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2002 Part XII: Hemostasis and Thrombosis Chapter 117: Thrombocytopenia 2003

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TABLE 117–4. Clinical Features of Idiopathic Thrombocy- patients who present with severe thrombocytopenia (<30 × 10 /L) and
do not respond to any therapy within 2 years, have a fourfold increased
topenic Purpura in Children and Adults
risk of death compared to the general population. 155
Children Adults The purpuric lesions seen in ITP are not palpable, do not blanch
Occurrence with pressure, and often develop on distal regions of the extremities
and on skin areas exposed to pressure (e.g., around tight belts and
Peak age (years) 2–4 15–40
stockings and at tourniquet sites). Hemorrhagic bullae, which may
Sex (Female-to-Male) Equal 1.2–1.7 develop in the buccal mucosa, generally reflect acute, severe throm-
Presentation bocytopenia. Bleeding after surgery, trauma, or tooth extraction is
common.
Onset Acute (most with Insidious (most with Besides the physical findings associated with platelet-type bleed-
symptoms lasting symptoms lasting
<1 week) >2 months) ing, the history and physical examination are usually unremarkable,
except for the possibility of similar symptoms in other family members.
Symptoms Purpura (<10% Purpura (typically Family history is especially important to discriminate familial thrombo-
with severe bleeding not severe) cytopenic syndromes from ITP. The spleen usually is not enlarged but
bleeding)
may be palpable in some patients, a finding considered to occur with the
Platelet count Most cases Most cases same incidence as in normal adults. Constitutional symptoms, such
156
<20,000/μL <20,000/μL as fever, significant weight loss, marked splenomegaly, hepatomegaly,
Course and lymphadenopathy provide evidence that the thrombocytopenia has
another cause. The presence of skeletal, cardiac, renal abnormalities,
Spontaneous 83% 2%
remission hearing loss, albinism. or immune deficiencies in patients with throm-
bocytopenia should trigger suspicion of IPDs.
Chronic disease 24% 43% Fatigue is one of the common, but often neglected, complaints
Response to 71% 66% of patients with primary ITP. In a survey including UK and U.S. ITP
splenectomy cohorts, the prevalence of fatigue was found to be significantly higher in
Eventual complete 89% 64% adult primary ITP patients (39 percent and 22 percent for the UK and
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recovery U.S. cohorts, respectively) compared with healthy controls. Fatigue
has also been described in 20 percent of pediatric patients with ITP;
Morbidity and fatigue resolved with the elevation of platelet counts. Although gluco-
158
mortality
corticoids and immunosuppressive agents may induce fatigue, fatigue
Cerebral hemorrhage <1% 3% can occur in untreated ITP patients. The mechanism of fatigue in
Hemorrhagic death <1% 4% patients with ITP is unknown.
Patients with ITP are at slightly increased risk of venous and arte-
Mortality of chronic 2% 5% rial thrombosis. A recent retrospective study evaluating 986 patients
159
refractory disease
with ITP showed the cumulative incidences of venous and arterial
thrombosis to be 1.4 percent and 3.2 percent, respectively. This study
found that increased thrombotic risk was associated with splenectomy,
are less common. Intracerebral hemorrhage is rare and generally occurs older age (>60 years), with the presence of more than two thrombotic
in patients with platelet counts less than 10 × 10 /L and usually is asso- risk factors at the time of diagnosis, and with glucocorticoid therapy. 160
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ciated with trauma or vascular lesions. The incidence of life-threatening
complications is highest in patients older than age 60 years. 150–154 The
majority of ITP patients have a good prognosis, the mortality rate being Laboratory Features
only slightly higher than that of the general population. However, ITP In ITP patients the blood film usually demonstrates isolated throm-
bocytopenia without erythrocyte or leukocyte abnormalities. Platelet
anisocytosis is a common finding. Mean platelet volume and platelet
distribution width are increased. Platelets may be abnormally large or
TABLE 117–5. Situations That Increase the Bleeding Risk abnormally small. The former reflect accelerated platelet production,
161
in Immune Thrombocytopenia Patients
and the latter represent platelet fragments associated with platelet
Drugs: Anticoagulants, antiplatelet drugs, nonsteroidal antiinflam- destruction. The observation of giant platelets should trigger consid-
162
matory drugs, chemotherapy eration of IPDs, which often are misdiagnosed as ITP. The bleeding
163
Gastrointestinal pathologies that may cause bleeding (e.g., active time correlates inversely with platelet count if the count is less than
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peptic ulcer, inflammatory bowel disease) 50 × 10 /L, but may be normal in patients with mild or moderate throm-
164
bocytopenia, making it an unreliable test for use in such patients. The
Miscellaneous disorders that disturb hemostasis (e.g., congenital
bleeding disorders, hepatic cirrhosis, uremia) ultrastructure of ITP platelets viewed by electron microscopy is similar
to that of normal platelets. 165
Older age (>60 years) Hemoglobin concentration and hematocrit are generally normal
Nutritional factors such as herbal teas, kinin, and tonic water in patients with ITP. Anemia that is not easily explained (e.g., resulting
Previous history of bleeding from iron deficiency in bleeding patients or associated with thalassemia
minor in endemic areas) must be investigated further. Autoimmune
Sport and occupational activities that increase bleeding risk hemolytic anemia with a positive direct antiglobulin (Coombs) test and
Trauma, surgery, and childbirth reticulocytosis may accompany ITP; this association is termed Evans
166
Uncontrolled hypertension syndrome. Neither erythrocyte poikilocytosis nor schistocytes should
be present. Total leukocyte counts and differential are generally normal.

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