Oncologic Emergencies (Weddle) Flashcards
Define tumor lysis sydrome (TLS).
a constellation of metabolic derangements resulting from the death of malignant cells
List some tumor-specific risk factors for TLS.
- High tumor burden
- High grade tumor with rapid cell turnover
- Treatment-sensitive tumor
List some patient-specific risk factors for TLS.
- Age
- Preexisting renal impairment
- Concomitant use of drugs that increase uric acid
List the four hallmarks of TLS pathophysiology.
- HYPERkalemia
- HYPERuricemia
- HYPERphosphatemia
- HYPOcalcemia
Give some keys to the successful management of acute TLS.
- Identify and prophylax high-risk patients
- Monitor electrolytes before and during cytoreductive regimens
- Aggressively hydrate
- Control hyperuricemia with uric acid-lowering drugs
What malignancies are associated with low risk TLS?
- Most solid tumors
- Myeloma
- Indolent lymphomas
- CML
What is the prophylaxis protocol for low-risk TLS?
- Monitoring
- Hydration
- (maaaayyyybbeee allopurinol but probably not)
What malignancies are associated with intermediate-risk TLS?
- DLBCL
- SCLC
What is the prophylaxis protocol for intermediate-risk TLS?
- Monitoring
- Hydration
- Allopurinol
What malignancies are associated with high-risk TLS?
- Burkitt’s lymphoma
- Lymphoblastic lymphomas
- Most acute leukemias
What is the prophylaxis protocol for high-risk TLS?
- Monitoring
- Hydration
- Rasburicase
What are the two fluid options when hydrating for TLS?
- D5/0.45 NS
- 0.9 NS
What is the desired urine output when hydrating for TLS?
80-100 mL/m2/hr
What should ALWAYS be considered when assessing fluid rate and volume in TLS patients?
cardiac function
What does allopurinol do?
blocks uric acid formation
How long will a TLS patient be on allopurinol?
until uric acid and other lab values normalize; NOT a lifelong medication
How does a TLS patient develop hyperuricemic AKI?
uric acid and xanthine crystlize within the tubular lumen
List some major limitations of using allopurinol for TLS.
- Doesn’t reduce already-formed uric acid
- May take several days
- Increases concentrations of xanthine and xanthine oxidase metabolites, which can then precipitate
- Decreased clearance of certain chemotherapies (6-MP, azathioprine, high-dose MTX)
What makes rasburicase different from allopurinol?
it can decrease already-formed uric acid also (and fast!)
Rasburicase catalyzes oxidation of uric acid into its soluble metabolite, __________.
allantoin
What should definitely be considered when doing a blood-draw for a high-risk TLS patient?
rasburicase degrades uric acid within blood samples, and could show falsely low uric acid levels
samples must be mixed with heparin, stored on ice, and evaluated within 4 hours
With rasburicase, risk of ____________ increases with subsequent use.
hypersensitivity reactions
In what groups is rasburicase contraindicated?
pregnant/breast-feeding
Some patients of African, Mediterranea, or Southeast Asian descent are at risk of severe hemolysis reactions with rasburicase. Why?
G6P dehydrogenase deficiency
What baseline levels should be taken before starting certain chemotherapy, in order to monitor TLS?
- Uric acid
- Phosphorus
- Potassium
- Calcium
- LDH
- SCr
- Urine output
What is the ultimate goal of TLS monitoring?
avoid dialysis and minimize morbidity/mortality
Which cancers are responsible for 2/3 of all MSCC cases?
breast, lung, and prostate
List some common symptoms of MSCC.
- Pain/tenderness
- Bladder/bowel dysfunction
- Paresthesia/decreased sensation/numbness of fingers or toes
- Hyperreflexia
- Limb weakness/motor deficits
In MSCC, _________________ as a result of spinal cord compression ischemia leads to white matter necrosis and gliosis.
vasogenic edema
What is the method of choice for diagnosing MSCC?
MRI of the whole spine
The strongest predictor of neurologic outcome with MSCC treatment is _________________________.
the neurologic status when treatment is initiated
What medication should be started immediately if MSCC is strongly suspected?
dexamethasone IVP
What are the only treatments that lead to immediate relief of MSCC?
surgery and radiotherapy
Define laminectomy.
surgical removal of some or all of the pathological vertebral body and tumor mass
Define vertebroplasty.
bone cement injected into fractured bone
Define kyphoplasty.
a balloon inserted and inflated to expand the compressed vertebra, before filling the space with bone cement
What drug should be offered to MSCC patients after surgery if they have vertebral involvement?
bisphosphonates; reduce the risk of vertebral fracture/collapse
What is SVC syndrome?
when the superior vena cava is compressed by tumors outside
What are some common signs/symptoms of SVC syndrome?
- Distention of the neck and chest wall veins
- Facial/arm edema
- Hypotension
- Dyspnea at rest
- Cough
- Stridor
- Dysphagia
- Headaches
- Syncope
- Dizziness
What can happen if SVC syndrome is left untreated?
- Hemodynamic compromise
- Airway compromise
- Increased intracranial pressure = cerebral edema, intracerebral bleeding
True or false: most SVC syndrome cases are true oncologic emergencies.
false
Based on the severity of SVC symptoms, what interventions may be considered?
- Resection
- Stenting
- Radiation
- Chemotherapy
- Anticoagulation
What are some adjunctive therapies that can be used to alleviate SVC syndrome symptoms?
- Head elevation (decrease hydrostatic pressure/edema)
- Steroids (only in patients with steroid-sensitive tumors/undergoing radiation)
- Diuretics (decrease arterial pressure to affect venous pressure distal to the obstruction)
What is malignant pleural effusion (MPE)?
uniformly fatal fluid accumulationin the pleural space
What is the most common presenting symptom of MPE?
dyspnea
What is the first radiodiagnostic to be used for MPE?
chest x-ray
When would an ultrasound be used in MPE?
pre-procedure, to identify appropriate drainage sites
What procedure is frequently perfomed for MPE diagnosis and therapeutics?
thoracentesis
What is thoracentesis?
needle aspiration of fluid from a pleural effusion
What MPE patient population(s) would you recommend thoracentesis for?
- Those seeking temporary relief of acute symptoms
- Patients with life expectancy < 1-3 months
What can happen if more than 1.5 L are taken out during thoracentesis?
re-expansion pulmonary edema
What is the recommended course of treatment for MPE patients with a life expectancy > 1-3 months?
pleurodesis
What is pleurodesis?
drainage of the pleural space with subsequent injection of either talc, doxycycline, or bleomycin
What is the mechanism of action of pleurodesis?
activates the inflammatory cascade, leading to adhesion of pleural layers
How often is a pleural catheter for MPE drained?
frequently, to comfort
What are some pros of using an indwelling pleural catheter for MPE?
- Decreased hospital stay
- Less frequent need for thoracentesis/pleurodesis
Provide two risks of an indwelling pleural catheter for MPE.
- Infection
- Tumor seeding of catheter
