What is the cause of delayed pupillary constriction after a concussion (mild traumatic brain injury)?

From the Guidelines

Delayed pupillary constriction after a concussion is a concerning sign that requires immediate medical attention, as it may indicate increased intracranial pressure or other serious brain injury, and prompt treatment is essential for preventing potential long-term neurological damage. This symptom, also known as a sluggish pupillary light reflex, occurs when the pupils take longer than normal to constrict when exposed to light. Normally, pupils should constrict quickly when light is shined into the eye. After a concussion, damage to the brain pathways controlling pupillary response can disrupt this reflex.

Key Points to Consider

• Healthcare providers will assess this using a penlight examination and may order imaging studies like CT scans to evaluate for bleeding or swelling in the brain 1.
• This symptom is particularly concerning because it may indicate progression from a mild traumatic brain injury to a more severe condition requiring urgent intervention.
• Other accompanying symptoms to watch for include worsening headache, vomiting, increasing confusion, slurred speech, or weakness on one side of the body.
• The American Academy of Pediatrics defines postconcussion syndrome as the presence of 3 or more symptoms, including headache, dizziness, fatigue, irritability, difficulty with concentrating and performing mental tasks, impairment of memory, insomnia, and reduced tolerance to stress, emotional excitement, or alcohol, lasting longer than expected, with a threshold of 1 to 6 weeks of persistent symptoms after a concussion 2.

Recommendations for Management

• If you notice delayed pupillary constriction after a concussion, go to the emergency room right away.
• Prompt treatment is essential for preventing potential long-term neurological damage.
• Healthcare providers should assess the patient using a penlight examination and may order imaging studies like CT scans to evaluate for bleeding or swelling in the brain.
• Patients with delayed pupillary constriction after a concussion should be closely monitored for other accompanying symptoms, such as worsening headache, vomiting, increasing confusion, slurred speech, or weakness on one side of the body.

From the Research

Delayed Constriction after Concussion

• Delayed constriction after concussion is a complex issue that may be related to persistent post-concussive symptoms (PPCS) 3.
• PPCS can include a variety of symptoms such as dizziness, unsteadiness, and imbalance, which can linger longer than 30 days after the initial injury 4, 5.
• Vestibular rehabilitation therapy (VRT) has been shown to be an effective treatment for adolescents and adults with persistent symptoms of dizziness, unsteadiness, and imbalance after a concussion 4, 6, 7.
• VRT can help improve perceived disability associated with dizziness post-concussion and reduce recovery time 4, 6.
• A multidisciplinary approach to management, including associated therapies such as cognitive, vestibular, physical, and psychological therapy, is recommended for patients with PPCS 3, 5.
• Early evaluation and treatment of vestibular dysfunction may result in a reduction of time lost from sport and a return to premorbid condition 4.