Patricia D. Silva

Epidemiology and Natural History of Acute Patellar Dislocation

Background The goals of this study were to (1) define the epidemiology of acute patellar dislocation, (2) determine the risk of subsequent patellar instability episodes (subluxation and/or redislocation) during the study period, and (3) identify risk factors for subsequent instability episodes. Study Design Prospective cohort study. Methods The authors prospectively followed 189 patients for a period of 2 to 5 years. Historical data, injury mechanisms, and physical and radiographic measurements were recorded to identify potential risk factors for poor outcomes. Results Risk was highest among females 10 to 17 years old. Patients presenting with a prior history of instability were more likely to be female (P < .05) and were older than first-time dislocation patients (P < .05). Fewer first-time dislocators (17%) had episodes of instability during follow-up than patients with a previous history of instability (49%) (P < .01). After adjusting for demographics, patients with a prior history had 7 times higher odds of subsequent instability episodes during follow-up than first time dislocators (adjusted odds ratio = 6.6, P < .001). Conclusions Patellar dislocators who present with a history of patellofemoral instability are more likely to be female, are older, and have greater risk of subsequent patellar instability episodes than first-time patellar dislocators. Risk of recurrent patellar instability episodes in either knee is much higher in this group than in first-time dislocators.

The Reliability and Validity of Knee-Specific and General Health Instruments in Assessing Acute Patellar Dislocation Outcomes

Background The most reliable and valid instruments for assessing patient outcome after patellar dislocation have not been identified. Hypothesis Knee-specific and general health instruments will differ in validity and reliability for patients with patellar dislocation. Study Design Prospective cohort study. Methods Subjects consisted of 153 patients with acute patellar dislocation (110 with first-time dislocations and 43 with a history of patellofemoral subluxation or dislocation). We administered the modified International Knee Documentation Committee form, Kujala, Fulkerson, Lysholm, Tegner, Short Form 36, and Musculoskeletal Function Assessment instruments on two separate occasions (test-retest reliability). Validity was assessed by comparing scores of the two groups and by comparing scores of patients with and without recurrent subluxations/dislocations during follow-up. Results The knee-specific instruments yielded the highest test-retest reliability. The knee-specific and general health instruments identified higher disability levels in the patients with a history of patellofemoral problems than in those with first-time dislocations. The general health instruments identified higher disability levels in patients with patellar dislocation than published norms. The Fulkerson and Lysholm scales were the only instruments to differentiate between patients with and without recurrent subluxations/dislocations. Conclusions Knee-specific scales yielded higher reliability coefficients and stronger validity than did general health instruments. Knee-specific, general health, and activity level instruments are complementary and in combination provide a more complete assessment for patients with patellar dislocation.

Loss of consciousness: when to perform computed tomography?

Objective: To determine the diagnostic value of physical examination (including neurologic exam) for positive computed tomography scan findings in children with closed head injury, Glasgow Coma Scale score 13–15 in the emergency department, and loss of consciousness or amnesia. Design: Prospective descriptive study. Setting: A large, tertiary, pediatric trauma center in San Diego County. Patients: Children ages 2–16 with an isolated closed head injury, history of loss of consciousness or amnesia, and Glasgow Coma Scale 13–15 who were referred for pediatric trauma evaluation and received a head computed tomography as part of this evaluation. Interventions: A standardized physical examination including skull/scalp exam, pupils, tympanic membrane, and brief neurologic exam was documented on each patient. Measurements and Main Results: Subjects age 2–16 being evaluated by the pediatric trauma team for closed head injury with loss of consciousness or amnesia and Glasgow Coma Scale 13–15 received a standardized physical exam, noncontrast head computed tomography scan, and follow-up telephone call at 4–6 wks. Outcome variables include intracranial injury visualized on computed tomography scan and need for neurosurgical intervention. Ninety-eight subjects were enrolled in the study over a 1-yr period. Computed tomography scans revealed evidence of intracranial injury in 13 of 98 subjects (13%). Normal examination increased the probability of a normal computed tomography scan from .87 pretest to .90 posttest. Four of 38 subjects with normal examination were noted to have evidence of intracranial injury on computed tomography. These four subjects did not require neurosurgical intervention. Two of 98 subjects underwent neurosurgical procedures. One intracranial pressure monitor was placed for decreasing level of consciousness. One subject underwent surgical elevation of a depressed skull fracture. Conclusions: Detailed clinical examination is of no diagnostic value in detecting intracranial injuries found on head computed tomography scan. Patients with observed loss of consciousness or amnesia and Glasgow Coma Scale 13–15 should have a head computed tomography scan as part of their evaluation to avoid missing an intracranial injury.

A comparison of respiratory symptoms and inflammation in sudden infant death syndrome and in accidental or inflicted infant death.

Upper respiratory infection and pulmonary inflammation are common in sudden infant death syndrome, but their role in the cause of death remains controversial. Controlled studies comparing clinical upper respiratory infection and inflammation in sudden infant death syndrome with sudden infant deaths caused by accidents and inflicted injuries (controls) are unavailable. Our aim was to compare respiratory inflammation and upper respiratory infection within 48 hours of death and postmortem culture results in these two groups. A retrospective analysis of upper respiratory infection and pathologic variables in the trachea and lung of 155 infants dying of sudden infant death syndrome and 33 control infants was undertaken. Upper respiratory infection was present in 39% of sudden infant death syndrome cases and 40% of control cases. Upper respiratory infection was more likely to have occurred in association with more severe lymphocytic interstitial pneumonitis when sudden infant death syndrome cases and control cases were combined (P = .04). Proximal and distal tracheal lymphocytic infiltration was more severe in control cases than in sudden infant death syndrome cases (P = .01 and .01, respectively). Lymphocytic infiltrations of the bronchi, bronchioles, and pulmonary interstitium were similar between groups. Bronchial associated lymphoid tissue was more prominent in control cases (P = .04). Cultures were positive in 80% of sudden infant death syndrome cases, 78% of which were polymicrobial. Among control cases, 89% were positive, with 94% being polymicrobial. This study confirms that microscopic inflammatory infiltrates in sudden infant death syndrome are not lethal.

Adenotonsillectomy in the very young patient: cost analysis of two methods of postoperative care

Postoperative management of the patient younger than 36 months undergoing adenotonsillectomy has been the subject of many debates. Concerns for early postoperative complications such as airway obstruction, emesis, dehydration, and hemorrhage have led many physicians to consider overnight hospitalization following adenotonsillectomy in very young children. Trends in health care management have had increasing focus on cost effective means of treating patients to limit unnecessary expenditure on the part of the patient, physician, and hospital facility. The purpose of this retrospective review was to analyze two methods of early postoperative management in children less than 36 months old undergoing adenotonsillectomy at the Childrens Hospital, San Diego from 1992 to 1997. Three hundred and seven cases were reviewed. Same-day discharge was compared with overnight inpatient observation based on the cost analysis of these two methods of postoperative care. Postoperative care was based on length of stay in the recovery room and as an inpatient. Expense of postoperative care was based on cost calculation for the recovery room and overnight hospitalization. Of the 307 patients, 194 went home the day of surgery and 113 were observed overnight in the hospital. Average hospital cost was higher in the outpatient group than in the inpatient group (P < 0.001). This difference reflects longer recovery room stay (350 min) in the outpatient group compared to the inpatient group (108 min) (P < 0.001). Outpatient adenotonsillectomy in the patient under 36 months may be safe; however, prolonged recovery room stays may actually make outpatient surgery less cost-effective than overnight admission. Recovery room costs are significantly higher per unit time than costs of inpatient hospitalization. Further investigation of cost-effective outpatient observation units may improve cost containment in the outpatient surgical setting.

Infanticide: Is its incidence among postneonatal infant deaths increasing? An 18-year population-based analysis in California

The decline in the incidence of sudden infant death syndrome (SIDS) and recent recommendations regarding the differentiation of SIDS and child abuse has generated speculation that some cases of infanticide were misdiagnosed as SIDS. The aims of this study were to determine the change in incidences and proportions of postneonatal deaths from all causes, SIDS, and infanticide in California over an 18-year interval encompassing years before and after the Back to Sleep campaign. Selected postneonatal mortality data from 1981 through 1998 obtained from the California Department of Health Services were analyzed and graphically displayed. The total postneonatal mortality and incidence of SIDS deaths per 100,000 live births decreased 45% and 66%, respectively, during the study interval; the incidence of infanticide remained low. The ratio of infanticide to SIDS increased from 4.3 per 100 in 1981 to 10.2 per 100 in 1998. Infanticide deaths, as a percentage of the total number of postneonatal deaths, increased slightly from the first to the second half of the study interval but never rose above 3.2%. It is concluded that this increased percentage is due to a decrease in SIDS deaths and not to an actual increase in infanticide deaths.

Pulmonary Intra-alveolar Siderophages in SIDS and Suffocation: A San Diego SIDS/SUDC Research Project Report

Pulmonary intra-alveolar siderophages (PS) have been suggested as a marker of previous attempts at imposed suffocation in infants dying suddenly and unexpectedly. The aims of this study were to (1) compare PS counts between cases of sudden infant death syndrome (SIDS) and a control group comprised of infants whose deaths were attributed to accidental or inflicted suffocation, (2) compare clinical variables in SIDS and control suffocation cases, and (3) review individual cases irrespective of the cause and manner of death with an average PS count greater than 200 per 20 high-power fields (hpf) per lung lobe. Retrospective assessment of siderophages in available iron-stained lung sections was undertaken in 91 SIDS cases and 29 cases of death due to suffocation (27 accidents and 2 homicides) from the San Diego SIDS and Sudden Unexplained Death in Childhood (SUDC) Research Project (SDSSRP) database. Neither the means of the log-transformed PS counts nor the medians of the raw PS counts were significantly different between the SIDS and control suffocation groups. The distributions of the PS data were different, however—the range was wider in the SIDS group. Only 6% of each group had a history of prior apparent life-threatening events. Approximately three fourths of the families from both groups had no prior referral to Child Protective Services. The number of PS varies widely in cases of sudden infant death caused by SIDS and accidental or inflicted suffocation and cannot be used as an independent variable to ascertain past attempts at suffocation.

Intrathoracic petechiae in sudden infant death syndrome: relationship to face position when found.

Previous studies have not addressed the relationship of intrathoracic petechiae (IP) to the position of the face when a caretaker finds a victim of sudden infant death syndrome (SIDS). The aims of this retrospective study were to determine (1) the rate of the facedown position in SIDS (not to be confused with the prone body position), (2) if the facedown position occurred more frequently among SIDS victims with intrathoracic petechiae than those without petechiae, and (3) if the facedown position occurred more frequently among cases with more severe petechial hemorrhage of the thymus. We selected 199 SIDS cases from the San Diego SIDS Research Project database and grouped them as IP-present and IP-absent. Each case was analyzed with regard to the face position when found unresponsive or dead. Among these 199 cases, 37% were found facedown, which represents 51% of the 142 cases found prone. The two groups were similar with respect to age, sex, and rate of premature birth. Thirty-nine percent (39%) of the IP-present group and 9% of the IP-absent group were found in the facedown position (P= 0.057; 95% confidence interval for the difference = 0.3%, 40%). Cases were also grouped by severity of thymic petechiae and analyzed regarding face position. Neither age nor the facedown position was associated with greater severity of thymic petechiae. The wide confidence interval yielded by our analysis of IP limits our ability to clarify the precise pathophysiologic role of external oronasal obstruction in SIDS. While it remains possible that a subset of SIDS cases occur as a result of external obstruction, we are unable to generalize its importance. Internal airway obstruction and rebreathing with terminal gasping, both of which have been documented in sudden infant death, remain other possible scenarios leading to the production of IP.

Child Protective Services Referrals in Cases of Sudden Infant Death: A 10-Year, Population-Based Analysis in San Diego County, California

The potential diagnostic significance of prior family referral to Child Protective Services (CPS) in cases of sudden infant death is unknown. Therefore, the authors retrospectively searched for CPS data for the 5-year referral history on all 533 families whose infants died suddenly from Sudden Infant Death Syndrome (SIDS), other natural diseases, accidents, or inflicted injuries and underwent postmortem examination by the medical examiner during a 10-year period. No family had more than one infant death. At least 27% of the families in each group had at least one CPS referral. The data suggest that a familys referral to CPS prior to their sudden death of their infant does not increase the likelihood that it was caused by inflicted injuries, and prior referral should not preclude a diagnosis of SIDS. The authors recommend future prospective studies that include refined exposure histories and that are large enough to have sufficient statistical power to compare family CPS referrals and outcomes in groups of infants who died suddenly with a matched group of living infants.

Neck extension and rotation in sudden infant death syndrome and other natural infant deaths.

It has been hypothesized that some cases of sudden infant death syndrome (SIDS) are a result of neck extension and/or rotation that causes vertebral artery (VA) compression and brain stem ischemia. There is a paucity of relevant literature on this topic. Therefore, our aim was to compare neck rotation and extension in SIDS and other natural infant deaths. Cases of SIDS and other natural infant deaths within the San Diego SIDS Research Project database were analyzed retrospectively with respect to neck and body position as reported by the trained, experienced scene investigators and/or the caretakers who discovered the infants. Information was used from 246 SIDS cases and 56 cases of other natural deaths. Simultaneous neck extension and rotation was not reported in either group. When data regarding neutral/flexed/extended position and rotation of the neck were combined, no significant differences were found between the two groups (P = 0.94); 40% of the SIDS cases and 41% of the other natural death cases were found with the neck either extended or rotated (odds ratio [OR] 0.97, [reference group = neck either neutral or flexed, and not rotated], 95% confidence interval [CI] 0.45, 2.11). There were also no significant differences between the groups when neck rotation and neck extension were analyzed independent of one another. Neck rotation among cases found in the prone position was common and was not significantly different between the two groups (49% of 146 SIDS cases, 58% of 24 other natural death cases, P = 0.38, OR 0.68, 95% CI 0.28, 1.62). Neck rotation among infants found in the supine position occurred one-third as often in the SIDS group (9% of 33 cases) as in the other natural death group (29% of 14 cases); however, the difference was not significant (P = 0.17; OR 0.25, 95% CI 0.05, 1.31). Although our analysis does not exclude VA compression and brain stem ischemia in some cases of SIDS, we found no evidence to affirm its importance. This study demonstrates the importance of meticulous scene descriptions, including neck position.