Diagnosing Immune Thrombocytopenia

James B. Bussel, MD:An important issue is, how would we know that she has ITP? We’ve alluded to the idea that she has no findings consistent with another diagnosis. We don’t know exactly how high her platelets went with the steroids in this case. If they had gone up substantially, that would argue in favor of ITP because she would have responded to treatment. This would be particularly true if she had received, for example, IV gamma globulin and if the platelets had gone up very rapidly, for example, within 2, 3, 4, or 5 days. If the platelet increase took weeks, it would be distinctly unlikely but not impossible that this was a case of leukemia. If there were any reasons to consider leukemia—perhaps the way the smear looked or slight leucopenia or something else—it might be important to do a bone marrow aspirate and/or biopsy to make sure that this is not the case. The fact that she is followed up, gets 2 courses of prednisone—which she tapers off and discontinues and does not have any progression—does not develop hepatosplenomegaly or lymphadenopathy, does not develop anemia or abnormal white count, etc, argues strongly that this is ITP and not leukemia or some other diagnosis.

However, that still does not mean that everything will automatically be OK. We know that she may persist and have chronic ITP. It could be more severe as opposed to less severe. She could develop another medical problem, have trauma, or something like that that would make her at higher risk with a low platelet count. She could develop other autoimmune diseases, especially thyroid disease but also lupus erythematosus. She also could have her life complicated by development of fatigue associated with thrombocytopenia, or she could have it complicated by becoming iron deficient if her menses get heavy, or since she takes occasional ibuprofen, we don’t know whether that’s for headaches or for joint pains. But since she can no longer take that, other treatments like that may be less effective, and therefore, her quality of life may decrease somewhat as a result.

Transcript edited for clarity.

Case: A 48-year-old woman presenting with unusual bruising

October 2017

• A 48-year-old woman presents with complaints of bruising after minor bumps, bleeding gums despite regular tooth cleaning, and a recent spontaneous bloody nose; symptom onset about 1 year ago
• Physical evaluation reveals a woman of normal weight and average height, afebrile, no splenomegaly
• No personal or family history of cancer, autoimmune disease; no recent viral illnesses; no bone pain or night sweats
• Current medications: ibuprofen as needed, generic hydrochlorothiazide (HCTZ)
• Laboratory findings:
  • CBC reveals platelets 28 X 10⁹/L
  • WBCs within normal
  • Renal and hepatic function within normal
• Diagnosis: idiopathic thrombocytopenic purpura
• Patient started on a course of prednisone 1 mg/kg for 21 days, then tapered off
  • Platelets: 29 X 10⁹/L
  • Second course of prednisone 1 mg/kg for 21 days

April 2018

• After 2 courses of prednisone, patient’s platelets have not recovered
  • CBC shows platelets at 28 X 10⁹/L
• Symptoms of easy bruising and bleeding from gums continue
• After discussion with patient, she is started on the thrombopoietin receptor agonist (TPO-RA) eltrombopag (PROMACTA), at a dose of 50 mg/day
  • Dose increased to 75 mg/day; last platelet count, 65 X 10⁹/L