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Detailed information of APLASTIC CRISIS
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APLASTIC CRISIS
DEFINITION:
A transient cessation of erythropoiesis resulting in the acute
onset of anemia in a patient with chronic hemolytic anemia.
EPIDEMIOLOGY:
- incidence: ?
- age of onset:
- 90% occur before age 15 with peak between 5-19 years of age
- risk factors:
- human parvovirus B19 (B19)
- any chronic hemolytic anemia:
PATHOGENESIS:
- aplastic crisis was first described in 1948 by Owren
- B19, a small single-stranded DNA virus, was discovered in
1975
- the link of B19 to aplastic crisis was first made in 1981 by
Pattison et al.
2. Epidemiology of B19
- B19 is associated with Fifth Disease, acute arthritis,
hydrops fetalis, chronic bone marrow failure in
immunocompromised patients
- response to B19 infection in patients with chronic
hemolyticanemia:
- APLASTIC CRISIS
- nonspecific illness
- asymptomatic seroconversion
- aplastic crises due to B19 tend to peak every 2-3 years
- rate of secondary transmission to susceptible household
members is 50% via respiratory secretions
3. Background
- in any chronic hemolytic anemia, individuals must maintain
an increased rate of erythropoiesis to maintain the hemoglobin
concentration (aplastic crises best characterized in sickle
cells anemias)
- B19 can lead to a bone marrow hypoplasia by disrupting
erythropoiesis and thus precipitate an aplastic crisis
- B19 is associated with about 90% of aplastic crises in
patients with underlying hemolytic disorders (10% have other
causes)
4. Pathogenesis
- B19 infection of the bone marrow where the host cells (of
erythropoiesis) are actively dividing in patients with chronic
hemolytic anemia
- B19 infection results in the specific inhibition of
erythroid colony formation (no effect of other cells lines)
- lytically infects and subsequently kills the erythroid
precursors
- production of IgM and IgG directed towards B19 results in:
- normoblasts and erythroid hyperplasia in the bone marrow
- reticulocytes to peripheral blood
- increased concentration of hemoglobin
- recurrence is rare due to the acquisition of lifelong B19
immunity after the first infection
CLINICAL FEATURES:
- viral-like illness in a patient with an underlying hemolytic
disorder
2. Symptoms (%)
- fever (80-100%)
- abdominal pain, diarrhea, nausea/vomiting (40-80%)
- malaise (40-80%)
- headache, myalgia, arthralgia (15-45%)
- URTI complaints - cough, rhinorrhea, sore throat (0-40%)
- rash (0-23%)
- conjunctivitis, eye pain, photophobia (0-15%)
3. Aplastic Crisis
- pallor
- anorexia
- irritability
- pica
- splenomegaly
- systolic murmer
- tachycardia
- episode lasts for 3-6 days
INVESTIGATIONS:
- profound anemia (Hb < 20-30 g/L)
- reticulocytes <1%
- occasionally lymphocytosis, eosinophilia, neutropenia, and
thrombocytopenia
2. Serology
- B19 IgM appears within 1-3 days of presentation and lasts
for 1-2 months (indicative of acute infection)
- B19 IgG appears within a few days of infection and
persists indefinitely (indicative of immunity)
2. Bone Marrow
- aplasia or hypoplasia of the erythroid series with other
cell lineages being normal
- giant pronormoblasts
MANAGEMENT:
- diagnosis, definition, epidemiology, prognosis, treatment
options
3. Treatment Options
- asymptomatic, self-limiting disorder
2. Treatment
- symptomatic - cardiopulmonary disease, congestive heart
failure
4. Goals of Therapy
- to support the patient until the bone marrow can recover
5. Management Strategies
- observe and await for peripheral blood reticulocytosis
- if hospitalized, put patient in strict respiratory and
contact isolation
2. RBC Transfusions
- 10-15 cc/kg PRBC IV:
- should increase the hematocrit by 10%
- give slowly over 3-4 hours if symptomatic +/- lasix
- may require multiple transfusions
3. Experimental
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