Recurrent Dialyzer-Associated Hypersensitivity with Complement Activation Complicated by Cardiac Arrest: A Case Report

Background: Dialyzer-associated hypersensitivity reactions are rare but potentially life-threatening complications of hemodialysis (HD). Their pathophysiology is heterogeneous. Methods: We report a 49-year-old patient with end-stage chronic kidney disease (CKD G5), severe secondary hyperparathyroidism, poorly controlled arterial hypertension, a long history of heavy smoking, severe coronary and valvular disease, reduced left ventricular ejection fraction, renal anemia, and chronic volume overload. Results: Shortly after initiation of HD with a polysulfone dialyzer (Diacap Pro), she repeatedly developed severe dyspnea, hypoxemia, and marked hypertensive responses. Similar reactions occurred after switching to a cellulose triacetate dialyzer (Sureflux), necessitating temporary conversion to peritoneal dialysis (PD). Progressive PD ultrafiltration failure and loss of residual kidney function eventually required a return to HD. Severe reactions recurred within 15–30 min of treatment despite premedication. During the most severe episode, the patient developed profound hypoxemia (SpO2 55%), severe hypertension (up to 240/130 mmHg), ventricular tachycardia, and cardiac arrest requiring successful cardiopulmonary resuscitation. Immunological evaluation demonstrated normal total IgE (17 U/mL), decreased C3 (0.76 g/L), markedly reduced total hemolytic complement activity (CH50, 18%), and elevated IL-6 (87.5 pg/mL). Chronic HD was successfully reinitiated using an FX CorAL dialyzer with a Helixone® hydro membrane. Since its introduction, no further hypersensitivity reactions have occurred, and corticosteroid, antihistamine, and bronchodilator premedication has been discontinued. This case demonstrates severe recurrent dialyzer-associated hypersensitivity with findings suggestive of complement involvement, complicated by cardiac arrest in a patient with markedly impaired cardiovascular reserve. Conclusions: Successful long-term treatment with a hydrophilic Helixone® dialyzer highlights the importance of individualized dialyzer selection in patients with severe hypersensitivity reactions.