What are the signs and symptoms of intracranial hypertension?

Signs and Symptoms of Intracranial Hypertension

The key signs and symptoms of intracranial hypertension include headache, visual disturbances, nausea/vomiting, and altered mental status, which require prompt recognition and management to prevent cerebral ischemia, brain herniation, and death. 1, 2

Clinical Presentation

Neurological Symptoms

• Headache - typically worse in the morning, aggravated by Valsalva maneuvers (coughing, straining) 3
• Visual disturbances - blurred vision, transient visual obscurations, diplopia 1
• Altered mental status - progressing from somnolence and lethargy to decreased consciousness 1
• Seizures, particularly tonic-clonic seizures 1
• Cortical blindness in severe cases 1
• Dizziness due to impaired cerebral autoregulation 1

Cranial Nerve Findings

• Papilledema (swelling of the optic disc) - key diagnostic finding 1
• Sixth cranial nerve palsy - causing lateral gaze weakness 1
• Focal neurological deficits are rare in pure intracranial hypertension and should raise suspicion for other pathologies like intracranial hemorrhage or stroke 1

Systemic Symptoms

• Nausea and vomiting 1, 3
• Gastrointestinal complaints - abdominal pain, anorexia 1
• In severe cases, progression to posturing and respiratory abnormalities 2
• Eventually, cardiopulmonary arrest in untreated cases 2

Advanced Signs of Deterioration

• Progression from headache and visual symptoms to stupor and coma 2
• Development of pupillary changes 2
• Hemiparesis or quadriparesis 2
• Abnormal respiratory patterns 2
• Loss of consciousness - late and ominous sign 1, 2

Diagnostic Findings

Imaging

• MRI brain findings may show:
  • White matter lesions in posterior regions (in hypertensive encephalopathy) 1
  • Signs of cerebral edema 1
  • Compression of basal cisterns - best sign of intracranial hypertension 1
  • Brain midline shift over 5 mm 1
  • Disappearance of cerebral ventricles 1

Lumbar Puncture

• Elevated opening pressure (>20-25 mmHg or >25 cm H2O) 4, 2
• Normal CSF composition in idiopathic intracranial hypertension 1

Other Diagnostic Tests

• Fundoscopy - reveals papilledema, flame-shaped hemorrhages, cotton wool spots 1
• Optic nerve sheath diameter measurement by ultrasound (>4.8-6.3 mm suggests increased ICP) 3
• ECG may show evidence of increased sympathetic tone 1

Special Considerations

Hypertensive Encephalopathy

• A form of posterior reversible leukoencephalopathy syndrome (PRES) 1
• Characterized by cerebral edema, microscopic hemorrhages, and infarctions 1
• MRI shows increased signal intensity on T2-weighted or FLAIR imaging, particularly in posterior brain regions 1

Idiopathic Intracranial Hypertension

• More common in females of reproductive age with BMI ≥30 kg/m² 1
• Requires exclusion of other causes of increased ICP 1
• Weight loss is the only disease-modifying therapy 1

Warning Signs Requiring Immediate Intervention

• Rapid deterioration in mental status 1
• New onset seizures 1
• Progression to cortical blindness 1
• Development of focal neurological deficits 1
• Signs of brain herniation 2

Pitfalls in Diagnosis

• Focal neurological lesions are rare in pure intracranial hypertension and should raise suspicion for intracranial hemorrhage or ischemic stroke 1
• Advanced hypertensive retinopathy may be lacking in up to one-third of patients with hypertensive encephalopathy 1
• Intracranial pressure can be elevated without all classic symptoms being present - the rate of increase may be more important than the absolute value 1
• Papilledema may be difficult to visualize for non-specialists using standard ophthalmoscopy 3

Early recognition and prompt management of intracranial hypertension are critical to prevent permanent neurological damage or death, with treatment aimed at reducing ICP below 20 mmHg and maintaining cerebral perfusion pressure between 60-90 mmHg 5, 2.