From the Guidelines
Pupil signs in raised intracranial pressure (ICP) include unilateral sluggish or absent pupillary responses, which are the only reliable signs, as well as unequal, dilated, or poorly responsive pupils. These signs are critical indicators of increased ICP and can be associated with a declining conscious level, focal neurology, and abnormal posturing. According to the study by 1, brain swelling is a major feature in fatal cases of raised ICP, and signs suggestive of raised ICP, including pupillary abnormalities, often develop in the later stages of the illness. Key pupil signs to monitor include:
- Unilateral sluggish or absent pupillary responses
- Unequal pupils (anisocoria)
- Dilated pupils
- Poorly responsive pupils It is essential to note that papilloedema and the combination of hypertension and relative bradycardia are late findings in acute raised ICP, and caution should be exercised when diagnosing raised ICP in children in the peri-ictal state, where pupillary signs and conscious level may be misleading, as stated in the study by 1. Monitoring these pupil signs is crucial in patients with conditions that can cause elevated ICP, such as traumatic brain injury, intracranial hemorrhage, brain tumors, or hydrocephalus, to promptly identify and manage increased ICP and prevent further brain damage.
From the Research
Pupil Signs in Raised Intracranial Pressure
- Pupil signs are an important indicator of raised intracranial pressure (ICP) 2
- However, the provided studies do not specifically mention pupil signs in raised ICP, instead focusing on other signs such as papilledema, headache, nausea, and vomiting 3, 4, 5, 2
- Papilledema is a well-recognized sign of increased ICP, but emergency physicians may find it difficult to visualize the optic disc or accurately interpret digital fundus photographs 2
- Other signs of increased ICP include optic nerve sheath diameter (ONSD) and optic disc elevation, which can be evaluated using emergency ultrasound 2
- Neuroimaging and neuroradiographic signs can also be helpful in suggesting idiopathic intracranial hypertension (IIH) or other structural causes of increased ICP 2
Diagnostic Evaluation
- Invasive ICP measurement remains the standard to measure and monitor raised ICP 2
- Cerebrospinal fluid (CSF) evaluation is also required to exclude other etiologies of elevated ICP such as infectious, inflammatory, and neoplastic meningitis 2
- Neuroimaging is an important step in the evaluation of patients with suspected raised ICP, as it can identify most structural causes or typical radiological patterns of increased ICP 2
Management
- Hyperosmolar therapy is one of the core medical treatments for brain edema and intracranial hypertension, with mannitol and hypertonic saline being the most common agents used 6
- Both mannitol and hypertonic saline are effective and have an acceptable risk profile for use in the treatment of elevated intracranial pressure secondary to brain edema 6