Systemic Amyloidosis with Cardiac Involvement: Features of Course and Diagnostic Difficulties

The diversity of clinical forms of amyloidosis is related to differences in amyloidogenic precursor proteins. Cardiac involvement is characteristic of AL- and ATTR-amyloidosis, with cardiac involvement developing in the vast majority of patients with AL-amyloidosis and in 50-60 % of patients with ATTR-amyloidosis. ATTR- (transthyretin) amyloidosis is one of the types of systemic amyloidosis, the precursor protein of which is transthyretin in the presence of mutations in its molecule (familial forms) or age-related disorders of its tetrameric secretion. Until recently, it was believed that transthyretin amyloidosis did not occur in Russia. However, the introduction of molecular genetic diagnostic methods for transthyretin mutations has demonstrated the occurrence of ATTR amyloidosis in Russia with a frequency close to the European average for non-endemic areas. The article presents the case report of systemic amyloidosis in a middle-aged woman. The disease presented at the age of 54 years with carpal tunnel syndrome. Subsequently, chronic heart failure refractory to treatment became the dominant manifestation of the disease. Heterogeneity of structure and significant myocardial thickening with preserved ejection fraction detected in dynamics in combination with new symptoms (diarrhea, orthostatic arterial hypotension, periorbital purpura, proteinuria) were considered as an infiltrative heart lesion within the framework of systemic amyloidosis. The result was a fatal asystole. Autopsy findings confirmed the diagnosis of systemic amyloidosis. The article discusses the issues of differential diagnosis of AL- and ATTR- amyloidosis based on the analysis of anamnestic and clinical data. The onset of the disease with carpal tunnel syndrome, the progressive distal neuropathy combined with autonomic dysfunction, the dominant cardiac involvement, the absence of renal amyloidosis according to autopsy data, and the duration of the disease from the time of clinical manifestation to death of 43 months are more indicative of ATTR amyloidosis. The article also discusses modern approaches to diagnostics of amyloid heart lesion in clinical practice, points out the difficulties arising in this case, emphasizes the importance of early diagnosis of cardiac amyloidosis, which allows to realize the possibilities of modern methods of amyloidosis treatment.