Fungal keratitis

Last updated
Keratomycosis
Other namesMycotic keratitis, keratomycosis, oculomycosis [1]
Specialty Infectious diseases
Symptoms Eye pain, blurred vision, red eye, eye discharge, photophobia, corneal ulceration [1]
Complications Blindness [1]
Causes Pathogenic fungi: Fusarium , Aspergillus , Candida , [1]
Differential diagnosis Other corneal infections [1]
Frequency>1 million/year, M>F [1]

Fungal keratitis is a fungal infection of the cornea, which can lead to blindness. [2] It generally presents with a red, painful eye and blurred vision. [1] There is also increased sensitivity to light, and excessive tears or discharge. [1]

Contents

It is caused by fungal organisms such as Fusarium , Aspergillus or Candida . [1] [3] Up to 70 different fungi have been found as causes. [2]

Fungal keratitis has a worldwide distribution, but is more common in the tropics. [1] Around 1 million people become blind every year due to fungal keratitis. [4] Theodor Leber first described a case of fungal keratitis caused by Aspergillus in 1879. [5]

Signs and symptoms

The symptoms of fungal keratitis typically emerge over 5-10 days and present with a painful eye, blurred vision, and redness of eye. [1] There is increased sensitivity to light, and excessive tears or discharge. [1] The symptoms are markedly less as compared to a similar bacterial ulcer. [1] Symptoms may be noted to persist after contact lenses are removed, or following antibiotic treatment.[ citation needed ]

Signs: The eyelids and adnexa involved shows edema and redness, conjunctiva is chemosed. Ulcer may be present. It is a dry looking corneal ulcer with satellite lesions in the surrounding cornea. Usually associated with fungal ulcer is hypopyon, which is mostly white fluffy in appearance. Rarely, it may extend to the posterior segment to cause endophthalmitis in later stages, leading to the destruction of the eye. (Note: Fungal endophthalmitis is extremely rare)

Causes

Fungal keratitis has been reported to be caused by more than 70 different fungi, [2] of which Fusarium , Aspergillus and Candida are responsible for 95% of cases. [1]

A. flavus and A. fumigatus are the most common types of Aspergillus to cause fungal keratitis. [2] F. Solani is the most common type of Fusarium and others include Curvularia and Acremonium . [2] C. albicans , C. guilliermondii and C. parapsilosis are the main types of Candida to cause fungal keratitis. [2]

Other fungus causes; such as Phaeoisaria clematidis was found in 2000. [6] Then Pleurothecium recurvatum (formerly Carpoligna pleurothecii) was found in 2010. [7]

Pathophysiology

The precipitating event for fungal keratitis is trauma with a vegetable / organic matter. A thorn injury, or in agriculture workers, trauma with a wheat plant while cutting the harvest is typical. This implants the fungus directly in the cornea. The fungus grows slowly in the cornea and proliferates to involve the anterior and posterior stromal layers. The fungus can break through the descemet's membrane and pass into the anterior chamber. The patient presents a few days or weeks later with fungal keratitis.

Diagnosis

The diagnosis is made by an ophthalmologist/optometrist correlating typical history, symptoms and signs. Many times it may be missed and misdiagnosed as bacterial ulcer. A definitive diagnosis is established only after a positive culture report (lactophenol cotton blue, calcoflour medium), typically taking a week, from the corneal scraping. Recent advances have been made in PCR ref 3./immunologic tests which can give a much quicker result.

Classification

Infectious keratitis can be bacterial, fungal, viral, or protozoal. Remarkable differences in presentation of the patient allows presumptive diagnosis by the eye care professional, helping in institution of appropriate anti-infective therapy.

Prevention

Prevention of trauma with vegetable / organic matter, particularly in agricultural workers while harvesting can reduce the incidence of fungal keratitis. Wearing of broad protective glasses with side shields is recommended for people at risk for such injuries.

Treatment

A presumptive diagnosis of fungal keratitis requires immediate empirical therapy. Natamycin ophthalmic suspension is the drug of choice for filamentous fungal infection. Fluconazole ophthalmic solution is recommended for Candida infection of the cornea. Amphotericin B eye drops may be required for non-responding cases, but can be quite toxic and requires expert pharmacist for preparation. Other medications have also been tried with moderate success. An updated Cochrane Review published in 2015 looking at the best treatment for fungal keratitis could not draw any conclusions as the studies included used different medications. [8] The review did find that "people receiving natamycin were less likely to develop a hole in their cornea and need a transplant."

Prognosis

The infection typically takes a long time to heal, since the fungus itself is slow growing. Corneal perforation can occur in patients with untreated or partially treated infectious keratitis and requires surgical intervention in the form of corneal transplantation.

Epidemiology

This disease is quite common in the tropics and with large agrarian population. India has a high number of cases with fungal keratitis, but poor reporting system prevents accurate data collection. Florida in US regularly reports cases of fungal keratitis, with Aspergillus and Fusarium spp. as the most common causes.

According to the Global Action Fund for Fungal Infections, every year there are around 1 million cases of blindness due to fungal keratitis. [4]

History

A case of fungal keratitis caused by Aspergillus was first described by Theodor Leber in 1879, in a 54 year old farmer who injured his eye. [5]

Society and culture

The loss of vision with fungal keratitis can be quite disabling in terms of economic impact and social consequences. Many people come with fungal keratitis in the only eye and thus become blind due to the disease. The lack of education and proper eye protection in such cases is evidently responsible for their plight.[ citation needed ]

Notable cases

Recently, one particular product, ReNu with MoistureLoc brand of soft contact lens solutions made headlines regarding a report from the United States Centers for Disease Control and Prevention suggesting an increased incidence of a specific type of fungal keratitis ( Fusarium keratitis) in people using Bausch & Lomb products. [9] Bausch & Lomb subsequently suspended, then recalled, shipments of one particular product, ReNu with MoistureLoc. [10]

Related Research Articles

<span class="mw-page-title-main">Bausch & Lomb</span> Canadian eye health company

Bausch + Lomb is an eye health products company based in Vaughan, Ontario, Canada. It is one of the world's largest suppliers of contact lenses, lens care products, pharmaceuticals, intraocular lenses, and other eye surgery products. The company was founded in Rochester, New York, in 1853 by optician John Bausch and cabinet maker turned financial backer Henry Lomb. Until its sale in 2013, Bausch + Lomb was one of the oldest continually operating companies in the United States.

<span class="mw-page-title-main">Keratitis</span> Medical condition

Keratitis is a condition in which the eye's cornea, the clear dome on the front surface of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves any of the following symptoms: pain, impaired eyesight, photophobia, red eye and a 'gritty' sensation.

This is a partial list of human eye diseases and disorders.

<span class="mw-page-title-main">Red eye (medicine)</span> Eye that appears red due to illness or injury

A red eye is an eye that appears red due to illness or injury. It is usually injection and prominence of the superficial blood vessels of the conjunctiva, which may be caused by disorders of these or adjacent structures. Conjunctivitis and subconjunctival hemorrhage are two of the less serious but more common causes.

ReNu is a brand of soft contact lens care products produced by Bausch & Lomb. By far the most popular brand of lens solutions until 2006, ReNu has rebranded its formulations as renu sensitive and renu fresh, the latter containing a patented ingredient called hydranate, known by chemists as hydroxyalkylphosphonate, that removes protein deposits and can eliminate the need for a separate enzymatic cleaner.

<span class="mw-page-title-main">Phlyctenular keratoconjunctivitis</span> Medical condition

Phlyctenular keratoconjunctivitis is an inflammatory syndrome caused by a delayed hypersensitivity reaction to one or more antigens. The triggering antigen is usually a bacterial protein, but may also be a virus, fungus, or nematode.

<span class="mw-page-title-main">Corneal ulcers in animals</span> Veterinary inflammatory condition of the cornea

A corneal ulcer, or ulcerative keratitis, is an inflammatory condition of the cornea involving loss of its outer layer. It is very common in dogs and is sometimes seen in cats. In veterinary medicine, the term corneal ulcer is a generic name for any condition involving the loss of the outer layer of the cornea, and as such is used to describe conditions with both inflammatory and traumatic causes.

<i>Acanthamoeba</i> keratitis Eye infection caused by a protist

Acanthamoeba keratitis (AK) is a rare disease in which amoebae of the genus Acanthamoeba invade the clear portion of the front (cornea) of the eye. It affects roughly 100 people in the United States each year. Acanthamoeba are protozoa found nearly ubiquitously in soil and water and can cause infections of the skin, eyes, and central nervous system.

Otomycosis is a fungal ear infection, a superficial mycotic infection of the outer ear canal cause by micro-organisms called fungi which are related to yeast and mushrooms. It is more common in tropical or warm countries. The infection may be either subacute or acute and is characterized by itching in the ear, malodorous discharge, inflammation, pruritus, scaling, and severe discomfort or ear pain. The mycosis results in inflammation, superficial epithelial exfoliation, masses of debris containing hyphae, suppuration, and pain. Otomycosis can also cause hearing loss.

<span class="mw-page-title-main">Corneal neovascularization</span> Medical condition

Corneal neovascularization (CNV) is the in-growth of new blood vessels from the pericorneal plexus into avascular corneal tissue as a result of oxygen deprivation. Maintaining avascularity of the corneal stroma is an important aspect of corneal pathophysiology as it is required for corneal transparency and optimal vision. A decrease in corneal transparency causes visual acuity deterioration. Corneal tissue is avascular in nature and the presence of vascularization, which can be deep or superficial, is always pathologically related.

<span class="mw-page-title-main">Corneal ulcer</span> Medical condition of the eye

Corneal ulcer, also called keratitis, is an inflammatory or, more seriously, infective condition of the cornea involving disruption of its epithelial layer with involvement of the corneal stroma. It is a common condition in humans particularly in the tropics and in farming. In developing countries, children afflicted by vitamin A deficiency are at high risk for corneal ulcer and may become blind in both eyes persisting throughout life. In ophthalmology, a corneal ulcer usually refers to having an infection, while the term corneal abrasion refers more to a scratch injury.

<i>Cochliobolus lunatus</i> Fungal plant pathogen

Cochliobolus lunatus is a fungal plant pathogen that can cause disease in humans and other animals. The anamorph of this fungus is known as Curvularia lunata, while C. lunatus denotes the teleomorph or sexual stage. They are, however, the same biological entity. C. lunatus is the most commonly reported species in clinical cases of reported Cochliobolus infection.

<i>Fusarium solani</i> Species of fungus

Fusarium solani is a species complex of at least 26 closely related filamentous fungi in the division Ascomycota, family Nectriaceae. It is the anamorph of Nectria haematococca. It is a common soil fungus and colonist of plant materials. Fusarium solani is implicated in plant disease as well as human disease notably infection of the cornea of the eye.

<span class="mw-page-title-main">Vision disorder</span> Medical condition

A vision disorder is an impairment of the sense of vision.

Interstitial keratitis (IK) is corneal scarring due to chronic inflammation of the corneal stroma. Interstitial means space between cells i.e. corneal stroma which lies between the epithelium and the endothelium. Keratitis means corneal inflammation.

<span class="mw-page-title-main">Fungal contamination of contact lenses</span>

Microbial corneal infection is the most serious and "most common vision threatening" complication of contact lens wear, which is believed to be strongly associated with contact lens cases. Such infections "are being increasingly recognized as an important cause of morbidity and blindness" and "may even be life-threatening." While the cornea is believed to be the most common site for fungal eye infections, other parts of the eye such as the orbit, sclera, eyelids, and more may also be involved. Contact lens cases are recognized as a "potential source of pathogens associated with corneal ulcers" and according to Moorfields Eye Hospital, contact lens wear is “the most prevalent risk factor for new cases of corneal ulcers.” Contaminants "isolated from contact lens associated corneal ulcers have often been shown to be" the same as found in the patient's contact lens case, thus providing evidence contaminated contact lens cases may be a "replenishable source of pathogenic microbes."

<span class="mw-page-title-main">Herpes simplex keratitis</span> Medical condition

Herpetic simplex keratitis is a form of keratitis caused by recurrent herpes simplex virus (HSV) infection in the cornea.

Neurotrophic keratitis (NK) is a degenerative disease of the cornea caused by damage of the trigeminal nerve, which results in impairment of corneal sensitivity, spontaneous corneal epithelium breakdown, poor corneal healing and development of corneal ulceration, melting and perforation. This is because, in addition to the primary sensory role, the nerve also plays a role maintaining the integrity of the cornea by supplying it with trophic factors and regulating tissue metabolism.

Exposure keratopathy is medical condition affecting the cornea of eyes. It can lead to corneal ulceration and permanent loss of vision due to corneal opacity.

Peripheral Ulcerative Keratitis (PUK) is a group of destructive inflammatory diseases involving the peripheral cornea in human eyes. The symptoms of PUK include pain, redness of the eyeball, photophobia, and decreased vision accompanied by distinctive signs of crescent-shaped damage of the cornea. The causes of this disease are broad, ranging from injuries, contamination of contact lenses, to association with other systemic conditions. PUK is associated with different ocular and systemic diseases. Mooren's ulcer is a common form of PUK. The majority of PUK is mediated by local or systemic immunological processes, which can lead to inflammation and eventually tissue damage. Standard PUK diagnostic test involves reviewing the medical history and a completing physical examinations. Two major treatments are the use of medications such as corticosteroids or other immunosuppressive agents and surgical resection of the conjunctiva. The prognosis of PUK is unclear with one study providing potential complications. PUK is a rare condition with an estimated incidence of 3 per million annually.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Brown, Lottie; Leck, Astrid K.; Gichangi, Michael; Burton, Matthew J.; Denning, David W. (22 October 2020). "The global incidence and diagnosis of fungal keratitis". The Lancet. Infectious Diseases. 21 (3): e49–e57. doi:10.1016/S1473-3099(20)30448-5. ISSN   1474-4457. PMID   33645500. S2CID   226330064.
  2. 1 2 3 4 5 6 Richardson, Malcolm D.; Warnock, David W. (2012). "8. Keratomycosis". Fungal Infection: Diagnosis and Management (4th ed.). John Wiley & Sons. p. 156. ISBN   978-1-4051-7056-7.
  3. ↑ "Basics of Fungal Keratitis | Contact Lenses | CDC". www.cdc.gov. 24 May 2021. Retrieved 13 August 2021.
  4. 1 2 Rodrigues, Marcio L.; Nosanchuk, Joshua D. (20 February 2020). "Fungal diseases as neglected pathogens: A wake-up call to public health officials". PLOS Neglected Tropical Diseases. 14 (2): e0007964. doi:10.1371/journal.pntd.0007964. ISSN   1935-2735. PMC   7032689 . PMID   32078635.
  5. 1 2 Rai, Mahendra; Ingle, Avinash P.; Gupta, Indarchand; Ingle, Pramod; Paralikar, Priti; Occhiutto, Marcelo Luis (2019). "1. Mycotic keratitis: an old disease with modern nanotechnological solutions". In Rai, Mahendra; Occhiutto, Marcelo Luis (eds.). Mycotic Keratitis. CRC Press. ISBN   978-0-429-66455-7.
  6. ↑ Guarro, J.; Vieira, L.A.; De Freitas, D.; Gené, J.; Zaror, L.; Hofling-Lima, A.L.; Fischman, O.; Zorat-Yu, C.; Figueras, M.J. (2000). "Phaeoisaria clematidis as a cause of Keratomycosis". J. Clin. Microbiol. 38: 2434–2437.
  7. ↑ Chew, H.F.; Jungkind, D.L.; Mah, D.Y.; Raber, I.M.; Toll, A.D.; Tokarczyk, M.J.; Cohen, E.J. (April 2010). "Post-traumatic fungal keratitis caused by carpoligna sp". Cornea. 29 (4): 449–452.
  8. ↑ FlorCruz, Nilo Vincent; Evans, Jennifer R (2015-04-09). Cochrane Eyes and Vision Group (ed.). "Medical interventions for fungal keratitis". Cochrane Database of Systematic Reviews (4): CD004241. doi:10.1002/14651858.CD004241.pub4. PMID   25855311. S2CID   40449321.
  9. ↑ "Fusarium Keratitis --- Multiple States, 2006." Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report. April 10, 2006 / 55(Dispatch);1-2.
  10. ↑ "Bausch & Lomb News". Archived 2006-04-12 at the Wayback Machine Bausch & Lomb. Retrieved. June 2, 2006.
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