Hemolytic Anemia and Hemoglobinuria by mohamed Abdelraheem

Acquired Haemolytic Anaemias

• Immune Haemolytic Anaemias:
  • Alloimmune: Haemolytic Disease of the Newborn
    • Results from transplacental transfer of maternal blood group antibodies
    • Interaction of maternal antibodies with incompatible erythrocytes causes haemolysis
    • Can lead to hydrops fetalis, anaemia, jaundice, hepatosplenomegaly, and oedema
  • Autoimmune Haemolytic Anaemia
    • Classified into warm and cold reacting types
    • Warm reacting type: associated with lymphoma, chronic lymphatic leukaemia, systemic lupus erythematosus, and other autoimmune disorders
    • Cold reacting type: associated with Mycoplasma pneumonia, infectious mononucleosis, lymphoproliferative disorders, and paroxysmal cold haemoglobinuria

Immune Haemolytic Anaemias (continued)

• Warm Autoimmune Haemolytic Anaemia
  • Diagnosis: Coombs test
  • Treatment: corticosteroids, splenectomy, immunosuppressive drugs, and rituximab
• Cold Haemagglutinin Disease
  • Agglutinate red cells preferentially at low temperatures (4°C)
  • IGM/C3, C9
  • Reaction occurs in cold parts of the body, leading to intravascular haemolysis, Raynaud's, and other vaso-occlusive phenomena
  • Treatment: keeping the patient warm, treating the underlying cause, and using alkylating agents or anti-CD20 (rituximab)

Non-Immune Acquired Haemolytic Anaemias

• Red cells may be prematurely destroyed through:
  • Increased mechanical stress
  • Acquired defects of the red cell membrane
  • Infections or chemical agents
• Paroxysmal Nocturnal Haemoglobinuria (PNH)
  • Unknown etiology
  • Characterized by chronic intravascular haemolysis with exacerbations associated with haemoglobiniuria and marked thrombotic tendency
  • Due to the presence of an abnormal haemopoietic clone
  • Clinical and haematological features: intravascular haemolysis, venous thrombosis, pancytopenia, and iron deficiency anaemia
  • Treatment: blood transfusion, oral iron, and eculizumab (a humanized antibody against complement C5)
• Microangiopathic Haemolytic Anaemia
  • A group of disorders in which there is intravascular haemolysis and fragmentation of the red cells secondary to disease of the small vessels
  • Causes: DIC, TTP, HUS, prosthetic valve, disseminated cancer, septicaemia, collagen vascular disorders, toxemia of pregnancy, and malignant hypertension
• March Haemoglobinuria
  • Characterized by attacks of haemoglobinuria following strenuous physical exercise
  • A similar picture has been described in practitioners of karate
• Haemolytic Anaemia caused by Chemicals
  • A variety of drugs and chemicals may cause haemolytic anaemia either by direct chemical action on the red cell or by altering red cell metabolism
  • Examples: lead poisoning, thermal cold, hot temperature, and infection

Aplastic Anaemia

• Definition: A gross reduction or absence of haemopoietic precursors in all 3 cell lineages in bone marrow resulting in pancytopenia in peripheral blood
• Etiology:
  • A. Hereditary: Fanconi syndrome, dyskeratosis congenita
  • B. Acquired: chemotherapy, radiotherapy, chronic benzene exposure, drug-induced, post-viral, and idiopathic
• Idiopathic aplastic anaemia constitutes the majority of cases

This quiz covers the causes and characteristics of hemolytic anemia and hemoglobinuria, including physical exercise, chemicals, and infections. It also touches on treatment options.