Immune thrombocytopenia in adults

Table 1 Frequent examples of differential diagnosis of immune thrombocytopenia and potential alternative causes of thrombocytopenia identified by patient history

Previously diagnosed or possible high risk of conditions that may be associated with autoimmune thrombocytopenia, for example, HIV, HCV or other infection; other autoimmune/immunodeficiency disorders (including systemic lupus erythematosus; malignancy (e.g., lymphoproliferative disorders); recent vaccination

Liver disease (including alcoholic liver cirrhosis)

Drugs (prescription or non-prescription), alcohol abuse, consumption of quinine, tonic water, exposure to environmental toxins

Bone marrow diseases including myelodysplastic syndromes, leukemias, other malignancies, fibrosis, aplastic anemia and megaloblastic anemia

Recent transfusions (possibility of post-transfusion purpura) and recent immunizations

Inherited thrombocytopenia: thrombocytopenia-absent radius syndrome, radioulnar synostosis, congenital amegakaryocytic thrombocytopenia, Wiskott-Aldrich syndrome, MYH9-related disease, Bernard-Soulier syndrome, type II B von Willebrand disease

HIV: Human immunodeficiency virus; HCV: Hepatitis C virus; MYH9: Myosin heavy chain 9.

Table 2 Summary of dosage and toxicity of drugs

Agent	Typical dosing	Time to response	Selected toxicities
Prednis(ol)one	0.5-2 mg/kg per day 2-4 wk followed by slow taper	Several days to several weeks	Mood swings, insomnia, anxiety, psychosis, weight gain, cushingoid facies, hyperglycemia, decreased bone density, hypertension, skin changes, gastrointestinal distress and ulceration, avascular necrosis, increased susceptibility to infections, cataracts, adrenal insufficiency
Methylprednisolone	30 mg/kg per day 7 d	2-7 d
Dexamethasone	40 mg/d for 4 d every	Several days to several weeks
	2-4 wk for 1-4 cycles
IVIg	0.4 g/kg per day 5 d or 1 g/kg per day 1-2 d	1-4 d	Headache, aseptic meningitis, renal insufficiency, fever, chills, nausea, thromboembolism, anaphylactoid reactions in patients with IgA-deficiency
Anti-Rh(D)	50-75 mcg/kg	1-5 d	Hemolytic anemia, fever, chills. Rarely, intravascular hemolysis, DIC, and renal failure
Splenectomy	N/A	0-24 d	Adverse effects of surgery and anesthesia, increased risk of infection, long-term vascular complications
Rituximab	375 mg/m2 weekly 4 wk (lower doses may be effective)	1-8 wk	Infusion reactions, reactivation of hepatitis B infection, rare cases of progressive multifocal leukoencephalopathy
Eltrombopag	12.5-75 mg PO daily	1-4 wk	Increased bone marrow reticulin, rebound thrombocytopenia, thrombosis, eltrombopag also associated with liver function test abnormalities
Romiplostim	(1-10 mcg/ kg) SC weekly	1-4 wk
Azathioprine	1-2 mg/kg per day (maximum 150 mg day)	1-4 wk	Liver function abnormalities, neutropenia, anemia, infection
Cyclosporine	5 mg/kg per day 6 d, then 2.5-3 mg/kg per day (titrated to blood levels of 100-200 ng/mL)	1-4 wk	Renal failure, hypertension, tremor, infection
Cyclophosphamide	1-2 mg/kg PO daily or 0.3-1 g/m2 iv every 2-4 wk 1-3 doses	1-4 wk	Myelosuppression, infection, secondary malignancy
Danazol	200 mg 2-4 times per day	1-4 wk	Acne, hirsutism, dyslipidemia, amenorrhea, liver function abnormalities
Dapsone	75-100 mg daily	1-4 wk	Hemolytic anemia in patients with G6PD deficiency, rash, methemoglobinemia
Mycophenolate mofetil	1000 mg twice daily	1-4 wk	Headache, back pain, infection
Vincristine	1-2 mg iv weekly (total dose 6 mg)	1-4 wk	Neuropathy, constipation, cytopenias, thrombophlebitis at the infusion site

IVIg: Intravenous immunoglobulin; DIC: Disseminated intravascular coagulation; PO: Per oral.