A 70-year-old man presents with a seven-day history of recurrent epistaxis, bruising and increasing haemoptysis. He has no significant past medical history other than a TIA for which he takes Aspirin. He does not have any epistaxis at present. His INR and APTT are normal.
Hb |
96 g/L * |
(135-175) |
RBC |
3.32 x 1012 /L* |
(4.50-6.00) |
PCV |
0.29 * |
(0.40-0.50) |
MCV |
86.7 fl |
(80.0-98.0) |
MCH |
28.9 pg |
(27.0-33.0) |
MCHC |
333g/L |
(315-355) |
Platelets |
2 x 109/L* |
(150-400) |
Immature Platelet Forms |
17%* |
(1.1-6.1) |
Reticulocytes |
0.6% |
(0.5-2.0) |
White Cell Count |
8.82 x 109/L |
(4.0-11.0) |
i. List 6 potential aetiologies for the above blood picture in this patient.
College Answer
- Decreased platelet production
- Marrow failure (eg aplastic anaemia, myelodysplasia)
- Exposure to drugs (eg quinine)
- Marrow infiltration (eg neoplastic)
- Nutritional
- Increased platelet destruction
- Immune thrombocytopenic purpura (incl idiopathic, CT disease, lymphoproliferative disease, medications, infection (eg HIV, Hep C)).
- Thrombotic microangiopathy
- Drug-induced
- Increased sequestration of platelets
- Hypersplenism
Discussion
This question favours the candidate who can generate a large number of differentials. Specifically, the differentials are for the question "what causes peripheral platelet breakdown". Because there is a large proportion of immature forms, one can presume that the bone marrow is functioning normally. However, the college offers a few differentials which involve bone marrow failure.
Furthermore, thrombotic microangiopathy is brought up, which would also cause a haemolysis of red cells. (well, the man is a little anaemia, but he has been having epistaxis for 7 days so its far from surprising)
So: I give up.
Here is a link to an article with a diagnostic approach to thrombocytopenia. The well-resourced candidate will also draw on UpToDate: Approach to the adult patient with thrombocytopenia.
Decreased platelet production
|
Increased platelet destruction
|
Pseudothrombocytopenia
|
Dilution of platelets
Sequestration
|
References
Stasi, Roberto. "How to approach thrombocytopenia." ASH Education Program Book 2012.1 (2012): 191-197.
UpToDate: Approach to the adult patient with thrombocytopenia.