Acute Bacterial Conjunctivitis
or Pink Eye
You may have Acute Bacterial Conjunctivitis if you have suffered from redness of your eyes with a foreign body sensation in them? Or have your lids been matted together in the morning from the purulent discharge from your eyes?
Bacterial Conjunctivitis often occurs with acute onset of discharge, irritation, and overall redness of one eye. The tarsal conjunctiva (the tissue lining the inside of the eyelids in direct contact with the eyeball) usually features a papillary response. Papillae are collections of lymphocytes and plasma cells.
They are best viewed by your eye doctor by flipping your eyelids and viewing their surface under the slit lamp. The slit lamp is like a “microscope” to help view small structures under magnification.
Acute Bacterial Conjunctivitis commonly is marked by mucopurulent or purulent discharge. One eye is usually affected first and then after about 48 hours the fellow eye becomes affected. Chemosis (swelling) of the conjunctiva may develop. The preauricular node is not palpable or tender.
Acute Bacterial Conjunctivitis in children 6 months to 3 years old can be more worrisome. If this conjunctivitis is accompanied by bluish discoloration and swelling of the periorbital skin, then the eye infection can suggest orbital cellulitis from the bacteria Haemophilus influenza.
This infection, which may be associated with fever and upper respiratory tract infection, may progress to include septicemia, metastatic meningitis, septic arthritis, or endophthalmitis, all of which are very serious infections.
What causes Acute Bacterial Conjunctivitis?
- Staphylococcus aureus is probably the single most common cause of bacterial conjunctivitis and blepharoconjunctivitis (involving the lids as well) in the Western world. It can complicate an eye infection by invading the cornea and cause infiltrates (cloudy, white circles in the cornea indicating inflammation), eczematous blepharitis, and other corneal and lid secondary infections.
- Staphylococcus epidermis is usually considered an innocuous inhabitant of the lids and conjunctiva, but in some instances it can cause eyelid infections along with conjunctivitis. The organism is capable of producing necrotic exotoxin and has been shown to colonize eye cosmetics, with subsequent production of blepharoconjunctivitis.
- Streptococcus pneumonia more commonly affects the conjunctiva of children and can run a self-limiting course of 9-10 days.
- Streptococcus pyogenes is a rare form of conjunctivitis although when present can produce a pseudomembranous conjunctivitis. The pseudomembrane consists of a fibrinous layer entrapping inflammatory cells and is attached to the conjunctival surface. Removal of this pseudomembrane is possible with minimal bleeding of the underlying tissue.
- Haemophilus influenza most commonly causes conjunctivitis in children rather than in adults. It is a toxigenic organism and can be accompanied by patchy conjunctival hemorrhages during an acute infection. An untreated case can last for 9-12 days, occurring as a self-limited infection, but occasionally can be a part of a more ominous periorbital cellulitis associated with respiratory infection. This infection can also be accompanied by an ear infection.
- Moraxella lacunata is a common cause of angular blepharoconjunctivitis.
How can Acute Bacterial Conjunctivitis be diagnosed?
When clinical findings are not enough to diagnose the infection, or in those situations where the reaction is severe or has not responded to routine antibiotic therapy, conjunctival scrapings for microscopic examination and routine culture techniques are indicated.
Stains most useful for identifying organisms and inflammatory cell type are the Gram and the Giemsa stain. The Gram stain is useful in revealing whether an organism is gram-positive or negative.
This information can help your eye doctor decide which antibiotic will be most effective in treating your eye condition. The Giemsa stain is useful in revealing the condition of epithelial cells and inflammatory cells.
How can Acute Bacterial Conjunctivitis be treated?
Bacterial Conjunctivitis will typically respond to antibiotic eye drops or ointment used for a seven-day course. When Haemophilus influenza is the cause of the infection, Augmentin (amoxicillin/clavulanate 20 to 40 mg/kg/day in three doses) should be used because of the other possible nonocular complications like ear infection or pneumonia.
