Death occurred due to undiagnosed systemic amyloidosis: a case report

Amyloidosis is a disorder related to errors in protein folding. We present a clinical case of systemic amyloidosis manifesting as hypotension, tachycardia, pain, weight loss, asthenia, anorexia, dysphagia, and mood deflection in a 49-year-old-year-old woman with a previous clinical history of articular and muscular pain, correlated to suspected seronegative arthritis. The blood test revealed kidney insufficiency, an electrocardiogram identified low voltages of the peripheral leads and T waves anomalies. A serum protein electrophoresis revealed the presence of high levels of monoclonal kappa free chains. The woman started to have a sense of suffocation, and after one week she was found dead in her bed. After the autopsy, the results of Congo red staining of the myocardium were characteristic of amyloid. According to the autoptic and the histological examination, death occurred due to acute cardiac and respiratory arrest secondary to amyloid cardiomyopathy in a patient with undiagnosed systemic amyloidosis.

Lethal cardiac amyloidosis: Microscopic differential diagnosis with microfibrillar cardiomyopathy in a forensic case

In a previous study, we presented a case of an elderly woman's sudden death, in which microscopic examinations showed intramyocardial eosinophilic material suspected for amyloid, but not definable as such to the classic Congo Red staining. To overcome the arisen interpretative and diagnostic difficulties, we experimentally modified the classic Congo Red staining, using a specific one for corpse. The finding of a low-intensity positivity allowed us to formulate a very likely diagnosis of occult lethal cardiac amyloidosis. However, this low-intensity positivity obtained after having applied this experimental method for the first time and in only one case, as well as the existence of the rare pathology known as microfibrillar cardiomyopathy, which may be related to the observed microscopic findings, have forced us to investigate the correctness of the diagnosis. For this purpose, we performed in-depth investigations with sodium sulphate-Alcian Blue (SAB) staining and immunohistochemistry. Thanks to them, the amyloid nature of the intramyocardial material was confirmed and has been proved not only the reliability of our experimentally modified technique, but also the appropriateness of the diagnosis previously formulated. Therefore, the supposed involvement of the microfibrillar cardiomyopathy was excluded.

Lethal cardiac amyloidosis: Modification of the Congo Red technique on a forensic case

Congo Red staining is usually used in diagnosing amyloidosis, a pathology characterized by the storage of abnormal proteins in several human organs. When assessed on samples fixated in formalin and embended in paraffin, this staining can undergo several artefacts, causing diagnostic and interpretative difficulties due to its weak stainability and a consequent reduced visibility of the amyloid. These complications, in time, requested several variations of this staining technique, especially in clinical practice, while in the forensic field no protocols has ever been adapted to cadaveric samples, a material that is already characteristically burdened by a peculiar stainability. In our work, studying a sudden death caused by cardiac amyloidosis and diagnosed only with post-mortem exams, we present a modified Congo Red staining used with the purpose to demonstrate amyloid in cadaveric material after the unsuccessfully use of all standard protocols.