Detailed account on Conjunctivitis
Infection of the conjunctiva is relatively common. It can be caused by specific microorganisms that have a predilection for eye tissues, by contaminants that proliferate due to the presence of a contact lens or an eye injury, or by accidental inoculation of the eye by a traumatic event.
▶ Signs and Symptoms
Just as there are many different causes of conjunctivitis, there are many different clinical presentations. Inflammation of this tissue almost always causes a discharge of some sort.
Most bacterial infections produce a milky discharge, whereas viral infections tend to produce a clear exudate. It is typical for a patient to wake up in the morning with an eye “glued” shut by secretions that have accumulated and solidified through the night. Some conjunctivitis cases are caused by an allergic response, and these often produce copious amounts of clear fluid as well. The pain generally is mild, although often patients report a gritty sensation in their eye(s). Redness and eyelid swelling are common, and in some cases patients report photophobia (sensitivity to light). The informal name for common conjunctivitis is pinkeye.
▶ Causative Agents and Their Transmission
Cases of neonatal eye infection with Neisseria gonorrhoeae or Chlamydia trachomatis are usually transmitted vertically from a genital tract infection in the mother. Either one of these eye infections can lead to serious eye damage if not treated promptly . Note that herpes simplex can also cause neonatal conjunctivitis, but it is usually accompanied by generalized herpes infection .
Bacterial conjunctivitis in other age groups is most commonly caused by Staphylococcus epidermidis, Streptococcus pyogenes, or Streptococcus pneumoniae, although Haemophilus influenzae and Moraxella species are also frequent causes. N. gonorrhoeae and C. trachomatis can also cause conjunctivitis in adults. These infections may result from autoinoculation from a genital infection or from sexual activity, although N. gonorrhoeae can be part of the normal biota in the respiratory tract.
A wide variety of bacteria, fungi, and protozoa can contaminate contact lenses and lens cases and then be transferred to the eye, resulting in disease that may be very serious. This means of infection is considered vehicle transmission, with the lens or the solution being the vehicle. Viral conjunctivitis is commonly caused by adenoviruses, although other viruses may be responsible. (Herpesvirus infection of the eye is discussed later on.) Both bacterial and viral conjunctivitis are transmissible by direct and even indirect contact and are usually highly contagious.
▶ Prevention and Treatment
Good hygiene is the only way to prevent conjunctivitis in adults and children other than neonates. Newborn children in the United States are administered antimicrobials in their eyes after delivery to prevent neonatal conjunctivitis from either N. gonorrhoeae or C. trachomatis. Treatment of those infections, if they are suspected, is started before lab results are available and usually is accomplished with erythromycin, both topical and oral. If N. gonorrhoeae is confirmed, oral therapy is usually switched to ceftriaxone.
If antibacterial therapy is prescribed for other conjunctivitis cases, it should cover all possible bacterial pathogens. Ciprofloxacin eyedrops are a common choice. Erythromycin or gentamicin are also often used. Because conjunctivitis is usually diagnosed based on clinical signs, a physician may prescribe prophylactic antibiotics even if a viral cause is suspected. If symptoms don’t begin improving within 48 hours, more extensive diagnosis may be performed.