Secondary amyloidosis in cystic fibrosis: a case from clinical practice

Increasing life expectancy of patients with cystic fibrosis is associated with an increased risk of systemic amyloidosis. At the same time, the rarity of this pathology determines the value of detailed analysis of individual clinical cases. The aim of the work was to discuss the pathogenesis and approaches to diagnosis, treatment, and prevention of complications of secondary amyloidosis in cystic fibrosis illustrated by a clinical case. Result. Mutation of the cystic fibrosis transmembrane regulatory protein gene leads to impaired function of the chlorine channel, which is localized mainly in the epithelial cells of the respiratory tract, salivary glands, sweat glands, pancreas, and intestine. As a result, mucociliary clearance of the respiratory tract becomes insufficient, which creates favorable conditions for the emergence and progression of respiratory infection and maintenance of chronic inflammation. The risk of secondary AA-amyloidosis in cystic fibrosis is associated with chronic inflammation and correlates with the level of markers of the acute phase of inflammation (C-reactive protein (CRP), serum amyloid A (SAA)). The article describes a 23-year-old patient. The manifestations of cystic fibrosis (recurrent respiratory infections and pancreatic insufficiency) were detected at birth. The diagnosis was made at the age of 2 years based on a sweat test; genotyping revealed a 2184insA/CFTRdele2,3 mutation. The peculiarity of the presented case is the development of secondary systemic amyloidosis in an adult patient with cystic fibrosis with kidney, liver, spleen, colon, and lymph node involvement. The clinical picture was dominated by nephrotic syndrome, which is associated with hypercoagulability due to loss of natural anticoagulant factors (antithrombin and protein S) with urine, as well as increased synthesis of procoagulants (factors V, VII, and fibrinogen). The immediate cause of death was pulmonary embolism from thrombosed veins of the lower legs, which is most likely associated with hypercoagulability and endothelial dysfunction due to nephrotic syndrome and secondary amyloidosis. Conclusion. Chronic systemic inflammation in cystic fibrosis contributes to the development of secondary amyloidosis with renal damage and the development of nephrotic syndrome, which in turn provokes hypercoagulability and the risk of thromboembolic complications.