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Basics

Christopher R. Newey, DO

Joao Gomes


BASICS

DESCRIPTION

PATHOPHYSIOLOGY

RISK FACTORS

Diagnosis

DIAGNOSIS

HISTORY

PHYSICAL EXAM

First, assess the airway, breathing, and circulation. Identify the Cushing's response if present. This is an increase in blood pressure and fall in heart rate with respiratory abnormalities. Make note of the breathing patterns given the localizable information they provide (e.g., Cheyne–Stokes (cortex), hyperventilation (midbrain), apneustic (pons), cluster (pons), and ataxic (medulla). Perform a Glasgow Coma Scale. Decorticate posturing localizes from the cortex to the red nucleus. Decerebrate posturing localizes from the red nucleus to the vestibular nucleus. Pupils can be small and reactive (diencephalic), fixed and dilated (third nerve palsy from compression of the uncus of the temporal lobe or the PCA), midposition and fixed (midbrain), pinpoint and reactive (pons), large and fixed with hippus (tectal). Papilledema and absent venous pulsation may be found on fundoscopy examination. Weakness is typically contralateral but can be ipsilateral to the herniation if the contralateral cerebral peduncle is also involved (Kernohan's notch).

DIAGNOSTIC TESTS AND INTERPRETATION

Lab

Initial Lab Tests

Complete blood count (CBC), complete metabolic panel (CMP), partial thromboplastin time (PTT), prothrombin time (PT)/international normalized ratio (INR), arterial blood gas (ABG), serum osmolality, type and cross

Follow-Up & Special Considerations

Serial neurological examinations with a focus on level of consciousness and changes in neurological function are critical in monitoring for cerebral herniation.

Imaging

Initial Approach

CT head without contrast is necessary to rapidly identify type and extent of herniation, treatable underlying causes of herniation (e.g., bleeds or large infarcts), and secondary pathologies. Look for midline shift, degree of pineal shift, mass effect, effacement of basal cisterns and sulci, global or focal edema, and obstructive hydrocephalus. In traumatic brain literature, it is estimated that 10% of patients with increased ICP will have normal head CT.

Follow-Up & Special Considerations

Serial neuroimaging (either MRI or CT) can be useful in confirming herniation as well as further identifying the underlying etiology.

Diagnostic Procedures/Other

These locations are in reference to the foramen of Monro which is estimated by the external auditory meatus. Normal ICP is typically defined as <15–20 mm Hg. ICP waveforms have three components. P1 is the arterial wave, P2 is the rebound wave, and P3 is the venous outflow. An elevated P2 waveform indicates poor compliance.

Pathological Findings

DIFFERENTIAL DIAGNOSIS

Cerebral herniation can result from any intracranial process causing mass effect. Diffuse processes are less likely to cause cerebral herniation.

Treatment

TREATMENT

MEDICATION

ADDITIONAL TREATMENT

General Measures

Additional Therapies

SURGERY/OTHER PROCEDURES

Neurosurgical evaluation is imperative in management of cerebral herniation syndromes. Surgical decompression may be an option for malignant cerebral edema in selecting patients with large infarcts. Patients are selected based on age, timing of surgery, and neuroimaging findings. Additionally, debulking surgery may be an option for tumors. Lastly, placement of ventricular pressure monitoring devices or ventricular drainage devices should be considered.

IN-PATIENT CONSIDERATIONS

Admission Criteria

Patients with signs and symptoms of increased ICP and brain herniation should be admitted to the ICU of the hospital. Discharge will be based on stabilization of the underlying cause.

Nursing

Discharge Criteria

Discharge will be determined upon stabilization of the underlying cause of the cerebral herniation.

Ongoing Care

ONGOING-CARE

FOLLOW-UP RECOMMENDATIONS

Patients should have follow up after discharge with appropriate departments. For example, ischemic strokes will need to be seen in stroke clinics, tumors will need to be seen in neuron-oncology clinics.

DIET

Prompt nutritional support should occur with either nasogastric tube or percutaneous endoscopic gastrostomy (PEG) tube.

PATIENT EDUCATION

ICUs are necessary for monitoring patients with cerebral herniation. Aggressive cardiac, respiratory, and ICP monitoring along with serial neurological examinations are necessary.

PROGNOSIS

The prognosis of cerebral herniation depends on the course and extent of the herniation, secondary injuries, and the primary pathology underlying the cerebral herniation.

COMPLICATIONS

Additional Reading

SEE-ALSO

Codes

CODES

ICD9

348.4 Compression of brain

Clinical Pearls

The key is to recognize patients at risk of herniating and also recognizing the clinical syndromes that occur with herniation. Once recognized, prompt treatment should be initiated along with neurosurgical consultation.