FDA Approves New Conjunctivitis Test

[MDBlogger]

According to the 2002 article in the American Journal of Infection Control by Guinan et al, more than 164 million school days are missed annually in American public schools due to the spread of infectious diseases and approximately 3 million school days are lost as a result of acute conjunctivitis. A study by the Carnegie Foundation revealed that missed school days represent the main problem that 83% of teachers face in their school. Approximately 2% of all primary care visits and 1% of all emergency room visits are related to conjunctivitis. Adenovirus represents the most common form of a red eye worldwide and most frequently presents to the primary care physician.

The FDA has recently approved a new, rapid point of care diagnostic test for viral conjunctivitis called the RPS Adeno Detector (Rapid Pathogen Screening, Inc.; http://www.rps-tests.com, South Williamsport, PA). The test completed a multi-center, blinded FDA clinical trial to compare the efficacy of the RPS Adeno Detector against cell culture for detecting adenoviral conjunctivitis. This study demonstrates the high degree of sensitivity and specificity of the RPS Adeno Detector at correctly identifying patients with adenoviral conjunctivitis in 10 minutes.

Currently viral conjunctivitis is a clinical diagnosis and viral cultures and PCR are not routinely done. The RPS Adeno Detector would make a laboratory confirmation of the diagnosis readily available. Because the RPS Adeno Detector test empowers a physician to accurately make a diagnosis and appropriately treat or not treat a patient, it ultimately allows a physician to practice better medicine. Physicians often feel pressured by their patients to institute a treatment even if they think it is unnecessary. When patients visualize a positive test result themselves, physicians can achieve better patient acceptance for more supportive therapies. The RPS Adeno Detector can effectively identify contagious viral conjunctivitis requiring more time away from work, school, or daycare. Unlike bacterial conjunctivitis that becomes relatively noncontagious after 48 hours of appropriate antibiotic therapy, adenoviral conjunctivitis does not improve and continues to shed a significant virus load until the eye is no longer red and tearing. Moreover, up to 30-50% of severe cases of adenoviral conjunctivitis can lead to significant long term morbidity including decreased visual acuity and photophobia from persistent subepithelial corneal infiltrates (superficial corneal opacities), chronic epiphora (tearing) from lacrimal drainage problems, and severe visual loss and pain from a cicatricial entropion associated with symblepharon (shortening and scarring of the conjunctiva) formation.

Thus, in some regions, nearly half of all patients with acute infectious conjunctivitis presenting to a primary care provider or emergency room physician may receive unnecessary antibiotic treatment. Antibiotic resistance is also a problem in the eye. Many studies have elicited high rates of antibiotic resistance for Staphylococcal and streptococcal species with commonly prescribed topical antibiotics including rates respectively approaching 30-40% for erythromycin; 20% of aminoglycosides, and a five-year review study reported that S. aureus resistance to both ciprofloxacin and ofloxacin dramatically increased from 5 percent in 1993 to 35 percent in 1997. In a 2000 study of resistance to Haemophilus influenzae and Streptococcus pneumoniae that caused bacterial conjunctivitis, older medications, such as gentamicin, polymyxin B, neomycin and sulfamethoxazole, were found to be either intermediately or not at all active against these pathogens. Furthermore, antibiotics such as aminoglycosides are toxic to the epithelia and tend to retard healing. For some topical antibiotics, adverse external ocular effects were estimated to be as high as 16%. Up to 8-20% of eyes treated with aminoglycosides will develop a hypersensitivity reaction and become red regardless of the type of infection. A recent 2005 study out of UCSF suggests that topical antibiotics may also contribute to nasopharyngeal antibiotic resistance.

The RPS Adeno Detector provides health care professionals with a true point of care test for infectious conjunctivitis. The test requires only 10 minutes to obtain a result that can empower physicians to practice better medicine, foster patient acceptance, and identify contagious viral conjunctivitis and limit spread of disease while simultaneously reducing ocular antibiotic resistance. The management style utilizing empiric antibiotic treatment may not only increase the risk of antibiotic resistance, side effects, allergies, and corneal toxicity, but also may lead to increased cost to the individual and society as a whole.