Background
: Otitis media with effusion(OME) is a very common disease in pediatric age, However, a few literatures on epidemiologic study of otitis media with effusion are available in Korea due to the great variability of its diagnostic criteria and clinical features. The aim of this study is to provide the estimate of silent otitis media prevalence for preschool age.

Methods : The study population includes 329 children enrolled in 6 kindergartens in Kunsan city from April 1 to 10, 1995. Silent otitis media was diagnosed with otoscopy, pneumatic otoscopy and impedance audiometry by DANAC 40 model impedance audiometer from DANA JAPAN Co.

Results : The prevalence of silent otitis media with effusion was 14.5% and peak at 6 years of age(17.8%). The prevalence of silent otitis media with effusion according to sex were 11.8% in boys group, 17.9% in girls group. Nine cases(11.8%) involved bilaterally. Forty-three cases(89.6%) were asymptomatic cases.

Conclusion : Among 329 preschool children, the prevalence of silent otitis media with effusion was 14.5%. The prevalence by sex showed slightly higher in girls group than boys group. OME involved unilateral site mostly and subjective symptoms were rare.

Background
: Lactobacilli play an important role in maintaining vaginal pH and preventing partho-gens. The population of lactobacilli and vaginal pH in patients complaining vaginal discharge differ from that in normal. This study is to eveluate the usefulness of vaginal pH measurement as a simple screening method for differentiation of the causes of vaginal discharge in primary care.
Method: 100 patients with vaginal discharge underwent several examinations, 86 cases were finally diagnosed by diagnostic criteria and classified by causes. Clinical features, vaginal pH and lactobacilli population of all 86 cases were reviewed to evaluate the usefulness for differential diagnosis.
Result: Bacterial vaginosis was found in 46%, fungal vaginits in 34% mixed infecton 13% and trichomonas vaginitis in 7% of 56 cases with known causes. Peak incidence was found in age group 21~50 without differences according to the causes. Vaginal douche did not affect on differential diagnosis. Appearance of discharge was not discriminative except for amine odor in bacterial vaginosis and combined itching in fungal vaginitis. Lactobacilli population and vaginal pH were highly discrimina- otive according to the causes. Decreased lactobacilli(100%) and high vaginal pH(92%) were found in bacterial vaginosis, and predominant lactobacilli(68%) and low vaginal pH(74%) in fungal vaginitis. Sensitivity of vaginal pH measurement were 92% in bacterial vaginosis and 74% in fungal vaginitis respectively.

Conclusion : Primary care practitioners should be able to diagnose actively and treat common vaginosis or vaginitis. This results indicate that sensitive vaginal pH measurement can be helpful in differentiating diagnoses for vaginal discharge in primary care setting when used with symptoms and physical signs. It seems to be desirable that pH measurement would be used in primany care setting because of low cost, simpleness, and time saving.