LWBK1006-39 LWW-Govindan-Review December 12, 2011 20:30
Chapter 39•Oncologic Emergencies 507cancer usually affects the lumbosacral spine. The most common causes
of MSCC at presentation are lung cancer, non-Hodgkin’s lymphoma, and
multiple myeloma.Answer 39.6. The answer is C.
Midsize and nonresponding pupils indicate midbrain dysfunction,
whereas coma is seen with damage to the mesencephalic reticular acti-
vating system. Ataxic breathing may be observed with cerebellar tonsil
herniation and indicates a damage to the medullary respiratory center.
Absence of the oculocephalic reflex (doll’s head maneuver) and horizon-
tal eye movements in response to caloric stimulation of the vestibular
system are signs of pontine damage.Answer 39.7. The answer is A.
Urate oxidase catalyzes the conversion of uric acid to allantoin. This
enzyme is present in most mammals but not in humans. Rasburicase is
a recombinant urate oxidase produced inSaccharomyces cerevisiae.This
medicine should be avoided in patients with G6PD because it may cause
hemolysis as a result of the increase in the byproduct hydrogen peroxi-
dase, and approximately 10% to 20% of patients taking rasburicase may
develop antibodies, increasing the risk of allergic reaction with subsequent
treatments.Answer 39.8. The answer is B.
Despite vigorous hydration, the most likely cause of death soon after initi-
ating chemotherapy is tumor lysis syndrome (TLS). Among the metabolic
complications of tumor lysis syndrome, hyperkalemia caused by the
release of intracellular potassium from tumoral cells represents the most
important cause of early mortality. Leukostasis, pulmonary embolism,
and cardiac arrhythmia are possible causes that are far less likely in this
patient.Answer 39.9. The answer is B.
The Kocher–Cushing reflex is characterized by changes in breathing pat-
tern, hypertension, and bradycardia. Despite being common in patients
with increased intracranial pressure, headaches are not a component of
this triad.Answer 39.10. The answer is B.
This patient has severe hypercalcemia and requires prompt reduction in
the calcium levels. Intravenous hydration is the most important initial
step, with or without the addition of furosemide, which may enhance the
renal calcium excretion. Bisphosphonates are also very effective and well
tolerated. However, because the patient is symptomatic and the effect of
bisphosphonates may take a few days, he will require an additional short-
acting agent. Gallium nitrate is usually given by continuous infusion for
5 days, with a gradual reduction in the calcium during the infusion time.