Acute Bacterial Conjunctivitis

Acute bacterial conjunctivitis

Signs and symptoms: The patient will present with injection of the bulbar conjunctival and episcleral vessels, and perhaps also the palpebral conjunctiva. Infection may begin in one eye and subsequently spread to the fellow eye. There may be mild photophobia and discomfort, but pain is not typical. There will be concurrent mucopurulent discharge, and the patient usually reports that the eyelids and eyelashes are matted shut upon waking. Visual function typically is normal. The discharge is corneotoxic and frequently results in a coarse punctate epitheliopathy. Significant epitheliopathy may cause vision reduction and discomfort in some cases. Due to drainage of the infection through the nasolacrimal system, there is no preauricular node involvement.

Pathophysiology: The eye has a series of defense mechanisms to prevent bacterial invasion. These include bacteriostatic factors within the tears, the shearing force of the blink, an intact immune system, and a population of normal colonizing non-pathogenic bacteria which competitively prevent invasion by abnormal organisms. When these defense mechanisms break down, infection by pathogenic bacteria can occur.

Invading bacteria, along with secreted exotoxins, represent foreign antigens which induce an antigen-antibody immune reaction and subsequent inflammation. In a normal, healthy eye, the bacteria will eventually be eradicated as the eye strives to return to homeostasis. However, the external load of organisms can potentially set the eye up for corneal infection or involvement of other adnexal structures. The most commonly encountered organisms are Staphylococcus aureus, Hemophilus influenzae, Streptococcus pneumoniae and Pseudomonas aeruginosa.

In cases of hyperacute bacterial conjunctivitis, the patient will present with similar signs and symptoms, albeit much more severe. The most common causative agents in hyperacute conjunctivitis are Neisseria gonorrhoeae and Corynebacterium diptheroides. There is more danger in hyperacute bacterial conjunctivitis as these organisms can penetrate an intact cornea.

Management: As in any bacterial infection, microbiologic studies with cultures and sensitivities is the optimum means to reach a conclusive diagnosis. However, due to the expense of microbiologic studies and relatively benign nature of the condition, most clinicians advocate the use of broad-spectrum, empirical therapy and reserve culturing for hyperacute conditions or those that fail to respond to initial therapy.

There are many options for empirical therapy. Excellent initial broad-spectrum antibiotics include Ciloxan (ciprofloxacin, Alcon), Ocuflox (ofloxacin, Allergan), Quixin (levofloxacin, Santen), Polytrim (polymixin B-trimethoprim, Allergan), gentamicin and tobramycin. These will give good coverage of gram-positive and gram-negative organisms, though the aminoglycosides (gentamicin and tobramycin) have weak activity against Staphylococcal speciesand some strains of Pseudomonas have been found to be resistant to the aminoglycosides. Polyantimicrobial therapy may be necessary to cover all possible organisms initially. Soon-to-be-introduced fourth-generation topical fluoroquinolones--moxifloxacin (Alcon) and gatifloxacin (Allergan)--have gram-negative coverage similar to the existing fluoroquinolones but with enhanced coverage of gram-positive species. Use these antibiotics qid to q1h, depending on the severity of the infection. Stress to patients that these conditions are highly contagious.

Although antibiotics will eradicate the antigenic bacteria, they will do nothing to suppress the concurrent inflammation. If there is no significant corneal disruption, then you can use corticosteroids such as Pred Forte (prednisolone, Allergan), Flarex (fluorometholone, Alcon) or Lotemax (loteprednol, Bausch & Lomb) concomitantly with the antibiotics to speed resolution of the inflammation. Steroid-antibiotic combinations such as Maxitrol (neomycin-polymixin B-dexamethasone, Alcon), Pred-G (gentamicin-prednisolone, Allergan), and Tobra Dex (tobramicin-dexamethasone, Alcon) are also excellent initial choices for therapy when the cornea is intact.

Ocular Allergies: Oral or Topical Therapy? Since the introduction of Livostin (levocabastine, Novartis Ophthalmics) in 1994, the eye-care market has seen an explosion of topical medications for the treatment of allergic conjunctivitis. With no less than 12 prescription topical agents now available, many eye-care practitioners and general physicians still maintain that oral agents are necessary and even preferable for treating moderate to severe allergic conjunctivitis. Are oral medications better? These recent studies indicate that topical medications may work as well or better than oral antihistamines: • A study by the Fort Worth, Texas, Allergy & Asthma Association compared two patient groups taking the nasal spray fluticasone proprionate (Flonase, Glaxo Wellcome), and either Patanol or Allegra (fexofenadine, Hoechst Marion Roussel). Patients taking Patanol experienced significantly less itching and ocular injection than those using Allegra, and an equivalent reduction in nasal symptoms in both groups.1 • Mark B. Abelson, M.D., showed that patients utilizing Claritin (loratadine, Schering) demonstrated a significant reduction in ocular itching when Patanol was added to the regimen. • Researchers in Boston found that patients with normal ocular health who took Claritin 10mg bid for four days were found to have increased keratitis and conjunctival staining, decreased tear volume and break-up time, and increased ocular discomfort when exposed to an adverse environment.3 This research shows most patients are better served by topical anti-allergy preparations for allergic conjunctivitis. Oral antihistamines with diphenhydramine and chlopheniramine may compromise a patient's ability to drive and work because of their sedating effects. Even those prescription agents touted as "non-sedating," such as Claritin and Allegra, may significantly impact ocular comfort and the ability to wear contact lenses because of surface drying. As we all know, ocular irritation secondary to dry eye is the single most common reason for discontinuation of contact lens wear.   1. Lanier BQ, Abelson MB, Berger WE, et al. Comparison of the efficacy of combined fluticasone propionate and olopatadine versus combined fluticasone propionate and fexofenadine for the treatment of allergic rhinoconjunctivitis induced by conjunctival allergen challenge. Clinical Therapeutics 2002;24(7):1161-74. 2. Abelson MB, Lanier BQ. Evaluation of Patanol and Claritin for allergic conjunctivitis using the conjunctival antigen challenge. Poster presented at the annual meeting of the American College of Allergy, Asthma, & Immunology; Philadelphia November 1998. 3. Nevius JM, Abelson MB, Welch D. The ocular drying effects of oral antihistamines (Loratadine) in the normal population ­ an evaluation. Poster presented at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO); Fort Lauderdale, Fla. May 1999.

Clinical pearls:

• Proper diagnosis is the hallmark of management of acute bacterial conjunctivitis. While patients with bacterial conjunctivitis will report that their lids are matted shut in the morning with mucopurulent material, patients suffering from viral and allergic conjunctivitis will sometimes report similar experiences. However, the patients with viral and allergic conjunctivitis will actually have crusting of the lashes due to drying tears and serous secretions; those with bacterial conjunctivitis will manifest the wet, sticky, muco-purulent matting of the lashes. Too often, clinicians consider the dry crusting of the lashes to be the same as the mucopurulent matting and misdiagnose the condition.
• Remember, due to the excellent defense systems of the external eye, acute bacterial conjunctivitis is an uncommon condition.
• Do not taper antibiotics because this can lead to resistance. Once a condition resolves, discontinue the therapy abruptly.

Other reports in this section

• Conjunctival Neoplasms
• Allergic Conjunctivitis
• Vernal Conjunctivitis
• Acute Bacterial Conjunctivitis