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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.

Treatment Treatment of Herpes Simplex Keratitis

  • 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