Title:

Managing severe photophobia secondary to Chiari malformation decompression surgery

Author/Co-authors:

 Mary D Vivirito, OD  Sally H Dang, OD  VA Long Beach HCS/Marshall B. Ketchum University

Abstract:

Patient with severe photophobia, worsened postoperatively from surgery for Chiari malformation, requests glasses allowing for comfortable vision and visibility of eyes. Management presents opportunities to improve care from medical, emotional and social perspectives.

Case History:

1. Demographics:  52 year old white male 2. Chief complaint:  Referral from ophthalmology department  Severe photophobia worsened post-operatively from decompression surgery for Chiari malformation type I  Patient presently wears dark tinted sunglasses indoors and outdoors to manage ocular pain from photophobia, notes indoors no one can see his eyes causing emotional distress. Requesting glasses for home use, where he controls lighting conditions, to enable others visibility of his eyes 3. Ocular history:  Severe photophobia  Unremarkable dilated ocular health Medical history:  s/p bilateral suboccipital craniotomy 2012 secondary to Chiari malformation type I (performed outside VA)  Depression  Posttraumatic stress disorder  Chronic pain syndrome 4. Medications:  Propranolol HCl 40 mg po bid by provider outside VA facility

Pertinent findings:

1. Clinical:  Extreme light sensitivity on pupil testing, otherwise entrance testing unremarkable  Myopia, astigmatism and presbyopia (correctable to 20/20 OD and OS)  Early cataracts, not visually significant  Severe photophobia  Glare sensitivity  Unremarkable dilated ocular health per last dilation 2. Physical:  Neurological testing unremarkable per neurology 11/2013 3. Radiology:  MRI 03/2013 shows stable expansion of posterior cranial fossa compatible with suboccipital craniotomy

Differential diagnosis:

1. Primary:  Severe photophobia, worsened post-operatively from decompression surgery for Chiari malformation type I

Diagnosis and Discussion:

Chiari malformation occurs when a structural defect of the skull allows for the cerebellar tonsils at the brain’s base to herniate through the foramen magnum. When the cerebellum pushes downward on the spinal canal it interrupts flow of cerebral spinal fluid leading to hydrocephalus and in some syringomyelia, causing weakness or paralysis. The condition is uncommon, affecting less than 200,000 in the US. There are 4 subtypes:

 Type I does not present until adolescence/ adulthood. It is the most common form and involves the cerebellum. Symptoms come in the form of headache aggravated by Valsalva maneuvers and other symptoms, including downbeat nystagmus, pupillary dilation, photophobia, vertigo, nausea and impaired coordination. However, some patients are asymptomatic and the defect is noticed only by imaging.  Type II is present at birth, involving both the cerebellum and the brainstem and accompanied by spina bifida  Type III involves the cerebellum, brainstem and sometimes the 4th ventricle of the brain, causing serious neurological defects. It is present at birth and has a high mortality rate  Type IV involves an underdeveloped or hypoplastic cerebellum  Types III and IV are the most serious and rare forms of the disorder

Treatment occurs for symptomatic type I patients by decompression surgery in which lamina of the 1st- 3rd vertebra are removed, along with part of the occipital bone. A graft may be placed to support the expanded posterior fossa of the brain base. Complications include bleeding, meningitis, fistula, and hydrocephalus. Surgery typically reduces or stabilizes symptoms however our patient experienced worsening of symptoms.

Treatment and Management:

Lighting conditions in exam room were simulated to patient’s home lighting. After demonstrating variable tints in which patient reports comfortable vision with goal of eyes being visible, green tinted glasses with antireflective coat were prescribed for use at home. Patient reports hope for improvement in social and emotional living aspects, as well as continued management of his photophobia. Patient to return for quarterly follow up with ophthalmology.

Current research is directed at treatment of symptomatic Chiari malformation and surgical procedures with fewer complications. Regarding type II, comparisons between infants who are corrected for the defect prenatally versus post birth are being investigated.

References:

 Liang, C et al. Posterior fossa decompression combined with resection of the cerebellomedullary fissure membrane and expansile duraplasty: a radical and rational surgical treatment for Arnold- Chiari type I malformation. Cell Biochem Biophys. July 2014

 Dora, B et al. Intracranial hypotension syndrome in a patient due to suboccipital craniectomy secondary to Chiari type malformation. World J Clin Cases. 2013 Dec 16;1(9):295-7

 www.mayoclinic.org  www.ninds.nih.gov

Conclusion:

Clinical pearls:

 Management of severe photophobia presents opportunities to better holistic patient care. Patient benefits extend beyond physical needs of managing pain to social and emotional needs of participating in everyday activities. Optometrists have the ability to create a positive impact in the lives of these patients.  Continued research in the areas of treatment for symptomatic Chiari malformation is indicated as well as further documentation of patients whose symptoms worsen post-surgically