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Editors
Keratitis
Essentials
- Keratitis is often easy to recognize based on fluorescein staining of the ocular surface.
- Early diagnosis improves treatment results significantly.
- Patients with keratitis should be referred to an ophthalmologist.
- If the infection is caused by the herpes simplex virus, treatment can be started by a GP.
Allergic keratitis
- Allergic eye infections and atopic keratoconjunctivitis, in particular, may also involve keratitis; see article on Allergic conjunctivitis Conjunctivitis.
- Untreated, prolonged atopic keratoconjunctivitis may cause permanent corneal opacity and decline in vision.
Symptoms and findings
- Often severe itching, which may lead to intensive rubbing of the eyes
- Red eyes, watery discharge, photophobia and foreign body sensation
- Often significant signs on lid skin: thickening, swelling, periocular dermatitis and erythema
- Under blue light, fluorescein staining shows inflammatory alteration of the corneal surface.
Treatment
- Allergic keratitis requires examination and treatment by an ophthalmologist.
- Frequent use of moisturizing drops may alleviate the symptoms.
- Intensified topical antiallergic medication and, if necessary, short-term use of glucocorticoid drops, both prescribed by an ophthalmologist
Referral for specialized care
- Allergic keratitis requires referral to an ophthalmologist within 1-3 days to confirm the differential diagnosis.
Bacterial keratitis
Aetiology
- The most common causative agents of bacterial keratitis are staphylococci.
- Bacterial keratitis associated with ocular injury is often caused by streptococci.
- The possibility of a Pseudomonas infection should be considered in patients using contact lenses.
- Patients confined to bed for a long time may have infections caused by enterococci, Proteus or Serratia species, Escherichia coli or Klebsiella.
Symptoms and findings
- Tearing and redness of the eye
- Foreign body sensation, pain, photophobia
- Reduced visual acuity
- Differential diagnosis by an ophthalmologist based on a corneal bacterial sample will improve the appropriateness of antimicrobial medication.
Treatment
- Topical antimicrobial medication: 1 fluoroquinolone eye drop (e.g. levofloxacin or ofloxacin) once an hour when awake
- Medication can be started by a GP.
- If Pseudomonas is suspected, microbial samples should be taken before starting the medication.
Referral for specialized care
- Patients should be referred to an ophthalmologist within 24 hours, contact lens users with suspected Pseudomonas infection as emergency cases.
Acanthamoeba keratitis
- Acanthamoeba keratitis may lead to a serious infection in the whole eye area and to permanent corneal opacity. Early diagnosis will improve the prognosis significantly.
- The possibility of Acanthamoeba keratitis should be kept in mind particularly if the patient uses contact lenses.
- The infection may be caused by contaminated water.
Symptoms and findings
- Severe pain in the eye area
- Reduced visual acuity
- Photophobia
- Often severe conjunctival redness
- Fluorescein staining may show an inflammatory focus and a superficial tissue defect in the central cornea. The inflammatory focus may be visible to the naked eye.
Treatment
- Chlorhexidine combined with either propamidine or polyhexamethylene biguanide (PHMB), as prescribed by an ophthalmologist
Referral for specialized care
- Emergency referral to an ophthalmologist
Herpes simplex keratitis
Symptoms and findings
- Bloodshot conjunctiva
- Photophobia, lacrimation
- Dendritic corneal epithelial defects seen after fluorescein staining are a typical finding.
- Corneal sensation is usually reduced.
- Initially: 3% aciclovir ointment 5 times daily for 7 days; for severe symptoms, additionally oral aciclovir (200-400 mg 5 times daily) or valaciclovir (500 mg twice daily)
Referral for specialized care
- Referral for further treatment by an ophthalmologist within 1-3 days
Herpes zoster ophthalmicus (HZO)
- More than 20% of all people will have herpes zoster at some point, and about 15% of these will have an eye infection associated with herpes zoster at some point.
- In most cases, the eye infection is due to reactivation of the varicella zoster virus (VZV).
- Rare in children
- Involvement of the cornea may lead to permanently reduced visual acuity.
- Herpes zoster in the eye area always requires treatment by an ophthalmologist.
Symptoms and findings
- Initially headache, fever and nausea; in addition, there may be scalp pain
- There are often either clusters of blisters or single such clusters on one side of the body
- The upper eyelid on the affected side may be quite swollen, erythematous and sore.
- Hutchinson's sign (vesicles on the tip of the nose); a high risk of corneal disease, too
- Inflammatory changes (discoid or punctate, for instance) may be seen after fluorescein staining on the cornea.
Workup
- The virus can be shown by antigen or PCR test. Viral culture may be considered.
Treatment
- Treatment should be started within 72 hours from the beginning of the infection. Symptom-based treatment started by a GP sufficiently early will improve the prognosis.
- Drug options
Referral for specialized care
- Referral to an ophthalmologist within 24 hours; emergency referral if reduced visual acuity is detected
Adenoviral keratitis
- No specific treatment exists so far.
- Treatment should concentrate on alleviating symptoms and preventing secondary diseases.
- In most cases, the acute stage of epidemic keratoconjunctivitis lasts 2-3 weeks but it may last up to 6 weeks.
- The disease is highly contagious and spreads by contact.
Symptoms and findings
- Red eye, watery discharge
- Foreign body sensation, pain, photophobia
- Reduced visual acuity
Workup
- The typical clinical picture is sufficient for diagnosis; no laboratory tests are necessarily needed.
- To investigate epidemics, laboratory diagnosis of conjunctival samples is recommended.
- Immunofluorescence test of the adenovirus antigen (results can be obtained urgently)
- Viral culture (results can be obtained in three weeks)
- Nucleic acid detection (more expensive but useful for investigating epidemics)
- A rapid test is also available, with results obtainable during the consultation
Treatment
- For mild forms of disease, artificial tears
- Eyelid swelling can be alleviated by using cold compresses.
- If needed, topical antimicrobials (such as chloramphenicol drops or ointment) should be administered if there is purulent discharge.
- It is important to inform patients about the course and duration of the disease and to remind them of good hygiene.
- Due to the risk of transmission, unnecessary follow-up visits should be avoided.
Referral for specialized care
- During epidemics, treatment can be started and follow-up arranged by a GP.
- In the case of more severe disease or unclear diagnosis, the patient should be referred to an ophthalmologist.
- The ophthalmologist
- often prescribes topical antimicrobial medication to prevent secondary bacterial infections
- releases pseudomembranes and adhesions in ulcerated conjunctiva mechanically every 1-2 days
- will not usually prescribe glucocorticoid drops at the acute stage because they increase the number of viruses and slow down healing at the acute stage.
- If the symptoms are abundant and the infection is serious, short-term use of mild glucocorticoid drops, monitored by an ophthalmologist, must be considered to alleviate the inflammation and to control severe symptoms.
Fungal keratitis
- A prolonged eye infection not reacting to ordinary antimicrobial treatment may be caused by fungi, particularly if there is eye trauma involved.
- Fungal keratitis is a usually slowly progressive inflammation beneath the superficial epithelial layer, which may lead to permanently reduced visual acuity if diagnosis is delayed.
- It is most commonly seen after injury where fungal spores get underneath the epithelium (scratching by a twig, organic material getting into the eye or the like).
- It is caused by Aspergillus, Fusarium or Candida species.
Symptoms and findings
- Foreign body sensation in the eye
- Gradually worsening eye pain
- Elevated corneal lesion, possibly with feathery margins and satellite foci outside the larger inflamed area
- Corneal ulcer
- Eye infection responding poorly to antimicrobials
Workup
- Ophthalmological workup
- Fungal sample from the cornea with a special fungal swab
- Bacterial culture to detect any simultaneous bacterial infection
Treatment
- As treatment may have adverse effects, it should be based on a microbiological sample.
- Antifungal medication (natamycin or amphotericin B) administered to the ocular surface, monitored by an ophthalmologist and combined with oral antifungal medication (such as itraconazole)
Referral for specialized care
- Referral for ophthalmological workup in 1-7 days
- If an inflammatory focus can be seen on the cornea after fluorescein staining or with the naked eye and a fungal infection is suspected, within 1-3 days
Differential diagnosis of keratitis
Evidence Summaries ⬆