Aplastic anaemia

Question 1

what is the key definition of aplastic anaemia?

Answer 1

panyctopenia, hypocellular marrow with no abnormal cell population ( Such as blasts) And no fibrosis

Question 2

define aplastic anaemia?

Answer 2

Rare stem cell disorder characterised by diminished haematopoietic precursors in the bone marrow and deficiency of all blood cell elements (pancytopaenia)

leads to pancytopenia ( no abnormal cells just less) and hypoplastic marrow ( marrow stops making cells)

At least 2 of the following peripheral cytopenias must be present: haemoglobin <100 g/L (<10 g/dL), platelets <50 × 10⁹/L, absolute neutrophil count <1.5 × 10⁹/L.[1]

Bone marrow should show hypocellularity without evidence of significant dysplasia, blasts, fibrosis, or other abnormal infiltrate.

Question 3

summarise the epidemiology of aplastic anaemia?

Answer 3

annual incidence: 204/1,000000

slightly more common in males

Question 4

explain the aetiology/risk factors of aplastic anaemia?

give the three classes

Answer 4

most cases are autoimmune triggered by drugs, viral infection or irradiation

idiopathic, acquired, inherited

Question 5

what are the idiopathic causes of aplastic anaemia?

Answer 5

more than 40%

may be due to destruction ot supression of stem cells via autoimmune mechanisms

Question 6

what ate the acquired causes of aplastic anaemia?

Answer 6

• Drugs (e.g. chloramphenicol, sulphonamides, methotrexate)
• Chemicals (e.g. benzene, DDT)
• Radiation
• Viral infection (e.g. parvovirus B19, hepatitis)
• Paroxysmal nocturnal haemoglobinuria- destruction of red blood cells (hemolytic anemia), blood clots (thrombosis), and impaired bone marrow function (not making enough of the three blood components).

Question 7

what are the inherited causes of aplastic anaemia?

Answer 7

• Fanconi’s anaemia (X-linked)
• Dyskeratosis congenita (a rare, progressive bone marrow failure syndrome) - X-linked
• Schwachman-Diamond syndrome – autosomal recessive
• GATA2-related disorder (persistent warts seen)

Question 8

what are the presenting symptoms of aplastic anaemia

Answer 8

• Can be both slow-onset (months) or rapid-onset (days)
• Anaemia Symptoms:
• Tiredness
• Lethargy
• Dyspnoea

• Thrombocytopaenia Symptoms:

• Easy bruising
• Bleeding gums
• Epistaxis

• Leukopaenia Symptoms:
Increased frequency and severity of infections

Question 9

what are the signs of aplastic anaemia on physical examination?

Answer 9

anaemia signs
- pallor

thrombocytopenia sign

• petechiae
• bruises

leukopaenia signs

• multiple bacterial and fungal infections
• no hepatomegaly, splenomegaly or lymphadenopathy

Question 10

what are the risk factors for aplastic anaemia?

Answer 10

drug or toxin exposure
paroxysmal nocturnal haemoglobinuria (PNH)
recent hepatitis
pregnancy

Question 11

what are the appropriate investigation for aplastic anaemia?

Answer 11

FBC

• low Hb
• low platelet
• low WCC
• normal MCV

reticulocyte count- low or absent reticulocytes

Bone Marrow trephine biopsy-> definitive diagnosis of hypocellular marrow with no abnormal cell population ( such as blasts)

Question 12

what investigations may you want to consider?

Answer 12

Blood Film
Exclude leukaemia (check for abnormal circulating white blood cells)

Serum B12/ folate should be normal – excluding other options

HIV testing – excluding other options

LFTs – excluding other options (if abnormal may suggest inherited syndrome like Schwachman-Diamond and dyskeratosis congenita)

Autoantibody screen – excluding other options

Fanconi’s Anaemia - Check for presence of increased chromosomal breakage in lymphocytes cultures in the presence of DNA cross-linking agents