Q:

9/26/2012
I have a 14 year old girl who was referred for chronic refractory severe thrombocytopenia. She was diagnosed with ITP at the age of 6 yrs and until 4/12 was under fairly good control. Since then her platelet count has dropped below 11000 and lately it is in the range of 1000-5000.

She has been on WinRho, Rituximab in the past, on IVIG and on N plate to help stimulate platelet production. Still not responding. Had a bone marrow biopsy a month ago which was negative for MDS. I have ordered anti platelet antibodies, ANA (negative), ESR, CRP, anti phospholipid antibodies. Any other tests that I should order? They are contemplating splenectomy.

Last CBC-4.9, platelets-2
Hb-9.7, MCV-78, RDW-17, L-37 M-11 G-49 B-none

Thank you.

A:

Thank you for your inquiry.

From a practical standpoint, I think that you have ordered all tests that may be indicated. As you know, the diagnosis of idiopathic thrombocytopenic purpura is not made by any particular test, but by ruling out the presence of any drug or disease state that could produce this condition. There are very few laboratory tests that would be of help in this regard. The condition is often associated with infections, and these include both HIV and hepatitis C (1).

It has also been recommended that thyroid function testing be done to rule out occult hyper or hypothyroidism before an elective splenectomy. Patients with common variable immunodeficiency have been reported to have common variable immunodeficiency, and therefore if there is any suspicion of this disorder, immunoglobulin levels can be ordered. However, more than likely a laboratory workup will add little to your patient’s practical management since, more than likely, she will have idiopathic thrombocytopenic purpura.

Thank you again for your inquiry and we hope this response is helpful to you.

Reference:
1. Provan D, et al. International consensus report on the investigation and management of primary immune thrombocytopenia. Blood 2010; 115(2):168.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology