What are the Earliest Signs of Increased Intracranial Pressure?

Intracranial hypertension (ICH) is a clinical condition associated with an elevation of pressure around the brain of more than 20 mmHg.

Based on etiopathogenesis, ICH is classified into four different forms that include:

1. Parenchymatous ICH
   • Appears in expansive intracranial processes caused by intrinsic cerebral causes such as tumors, hematomas, cerebral abscesses, traumatic brain edema, and general intoxication with neural toxins (exogenous or endogenous).
2. Vascular ICH 
   • Intracranial pressure is determined by disorders of the cerebral blood volume.
   • Vascular ICH is seen in:
     • Vascular cerebral diseases such as cerebral venous thrombosis, superior sagittal sinus thrombosis, and mastoiditis with transverse, or sigmoid sinus thrombosis.
     • Extra cerebral diseases such as hypertensive encephalopathies, malignant hypertension, glomerulonephritis, eclampsia chronic hypertensive encephalopathy, congestive cardiac failure, and intrathoracic mass lesions.
3. Meningeal ICH
   • Results from the diminution of cerebrospinal fluid (CSF) absorption in acute meningitis, subarachnoid hemorrhage, carcinomatous meningitis, and chronic meningitis-sarcoidosis.
4. Idiopathic ICH
   • May occur in endocrine, metabolic, hematological diseases, and hormonal treatments.
   • More often seen in obese women of childbearing age, with some associated conditions such as the use of drugs (tetracycline, cimetidine), oral contraceptives, Cushing’s disease, and hypothyroidism.
   • Although the exact etiology has not been established, researchers have speculated three major theories of the cause of idiopathic ICH, which include:
     • Increased resistance to CSF absorption
     • Increased CSF production
     • Increased venous sinus pressure

Three clinical stages (reversible) of intracranial hypertension (ICH) are as follows:

1. Infraclinic form: Intracranial pressure (ICP) increases over the physiological values (≤15 mmHg).
2. ICH syndrome: ICP increases up to 20 mmHg along with the presence of clinical symptoms (chronic form).
3. ICH disease: It is the acute form with ICP over 20 mmHg; the symptoms of the preceding stage increase until decompensation.

Increased intracranial pressure (ICP) occurs as a result of the disturbance of the regulatory ICP mechanisms, caused by the changes in the volumes of the intracranial components, which are the brain parenchyma, cerebrospinal fluid (CSF), and cerebral blood volume.

Increased ICP could be a result of the following:

• Subdural or epidural hematoma (bleeding in the brain)
• Swelling in the brain (Reye's syndrome, lead encephalopathy, water intoxication, or near drowning)
• Brain or head injury
• Brain tumor or abscess
• Stroke
• Aneurysm
• Hypertensive brain hemorrhage (bleeding in the brain caused by high blood pressure)
• Brain infections (encephalitis or meningitis)
• Excess production of CSF
• Obstructive or communicating hydrocephalus (increased fluid within the brain)
• Meningeal inflammation or granulomas
• Heart failure
• Craniosynostosis (skull deformities)
• Hypervitaminosis A (tetracycline use)
• Sinus thrombosis (blood clots in the major veins of the brain)

• Physical examination: The doctor may ask about medical history, any recent injuries, or illnesses, and check for general health status.
• Neurological examination: To test senses, balance, orientation, and mental status.
• Spinal tap (lumbar puncture): To measure the pressure of the cerebrospinal fluid.
• Ocular examination: Papilledema is the hallmark sign of intracranial hypertension, which is graded using the Frisen scale. 
• Fundoscopic examination: Shows blurring of the disc margins, loss of venous pulsations, disc hyperemia, choroidal compression across the macula, choroidal neovascularisation, and retinal elevation around the optic nerve head.
• CT scan: To create a series of cross-sectional X-ray images of the head and brain.
• MRI: Magnetic fields are used to detect subtle changes in brain tissue.

Increased intracranial pressure (ICP) is treated by treating the underlying cause, which could be an infection, high blood pressure, tumor, or stroke.

The treatment of ICP might include:

• First-line therapy
  • Treatment of pyrexia
  • Management of seizures
  • Drainage of cerebrospinal fluid
  • Head of the bed elevation
  • Analgesia and sedation (intravenous propofol, etomidate, or midazolam for sedation and morphine or alfentanil for analgesia and antitussive effect)
  • Neuromuscular blockade
  • Mannitol (an intravascular osmotic agent)
• Second-line therapy
  • Optimized hyperventilation
  • Hypothermia
  • Barbiturate coma (high doses of barbiturates effectively lowers refractory intracranial hypertension)
  • Decompressive craniotomy (surgical removal of a part of the skull)

Some of the serious complications of increased intracranial pressure (ICP) include:

• Seizures
• Stroke
• Neurological damage
• Permanent vision loss
• Death

Although ICP cannot be prevented completely, the risk can be reduced by controlling certain underlying conditions such as high blood pressure, stroke, or infection.