Elevated ICP

Elevated ICP Definition Sustained abnormal pressure within the cranium and the compartments e.g. ventricles and arachnoids space that exceeds 15-20 mmHg. Key Info Adults at supine position have a physiological ICP of 15 mm Hg or less Monro-Kellie principle: the sum of the volumes of intracranial blood, CSF and brain within the cranium is constant Causes Traumatic brain injury/head trauma Most common cause? Space occupying lesions Tumours Aneurysms Hematoma IC haemorrhage Hydrocephalus Seizures Hyponatremia Hepatic encephalopathy Idiopathic intracranial hypertension Meningitis Encephalitis Oedema Abscess Coughing/Valsalva Artefact Clinical features Cushing triad Irregular breathing Widening pulse pressure Bradycardia Reduced LOC Headache Vomit Papilledema Psychiatric symptoms Diplopia Features of cerebral herniation In infants Macrocephaly bulging fontanel Sunset sign Investigations Imaging CT First line MRI Findings: Midline shift Mass lesions Effacement of basilar cisterns Effacement of cerebral sulci Evidence of brain herniation Changes to ventricular size Hydrocephalus enlargement Invasive ICP monitoring Confirmation and accurate ICP measurement Does not have absolute contradictions Indications: Traumatic brain injury Mass lesions Diffuse brain injury E.g. meningitis, encephalitis, hydrocephalus, cerebral venous thrombosis ICP monitoring Intraventricular catheters with an external ventricular drain (EVD) and intraparenchymal catheters Gold standard Highest accuracy compared to other monitoring methods Allows for continuous monitoring ICP more than 20 mmHg intracranial HTN needs management Management Goal Maintain CBF and prevent secondary brain injury Target an ICP of less than 20 mmHg ABCDE If GCS less than 8 emergency airway management Mechanical ventilation if needed Conservative management Head elevation 30 degrees Avoid neck flexion Sedation and analgesia Usually a combo of: benzothiazines + opioids + dexamethasone Temperature management Aim for normothermia Fever anti-pyretic Fluid management Aim for euvolemia Avoid serum hypoosmolality Seizure management Routine prophylaxis not recommended Medical management Indications: Refractory to conservative management Herniation syndrome Neurological deterioration Options: IV hypertonic saline First line IV mannitol Glucocorticoids e.g. dexamethasone If elevated ICP is secondary to vasogenic oedema secondary to CAN infection or inflammation or neoplasms Surgical management Emergency for: brain tumour, hematoma evacuation CSF drainage Indications: Acute obstructive hydrocephalus Diffuse cerebral oedema Intracranial lesion causing a mass effect Options EVD Lumbar drain Cerebral shunt Risks: haemorrhage, infection, anaesthesia risk Decompressive craniectomy Removal of a portion of the skull allows brain to expand in volume reduces ICP Non-surgical management options for refractory ICP Indications: Bridge to surgery for expanding lesions Treatment of a life-threatening case that has pending investigations results Controlled hyperventilation Mechanical ventilation intubation + mechanical ventilation Always use with monitoring Aims to induce hypocapnia First 30 minutes PaCO2 30 to 35 mmHg After 30 minutes normocapnia PaCO2 35 to 45 mmHg Lowers CO2 cerebral arteriolar vasoconstriction decreases CBV reduces total volume in skull reduces pressure Advanced options Barbiturate coma Therapeutic hypothermia Early consult Irreversible loss of brain function Brian death Cerebral oedema Brain herniation Most common Neurological damage Vision loss Seizures Stroke and infractions Prognosis Poor Severe long term neurological disability High mortality rates Higher risk of developing it again