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TIME TO DEVELOPMENT OF ACUTE OTITIS MEDIA DURING AN UPPER RESPIRATORY TRACT INFECTION IN CHILDREN

1999; Lippincott Williams & Wilkins; Volume: 18; Issue: 3 Linguagem: Inglês

10.1097/00006454-199903000-00023

1532-0987

Petri Koivunen, Tero Kontiokari, Marjo Niemelä, Tytti Pokka, Matti Uhari,

Respiratory viral infections research

A viral infection often precedes the development of acute otitis media (AOM), and about every fifth URI episode results in AOM.1-3 Most of the symptoms of AOM are caused by the viral respiratory infection, whereas AOM has only few specific symptoms.4, 5 Thus it is often difficult for the parents to know when they should suspect AOM and seek medical help for their child during upper respiratory tract infection (URI). There have been few studies in which temporal development of AOM has been evaluated. In the study of Heikkinen and Ruuskanen6 54% of AOM episodes were diagnosed during the first 4 days and 75% during the first week after the onset of URI. Arola et al.2 found that the mean duration of preceding symptoms before the diagnosis of AOM was 5.9 days. To further evaluate when parents could be advised to contact a physician during a URI, we carried out a prospective study in which the temporal development of AOM was determined. We also analyzed whether children had individual tendencies to develop AOM and whether children with a history of recurrent episodes had a different pattern in developing AOM after the onset of URI. Patients and methods. A total of 857 previously healthy day-care children ages 0.6 to 6.9 years (mean, 3.7 years) were enrolled in a clinical trial for preventing of AOM7 (there were no differences in results concerning temporal development of AOM between intervention group and placebo group). The ethical committee of the Health Center of the City of Oulu approved the study protocol, and informed consent was obtained from the parents. The study was carried out in the Department of Pediatrics, University of Oulu, during a 3-month period (September to December) in 1996. The parents were asked to register daily all the URI symptoms during the study period (fever >38°C, cough, rhinitis, sore throat, vomiting, diarrhea, night restlessness, irritability, poor appetite and conjunctival symptoms). When a child had any of the following acute symptoms, rhinitis, cough, sore throat or conjunctivitis, the child was diagnosed as having URI. The parents were also asked to especially record if their child complained of earache, and in case their child was too young to express it, they were asked to register their own suspicion of earache. The symptoms were recorded daily on a symptom sheet and collected monthly. At the beginning of the study, all the children were screened for MEE with a handhold Micro Tymp (Welch Allyn) minitympanometer and if the finding was abnormal, with pneumatic otoscopy. Children were included into the study only after complete resolution of MEE detected by minitympanometry (A curve) and pneumatic otoscopy (detection of normal motility of tympanic membrane). When a child had any symptoms of URI, the parents were asked to contact the study office and the child was scheduled for an appointment within 3 days. Whenever the child had earache or a sore throat or if the parents suspected AOM, they were asked to bring their child to the office visit on same day. If AOM was not diagnosed at the first visit, the parents were asked to bring their child to the study office immediately when suspecting AOM or weekly until the symptoms resolved. During each visit a trained nurse performed a minitympanometric examination. The tympanogram was repeated at least three times before it was interpreted as abnormal. The tympanogram was classified as abnormal when static admittance (SA) was <0.2 mmho (B-curve) and/or if the tympanic peak pressure (TPP) was <−139 or >+11 daPa. An A curve (SA ≥ 0.2, TPP −139 to +11 daPa) was interpreted as normal. Pneumatic otoscopy was always performed by a validated (against tympanocentesis and tympanometry) pediatrician, when the finding in tympanometry was interpreted as abnormal or the examination was not reliable or if the child had a sore throat or earache (or if the parents suspected it) or if there was discharge from the ear. The otoscopic criteria for the diagnosis of AOM were discharge from the ear, an air-fluid level behind the tympanic membrane or a cloudy or red tympanic membrane together with impaired tympanic membrane mobility accompanied by symptoms of URI. At least three asymptomatic days between different URI episodes were required before they were registered as separate events. The disappearance of possible previous middle ear effusion had also to be verified before registering a new episode of AOM. Only the first attack of AOM during each URI episode was included in the analyses. Children who had persistent symptoms of URI for >30 days were excluded from the analyses. Acute otitis media was treated with amoxicillin for 7 days whenever there was no contraindication for this medication. The children who had had at least one episode of respiratory tract infection with AOM during the 3-month follow-up were included in the analysis of temporal development of AOM. The time lag preceding the diagnosis of AOM after the beginning of URI was registered, and the onset of earache was calculated from the symptom diary. The possible individual tendency to develop AOM with a consistent pattern was analyzed among the children who had had more than one episode of AOM. The hypothesis that children with a history of recurrent episodes of AOM have a different pattern in developing AOM than children who have had only few attacks was tested by comparing the temporal development of AOM between these two groups. The children who had undergone operative treatment because of recurrent AOM or had had more than five episodes of AOM until entering to the study were classified as having recurrent episodes of AOM. The duration of symptoms of URI with or without AOM was compared by Mann-Whitney U test. The possible effect of gender or age on the pattern in developing AOM was also analyzed. Because the children were not examined daily during their URI, we made two further analyses to assess the possible delay in the diagnosis of AOM. The pattern of development of AOM was compared between the children whose diagnosis of AOM was based on discharge from a ventilatory tube or from a spontaneous perforation and all the other children with a diagnosis of AOM. We also compared the time lag in developing AOM after the onset of URI in children with and without earache. Results. A total of 250 episodes of AOM were diagnosed in 184 children (mean age, 3.0 years). Sixty-three percent of cases of AOM complicating URI occurred during the first week, and 89% occurred by the end of the second week after the onset of URI. The highest incidence was observed on Days 2 to 5 (Fig. 1). The onset of AOM in children with a history of recurrent episodes of AOM did not differ from those who had experienced only a few episodes of AOM. Nor did gender or age affect the onset of AOM.Fig. 1: Occurrence of acute otitis media after the onset of URI in 250 episodes. Bar, number of cases on each day; line, cumulative force of morbidity.Sixty-one children had more than one occurrence of AOM in two distinct URI episodes. The temporal development of AOM during the first event did not correlate with the time lag during the second event, which was interpreted to indicate that there was no individual tendency in the temporal development of AOM (Fig. 2).Fig. 2: The time lag in developing two consecutive episodes of AOM after the onset of symptoms of upper respiratory tract infection in children who suffered at least two AOM episodes during the 3-month follow-up (Spearman rank correlation between the AOM episodes, 0.219).There were 655 URI episodes without AOM and 250 URI episodes complicated by AOM. The mean durations of the symptoms of URI in the subgroups with and without AOM were 11.0 and 11.1 days, respectively. Thus symptoms of URI complicated with AOM did not last longer than symptoms of URI without AOM, when AOM was treated effectively. In 127 episodes of AOM the child had or was suspected to have earache. These children had a similar time lag in developing AOM compared with the children not recorded to have earache. Fifteen AOM episodes were diagnosed on the basis of discharge from the ear through a ventilation tube. There was no difference in the temporal development of AOM in these cases compared with the children whose diagnosis was based on the appearance and motility of the tympanic membrane at pneumatic otoscopy. Discussion. The number of office visits for otitis media has been increasing in the US. Since 1975 the number of these visits has more than doubled; there were 24.4 million visits/year in 1990.8 An assessment of the temporal development of AOM would help parents to avoid possible multiple visits during a URI episode because of a suspicion of AOM. Apart from the earache symptoms of AOM are nonspecific and usually provide no help for parents to determine when to contact a physician. According to this study AOM can develop anytime during URI. Furthermore AOM develops irregularly even in the same child, and the temporal development of AOM in children with multiple episodes is not different from those with only a few episodes. Thus it is not possible to predict the development of AOM on the basis of the duration of the symptoms of URI. In this study the cumulative incidence of AOM was 41% in the first 4 days and 63% in the first week after developing an URI. The children in our study developed AOM during URI later than those in the study of Heikkinen and Ruuskanen,6 who found 54% of AOM episodes to appear in the first 4 days and 75% in the first week after the onset of URI. In both studies the peak incidence of AOM was during the second through fifth days, which is in accord with the finding that negative middle ear pressure manifests within the first few days after the start of an URI.9 The parents were asked to contact the study office immediately after the onset of the symptoms of URI and the child was examined within 3 days. Whenever the child had purulent discharge from an ear or had earache or a sore throat, or when parents suspected AOM, the child was examined on that day. Children were thus not examined daily, which may have distorted the results. However, discharge from a ventilatory tube or a spontaneous perforation began at the same interval after the onset of URI as did the diagnosis of AOM made in other children. Also the onset of AOM episodes with earache did not differ from those without earache, supporting our results and the postulation that there is no significant time lag in the diagnosis of AOM in our figures. There was no difference in the duration of the symptoms of URI with or without AOM. Studies of the symptoms of AOM usually show fever and ear-related symptoms to be associated with AOM.4, 5 In this study where AOM was always treated with antibiotics, the symptoms did not last longer in the URI episodes with AOM than in those without AOM. In conclusion we found that only one-third of AOM episodes developed during the first 4 days, whereas ∼40% of episodes appeared later than one week after the onset of URI. Thus parents should be advised to wait for a few days after the onset of URI before bringing their child to a physician because of a suspicion of AOM, except in the case of ear-related symptoms, when the child should be examined without delay. Petri Koivunen, M.D. Tero Kontiokari, M.D. Marjo Niemelä, M.D. Tytti Pokka, B.Sc. Matti Uhari, M.D. Departments of Otolaryngology (KP) and Pediatrics (KT, NM, PT, UM); University of Oulu; Oulu, Finland