Definition
A bacterial type of infectious conjunctivitis is called bacterial.
Together with the viral and allergic variant, bacterial conjunctivitis represents one of the most common disorders affecting the eye; precisely, it is an infection that affects the conjunctiva, the thin protective film that covers the inner eyelid and the eyeball.
Despite being rather easy to eradicate, bacterial conjunctivitis should not be underestimated: it is in fact important to always carry out all the necessary investigations to ascertain that the infection has an actual bacterial origin and does not hide a systemic pathology.
Causes and risk factors
We have seen that bacterial conjunctivitis is an extremely common infection: this type of ocular infection appears to constitute more than half of all types of acute conjunctivitis.
In adults, the bacterial inflammation of the conjunctiva is more often supported by Staphylococcus spp., Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis . In children, however, bacterial conjunctivitis is mainly caused by H. influenzae, S. pneumoniae and M. catarrhalis .
Some patients are more exposed to bacterial infections in general and to infective conjunctivitis in particular. Risk factors include:
- Frequent contact with infected individuals
- Use of contact lenses
- AIDS (acquired immunodeficiency syndrome)
- Sinusitis
- Cooling diseases (main risk factor for viral conjunctivitis)
- STDs (not surprisingly, even babies born to infected mothers can be affected by bacterial conjunctivitis immediately after birth).
Symptoms
All forms of conjunctivitis manifest themselves with common symptoms, such as hyperemia (redness of the eyes), abnormal tearing, photophobia and swollen eyelids: precisely because of the unspecific nature of the symptoms, it is often difficult to identify, immediately, the precise type of conjunctivitis. Nevertheless, some symptoms are peculiar and characteristic of a conjunctiva infection; therefore, from the meticulous analysis of the clinical picture we can move towards a precise variant of conjunctivitis.
Specifically, bacterial conjunctivitis is recognized by the observation of the lacrimal secretion: typically infectious conjunctival secretion is abundant and purulent, and takes on a yellowish, sometimes greenish tone. Gathering in the conjunctival sac and partially overflowing, this secretion causes the typical "glue" effect on the eyelids, which struggle to open up.
Unlike allergic conjunctivitis, the bacterial form does not manifest an intense itching and the tearing is not particularly abundant.
Complications
When the conjunctivitis is treated with the right drugs, fully respecting the dosage of the medicines, the prognosis is excellent.
Complications can occur when the disease spreads to the cornea, an eventuality not uncommon when bacterial conjunctivitis - especially when caused by chlamydia or gonorrhea - is not adequately treated.
In the context of bacterial conjunctivitis, mortality (a remote event) is linked to the failure to recognize the disease, particularly in immunocompromised patients. Sepsis (or septicemia) and meningitis resulting from conjunctivitis supported by N. gonorrhoeae can indeed endanger the patient's life. In newborns, untreated chlamydial conjunctivitis can cause otitis media or pneumonia.
Diagnosis
A suspicion of bacterial conjunctivitis must be ascertained by specific investigative medical tests, which are also indispensable for the differential diagnosis. It is important to distinguish bacterial conjunctivitis from diseases that involve similar symptoms, such as: uveitis, glaucoma, keratitis, eye trauma, episcleritis (inflammation of the superficial layers of the sclera of the eye), viral conjunctivitis, allergic conjunctivitis, eye syndrome dried, cancer (ocular carcinoma of the eye).
The diagnosis begins with the anamnesis, that is with the medical evaluation of the symptoms reported by the patient and his clinical history. Afterwards, the doctor proceeds with the eye examination, in which the degree of redness and palpebral swelling is evaluated; here, a sample of conjunctival secretion is generally taken, and subsequently sent to the laboratory for a cytological (cellular) investigation.
Treatment
Bacterial conjunctivitis therapy uses eye drops and ophthalmic ointments to be applied directly to the eye. In general, broad-spectrum antibiotics are prescribed, therefore active on more bacteria; when the germ is isolated, the doctor prescribes a specific type of eye drops. For example, for the treatment of an eye infection sustained by Pseudomonas aeruginosa the most indicated eye drops are formulated with gentamicin; fusidic acid is recommended for bacterial staphylococcal conjunctivitis.
Other drugs indicated to fight bacterial conjunctivitis are: Trimethoprim with polymyxin B, Tobramycin, Neomycin, Ciprofloxacin, Gatifloxacin and Erythromycin.
As a support to antibiotic therapy, the doctor often recommends a complementary use of corticosteroid eye drops with an anti-inflammatory action, formulated for example with Cortisone, Triamcinolone, Dexamethasone and Hydrocortisone.
On the market there are specific eye drops for bacterial conjunctivitis consisting of a mixture of active antibiotics and corticosteroids. For example, the medicinal product Mixotone is an eye drop consisting of hydrocortisone (a corticosteroid drug) and two antibiotics (neomycin and polymyxin B).
Prevention
Hygiene first and foremost: compliance with normal hygiene rules is essential to minimize the risk of any type of infection, including bacterial conjunctivitis. Strictly speaking, it is advisable to always wash your hands, especially before touching your eyes (a habit, the latter, which should be avoided as much as possible). When a family member or cohabitant accuses the symptoms of bacterial conjunctivitis, the advice is to avoid the promiscuous use of towels, sheets or other clothing: this is important to limit the risk of infection. Needless to say, bacterial infections such as conjunctivitis can be prevented by avoiding contact with infected patients as much as possible.
Nursery children, students and workers (especially those who practice their profession in public places) should stay at home for the whole time of the therapy or until the bacterial conjunctivitis is no longer contagious.
