Aplastic anemia is seen in all of the following except.
Hepatitis A (Ref. Hari- 17th Edi, Pg. 663)
Note: Hepatitis A is not a cause of Aplastic anemia.
Etiology of Aplastic Anemia
1. Idiopathic (more than 50%)
2. Drug – induced (dose dependent, idiosyncratic) Anticancer drugs
a. Antimicrobials (chloramphenicol, sulfonamides, penicillins)
b. Anticonvulsants (phenytoin, ethosuximide, carbamazepine)
c. Antithyroid agents (carbimazole, propylthiouracil)
d. Antidiabetic agents (tolbutamide, chlorpropamide)
e. Miscellaneous (gold compounds, D – penicillamine, bismuth, ticlopidine, thiocyanates, acetazolamide).
3. Chemical or toxin (benzene, carbon tetrachloride, insecticides)
5. Infection (Non A, Non B, Non C hepatitis, EBV, parvovirus, tuberculosis, HIV)
(Ref. Cecil. 23rd ed., Table 171-1)
6. Pregnancy (remits following delivery in some)
7. Thymoma (usually associated with pure red cell aplasia)
8. Paroxysmal nocturnal hemoglobinuria (PNH develops in 5 – 10% of patients with aplastic anemia and 25% of patients with PNH develop aplastic anemia)
9. Constitutional (Fanconi’s anemia, familial aplastic anemia, dyskeratosis congenita)
10. Associated with myelodysplasia (patients with aplastic anemia may develop a myelodysplastic syndrome later).
11. Pernicious anemia
Fanconi's anemia is a congenital disorder responsible for a form of aplastic anemia. It is a cause of normocytic normochromic anemia.
Causes Of Aplastic Anemia (Ref. Cecil, 23rd ed., Table 171-1)
a. Drugs: antimetabolites, antimitotic agents, chloramphenicol, phenylbutazone, sulfonamides
c. Chemicals: benzene, solvents, insecticides
d. Viruses: non-A, non-B, non-C hepatitis, Epstein-Barr virus
e. Paroxysmal nocturnal hemoglobinuria
f. Miscellaneous: pregnancy, connective tissue disorders
a. Fanconi anemia b. Dyskeratosis congenita c. Schwachman syndrome
3. IDIOPATHIC: 50–65% OF CASES