Pediatric emergency medicine trisk 2671 2671

imaging with CT or MRI

oncology and neurosurgery
in the setting of spinal cord
compression

a Consider

whether renal function or metabolic derangements may necessitate dialysis.
BUN, blood urea nitrogen; PT, prothrombin time; PTT, partial thromboplastin time; TLS, tumor lysis syndrome;
q, every; IV, intravenous; WBC, white blood cell; CT, computed tomography; ANC, absolute neutrophil count;
NSAIDs, nonsteroidal anti-inflammatory drugs; CNS, central nervous system; MRI, magnetic resonance
imaging.

In constructing a differential diagnosis, it is helpful to consider whether leukemic
blasts are present in the peripheral circulation. If blasts are present in substantive
quantities (greater than 20%), then leukemia is the most likely diagnosis. A smaller
percentage of blasts could indicate a myelodysplastic syndrome, a
myeloproliferative disorder, recovery from an aplastic process, or a leukemoid
reaction. If blasts are not evident on the CBC, and the patient has pancytopenia, one
must consider not only leukemia but also bone marrow failure from aplastic anemia,
infection (usually viral), or marrow replacement by a solid tumor. If only one or two
cell lines seem to be affected, the clinician should consider the differential diagnoses
for each cytopenia individually (see Chapter 93 Hematologic Emergencies ).
In addition to the laboratory investigations needed for diagnosis, screen for
metabolic abnormalities due to tumor lysis by checking serum chemistries, including
potassium, calcium, magnesium, phosphorus, and uric acid. Renal function should
be assessed with a blood urea nitrogen (BUN) and creatinine. The results of the
CBC should be reviewed to assess needs for transfusions of blood products and a
prothrombin time (PT) and partial thromboplastin time (PTT) should be checked to
look for coagulopathy ( Table 98.3 ). A chest x-ray may indicate the presence of a

mediastinal mass, or pericardial or pleural effusion.
Management
Cytopenias. As the leukemia proliferates in the bone marrow it disrupts the normal
production of cell lines leading to anemia, thrombocytopenia, and neutropenia. This
is most common in the setting of leukemia but can also occur with solid tumors,
such as neuroblastoma and rhabdomyosarcoma with bone marrow metastasis.
Anemia can be mild or severe but is often asymptomatic because of its slow
development. Anemia with associated clinical signs or symptoms should be treated
with a red cell transfusion. Severely anemic but stable patients should be transfused
slowly to avoid rapid development of pulmonary edema and respiratory failure.
Thrombocytopenia can present with mucocutaneous bleeding such as epistaxis,
gingival bleeding, petechiae, and ecchymosis. The risk of bleeding may also be