Genital tract of female is prone to be infected during menstruation, pregnancy, sexual intercourse and during delivery. The organisms commonly infecting the vaginal tract are bacteria (Treponema pallidum, mycobacterium, Niesseria gonorrhoea), virus (Herpes, human papilloma virus), fungus (Candida) and protozoa (Trichomonas).
Fungal infection of genital tract is commonly caused by yeast like fungus known as Candida. Its various species infect the genital tract like Candida albicans, Candida glabrata, Candida tropicalis etc. Among these C. albicans is the responsible for Candida vaginitis or vaginal thrush. It is a gram positive fungus which develops pseudo mycelia thread with septate division. It resides in acidic media (pH 4.0- 5.5) and needs carbohydrate for survival. It is widely distribution in the body especially in the mouth, perianal area and in the vagina but is mostly non pathogenic.
The pathogenic property of Candida increases in pregnancy, diabetes mellitus, use of oral contraceptives and broad spectrum antibiotics. In all these condition the normal flora of vagina gets disturbed and growth of Candida supervene in vagina. In pregnancy the vaginal secretion contains high amount of carbohydrate and the acidity of vagina increases which tends to destroy other bacteria. The use of immunosuppressive drug or antibiotic also increases the risk of yeast infection. Sometimes, females may also develop oral thrush along with vaginitis. This infection can occur through sexual intercourse with a man suffering from urethritis or balanitis. The infection may also be transmitted from a male having asymptomatic yeast infection.
A combination of Candida and Trichomonas vaginitis (a protozoan infection) is quite common; the dual infection is most probably being sexually transmitted.
The main symptom is vaginal discharge and pruritus. The discharge is thick curdy white in colour. These are adherent to vaginal wall which on separation leads to multiple haemorrhagic spot. The pruritus is out of proportion to the amount of discharge. The vaginal wall and vulva are reddened and oedematous. The local soreness leads to difficulty in sexual intercourse. The infection may also be transmitted to the partner who may complain of itching of external genitalia after an act of coitus.The woman who is infected in late pregnancy may also infect the baby during its birth and leads to Candida stomatitis in the newborn.
The diagnosis of Candida infection is suspected by colour of the vaginal discharge and the feature of pruritus. It is confirmed by visualization of yeast cell in vaginal discharge. A preparation of vaginal discharge observed under microscope can identify the presence of yeast cell and exclude the presence of other organisms. A 10 percent potassium hydroxide preparation is used for preparing the slide which dissolves the red blood cell and white blood cell and helps in proper visualization. If on direct microscopy large number of white cell are seen and pH is greater than 4.5, mixed infection is suspected. If WBC is absent and pH is less than 4.5 antifungal treatment should be started. If direct microscopy do not show yeast cell then vaginal swab can be sent for culture. Recently the dual infection of Candida and Trichomonas can be detected by use of Feinberg Whittington medium which permits the detection of both Candida and Trichomonas in one specimen.
The aim of treatment is removal of aetiological factor like discontinuation of oral contraceptive temporarily, control of diabetes and stop misuse of broad spectrum antibiotic followed by use of local or systemic antifungal treatment.
A wide variety of highly affective imidazole agents are now available. Topical preparation are available as pessaries and cream as for example Miconazole 100 mg vaginal pessaries to be inserted daily at bedtimes for 6 night or 2 tablets daily for three night, Clotrimazole 500 mg vaginal tablet is administered as single dose similarly Ticonazole 300mg is inserted once daily. Vaginal cream is used with an applicator include 2 percent Miconazole or 1percent Clotrimazole for 7 nights. Cure rate against Candida is in the range of 80 – 90 percent. Mild to moderate burning sensation can occur with topical use.
Local application of Gentian violet solution was used in the past. Although effective in treatment it is messy and can cause severe local reaction with exfoliation of superficial of epithelium.
Oral systemic antifungal imidazole achieve comparable or marginally higher therapeutic cure rate. Most of the vaginal yeast infection can be cured with single dose of 150mg fluconazole. Itraconazole in higher dose and for longer duration has to be given for resistant cases. With respect to topical imidazole oral agent are more convenient, less messy but may have more side effects e.g. all imidazole are contraindicated in pregnant and nursing mother. Oral ketoconazole may lead to nausea, vomiting, hair loss, gynaecomastia and hepatotoxicity.
Severe local treatment may necessitate adjunctive topical treatment for the first 48 hour. A douche of 1 percent sodium bicarbonate can relieve the pruritus. A combination of topical antifungal with topical steroid is useful if vulva is erythematous is inflamed and erythematous. Single dose therapy is effective in mild to moderate disease. Severe or recurrent disease may need once weekly regimen of either Clotrimazole suppositories or ketoconazole 100 mg daily till the symptom subsides.
Strict control of sugar level by use of oral drugs or insulin is important in case of diabetics to treat the infection. The use of other method of contraception should be practised in place of oral contraceptive. The use of broad spectrum antibiotic should be for shorter duration and irrational use should be condemned. These measures help in controlling yeast infection.
In cases of dual infection with Trichomonas and Candida, metronidazole is prescribed for treatment of Trichomonas in a dose of 2 gm single oral dose for both partner or 400mg tablet given twice daily by mouth for 1 week along with antifungal for control of Candida infection.
The imidazoles are fungistatic agent and non albicans strains of Candida respond poorly to Fluconazole. Ticonazole has been shown to be effective in treating infection with Candida glabrata and Candida tropicalis.
