From the Guidelines
Diagnosing elevated intracranial pressure (ICP) requires a combination of clinical assessment and diagnostic tests, with MRI being the imaging modality of choice if there are signs of increased intracranial pressure and concern for possible tumor, as stated in the study by Hayes et al 1. To diagnose elevated ICP, begin by evaluating for symptoms such as:
- Severe headache (typically worse when lying down or in the morning)
- Nausea
- Vomiting
- Altered consciousness
- Vision changes
- Papilledema (swelling of the optic disc visible on fundoscopic examination) Neurological examination should assess for:
- Focal deficits
- Abnormal pupillary responses
- Cushing's triad (hypertension, bradycardia, and irregular breathing) which indicates severe elevation Diagnostic imaging is essential, with non-contrast CT being the first-line test to identify mass lesions, hemorrhage, edema, or hydrocephalus. However, MRI is more sensitive for detecting early changes of a stroke, and concurrent MRA plays an important role in stroke imaging, as noted in the study by Hayes et al 1. Direct measurement of ICP via an invasive monitor is the gold standard, with normal ICP being 7-15 mmHg; sustained readings above 20-25 mmHg indicate elevation requiring intervention, as recommended by the international multidisciplinary consensus conference on multimodality monitoring in neurocritical care 1. Lumbar puncture can measure cerebrospinal fluid pressure but should be avoided if there's concern for brain herniation. Transcranial Doppler ultrasonography and optic nerve sheath diameter measurement by ultrasound are non-invasive options for ongoing monitoring. Early diagnosis is critical as untreated elevated ICP can lead to brain herniation and death, so maintain a low threshold for investigation in patients with concerning symptoms, especially following head trauma or in those with known intracranial pathology. Some key points to consider in the diagnosis of elevated ICP include:
- The threshold value of ICP is uncertain, but generally considered to be greater than 20–25 mmHg, as noted in the study by the international multidisciplinary consensus conference on multimodality monitoring in neurocritical care 1
- The indications and method for ICP monitoring should be tailored to the specific diagnosis, such as SAH, TBI, or encephalitis, as recommended by the international multidisciplinary consensus conference on multimodality monitoring in neurocritical care 1
- Other intracranial monitors, such as MRA and MRV, can provide useful information, but ICP monitoring is the gold standard, as stated in the study by Hayes et al 1.
From the Research
Diagnostic Approaches for Elevated Intracranial Pressure
- History and physical examination are crucial in the initial assessment of patients with suspected elevated intracranial pressure (ICP) 2, 3
- Imaging studies, such as head computed tomography (CT), can help identify structural causes of elevated ICP 3, 4
- Invasive ICP monitoring is considered the gold standard for measuring and monitoring ICP 3, 5
- Non-invasive methods, such as optic nerve sheath diameter (ONSD) measurement using emergency ultrasound, can be used as an adjunct to invasive monitoring 3
- Laboratory tests, including cerebrospinal fluid (CSF) analysis, can help exclude other etiologies of elevated ICP, such as infectious or inflammatory meningitis 3
Clinical Presentation and Risk Factors
- Patients with elevated ICP often present with headache, nausea, vomiting, and papilledema 3
- Younger age, modified Fisher scale (mFS) score, and combined volume of contusional hemorrhage and peri-hematoma edema are associated with increased risk of ICP elevation in patients with severe traumatic brain injury (sTBI) 4
- Other risk factors for elevated ICP include trauma, ischemic stroke, and idiopathic intracranial hypertension (IIH) 2, 3, 5
Diagnostic Algorithms and Guidelines
- A stepwise approach to diagnosis, including history, physical examination, imaging, and laboratory tests, can help clinicians develop a comprehensive diagnosis and management plan for patients with elevated ICP 6
- Various guidelines and expert recommendations exist for the management of elevated ICP, including non-invasive maneuvers, neuroprotective intubation and ventilation strategies, and pharmacologic therapies 2, 5