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.
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
Other reports in this section
& Eyelashes | Conjunctiva
& Sclera | Cornea
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