Eye infections

                 Eye infections

The eye is well protected from infection by the conjunctiva and the corneal epithelium. In addition, the tear film contains antimicrobials while the tear flow itself tends to wash away pathogens. The eye also harbors a host of non-pathogenic bacteria that competitively prohibit new bacteria growth. However, these eye-defenses can be breached by trauma, improper tearing, or contact lens wear and lead to an infection. An eye infection not only threatens vision, but the orbit can act as an entry portal to the rest of the body and infections can progress to systemic involvement, meningitis, and even death.

RED Eye: three types of Conjunctivitis
The conjunctiva is the semi-transparent skin covering the white part of the eye. This layer protects the eye from foreign bodies, infections, and irritants. However, the conjunctiva itself is susceptible to irritation and infection from virus and bacteria. Conjunctivitis, or “pink eye,” is the term used to describe inflammation of the conjunctiva and commonly occurs from three different sources: viral, bacterial, or allergic.

1. Viral conjunctivitis is the most common type, making up half of all cases of conjunctivitis in the adult. It is usually caused by an adenovirus, often following an upper respiratory infection or cold. Viral conjunctivitis is quite contagious and other family members may also complain of having “red eye.” Infected patients typically present with eye redness and watery tearing, but little mucous discharge. Often, only one eye is infected, but the infection may hop to the other side before the end. Two specific signs on exam are enlarged follicular bumps on the inside of the eyelids (these look like tiny blisters) and swelling of the preauricular node located in front of the ear. Most of these infections clear up on their own within a few days. Like the common cold, treatment is geared toward relieving symptoms. Viral conjunctivitis is so contagious that I also recommend good hygiene and no towel/makeup sharing in the home. A lot of people at our hospital present with pink-eye, and this diagnosis is often an instant three-day vacation from work as we don’t want to spread the infection to patients. 

2. Bacterial conjunctivitis presents with a mucupurulent (pus) discharge. This creamy discharge may cause your patient to complain of sticky eyelashes, with patients finding their eyes matted shut upon waking in the morning. Bacterial conjunctivitis often develops a papillary conjunctival reaction (red bumps on the inside of the lids) and, unlike viral infections, typically does NOT have preauricular node enlargement.


The most common culprits are staph and strep, although with children you should also consider Hemophilus influenza bacteria. In addition, sexually active adults may harbor chlamydial and gonococcal infections (especially with severe or sudden discharge). We treat most conjunctivitis with erythromycin
ointment. 

3. Allergic Conjunctivitis: Finally, patients with allergic conjunctivitis present with red, watery eyes. The hallmark symptoms of allergy are itching and swelling. On exam you may see swelling around the eyes that we call “allergic shiners.” Patients often have a history of seasonal allergies and will usually present with other allergic symptoms such as a stuffy nose and cough. Treatment for allergic conjunctivitis involves avoidance of the offending allergens. These patients may need antihistamines, mast-cell stabilizers, and possibly steroids.

                                                   Pathognomonic symptoms include:
1. Viral: watering, follicles, swollen lymph nodes
2. Bacterial: creamy discharge, unilateral
3. Allergy: bilateral itching and swelling

Blepharitis:
Blepharitis means inflammation (itis) of the eyelids (bleph), specifically the eyelid margin. This condition is a common diagnosis in an eye clinic, with patients complaining of stinging, tearing, and a “gritty” sensation in their eyes.
The primary treatment for blepharitis involves good lid hygiene. Most cases can be relieved in a few weeks by having your patient wash their eyelashes daily with baby shampoo and a washcloth. Warm compresses will also help as they open up the orifices of the meibomian glands , also may require topical some times oral antibiotics.

Chalazion:
Chalazions are granulomatous inflammations of the meibomion gland. These glands produce the lipid component of the tear film and are deeply located within the supporting tarsal plate of the lid. Chalazions occur when meibomian gland pores become clogged (such as in blepharitis) — lipid backs up into the gland, and a noninfectious inflammatory granuloma reaction occurs.
On exam, the patient will have a firm and mobile nodular bump on their eyelid. When you evert the lid, you’ll often see the chalazion bump more clearly. They are non-tender and are not painful.
Early treatment involves warm compresses, massage, and lid scrubs in an attempt to reopen the meibomian pore and allow the material to flow out. If this doesn’t work, we flip the lid and incise/drain the chalazion from the inner eyelid surface. Some people are more prone to developing chalazions and they tend to reoccur.

Chlamydial Conjunctivitis:
Chlamydia causes two different kinds of conjunctivitis: inclusion conjunctivitis and trachoma. 

Gonococcal Infection:
While gonococcal infection is much rarer than chlamydial infection, it is very serious as gonorrhea can progress rapidly. These patients will present with redness of the conjunctiva and profuse mucopurulent discharge. This is a serious infection, as the organism can penetrate through a healthy cornea and perforate within 24-48 hours, leading to endophthalmitis and loss of the eye. The eye can also act as an entry portal for meningitis and septicemia.

Corneal Abrasions and Ulcers:
Corneal abrasions are very common and the most common consult that we get from the ER. Superficial epithelial defects can occur after trauma, infection, or from exposure. The cornea contains more nerve endings per area than anywhere else in the body, so scratches here are painful, and patients will often have photophobia (pain with bright lights) with the sensation that “something is in the eye.” Fortunately, with aggressive lubrication, the superficial epithelial layer heals quickly, literally within a day or two, and the patient feels better. We’ll often treat the eye with empiric erythromycin until the epithelium reforms.
If an epithelial defect has an associated bacterial infiltrate, this is called a corneal ulcer. Ulcers are treated aggressively with antibiotics and should be followed on a daily basis until the epithelial defect has closed. For straightforward, small ulcers, we typically use a fluoroquinolone like ciprofloxacin. If the ulcer is large, centrally located, or not healing, then we culture and tailor antibiotics accordingly.

Contact lens:
Contact lens wearers are more likely to have a dangerous infection with pseudomonas. In these patients, we cover with ciprofloxacin. If the ulcer looks bad, we’ll admit for hourly fortified antibiotics (ex. vancomycin and amikacin). Also, we treat any “dirty” ulcer (i.e., caused by tree branch, fingernail, soil) with more aggressive antibiotics.
With sterile epithelial defects you can patch the eye to promote lubrication and speed healing. However, you don’t want to patch an eye with a potential infection and you should follow patched eyes on a daily basis to make sure a perforating ulcer isn’t brewing under that patch.

Pre- and Post-septal Cellulitis:
Patients may present with a swollen eyelid that appears to be infected (swelling, erythema, warmth, systemic fever). When approaching a patient with a taut, infected eyelid the important distinction you must determine is whether the infection is located pre- or post-septally.
The “septum” is a layer of connective tissue that runs from the tarsal plate of the eyelid to the surrounding orbital rim. Infections superficial to this septum can look bad, but generally resolve without problems. However, if an infection tracks back behind the septum, you’re in trouble and will need to admit the patient for IV antibiotics and possible surgical abscess drainage. Orbital cellulits occurs most commonly from sinus disease, especially in children, with bacteria eroding through the thin ethmoid bone into the orbit. They can also arise from tooth abscess and even from fungal infections in patients that are immuno-compromised with glycemic problems.
Symptoms of post-septal orbital involvement are pretty obvious: soft-tissue swelling will cause proptosis and chemosis (swelling of the conjunctiva). Intraocular muscle inflammation causes decreased motility and painful eye movement. If the optic nerve is affected they’ll have decreased vision and possibly an APD.
Whenever you see a big swollen eyelid you should always check for these signs of post-septal involvement and if suspected, order a CT scan. Ophthalmology and ENT has to make this distinction frequently, often in the pediatric emergency room. 

Herpes Simplex Virus:
Herpes infection around the eye is quite common - when herpes attacks the cornea, we call this “herpetic keratitis.” Herpetic keratitis is caused by HSV Type-1. This is a common virus, and the vast majority of people contract it during childhood with almost 100% of people over 65 years with latent infection.