treatment plan

Avoid Masquerade Syndromes

BY BRUCE E. ONOFREY, OD, RPH, FAAO
November 2000

A 36-year-old male was referred by his primary care physician to the eye clinic for treatment of a worsening case of "pink eye" (the referring physician's description). The patient had been using gentamycin eyedrops for approximately one month. The current BVA in the affected right eye was counting fingers at three feet and 20/20 in  the unaffected OS. The patient complained of eye pain, light sensitivity and steadily worsening visual acuity OD. The right pupil was non-reactive and irregular. The anterior chamber exhibited (+) 3 flare and (+) 2 cells with 270 degrees of posterior synechiae. IOP was 2mm Hg in the affected eye. The patient had no significant medical history or eye trauma. He did admit occasional lower back pain.

Case Management

Let's review. Eye pain, anterior chamber inflammation and synechiae do not sound like a typical "pink-eye" (whatever that is). They certainly indicate some form of uveitis. Furthermore, lower back pain suggests that the patient may suffer from ankylosing spondylitis, a not uncommon cause of anterior uveitis. It's time to order an HLA-B27 test, specific for ankylosing spondylitis. Prior to ordering lab tests, ask why the patient's back hurts. He said he injured his back in a slip and fall accident. A simple question avoided an unnecessary lab test.

First, break the synechiae and control the inflammation. Also look at the posterior pole as soon as possible. Upon the patient's return 24 hours after initiation of treatment with topical steroids and a cycloplegic agent, the synechiae were broken and the eye dilated. I was faced with a startling reason for the vision loss and ocular inflammation: the patient had a long-standing retinal detachment. This is a long way from the initial diagnosis of conjunctivitis and uveitis.

Classic Masquerade Syndrome

What I saw is a classic example of a masquerade syndrome: a collection of signs and symptoms that can lead a clinician to an incorrect and sometime disastrous diagnosis. Some of the more infamous examples of masquerade syndromes include:

1. Acanthamoeba. This condition is commonly mistaken for bacterial or herpetic keratitis. The delay in a correct diagnosis can markedly reduce the chance of a favorable outcome in affected patients.

2. Meibomian carcinoma. This disorder is commonly treated as recurrent chalazia. This is a potentially devastating error.

3. Pediatric intraocular tumors. Standard of care is ruling out organic causes of reduced vision and resulting esotropia before assuming that the strabismus has a non-organic origin.

4. Low-tension glaucoma. Patients with glaucomatous visual field defects and disc changes with consistently "normal" IOPs represent a diagnostic dilemma. Diurnal pressure evaluation, laboratory testing (ESR), evaluation of progression and an MRI may all be necessary prior to coming to a "diagnosis of exclusion" of true low-tension glaucoma.

5. Tuberculosis. One of the great masqueraders, TB is making a comeback. Phlectenular disease and anterior and posterior uveitis are all manifestations of this potentially fatal condition.

6. Chlamydia. One of the most common causes of chronic conjunctivitis and a sexually transmitted disease of epidemic proportions, chlamydia can easily be mistaken for host of other infectious disorders. Proper lab testing is the best way to identify this frequently missed condition.

Clinicians must be ever diligent and exercise an index of suspicion when the expected course of a disease deviates from the norm. Timely clinical testing and specialty referrals reduce the risk of a missed diagnosis. 

Dr. Onofrey, editor and author of various ophthalmic texts, practices in Alburquerque, N.M.