Page 100 - Cote clinical veterinary advisor dogs and cats 4th

28.e2 Acute Tumor Lysis Syndrome

Acute Tumor Lysis Syndrome Client Education
Sheet
VetBooks.ir Acute General Treatment

• Elevated serum phosphate precipitates with
BASIC INFORMATION
serum calcium, forming CaPO 4 salts and • Aggressive crystalloid fluid therapy; consider
Definition causing secondary hypocalcemia. non-lactate–, non-potassium–containing
Acute tumor lysis syndrome (ATLS) is a rare but • Acute release of intracellular potassium leads fluids such as 0.9% NaCl to address hyper-
underreported disorder consisting of a group to hyperkalemia within 12 hours, which can phosphatemia or hyperkalemia. Administer
of metabolic disturbances caused by massive cause bradycardia and arrhythmias. Hyper- fluids at rates appropriate for patients in
death of neoplastic cells and subsequent release kalemia may be accentuated by renal shock, and follow with fluid diuresis at 2 to
of intracellular contents. Veterinary ATLS is impairment. 3 times maintenance rates.
characterized by hyperphosphatemia, hyper- • Hyperuricemia is seen in humans with ATLS • Delay further treatment for neoplasia until
kalemia, and hypocalcemia, with or without as a result of release of intracellular urate patient has been stabilized.
azotemia. ATLS rarely occurs spontaneously; it from nucleic acids. Hyperuricemia and • Urine alkalinization is used in humans to
occurs in patients after antineoplastic therapy. resulting obstructive nephropathy occur less increase the solubility of uric acid. It is not
often in animals. Dogs at increased risk recommended in veterinary patients, because
Epidemiology include those that are azotemic, Dalmatians, urate nephropathy is less significant, and
SPECIES, AGE, SEX or dogs with severe liver disease. alkalinization increases urine phosphate
ATLS can occur after rapid cytoreduction • Renal failure is related to precipitation of deposition.
(neoplastic cell death) after treatment of any CaPO 4 in renal tubules and to cardiovascular • Allopurinol, which inhibits xanthine oxidase,
dog or cat with a large tumor burden. collapse. In humans, serum urate precipita- is used in humans to prevent uric acid forma-
tion contributes to acute kidney injury. tion. In dogs, it is recommended only for
RISK FACTORS • Metabolic acidosis is typically a high–anion those with urate metabolism problems (i.e.,
• Patients at highest risk are dogs and cats gap lactic acidosis. Dalmatians) at a dose of 10 mg/kg PO q
with some degree of volume contraction and 8-24h.
large tumor burdens that rapidly respond DIAGNOSIS • Monitor for acute kidney injury and treat
to cytolytic therapy. appropriately. Hemodialysis, if available,
• Clinically, it is most common in patients Diagnostic Overview can be performed until renal function
with advanced-stage lymphoma or leukemia The diagnosis is suspected in patients with a resumes.
because these are highly chemosensitive history of chemosensitive or radiation-sensitive
tumors. tumors, such as advanced lymphoma or Recommended Monitoring
• Associated risk factors include leukemia, and an onset of signs after initia- Monitor the patient closely. Rate of fluid
○ Large tumor burden tion of chemotherapy or radiation therapy. A administration should be adjusted based on
○ Dehydration biochemical panel is required for confirmation patient’s body weight, hydration, cardiovascular,
○ Pre-existing renal disease of hyperphosphatemia, with or without azo- renal, and electrolyte status.
○ Hypercalcemia of malignancy temia, metabolic acidosis, hyperkalemia, and
○ High tumor growth fraction hypocalcemia. PROGNOSIS & OUTCOME
○ High serum lactate dehydrogenase
activity Differential Diagnosis Prompt diagnosis and aggressive treatment to
• It is rare in patients with solid tumors. • Disorders associated with chemotoxicity, such correct fluid deficits, electrolytes, and acid-base
as severe gastrointestinal toxicosis and disturbances are essential to prevent renal
Clinical Presentation dehydration, neutropenia, and/or sepsis after damage and further decompensation.
HISTORY, CHIEF COMPLAINT chemotherapy
Signs occur after recent initiation of chemo- • Disorders due to primary neoplasia, such as PEARLS & CONSIDERATIONS
therapy or radiation therapy, typically within coagulopathies and organ failure
48 hours; rarely, ATLS has been reported to Comments
occur up to 8 days after treatment. Presenting Initial Database ATLS is a preventable disorder that requires
complaints include anorexia, vomiting, diarrhea, • CBC, biochemical profile, urinalysis, blood identification of patients at risk. In practice
lethargy, and collapse. Patients can present in gas analysis these are sick canine lymphoma patients with
shock. • In dogs, the most consistent abnormality is advanced stage disease. These patients should
hyperphosphatemia, with or without azote- not be treated with chemotherapy as outpa-
PHYSICAL EXAM FINDINGS mia and metabolic acidosis. Hypocalcemia tients. They require close monitoring and
Patients are typically dehydrated, depressed, and hyperkalemia are not prominent in inpatient supportive care.
and may be tachycardic or bradycardic. Patients ATLS, and clinical signs due to these meta-
can present in shock with signs such as mental bolic abnormalities are rarely recognized. Prevention
depression, pale mucous membranes, decreased Prevention is key to avoiding ATLS in patients
capillary refill time, and cardiac arrhythmias. TREATMENT undergoing therapy:
• Identify patients at risk. Recognition of
Etiology and Pathophysiology Treatment Overview risk factors is essential (see Risk Factors
• With treatment of very sensitive tumors, Treatment consists mainly of therapy for shock above).
rapid tumor lysis liberates large quantities to correct dehydration, fluid deficits, and • In patients at risk, initiate fluid therapy 24-48
of intracellular contents into the circulation. electrolyte abnormalities. The goal of treatment hours before treatment, and continue for
• Acute release of intracellular phosphates is to increase elimination of excess electrolytes 24-96 hours after chemotherapy.
(adenosine triphosphate, nucleic acids) causes with fluid diuresis. Monitoring these patients • Monitor these patients for early biochemical
hyperphosphatemia, usually within 48-96 is critical, and referral to a 24-hour specialty abnormalities and arrhythmias, and adjust
hours. center is recommended. treatment accordingly.

www.ExpertConsult.com