Damage to the trigeminal nerve — a large and complex nerve that controls tear production, and facial movement and sensation — during brain surgery led to neurotrophic keratitis (NK) developing in a child, a case study reports.
The study, “Acute neurotrophic keratitis with trigeminal trophic syndrome after craniotomy,” was published in the Journal of American Association for Pediatric Ophthalmology and Strabismus.
Craniotomy, a type of brain surgery that requires surgeons to remove a portion of the skull to access the brain, is one of the standard procedures to remove brain tumors or other types of brain anomalies. But it can be risky and cause unintended damage, including to nerves.
Physicians at the University of Texas Health at San Antonio described the case of a young boy who developed NK shortly after having a craniotomy to remove a cavernoma, or a cluster of abnormal blood vessels, in the brain.
The 10-year-old arrived at the hospital after developing an unsteady gait and experiencing weakness and numbness on his right extremities. Brain imaging scans revealed a cavernoma in the medulla, which makes up the lower portion of the brainstem.
A suboccipital craniotomy — a type of craniotomy where surgeons remove the back portion of the skull — was done to remove the cavernoma.
Although the boy’s initial post-operative recovery was normal, six days after surgery, swelling and redness began along his right upper and lower eyelids. This progressed over the next three days to redness and blurry vision in his right eye, along with lip swelling, and skin erosion (loss of upper skin layers) in his right nostril.
Additional eye exams showed that the cornea — the transparent outer layer of the eye that is responsible for controlling the entry and focus of light — on his right eye had started to breakdown, a telltale signs of NK.
He also had redness across his right eye, along with erosions and crusting in the skin of his right eyelids, nostril, and lip. Sensation was lost on the right side of his face.
“This combination of findings likely results from acute injury to the ipsilateral trigeminal ganglion [part of the trigeminal nerve], leading to acute neurotrophic keratitis and trigeminal trophic syndrome,” the researchers wrote.
Trigeminal trophic syndrome (TTS) is a rare condition in which damage to the trigeminal nerve causes a patient to lose sensation and develop persistent or recurrent skin lesions across a portion of the face.
The boy then underwent an amniotic membrane transplant — a procedure in which a portion of the amniotic membrane (the innermost layer of the placenta) is grafted into the eye — to promote cornea healing.
Two weeks later, a physical examination found his visual acuity had improved, and he no longer showed signs of inflammation or corneal damage to his right eye. His skin lesions had also healed.
Six months after brain surgery, however, his visual acuity started changing, and mild redness was evident across the right eye. Although his nostril and lip lesions had healed, physicians found some signs of damage and tissue irregularities in parts of the cornea of the right eye. Interestingly, these alterations were observed after brain imaging scans showed an enlargement of a different portion of the trigeminal nerve.
Physicians then placed punctal plugs — small devices that can be placed in the eyes’ tear ducts to keep the eye surface moist — and prescribed a topical antibiotic and Oxervate (cenegermin) to keep the boy’s right eye free of inflammation and well lubricated.
“We believe that our patient had two different patterns of NK. First, he developed an acute NK as a part of acute TTS involving the eye, nose, and lips, likely because of injury to the trigeminal nerve during craniotomy and resection of the cavernoma,” the researchers wrote.
“However, the 6-month examination findings in our patient were consistent with chronic NK, [and] … were more likely caused by enlargement of the previously present small lesion at the base of the right trigeminal nerve, as evidenced on subsequent neuroimaging,” they added.