Tiny Pupils

Near dusk late in the third quarter of a junior high football game, a member of the opposing team remained on his back on the field after being tackled. I saw the hit and it appeared to be a coup-contrecoup mechanism of injury. When I arrived he was holding the right side of his neck between his helmet and shoulder pads while squinting hard. He was alert, responsive, and remarkably calm. He had no complaint of head pain or altered sensation in the shoulder or upper extremity, only right sided neck pain. Performing an on field assessment and evaluation I determined that the injury was not spinal in nature as the patient had full function and strength of both the upper and lower extremities. He was able to plantarflex and dorsiflex with full equal strength, bend his knees and flex his hips against resistance. He also had equal and strong grip. Palpation of the spinous processes of the patient’s cervical spine rendered no tenderness.  His only complaint and painful region to palpate was in the area of the right posterior scalenes. However, he never opened his eyes until he was standing and walking off the field.

When we arrived on the sideline complaints of headache arose as I asked that the patient take his helmet off and sit on the bench so that I could continue my evaluation. It was then that I was able to finally see the patient’s eyes. PERRLA was seemingly clear without anisocoria though this was difficult to assess as the patients pupils were tiny. This was alarming but not something I had previously experienced nor did I have any recollection of Miosis or Microcoria, as I would find out the condition is called later that evening thanks to Google, in my education. A cranial nerve assessment also presented without issue, save for this potential trigeminal nerve injury of course, and the patient had no reports of nausea. The patient was having difficulty with neck movement through any AROM and, while not one of my patient-athletes, did not seem to be entirely mentally clear though his memory was also without issue. I decided then to recheck his pupils and although the light made his headache worse, his eyes presented with mild changes in the dilation of his teeny-tiny pupils. At this point his mother arrived. The patient’s mother had even smaller pupils. When I inquired about this, she didn't seem surprised but also didn't seem to understand that this was a bit abnormal. I expressed my concerns, and now my relief, regarding her son’s presentation at which time she responded with a laugh and a smile directed at her son saying "well I guess were tiny pupil people". I was relieved at the idea that perhaps this was a genetic anomaly, told the patient's coach that he was done for the evening, advised his mother regarding signs and symptoms of a worsening condition and when to seek immediate medical attention, unsuccessfully called his schools Athletic Trainer, and went back to the suspected ankle fracture I had been evaluating, also on the visiting team, when this injury occurred. This was a fairly routine patient, parent, and professional encounter except for the family with the tiny pupils.

When I arrived home and began reflecting on my patient care for the day, I, of course, had to research why someone, and their parent, would present with extremely small pupils. The results are a bit disheartening. According to the American Academy of Opthalmology: "Congenital miosis, or microcoria, may represent an absence or malformation of the dilator pupillae muscle. Congenital miosis can also occur secondary to contracture of fibrous material on the pupil margin from remnants of the tunica vasculosa lentis or neural crest cell anomalies. The condition may be unilateral or bilateral and sporadic or hereditary. Severe cases require surgical pupilloplasty.The pupil diameter rarely exceeds 2 mm, is often eccentric, and reacts poorly to mydriatic drops. Some patients with eccentric microcoria also have lens subluxation and are therefore part of the spectrum of ectopia lentis et pupillae. Congenital miosis may be associated with microcornea, cataract, megalocornea, iris atrophy, iris transillumination, myopia, and glaucoma. Congenital miosis can also be seen with congenital rubella syndrome and hereditary ataxia and in 20% of patients with Lowe oculocerebrorenal syndrome." - https://www.aao.org/bcscsnippetdetail.aspx?id=3711a310-42e6-4487-ad8e-0b612ebb5c29

However, most search results including but not limited to Wikipedia, WebMD, and science-direct mention a variety of potential causes including but also not limited to:

Fatal Familial Insomnia (wait... what?)
Intracranial hemorrhaging into the pons (yikes, this was after all a concussion evaluation)
Iridocyclitis (associated with infections disease and/or autoimmune disorders)
Cluster Headaches
Exposure to Mustard Gas (glad we can rule that one out!)
A whole host of pharmaceuticals, not the least of which on the list being opioid use and abuse.

As I am new to the Athletic Training profession, these types of learning experiences are invaluable. It is likely that I would have sent this patient to the hospital as a precaution considering the odd presentation coupled with the area of injury. Given what I now know about this condition and some of its potential causes, I am glad that I tend to err on the side of caution. I now have this case etched into my memory during concussion evaluation and as a teaching tool for atypical presentations. I am also now more grateful than ever for parents who travel to their children’s away sporting events.