Idiopathic Thrombocytopenic Purpura Disease

BASICS

DESCRIPTION

A decrease in the circulating number of platelets (< 100,000 per microliter) in absence of toxic exposure or a disease associated with a low platelet count. It occurs as a secondary effect of peripheral platelet destruction as well as decreased platelet production. It is a diagnosis of exclusion.

Acute ITP - a disease of childhood which often follows an acute infection and has spontaneous resolution within 2 months. Platelet counts < 20,000. This is a common disorder.
Chronic ITP - a disease which persists after 6 months without a specific cause. Usually seen in adults and persists for months to years. Platelet count typically 30,000–80,000.
System(s) affected: Hemic/Lymphatic/Immunologic
Genetics: No known genetic pattern
Incidence/Prevalence in USA: 1 in 10,000
Predominant age:
- Acute ITP - children ages 2–9 years old
- Chronic ITP - 20–50 years old
Predominant sex:
- Acute ITP - Male = Female
- Chronic ITP - Female > Male (3:1)

SIGNS AND SYMPTOMS

Post traumatic bleeding at 40,000–60,000 platelet count
Petechial hemorrhages
Purpura
Bruising tendency
Gingival bleeding
Gastrointestinal bleeding
Mucocutaneous hemorrhages
Menometrorrhagia
Menorrhagia
Recurrent epistaxis
Neurological symptoms secondary to intracerebral bleeding
Non-palpable spleen (absence of splenomegaly is an essential diagnostic criterion)
Spontaneous bleeding < 20,000 platelet count

CAUSES

IgG autoantibodies on platelet surface

RISK FACTORS

Acute infection
Age
Cardiopulmonary bypass
Hypersplenism
Antiphospholipid antibody syndrome
Preeclampsia
HIV infection

DIAGNOSIS

LABORATORY

Decreased platelet count: 5,000–75,000
Relative lymphocytosis and slight eosinophilia
Prolonged bleeding time (not useful in the presence of thrombocytopenia)
Anemia
PT, PTT normal

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

Peripheral smear shows normal red and white cells with diminished but large platelets
Marrow reveals abundant megakaryocytes with normal erythroid and myeloid precursors

SPECIAL TESTS

Peripheral smear - routinely recommended
Platelet associated antibody (PA-IgG) - optional

IMAGING

CT of head to rule out intracranial bleeding if clinically indicated

DIAGNOSTIC PROCEDURES

Bone marrow aspiration/biopsy (consider in refractory cases). Does not need to be done before giving gamma globulin.

TREATMENT

APPROPRIATE HEALTH CARE

Outpatient management unless patient at risk for bleeding (platelet count < 20,000)
Admit patients with active bleeding

GENERAL MEASURES

Children with platelet counts > 30,000 do not require treatment if they are asymptomatic or those with minor purpura do not need treatment
Treatment for adults if platelet < 20,000, or platelets < 50,000 with symptoms or risks for bleeding such as HTN or peptic ulcers
Specific treatment usually not necessary unless count is < 100,000; possibly < 30,000 with chronic ITP
Platelet transfusions for significant bleeding

SURGICAL MEASURES

Splenectomy in patients who fail medical therapy. Be sure to administer pneumococcal vaccine at least 2 weeks prior to splenectomy.

ACTIVITY

Minimal activity to prevent injury or bruising. Avoid contact sports.

DIET

No special diet

PATIENT EDUCATION

Avoidance of ASA and other platelet inhibiting drugs

FOLLOW UP

PREVENTION/AVOIDANCE

Avoid medications (when feasible) that inhibit platelet function (such as aspirin), or those that suppress bone marrow

POSSIBLE COMPLICATIONS

1% mortality due to intracranial hemorrhage
Severe blood loss
Corticosteroid adverse effects
Pneumococcal infections if patient must have splenectomy. Use pneumococcal vaccine.

EXPECTED COURSE AND PROGNOSIS

Acute ITP:
- 80–85% completely recover within 2 months
- 15% proceed to chronic ITP
Chronic ITP:
- 10–20% recover spontaneously
- Remainder with diminished platelets for months to years
- May see spontaneous remissions (5%) and relapses

MISCELLANEOUS

ASSOCIATED CONDITIONS

Acute ITP:
- Varicella
- Other viral infections
Chronic ITP:
- HIV
- Graves' disease
- Hashimoto's thyroiditis
- Sarcoidosis
- Systemic lupus erythematosus
- Autoimmune hemolytic anemia (Evans' syndrome)

AGE-RELATED FACTORS

Pediatric:

The acute form is primarily a childhood disease
Better prognosis than adults

Geriatric: ITP is uncommon in this age group; look for other cause of low platelet count
Others: N/A

PREGNANCY

Only if < 50,000 platelet count, may consider C-section
Patient in labor should receive intravenous gamma globulin due to risk to the infant
Platelet autoantibodies cross the placenta and may cause neonatal thrombocytopenia. Consider prednisone 10–20 mg/day for 10–14 days prior to delivery.
Preeclampsia or gestational thrombocytopenia may cause thrombocytopenia unrelated to ITP

OTHER NOTES

N/A

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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