Keratitis - Fungal Keratitis, Symptoms And Treatment

2024 Author: Josephine Shorter | [email protected]. Last modified: 2023-12-16 21:43

Symptoms and treatment of fungal keratitis

Fungal keratitis was first described in 1979 by Leber. The causative agent of the disease is not a typical cause of corneal inflammation and is especially dangerous in tropical countries. We must not forget about the possibility of a fungal etiology in eye diseases, since in the case when the diagnosis is untimely and there is no effective treatment, irreparable disorders in the cornea quickly appear.

Fungal keratitis is an umbrella term for inflammatory processes in the cornea that are caused by certain microorganisms. These fungi can infect and therefore cause inflammation of the outer layers of the eye. The main causative agent is the genus Fusarium, in Latin Fusarium, it causes fusarium keratitis.

The most common pathogens are Aspergillus, which cause fungal keratitis worldwide. The epidemiology of the disease is associated with climatic features. For example, there are fusarium lesions in the southern latitudes, especially in the state of Florida. In contrast, northern latitudes are more prone to candidal and Aspergillus keratitis.

The most common risk factors for fungal keratitis are trauma, tropical corticosteroid use, surgery, chronic viral keratitis, and herpes zoster and vernal keratoconjunctivitis. Injuries, for example, occur when wearing contact lenses or getting foreign objects. According to studies of morbidity in the south of Florida (USA), in 44 percent of cases, the cause of diseases is an injury of a completely natural nature: the banal hit of leaves or branches in the eye. Fungal keratitis can be triggered by surgery on the cornea of the eye, for example, penetrating keratoplasty or sutureless corneal surgery for cataracts, as well as a laser treatment of keratomillosis called LASIK.

Young, healthy men with no significant visible eye disease may develop fungal keratitis due to recent trauma related to agricultural work.

Risk factors for the development of candidal keratitis include the following: old age, previous eye diseases, other corneal diseases, chronic diseases, chronic keratitis, prolonged use of steroids, suppression of the immune system under the influence of various diseases.

Content:

• Symptoms of fungal keratitis
• Fungal keratitis treatment

Symptoms of fungal keratitis

What changes occur during fungal keratitis?

Clinically, the diagnosis of fungal keratitis can be based on the results of the analysis of risk factors, as well as on the assessment of the general condition of the cornea of the eye.

The most common signs of fungal keratitis during a slit lamp examination are:

• conjunctival injections;
• defects of the epithelium;
• suppuration;
• stromal infection;
• anterior chamber reactions;
• hypopyon.

Specific factors of fungal keratitis are infiltration with already raised feathery edges, as well as with an extremely uneven texture, with the presence of gray-brown pigmentation, with adjacent lesions, the presence of a coarse granulation infiltrate of the epithelium or anterior stroma. There are also white, rounded plaque on the cornea of the eye and adjacent lesions at the edge of the first focus of infection with the presence of endothelial plaques.

Fungal keratitis treatment

Polyenes are very effective in combating filamentous and yeast fungi, they have a destructive effect on fungi, since they introduce ergosterol into their cell walls.

Amphotericin B is the first choice for treating patients with yeast-induced fungal keratitis.

Since polyenes penetrate rather poorly through the eye tissue, deeply penetrating amphotericin B is best suited for the treatment of candidal fungal keratitis. In addition, this drug is very effective in killing most filamentous fungi. Amphotericin B should be used according to a strict scheme: on the first day - every 30 minutes, on the second day - every hour, then slowly reduce the frequency of administration, already based on the results of treatment.

Natamycin is also used for a wide range of pathogens, given its activity against filamentous fungi. It is the only commercially available topical drug for fungal eye infections. The remedy is effective against filamentous fungi, especially the Fusirium genus. Since the drug weakly penetrates the internal structure of the eye, it is used more in the fight against superficial infection.

Azoles - these are imidazoles and triazoles - have miconazole, ketoconazole, fluconazole, clotrimazole, intraconazole, econazole as active substances. All drugs of this group have a depressing effect on the synthesis of ergosterol in small concentrations, and in significant concentrations they show a strong destructive effect on the cell walls.

Oral drugs that are used orally - fluconazole or ketoconazole - are absorbed gradually and are found in high concentrations in the anterior chamber and in the cornea, therefore it is recommended to use them for deeper fungal keratitis.

Imidazoles or triazoles are synthetic chemical antifungal agents that increase the level of ketoconazole and, accordingly, fluconazole in the cornea. These data were discovered during the study of the effectiveness of drugs in animals. Due to their excellent permeability into the eye tissue, the drugs can be used systemically in the treatment of keratitis, which are caused by filamentous or yeast fungi.

Subconjunctival injections are required for patients with severe keratitis and keratoscleritis, and they are also used in case of a weak response to treatment.

For antifungal treatment to be successful, keratitis requires frequent drug use over a long period of time (minimum 12 weeks).

The primary signs of drug overdose or toxicity include: long-term non-healing epithelial ulcers, pronounced erosion on the epithelium of the cornea of the eye, diffuse lesions of the stroma.

Patients who do not respond to systemic and even local treatment with antifungal drugs require surgical treatment, which includes corneal transplantation. About 15–27% of patients cannot do without surgery. There are isolated cases when even the surgical method did not help restore vision: patients remained blind or other vision problems persisted. This is why early diagnosis as well as adequate therapy are very important in the treatment of fungal keratitis.

Article author: Mochalov Pavel Alexandrovich | d. m. n. therapist

Education: Moscow Medical Institute. IM Sechenov, specialty - "General Medicine" in 1991, in 1993 "Occupational Diseases", in 1996 "Therapy".