Anisocoria and Horner’s Syndrome
- Anisocoria refers to a difference in pupil size between the two eyes. Anisocoria may be physiologic if the pupil-size difference is 2mm or less.
- Horner’s syndrome is characterized by unilateral ptosis and miosis secondary to a loss of sympathetic neurologic tone to the eye. May be associated with iris heterochromia and/or difference in amount of sweating between the right and left side of the face, head, or body.
- Dr. Shin provided a general explanation of the sympathetic and parasympathetic nervous systems and the pupil abnormalities that occur with imbalance between the two systems.
- With Horner’s syndrome, the pupil size difference is generally more apparent in the dark than the light.
- Pharmacologic testing for Horner’s syndrome with cocaine drops was positive because cocaine caused dilation of the unaffected pupil but not the smaller affected pupil.
- Cocaine blocked the reuptake of norepinephrine (NE), the sympathetic neurotransmitter, and since there was a lack of NE in the space after the nerve ending (postganglionic synapse), the affected eye failed to dilate.
- The positive cocaine test for Horner’s syndrome indicates an adverse effect on the sympathetic nervous system, but does not reveal the pathologic location along the pathway.
- Differential diagnosis includes neuroblastoma, other upper chest/lower neck masses, and carotid and brainstem lesions.
Uveitis refers to inflammation of any of the structures of the uvea: iris, ciliary body, or choroid. Iridocyclitis or iritis, also known as anterior uveitis, refers to inflammation of the iris, anterior chamber, or ciliary body. Chronic intraocular inflammation among children is most frequently associated with JIA, an autoimmune disease classification that encompasses juvenile chronic arthritis and juvenile rheumatoid arthritis (JRA) and is further differentiated by type of onset: oligoarticular, polyarticular, or systemic.
- Oligoarticular or Pauciarticular (40-60%): It involves 4 or fewer joints in the first 6 months of the disease. It commonly affects the knees, and less frequently, the ankles and wrists, often asymmetrically. There is a high risk for uveitis with this type and approximately 75% of these patients test positive for antinuclear antibody (ANA). Affects females more than males (5:1) and most often presents at approximately 2 years of age.
- Polyarticular (20/40%): It involves 5 or more joints in the first 6 months of the disease. This subtype of JIA commonly affects the small joints of the hand, and less frequently, the larger joints of the knee, ankle, or wrist. It is often asymmetric and may be chronic or acute. There is an intermediate risk for uveitis. Immunoglobulin M (IgM) rheumatoid factor (RF) is present in 10% of children with this type of JIA, and approximately 40% test positive for ANA. It affects females more than males (3:1) and most often presents at or around 3 years of age.
- Systemic (10-20%): This JIA subtype may involve the hands, wrists, feet, ankles, elbows, knees, shoulders, cervical spine, and jaw and is typically symmetric. Patients with this type have a low risk for uveitis. Only 10% of these patients are positive for ANA. It may appear at any age and onset is associated with a normal temperature in the morning, but high fever in the evening, macular rash, leukocytosis, lymphadenopathy, and hepatomegaly. Pericarditis, pleuritis, splenomegaly, and abdominal pain are also present in some patients. This type of JIA affects boys and girls equally.
JIA affects nearly 300,000 children in the US and while chronic iridocyclitis only occurs in approximately 10-20% of children with JIA. However, because eyes with JIA-associated intraocular inflammation are typically asymptomatic and have white and noninflamed-appearing eyes, 30-40% of patients with JIA-associated uveitis experience severe vision loss.
SIGNS OF IRITIS
Many signs of iritis and uveitis are not apparent or visible on the exterior of the eye and may not be appreciated by the naked eye. They include:
- Cells and flare in the anterior chamber (like the dust particles and fog seen in front of a projector in a movie theater) due to increased permeability of inflamed iris (or iris and ciliary body in iridocyclitis)
- Band keratopathy-calcium deposition in the cornea
- Keratic precipitates-Inflammatory deposits on the endothelium (backside) of the cornea
- Inflammation of the cornea which causes cloudiness
- Nodules on the iris
- Posterior synechia(e)-Adhesions between the iris and lens
- Swelling in the retina (CME-cystoid macular edema)
- Swelling of the optic nerve head
- Low, high, or normal intraocular pressure
First-line ophthalmic treatment frequently includes administration of topical steroid eye drops to reduce inflammation and/or cycloplegic drops to prevent ciliary spasm and iris adhesions. JIA-associated iritis is chronic and can cause cataracts and glaucoma, which unfortunately can be caused by treatment with steroids as well. Compliance with steroid drops to reduce inflammation in the eye is important though because they represent the mainstay of treatment. If cataracts and/or glaucoma occur, then we also treat those conditions.
If the inflammation is not adequately addressed with conservative treatments, intravitreal steroid injections may be indicated.
Receiving proper care from a pediatric rheumatologist is integral to managing the disease because treating the underlying JIA medically with systemic immunosuppressive medications reduces intraocular inflammation.