Invading bacteria, and the exotoxins they produce, are considered foreign antigens. This induces an antigen-antibody immune reaction and subsequently causes inflammation. In a normal, healthy person the eye will fight to return to homeostasis, and the bacteria will eventually be eradicated. However, an extra heavy load of external organisms can be too difficult to fight off, causing a conjunctival infection and setting the eye up for potential corneal infection.
The most commonly encountered organisms are Staphylococcus aureus, Haemophilus 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 infectious organisms 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.
There are many antibacterial options. Excellent initial broad spectrum antibiotics include Polytrim (polymixin B sulfate and trimethoprim sulfate), gentamicin 0.3%, and tobramycin 0.3%. These will give good coverage of gram-positive and gram-negative organisms, though the aminoglycosides (gentamicin and tobramycin) have weak activity against Staphylococcal species; there are also resistant strains of Pseudomonas. Fluoroquinolones such as Ciloxan, Ocuflox and Chibroxin are also excellent options. Therapy should be aggressive, with administration from QID to Q1H for the first few days.
Although antibiotics will eradicate the bacteria, they will do nothing to suppress the concurrent inflammation. If there is no significant corneal disruption, prescribe a steroid such as Pred Forte, Vexol or Flarex along with your antibiotic of choice, or a steroid-antibiotic combination such as Maxitrol (neomycin, polymyxin B, dexamethasone 0.1%), Pred-G (gentamicin 0.3%, prednisolone acetate 0.1%), or Tobradex (tobramycin 0.3%, dexamethasone 0.1%).
Other reports in this section
Eyelids & Eyelashes | Conjunctiva & Sclera | Cornea
Uvea | Vitreous & Retina | Optic Nerve & Brain | Oculosystemic Disease
Handbook Main Page