Generalized glycogenosis and associated endocardial fibroelastosis. Report of 3 cases with biochemical studies

Endocardial fibroelastosis in infants and young children: a state-of-the-art review

Endocardial fibroelastosis (EFE) is a rare cardiac condition characterized by excessive endocardial thickening secondary to fibroelastic tissues that commonly present in infants and young children. Most of endocardial fibroelastosis cases are secondary forms, which occur in conjunction with other cardiac diseases. Endocardial fibroelastosis has been associated with poor prognosis and outcomes. In light of recent advancements in understanding pathophysiology, several new data have revealed compelling evidence that abnormal endothelial-to-mesenchymal transition is the root cause of endocardial fibroelastosis. This article aims to review the recent development in pathophysiology, diagnostic workup, and management, and to discuss possible differential diagnoses.

Distention of the Immature Left Ventricle Triggers Development of Endocardial Fibroelastosis: An Animal Model of Endocardial Fibroelastosis Introducing Morphopathological Features of Evolving Fetal Hypoplastic Left Heart Syndrome

Background. Endocardial fibroelastosis (EFE), characterized by a diffuse endocardial thickening through collagen and elastin fibers, develops in the human fetal heart restricting growth of the left ventricle (LV). Recent advances in fetal imaging indicate that EFE development is directly associated with a distended, poorly contractile LV in evolving hypoplastic left heart syndrome (HLHS). In this study, we developed an animal model of EFE by introducing this human fetal LV morphopathology to an immature rat heart. Methods and Results. A neonatal donor heart, in which aortic regurgitation (AR) was created, was heterotopically transplanted into a recipient adult rat. AR successfully induced the LV morphology of evolving HLHS in the transplanted donor hearts, which resulted in the development of significant EFE covering the entire LV cavity within two weeks postoperatively. In contrast, posttransplants with a competent aortic valve displayed unloaded LVs with a trace of EFE. Conclusions. We could show that distention of the immature LV in combination with stagnant flow triggers EFE development in this animal model. This model would serve as a robust tool to develop therapeutic strategies to treat EFE while providing insight into its pathogenesis.

Changing concepts of endocardial fibroelastosis

Endocardial fibroelastosis is not a disease but a reaction of the endocardium. I review the history of the term with emphasis on the gradual understanding of the many causes of this reaction. I include a comprehensive list of diseases or other cardiac stresses that authors have reported in association, and I try to explain the mechanism of the reaction. Although endocardial fibroelastosis is rare today, I issue a warning of a possible epidemic recrudescence of some of the associated diseases. My hope is for nosologic purity, therefore that outworn but surviving concepts will be firmly rejected.

The histopathology of endocardial sclerosis

This histological study of endocardial thickening in human hearts revealed that as in adult hearts, the proliferation in fetal, neonatal, and infant hearts consisted of collagen, elastin, and smooth muscle cells. Variation in severity from chamber to chamber and site to site indicated that severity is not an aging phenomenon and that predominantly local blood flow conditions determine localization and progression of proliferation. The similarity to endocardial thickening of cardiac valves and to intimal proliferation in blood vessels was remarkable. In old age and in chronic rheumatic heart disease the proliferation exhibited hyalinization, cell depletion, loss and fragmentation of elastin, lipid accumulation, and thrombosis, indicative of a similar pathogenesis to atherosclerotic changes in valvular endocardium and blood vessels. It was concluded that these chronic hemodynamically induced degenerative changes in the endocardium, including cardiac valves, should be classified as endocardial atherosclerosis analogous to that in arteries and veins and that severity is aggravated by high blood pressure, cardiac malformations, and dysfunction or damage caused by other disease processes.

Hydrocephalus associated with glycogen storage disease type II (Pompe's disease)

The authors describe a case of hydrocephalus in an 8-month, 2-week-old infant who had been previously diagnosed with glycogen storage disease type II. Cranial imaging revealed no evidence of obstruction within the ventricular system. This case adds to the central nervous system complications associated with this disorder. Several possible mechanisms for the hydrocephalus observed in this infant are discussed.

Alpha-glucosidase deficiency and basilar artery aneurysm: report of a sibship

Glycogen deposition in vascular smooth muscle has been demonstrated previously in alpha-glucosidase deficiency but has not been clinically significant. Three sons of healthy, nonconsanguineous parents developed progressive proximal muscular weakness secondary to alpha-glucosidase deficiency. Each patient developed a fusiform basilar artery aneurysm, which was complicated by fatal rupture in two patients and a cerebellar infarction in the third. Postmortem examination demonstrated severe vacuolation of skeletal muscle, liver, and vascular smooth muscle with accumulation of periodic acid-Schiff-positive, diastase-sensitive material. In the surviving brother, similar glycogen deposition was demonstrated in the smooth muscle of the superficial temporal artery. Basilar artery aneurysm formation in this sibship may be a consequence of alpha-glucosidase deficiency.

Unusual angiographic appearances of the left ventricle in 2 cases of Pompe's disease (glycogenosis type II)

The angiographic and haemodynamic findings in 2 cases of Pompe's disease (glycogenosis type II) indicated an abnormal trabecular pattern, not previously reported, on the left ventricular angiogram of both patients. This feature may be helpful in distinguishing Pompe's disease from other forms of myocardial abnormality.

Generalized glycogenosis type II (Pompe's disease)

The characteristic clinical features of 2 cases of Pompe's disease are presented, namely, signs of a cardiomyopathy with skeletal hypotonia and a characteristic ECG with a short PR interval and high voltage QRS complexes. Glycogen storage disease is confirmed by staining tissue such as lymphocytes, liver, or skeletal muscle with PAS, and the same tissues may be examined for glycolytic enzyme activity in order to characterize the type of glycogen storage disease present.