From the Guidelines
Constricted pupils in encephalopathy are a significant finding that may indicate life-threatening conditions, and immediate evaluation and treatment are crucial to prevent morbidity and mortality. When evaluating a patient with encephalopathy who has constricted pupils, consider opioid overdose, pontine damage, or other serious conditions as potential causes.
- The presence of constricted pupils in encephalopathy is a concerning clinical picture that requires prompt evaluation, as it may indicate life-threatening conditions affecting the brainstem's reticular activating system or neurotransmitter imbalances 1.
- A thorough neurological examination, toxicology screen, and brain imaging (particularly of the brainstem) are essential for diagnosis.
- Treatment should target the underlying cause while providing supportive care for the encephalopathy.
- According to the consensus guidelines for management of hyperammonaemia in paediatric patients receiving continuous kidney replacement therapy, constricted pupils are a sign of moderate encephalopathy, which is defined as lethargy, distal flexion, decreased activity, complete extension, hypotonia, weak suck or incomplete moro reflex, constricted pupils or bradycardia 1.
- The patient should be closely monitored, and treatment should be initiated promptly to prevent further deterioration and improve outcomes.
- The combination of encephalopathy with miosis (pupillary constriction) creates a concerning clinical picture requiring prompt evaluation, as it may indicate life-threatening conditions affecting the brainstem's reticular activating system or neurotransmitter imbalances.
- In patients with hyperammonaemia, constricted pupils are a sign of moderate or severe encephalopathy, and continuous kidney replacement therapy (CKRT) is recommended as the first-line treatment 1.
- CKRT should be initiated in patients with rapidly deteriorating neurological status, coma, or cerebral oedema, and in those with moderate or severe encephalopathy, as defined by the presence of constricted pupils, among other signs 1.
From the Research
Significance of Constricted Pupils in Encephalopathy
- Constricted pupils are a recognized feature of Wernicke's encephalopathy, a nutritionally disabling encephalopathy resulting from thiamine deficiency 2
- The typical triad of symptoms in Wernicke's encephalopathy includes impaired consciousness, ocular motility disturbances, and ataxic gait, with constricted pupils and diminished light reflexes being key ocular findings 2, 3
- Tracking pupillary findings using a pupillometer may be useful in determining treatment efficacy in Wernicke's encephalopathy 2
- Encephalopathy in children is an uncommon but significant paediatric presentation, and while constricted pupils are not specifically mentioned as a common finding, the condition is associated with significant mortality and long-term morbidity in survivors 4
- Infection-associated encephalopathies, such as septic encephalopathy, can present with reduced level of consciousness, but constricted pupils are not a specific finding mentioned in this context 5
- Posterior reversible encephalopathy syndrome (PRES) is a condition that presents with sudden onset of symptoms including headache, altered mental status, seizures, and visual disturbances, but constricted pupils are not a characteristic feature of this condition 6