Causes of anaemia

• 23 year old, male, recurrent nose-bleeds, infection after chemotherapy
• Aplastic anaemia
• Presentation of pancytopenia with hypoplastic marrow
• Primary or secondary
• Most common primary is idiopathic acquired aplastic anaemia
• Congenital causes of primary aplastic anaemia are very rare (e.g. Fanconi's anaemia)
• Secondary causes of aplastic anaemia include infection (especially viral, e.g. hepatitis, measles, parvovirus B19) and drugs
• Cytotoxic drugs such as busulphan and doxorubicin are well-recognised causes of secondary aplastic anaemia via a type A (dose-related response)
• Non-cytotoxic drugs such as chloramphenicol and gold have also been reported to cause aplastic via a type B (not dose-related) response
• Rarely, pregnancy is associated with a secondary aplastic anaemia
• 24 year old, Cypriot, male, worsening anaemia and jaundice, Heinz bodies
• Glucose-6-phosphate dehydrogenase deficiency
• G6PDH deficiency
• Most common red blood cell enzyme defect
• These individuals are susceptible to oxidative crises precipitated by fava beans and drugs such as ciprofloxacin and sulphonamides
• G6PDH plays an important role in the hexose monophosphate shunt which provides NADPH (reduced nicotinamide adenine dinucleotide phosphate - the reducing agent)
• NADPH is used to regenerate glutathione
• In the absence of glutathione, red blood cells are exposed to oxidative stress
• Heinz bodies represent oxidised haemoglobin
• 50 year old, male, tiredness, dyspnoea and paraesthesia, on examination extensor plantars, brisk knee jerks, and absent ankle jerks, blood film shows macrocytic anaemia
• Pernicious anaemia
• Most common cause of vitamin B12 deficiency
• Atrophy of gastric mucosa with subsequent failure of intrinsic factor production
• Intrinsic factor is required for vitamin B12 absorption
• Other causes are terminal ileum disease, gastrectomy, and low dietary intake (e.g. vegans)
• Vitamin B12 can just be taken orally in those with lack in diet
• It has to be given intramuscularly in those with pernicious anaemia (intramuscular hydroxocobalamin)
• 23 year old, woman, trimethoprim for recurrent urinary tract infections (UTIs), macrocytic anaemia
• Folate deficiency
• Macrocytosis causes include vitamin B12/folate deficiency, alcohol, liver disease, hypothyroidism, and myelodysplasia
• Trimethoprim is a bacterial dihydrofolate reductase inhibitor, but with prolonged therapy it can act in humans
• It is avoided in pregnancy because interference with folate makes it teratogenic
• Bone marrow biopsy is indicated if the cause of the macrocytosis is not established with blood tests
• 25 year old, woman, SLE, acute anaemia, steroid treated, Direct Coomb's test was strongly positive, direct antiglobulin test was positive with IgG alone
• Autoimmune haemolytic anaemia
• Many causes of anaemia in patient with SLE
• These include iron deficiency anaemia secondary to NSAID use, bone marrow suppression secondary to immunosuppressive drugs such as cyclophosphamide/azathioprine
• AHA is the cause in this patient since the direct Coombs' test demonstrates and confirms the presence of antibody binding to red blood cells
• Other causes of secondary AHA include lymphoma, infections (e.g. EBV, Mycoplasma spp.), carcinoma and other autoimmune conditions
• Drugs may also cause immune haemolysis e.g. methyldopa treatment can induce the formation of red cell autoantibodies