patients should begin in the ICU during the first few days after injury, with the consultation of a physiatrist and passive range-of-motion exercises of the extremities. Mobilisation helps prevent deep venous thrombosis and studies indicate that early sitting of comatose patients may hasten the return of consciousness.

dr_fkapadia@hindujahospital.com
With inputs from Dr Rishi Kumar and Dr Shankar Kalgudi of Department of Intensive Care, PD Hinduja Hospital, Mumbai