Two case studies and a review of paroxysmal cold hemoglobinuria.

Paroxysmal cold hemoglobinuria (PCH) is an acquired hemolytic anemia caused by immunoglobulin G (IgG) antibodies that sensitize red blood cells (RBCs) at cold temperatures by fixing complement to the RBCs causing intravascular hemolysis on rewarming. PCH usually appears in young children as recurrent high fevers, chills, and passage of red-brown urine. The diagnostic test for PCH is the Donath-Landsteiner test, an in vitro assay for biphasic hemolysis. Herein, we present 2 cases of PCH that occurred within 12 months of each other. We quickly diagnosed the second case and treated the patient successfully, in part due to our recognition of its characteristics based on the first case. PCH is a hemolytic anemia for which there is a specific diagnostic test; the timely recognition of this entity by physicians and laboratory staff will allow prompt, supportive therapy and will raise the odds of quick resolution of hemolysis.

Giant cell arteritis presenting with uveitis.

Giant cell arteritis, also known as temporal arteritis, is the most common primary vasculitis affecting the nervous system. Early recognition of this treatable condition is essential to avoid potentially devastating complications. Giant cell arteritis occurs in adults older than 50 years and affects large and medium-sized arteries, especially the external and internal carotid arteries and their branches. Severe inflammation of the vessel wall may result in obstruction of the lumen and end-organ ischemia. Typical giant cell arteritis symptoms include headache, scalp tenderness, jaw claudication, and polymyalgia rheumatica. Ischemia induced by the arteritis can lead to blindness. Herein, we describe a rare case of giant cell arteritis in a patient who initially presented with uveitis, thus eluding timely diagnosis and prompt therapy.