10 November 2011
Paroxysmal cold haemoglobinuria (PCH) was first described by Donath and Landsteiner in 1904. PCH is the most common cause (30–40%) of acute autoimmune haemolytic anaemia (AIHA) in childhood.1 PCH has been reported in children from 1 year of age, with male preponderance.2 PCH usually follows a nonspecific viral, bacterial or mycoplasma infection.1
The Donath Landsteiner (DL) antibody is an immunoglobulin G that binds the P antigen on red cell surface at low temperature in peripheral circulation and fixes complement when the red cells return to warmer temperature in core circulation and causes lysis at 37°C.2,3 Clinical haemolysis occurs when the ambient temperature is below 18°C.2,3
We describe an 18-month-old Sudanese boy who presented during spring with a 1-week history of lethargy, reduced intake, pallor and cough following an episode of gastroenteritis. The physical examination showed pallor, tachypnoea (38/min) and tachycardia (155/min), but no signs of congestive cardiac failure. The investigations revealed haemoglobin 40 g/L, a peripheral smear showing spherocytosis, polychromasia with moderate autoagglutination and increased reticulocyte count (18.3%), elevated lactate dehydrogenase (3274/L), decreased serum haptoglobin (<0.06 g/L), normal G6PD and Hb electrophoresis. Notably, the blood film showed the characteristic appearance of neutrophils phagocytosing erythrocytes (Fig. 1). The urinalysis revealed bilirubinuria, pyuria and nitrites. The direct antiglobulin test (DAT) was positive with C3d only. Donath Landsteiner haemolytic test (DLT) was positive. Subsequent urine culture grew Escherichia coli. However, the haemolysis was most likely related to the preceding gastroenteritis. He responded well to blood transfusion with no haemolytic relapse.
Clinically, PCH is characterised by a sudden onset of haemoglobinuria and anaemia following cold exposure. The diagnosis is suspected following the haematological and biochemical evidence of haemolysis. A positive DAT at cold temperature may be found in many AIHA, including Mycoplasma-induced cold agglutinin disease. Therefore, a positive DLT is essential in confirming PCH diagnosis.2,4 In our patient, the history of cold exposure was not prominent, especially because people living in western Sydney experienced the warmest spring (2009) since 1990.5
PCH is usually self-limiting. The treatment is symptomatic, including avoidance to cold exposure and management of haemolysis.4 Corticosteroids may limit persistent haemolysis.4 In severe haemolysis, cardiac failure and shock may result. However, a child's haemodynamic status generally adapts well to gradual anaemia, as in our patient.3
In conclusion, PCH should be considered in a child with sudden onset of haemolysis and haemoglobinuria following an exposure to a relatively cool ambient temperature.