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Increased Intracranial Pressure (ICP)

Overview

Intracranial pressure (ICP) is the pressure exerted by the brain tissue, blood, and cerebrospinal fluid (CSF) within the rigid skull. Increased intracranial pressure (IICP) occurs when this pressure rises above the normal range of 5–15 mmHg in adults. The condition is a medical emergency because the brain can be compressed, blood flow can be reduced, and permanent neurologic damage may result.

Who it affects: IICP can affect anyone, but it is most common in:

• Adults after traumatic brain injury (TBI) – 30–40% develop elevated ICP.
• Patients with intracranial hemorrhage (subdural, epidural, intracerebral) – up to 50% develop IICP.
• Individuals with brain tumors, hydrocephalus, meningitis, or cerebral edema.

Prevalence: In the United States, an estimated 2.8 million emergency department visits each year involve TBI, and a sizable fraction of these patients experience IICP. Worldwide, stroke and central nervous system infections remain leading causes of raised ICP, contributing to an estimated 5–10 million new cases annually.

Symptoms

Symptoms reflect the brain’s reduced ability to tolerate the increased pressure and may develop rapidly or over several hours. Common manifestations include:

Headache

A persistent, often “pressure‑like” headache that worsens when lying down and improves when sitting up. It may be accompanied by nausea.

Nausea & Vomiting

Vomiting is usually projectile and not related to food intake. It is a hallmark sign of raised ICP.

Altered Consciousness

• Confusion, disorientation, or slowed mental processing.
• Decreasing level of alertness leading to stupor or coma.

Visual Disturbances

• Blurry vision or double vision (diplopia).
• Papilledema – swelling of the optic disc seen on eye exam.

Pupillary Changes

• One pupil may become dilated and non‑reactive (afferent pupillary defect).

Motor Weakness or Seizures

Focal weakness, especially on one side of the body, or new‑onset seizures can indicate localized pressure.

Speech & Swallowing Difficulties

Slurred speech (dysarthria) or trouble swallowing (dysphagia) may appear.

Other Symptoms

• Neck stiffness (often confused with meningitis).
• Hearing changes or ringing in the ears (tinnitus).
• Changes in heart rate or blood pressure (Cushing’s triad – hypertension, bradycardia, irregular respiration).

Causes and Risk Factors

Raised ICP is not a disease itself but a physiologic response to several possible insults.

Traumatic Causes

• Severe head trauma – contusions, diffuse axonal injury.
• Acute subdural, epidural, or intracerebral hemorrhage.

Vascular Causes

• Ischemic stroke with cytotoxic edema.
• Hemorrhagic stroke or aneurysmal subarachnoid hemorrhage.

Neoplastic Causes

• Primary brain tumors (glioblastoma, meningioma).
• Metastatic lesions.
• Tumor‑associated obstructive hydrocephalus.

Infectious & Inflammatory

• Bacterial or viral meningitis.
• Encephalitis.
• Autoimmune encephalitis.

Obstructive CSF Flow

• Hydrocephalus (communicating or non‑communicating).
• Chiari malformation.

Metabolic & Toxic

• Severe hyponatremia or hyperammonemia.
• Carbon monoxide poisoning.

Risk Factors

• Age > 65 (higher stroke incidence).
• Anticoagulant or antiplatelet therapy (increases bleeding risk).
• Uncontrolled hypertension.
• History of prior brain injury or neurosurgery.
• Certain genetic conditions (e.g., familial cerebral cavernous malformations).

Diagnosis

Rapid identification is essential. Diagnosis combines clinical assessment with imaging and monitoring tools.

Clinical Examination

• Neurological exam – Glasgow Coma Scale (GCS) scoring.
• Fundoscopic exam for papilledema.
• Assessment of pupil size/reactivity.

Neuroimaging

• CT scan (non‑contrast) – first‑line; quickly reveals hemorrhage, mass effect, midline shift, or hydrocephalus.
• MRI – more sensitive for diffuse axonal injury, posterior fossa lesions, or early ischemia.

Invasive ICP Monitoring

Indicated for severe TBI, intracerebral hemorrhage, or postoperative patients.

• External ventricular drain (EVD) – measures pressure and allows CSF drainage.
• Intraparenchymal fiber‑optic or strain‑gauge transducers – provide continuous real‑time values.

Additional Tests

• Blood work – electrolytes, coagulation profile, arterial blood gas.
• Lumbar puncture – rarely performed when ICP is suspected; can precipitate herniation if pressure is high.
• Transcranial Doppler ultrasound – evaluates cerebral blood flow velocity changes related to ICP.

Treatment Options

Treatment aims to lower ICP, protect cerebral perfusion, and treat the underlying cause.

Medical Therapies

• Osmotic agents
  • Manitol 0.25–1 g/kg IV bolus – creates an osmotic gradient, drawing water out of brain tissue.
  • Hypertonic saline (3%–7.5%) – especially useful when manitol is contraindicated or refractory.
• Corticosteroids – indicated for vasogenic edema associated with brain tumors (e.g., dexamethasone), but NOT for traumatic or ischemic edema.
• Sedation & Analgesia – propofol, fentanyl, or midazolam to reduce metabolic demand and prevent agitation‑related ICP spikes.
• Ventilatory Strategies – hyperventilation (PaCO₂ ≈ 30‑35 mmHg) short‑term to cause cerebral vasoconstriction; used cautiously because prolonged hypocapnia reduces cerebral blood flow.
• Anti‑seizure medications – levetiracetam or phenytoin if seizures occur.

Surgical & Procedural Interventions

• External Ventricular Drain (EVD) – drains CSF, directly lowering pressure; also provides a route for intraventricular medication.
• Decompressive Craniectomy – removal of a portion of skull to allow brain swelling to expand outward; shown to improve survival in severe refractory TBI (DECRA and RESCUEicp trials).
• Hemorrhage Evacuation – stereotactic or open craniotomy to remove hematoma.
• Tumor Resection – removes mass effect.
• Ventriculoperitoneal (VP) Shunt – for chronic hydrocephalus.

Lifestyle & Supportive Measures

• Head‑of‑bed elevation to 30°–45° (helps venous outflow).
• Avoidance of Valsalva maneuvers (straining, coughing).
• Maintain normothermia (target 36.5–37.5 °C).
• Strict fluid balance – isotonic fluids; avoid hypotonic solutions that can worsen cerebral edema.

Living with Increased Intracranial Pressure

Even after acute management, many patients live with chronic ICP concerns. Practical strategies help maintain safety and quality of life.

• Medication adherence – Take steroids, anti‑seizure drugs, or diuretics exactly as prescribed.
• Regular follow‑up – Neurology and neurosurgery visits every 3–6 months or as directed.
• Symptom diary – Record headaches, visual changes, or new neurological signs; share with your provider.
• Activity modifications
  • Avoid high‑impact sports, heavy lifting, or activities that cause sudden increases in intrathoracic pressure.
  • Use a soft helmet when biking or skating if advised by a physician.
• Vision care – Annual ophthalmology exams to monitor papilledema.
• Sleep hygiene – Sleep with a modestly elevated head of bed; treat sleep apnea, which can raise ICP.
• Psychosocial support – Counseling, support groups, or cognitive rehabilitation can address mood changes, memory problems, or frustration.

Prevention

Because many causes are acute events, prevention focuses on risk reduction and early detection.

• Wear helmets for biking, motorcycling, skiing, and during high‑risk sports.
• Use seatbelts and airbags; practice safe driving.
• Control hypertension, diabetes, and hyperlipidemia to lower stroke risk.
• Avoid excessive alcohol intake and illicit drug use (e.g., cocaine) which predispose to hemorrhagic stroke.
• Take anticoagulant/antiplatelet medications only as prescribed; have regular INR checks if on warfarin.
• Promptly treat infections (meningitis, sinusitis) with appropriate antibiotics.
• Maintain adequate hydration and electrolyte balance; especially important in patients on diuretics or with SIADH.
• Vaccinate against influenza, pneumococcus, and meningococcal disease to reduce CNS infection risk.

Complications

If elevated ICP is not promptly managed, several serious complications can occur:

• Brain herniation – downward (tonsillar) or upward (transtentorial) shift leading to brainstem compression, a rapidly fatal event.
• Ischemic injury – reduced cerebral perfusion pressure (CPP) causes infarction.
• Permanent neurological deficits – weakness, speech impairment, visual loss, or cognitive decline.
• Seizure disorder – chronic epilepsy may develop.
• Hydrocephalus – persistent CSF flow obstruction requiring shunting.
• Infection – ventriculitis or meningitis associated with invasive monitoring devices.
• Psychiatric sequelae – depression, anxiety, or PTSD after traumatic brain injury.

When to Seek Emergency Care

Sources: Mayo Clinic, CDC, NIH (Neuroscience and Brain Initiative), World Health Organization, Cleveland Clinic, “Management of Severe Traumatic Brain Injury” (NEJM 2020), DECRA and RESCUEicp trial publications.

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