Year : 1979 | Volume
: 27 | Issue : 4 | Page : 190--192
Medical treatment in keratomycosis
SRK Malik, S Mitter
Sir Ganga Ram Hospital, New Delhi, India
Sir Ganga Ram Hospital, New Delhi
|How to cite this article:|
Malik S, Mitter S. Medical treatment in keratomycosis.Indian J Ophthalmol 1979;27:190-192
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Malik S, Mitter S. Medical treatment in keratomycosis. Indian J Ophthalmol [serial online] 1979 [cited 2019 Nov 13 ];27:190-192
Available from: http://www.ijo.in/text.asp?1979/27/4/190/32623
The incidence of keratomycosis has risen sharply over the recent years. Cases are being reported with increasing frequency over the last two decades. The reasons for this sudden increase in frequency of fungal infection could be (1) widespread use of corticosteroids (2) widespread use of broadspectrum antibiotics (3) improved recognition of the disease and (4) an increasing academic interest in this entity.
In our previous papers, we had recommended keratoplasty in all cases, but recent experience has shown that surgery may not be required if cases are diagnosed early and treated promptly. The purpose of this study has been to evaluate the two anti-mycotic drugs i.e. Pimaricin and Fungi zone clinically on 18 proved cases of mycotic keratitis.
Materials and Methods
A total of 18 cases were included in this study, and divided into 2 groups-one for treatment with Pimaricin and the second for treatment with Fungizone.
The clinical features have been summarised in [Table 1].
The mycotic etiology was established by culture. As many as 12 cases had history of injury. The majority were agricultural workers (10 out of 18). The majority were males (14 out of 18). The age distribution is shown in [Table 2].
Group I cases were treated by a 5% suspension of Pimaricin instilled topically every 2 hours. Group II cases were put on a course of 5% Fungizone eye drops instilled every 2 hours and supplemented by one subconjunctival injection of Fungizone 0.5 ml. containing 2 mg. of the drug. Alongwith this specific anti-mycotic drug therapy, cases of both groups were given injections of garamycin 40 mg. and ampicillin 500 mg. by subconjunctival route for 2 days to check secondary infection.
Of the 10 cases in the Pimaricin Group, 4 healed (40%) while 6 required keratoplasty. The healed cases included 3 due to Aspergillus fungigatus and 1 due to Fusarium solani; and three of the cases had initially superficial ulcers while 1 had started with a deep ulcer.
In the Fungizone group, 3 out of 8 cases (37.5%) healed and 5 needed keratoplasty. Out of the healed cases, all three were of the superficial ulcer group and 2 were due to candida albicans, while in one the causative fungus was Aspergillus fumigatus.
It is evident by the results of the study that in mycotic keratitis many cases (2/5) may be treated successfully if topical antimycotic therapy is started early. Diagnosis at an early stage, is therefore an important factor in the prognosis of the disease process, as seen by the favourable response of superficial ulcer (6 out of 7 cases) to antimycotic therapy.
As far as individual fungi are concerned, Aspergillus and Fusarium showed a 50% response to Pimaricin, but were not so favourable with Fungizone, although Aspergillus responded in one case. On the other hand, candida albicans was resistant to Pimaricin, but showed an excellent response to Fungizone in 2 cases. The only case due to Penicillium citrinum was resistant to Fungizone. Failure of treatment was also related to the depth of corneal ulcer.
To treat keratomycosis, a drug must be non-irritating, non toxic in the eye, must penetrate the eye well and must have a high level of antifungal activity against atleast one significant ocular pathogen. The objective of antifungal therapy should be to inhibit fungal growth over a long period, so that the body's defense mechanisms can manage the fungus.
Certain basic principles must therefore be kept in mind.
1. Any existing defects in resistance, either due to underlying diseases or due to immunosuppression must be attended to. Failure in this indicates the need for intensified and prolonged antifungal therapy.
2. Fungal infection calls for weeks of therapy since antifungal drugs are effectively fungistatic, but rarely fungicidal.
3. Double infection or intercurrent infection must be cautiously guarded against. Common infctions are of staphylococcus aureus with either candida or Aspergillus infections.
Pimaricin is a drug of the tetrene group of Polyene antibiotics. It is most stable, safe and highly effective. A comparative study of Pimaricin and Amphotericin B (fungizone) shows:[FIgure 1]
Pimaricin has the widest range of antifungal activity against ocular pathogens especially Aspergillus fumigatus and Fusarium solani. Its penetration is however not very good and although it is curative against many superficial infections, it is ineffective against many deeper corneal infections. A 5% suspension or 1 ointment can also be used as a prophylactic in ocular injuries especially in areas of high prevalence of ocular mycosis. It can also be used as a first line treatment in any suspected fungal infection, until sensitivity of the invading organism can be established.
Fungizone or Amphotericm B has a higher level of activity against fungi like candida, coccidiodes, histoplasma and blastomyces. The reasons for its limited success are:
(a) Poor ocular penetration
(b) Increased invitro resistance by many fungi
(c) Local and systemic toxicity
It may be given topically as 5% eye drops or subconjunctival 0.5 ml. injections or even systemically in the form of I.V. therapy.
Intravitreal injections are now no longer advised, as they may cause intolerable damage.
This study clearly indicates that a trial with medical treatment should be given especially in the superficial ulcers. Keratoplasty should be done in cases which do not respond to the treatment or fungal corneal ulcer is deep.
Antimycotic therapy by Pimaricin and fungizone was evaluated in 18 cases of mycotic keratitis. It was seen that antimycotic drugs may prove curative in early cases of mycotic keratitis with superficial ulcers. Thus, surgery may not be necessary in every case as was previously thought. Cases due to Aspergillus fumigatus, and Fusarium responded best to Pimaricin, while cases due to candida responded only to Fungizone.