EMQs in Clinical Medicine.pdf - Peshawar Medical College

60 Haematology and oncology
ANSWERS
20 Causes of anaemia
Answers: D F L J A
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A 23-year-old man presents with recurrent nose-bleeds and infection
after a course of chemotherapy.
Aplastic anaemia is a presentation of pancytopenia with hypoplastic
marrow. Aplastic anaemia can be either primary or secondary. The most
common cause of primary aplastic anaemia 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 wellrecognized
causes of secondary aplastic anaemia via a type A (doserelated)
response. Non-cytotoxic drugs such as chloramphenicol and gold
have also been reported to cause aplasia via a type B (not dose-related)
response. Rarely, pregnancy is associated with a secondary aplastic
anaemia.
A 24-year-old Cypriot man presents with a worsening anaemia and
jaundice. A blood film taken several weeks after the incident shows
the presence of Heinz bodies.
Glucose-6-phosphate dehydrogenase (G6PDH) deficiency is the most
common red blood cell enzyme defect and is more common in patients
of Mediterranean origin. Individuals with this condition 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 oxidized
haemoglobin.
A 50-year-old man presents with tiredness, dyspnoea and paraesthesia.
On examination he showed extensor plantars, brisk knee jerks and
absent ankle jerks. His blood film shows macrocytic anaemia.
Pernicious anaemia is the most common cause of vitamin B 12 deficiency.
This is an autoimmune condition characterized by atrophy of the gastric
mucosa with subsequent failure of intrinsic factor production. Intrinsic
factor is required for vitamin B 12 absorption. Other causes of vitamin B 12
deficiency are terminal ileum disease, gastrectomy and low dietary intake
(e.g. vegans).