Sudden infant death due to asplenia syndrome

Unexpected death involving the spleen - an overview

The spleen is located in the left upper quadrant of the abdominal cavity and has both immunological and haematological functions. A variety of quite different entities may be associated with sudden death due to splenic involvement. These range from simple traumatic disruption of the parenchyma of a normal spleen with marked intra-abdominal haemorrhage, to conditions such as malaria and infectious mononucleosis where splenomegaly predisposes to rupture. Haematological diseases such as malignancies and haemoglobinopathies may causes sudden death due to haemorrhage or red cell sequestration. Asplenia or polysplenia may be associated with significant congenital heart disease. Hyposplenia, both structural and functional, may also result in rapid demise from sometimes unusual bacterial infections. Vascular abnormalities causing death include entities such as splenic artery aneurysms. Thus, deaths from splenic pathology may be due to localised issues or may be part of more generalised disease. For this reason the autopsy in cases of splenic-associated deaths must be comprehensive and include special testing such as microbiological screening and/or haematologic/genetic evaluation.

The multisystem nature of isomerism: left isomerism complicated by Abernethy malformation and portopulmonary hypertension

Isomerism, also referred to as "heterotaxy" is a complex set of anatomic and functional perturbations. One of the most obvious manifestations of isomerism is the disturbance of organ arrangement, such that the thoracic organs are no longer asymmetric on the left and right. We report the case of a 14-year-old female in whom exercise-induced dyspnea led to a late diagnosis of left isomerism complicated by Abernethy malformation and portopulmonary hypertension. A comprehensive evaluation revealed two anatomic left lungs and hyparterial bronchi, bilateral left atria, an interrupted inferior caval vein with azygos continuation, multiple spleens, sinus node dysfunction, hepatic hypertrophy with focal nodular hyperplasia, and absence of the portal vein. Pulmonary vasodilator therapy was initiated resulting in clinical improvement. This case exhibits unique features including a late diagnosis of isomerism with Abernethy malformation and portopulmonary hypertension. The patient's presentation, medical workup, and future treatment emphasise the importance of multidisciplinary care in children with complex multisystem disease. We review the multiple cardiac and extracardiac manifestations of isomerism.

Heterotaxy syndrome -- asplenia and polysplenia as indicators of visceral malposition and complex congenital heart disease

Heterotaxy results from failure of the developing embryo to establish normal left-right asymmetry. Typical manifestations include abnormal symmetry and malposition of the thoraco-abdominal organs and vessels, complex congenital heart disease and extracardiac defects involving midline-associated structures. The spleen is almost always affected, and there is syndromic clustering of the malformations corresponding to the type of splenic abnormality present. This review outlines the embryologic and genetic background of the heterotaxy syndrome as well as the characteristic anatomic features, clinical manifestations, and diagnostic clues of its two main presentations with asplenia or polysplenia.

Ivemark syndrome with agenesis of the corpus callosum: a case report with a review of the literature

Asplenia associated with situs ambiguus, symmetric liver, bilateral trilobulated lungs, and a complex heart defect was diagnosed on autopsy in a 14-day-old infant. Furthermore, examination of the brain displayed agenesis of the corpus callosum (ACC) with pachygyria and hydrocephalus. The characteristic association of asplenia with visceroatrial heterotaxia is traditionally named after the Swedish pediatrician, Ivemark. Although exceptional, association of Ivemark syndrome with callosal agenesis has been reported recently. The concept of 'developmental fields' describes morphogenetically reactive units of the embryo determining and controlling the development of complex structures in a hierarchical manner. Lateralization defects such as situs inversus, asplenia or polysplenia due to defective left-right axis development, as well as decussation defects such as ACC, are considered as defects of the primary developmental field. Therefore, additional callosal agenesis in Ivemark syndrome may be a coherent and synchronic defect in the primary developmental field rather than a causally independent malformation.

Failure to diagnose congenital heart disease in infancy

OBJECTIVE

To identify factors that predict failure to diagnose congenital heart disease in newborns.

DESIGN

All fatal cases in the Baltimore-Washington Infant Study were compiled. The Baltimore-Washington Infant Study includes 4390 cases of infants with congenital cardiovascular malformations identified in a population-based study between 1981 and 1989 in the Baltimore-Washington metropolitan area. Death occurred in 800 such infants in the first year of life. In 76 of these infants, death occurred before diagnosis of heart disease. These cases were identified by community search of autopsy records. Their characteristics are compared with those of infants who died after a cardiac diagnosis was made.

RESULTS

Infant characteristics (birth weight, gestational age, intrauterine growth retardation, and chromosomal anomaly) are associated with death of infants with congenital cardiovascular malformations and with death of such infants before diagnosis. Diagnoses of coarctation of the aorta, Ebstein's anomaly, atrial septal defect, and truncus arteriosus are overrepresented in infants found by community search, particularly in those infants without associated malformations. Paternal education is associated with failure to diagnose congenital heart disease in life but other sociodemographic characteristics of the infant's family are not.

CONCLUSIONS

Diagnosis of congenital cardiovascular malformations requires close observation in the neonatal period. Analysis of age at death of infants with undiagnosed congenital cardiovascular malformation suggests that such infants may be at risk if discharged within the first 2 days of life.

Asplenia syndrome: insight into embryology through an analysis of cardiac and extracardiac anomalies

Asplenia syndrome is characterized by complex congenital heart defects, asplenia and abdominal heterotaxy. Recent interest in the syndrome has been increased by new knowledge arising from animal models and by continuing improvements in surgical outcome in childhood. To further elucidate the embryologic timing and mechanisms of the asplenia syndrome, 32 necropsy cases were reviewed and 487 published autopsy cases were reanalyzed at the hospital. The most common congenital heart defects were atrial septal defects, common atrioventricular canals and conotruncal anomalies. With use of current information on the timing of normal development, it was hypothesized that most defects originate at Streeter Horizon XIII; patients averaged 3.2 Horizon XIII defects, more than at any other stage. Distribution was unimodal. Extracardiac anomalies also exhibited a developmental spectrum. Because the normal spleen develops by Horizon XIII, asplenia, the sine qua non of the syndrome, originates then or earlier. Abnormal pulmonary lobation occurred in 80% of cases, with right isomerism occurring most often; pulmonary branching asymmetry also originates at or before Horizon XIII. Abdominal heterotaxy occurred in 72% of cases, but the timing of origin is unclear. Anomalies of other systems, including genitourinary, musculoskeletal, endocrine, and nervous systems, develop later (typically XV to XXIII); specific anomalies were less frequent, although much more prevalent than in the general population. It is concluded that asplenia syndrome is a focal developmental disturbance in laterality which occurs primarily at Horizon XIII.