Brian D. Blackbourne

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.

Specific dangers associated with infants sleeping on sofas

Aim: A study was undertaken to examine specific circumstances that may lead to accidental asphyxial deaths in infants on sofas.

Shared bathing and drowning in infants and young children

Objective: A study was undertaken to look at possible risks of shared bathing in early childhood.

Death due to electrocution in childhood and early adolescence.

Objectives:  To delineate the clinicopathological features of fatal childhood electrocutions and to identify specific risk factors.

Oronasal blood in sudden infant death.

Oronasal secretions are observed frequently in sudden infant death syndrome (SIDS), but overt blood is uncommonly reported. The literature on oronasal blood in sudden infant death is limited. The goal of this study was to determine the frequency of oronasal blood in sudden infant deaths and to examine possible causative factors. Oronasal blood was described in 28 (7%) of 406 cases of sudden infant death. Oronasal blood could not be attributed to cardiopulmonary resuscitation in 14 cases, including 10 (3%) of 300 cases of SIDS, 2 (14%) of 14 accidental suffocation cases, and 2 (15%) of 13 undetermined cases. Eight of the 10 infants in cases of sudden infant death were bedsharing: 5 with both parents, 2 between both parents. The infant in 1 SIDS case was from a family that had had three referrals to Child Protective Services. Oronasal blood not attributable to cardiopulmonary resuscitation occurs rarely in SIDS when the infant is sleeping supine in a safe environment. Bedsharing may place infants at risk of suffocation from overlaying. Oronasal blood observed before cardiopulmonary resuscitation is given is probably of oronasal skin or mucous membrane origin and may be a sign of accidental or inflicted suffocation. Sanguineous secretions that are mucoid or frothy are likely of remote origin, such as lung alveoli. The use of an otoscope to establish the origin of oronasal blood in cases of sudden infant death is recommended.

Environmental hyperthermic infant and early childhood death: circumstances, pathologic changes, and manner of death.

Infant and early childhood death caused by environmental hyperthermia (fatal heat stroke) is a rare event, typically occurring in vehicles or beds. The aims of this study were to describe the demographics, circumstances, pathology, and manner of death in infants and young children who died of environmental hyperthermia and to compare these cases with those reported in the literature. Scene investigation, autopsy reports, and the microscopic slides of cases from three jurisdictions were reviewed. The subjects in 10 identified cases ranged in age from 53 days to 9 years. Eight were discovered in vehicles and 2 in beds. When the authors’ cases were grouped with reported cases, the profile of those in vehicles differed from those in beds. The former were older, were exposed to rapidly reached higher temperatures, and often had more severe skin damage. The latter were mostly infants and were exposed to lower environmental temperatures. Hepatocellular necrosis and disseminated intravascular coagulation were reported in victims who survived at least 6 hours after the hyperthermic exposure. The consistent postmortem finding among nearly all victims was intrathoracic petechiae, suggesting terminal gasping in an attempt at autoresuscitation before death. The manner of death was either accident or homicide. Recommendations for the scene investigation are made.

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.

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.

Medial smooth muscle thickness in small pulmonary arteries in sudden infant death syndrome revisited.

Increased relative medial thickness (RMT) of smooth muscle in small pulmonary arteries, peripheral extension of smooth muscle into the alveolar wall arteries, and right ventricular hypertrophy (RVH), in response to purported prolonged hypoxia, have been reported in sudden infant death syndrome (SIDS). Prone sleep position, an important risk factor for SIDS, predisposes infants to hypoxia from airway obstruction or rebreathing. Since publication of the earlier pulmonary artery studies, the SIDS definition has been expanded, and sudden infant death investigational protocols have been implemented. Our aims in this study were to (1) compare RMT in preacinar arteries (PA), intra-acinar arteries accompanying small airways (SIA), and alveolar wall arteries (AW) in SIDS infants and controls; (2) correlate RMT with postmortem variables; (3) determine if peripheral extension occurred more often in SIDS infants than in controls; and (4) determine if RVH occurred in SIDS. Movat-stained sections from standardized tissue blocks taken prospectively from the apex of the right upper lobe from 88 SIDS cases and 17 controls were evaluated using a computer-assisted digitizing system with images obtained from a microscope with an attached video camera. When adjusted for age, the RMT values for the SIA arteries were significantly greater in controls, while the PA and AW arteries were not statistically different between the SIDS cases and controls. Peripheral medial smooth muscle extension did not differ between the groups, and RVH was not seen in SIDS cases. Given the recent identification of brain stem abnormalities interfering with protective cardiorespiratory responses against acute life-threatening hypoxia perhaps precipitated by prone sleeping, our data suggest that SIDS is an acute event not preceded by recurrent or prolonged apnea and hypoxia.