From the Guidelines
A hemolytic reaction is characterized by signs such as fever, chills, back or flank pain, and a feeling of unease or anxiety, and can be accompanied by hyperhemolysis, which is a severe hemolysis causing the hemoglobin to drop below pretransfusion levels, as noted in the 2020 guidelines for sickle cell disease: transfusion support 1. The most common signs of a hemolytic reaction include:
- Fever
- Chills
- Back or flank pain
- A feeling of unease or anxiety
- Shortness of breath
- Chest pain
- Rapid heart rate Visible changes can include:
- Jaundice (yellowing of the skin and eyes)
- Dark or red-colored urine (hemoglobinuria)
- Hypotension or shock in severe cases These reactions often occur during or shortly after blood transfusions but can also result from certain medications, autoimmune conditions, or infections. Laboratory findings typically show:
- Decreased hemoglobin levels
- Elevated bilirubin
- Increased lactate dehydrogenase (LDH)
- Reduced haptoglobin
- The presence of schistocytes (fragmented red blood cells) on a peripheral blood smear It is essential to monitor patients for adverse events or reactions during transfusions, including heart rate, blood pressure, temperature, and respiratory rate, as per local guidelines, and to stop the transfusion and contact the laboratory immediately if any signs of a transfusion reaction occur, such as tachycardia, rash, breathlessness, hypotension, or fever 1. In patients with sickle cell disease, hyperhemolysis can occur with no identifiable antibody and a negative direct antiglobulin test, and recognition is critical, as additional transfusions should be avoided if possible, to prevent worsening of the hemolysis and potential induction of multiorgan failure and death 1.
From the Research
Signs of a Hemolytic Reaction
- The signs and symptoms of acute hemolytic transfusion reactions include anaemia, fever, haemoglobinuria, and jaundice 2
- Subjective responses of pain, restlessness, nausea, skin flushing, dyspnoea, and shock are mediated by cleavage products of complement (C3a, C5a) activated by red cell antigen-antibody reaction 2
- Severe hemolysis, acute renal failure, and disseminated intravascular coagulation can occur in acute hemolytic transfusion reactions 3
- Hemoglobinemia and hemoglobinuria can result in disseminated intravascular coagulation (DIC), acute renal failure, shock, and sometimes death 4
- Delayed hemolytic transfusion reactions can cause an additional bystander hemolysis of the patient's RBCs 5
Clinical Presentation
- Acute hemolytic transfusion reactions can be defined as the occurrence after transfusion of measurably increased destruction of red cells, of donor or recipient, by alloantibodies 2
- The clinical consequences of hemolytic transfusion reactions are triggered via several pathophysiological pathways like formation of anaphylatoxins, release of cytokines causing a systemic inflammatory response syndrome, activation of the kinin system, the intrinsic clotting cascade and fibrinolysis resulting in hypotension, disseminated intravascular coagulation, diffuse bleeding, and disruption of microcirculation leading to renal failure and shock 5