oncologic emergencies Flashcards
what presentation of hyponatremia constitutes an oncologic emergency?
severe hyponatremia with neurologic changes
how to treat euvolemic, severe hyponatremia from SIADH with no neurologic changes
free water restriction and treatment of underlying cause
what is the max rate of sodium correction to avoid central pontine myelinolysis?
less than 0.5 mEg/L/h
hypertonic saline should be reserved for what patients?
those with severe hyponatremia with neurologic symptoms
what drug class bind to the v2 receptor of the collecting ducts where ADH exerts its effects, in order to cause aquaresis?
vaptans
for asymptomatic and euvolemic hyponatremia, what is the recommended water restriction?
restrict to less than 0.5 to 1 liter per day
to diagnose the cause of hyponatremia, what conditions must be excluded to rule out SIADH
hypothyroidism and adrenal insufficiency
what urine osmolality is supportive of the diagnosis of SIADH
> 40 mOsm/kg
what is the most common cause of euvolemic hyponatremia?
SIADH
what is the differential for hyponatremia in the oncologic setting?
SIADH from tumors, brain mets, N/V, several chemotherapy drugs, imatinib, and unrelieved pain
cisplatin, cyclophosphamide, ifosphamide, vinca alkaloids, and imatinib can all cause what condition that can affect nervous system function?
hyponatremia
what is the gold standard for evaluating spinal cord compression?
MRI
cancer and back pain should be considered what until proven otherwise
spinal cord compression
what are the most common causes of spinal cord compression?
breast, lung, and prostate cancer (15-20% of cases)
what are the less common causes of spinal cord compression?
renal cancer, myeloma, and hodgkin lymphoma (5-10% of cases)
what masses can compress the spinal cord yet present with normal plain spine films and normal bone scans?
paraspinous masses. They invade through the intervertebral foramen, most commonly lymphomas, sarcomas, and lung cancer.
cancer patients with back pain with a normal neurologic exam should be evaluated for spinal cord compression within what time frame?
24-48 hours
cancer patients with back pain and an abnormal neurologic exam should be evaluated for spinal cord compression within what time frame?
immediately
what is a key pharmacologic treatment in spinal cord compression?
standard dose of dexamethasone 16 mg bolus IV followed by 4-6 mg q 4-6 hours, followed by rapid taper after resection or radiation therapy
surgical decompression and radiation therapy should be used when?
highly selected cases not involving radiosensitive tumors, multiple discrete lesions, only cauda equina or spinal root compression.
what are the life-threatening symptoms of SVC syndrome?
central airway obstruction
laryngeal edema
coma from cerebral edema
what imaging is indicated for suspicion of SVC syndrome when there are mild symptoms?
CT or MRI
what imaging is indicated for suspicion of SVC syndrome when there are severe symptoms?
CT venogram
what is the NCCN recommended approach for life threatening SVC syndrome, non-radiation/non-chemotherapy sensitive malignancies, and non-iatrogenic related SVC syndromes?
endovascular stent
new onset dyspnea/orthopnea, cough, hoarse voice, stridor, syncope, and/or headaches/mental status changes are all symptoms of what serious condition?
SVC syndrome
what ecg findings are strongly suggestive of pericardial effusion, and not necessarily cardiac tamponade?
electrical alternans
what is the name of the classic xray finding for pericardial effusion?
water bottle pattern of cardiomegaly
what echocardiogram finding is diagnostic for cardiac tamponade?
pericardial effusion andright ventricular collapse during diastole
hypotension, muffled precordium, and elevated JVP are known as what finding suggestive of tamponade?
Beck’s triad
what test is the definitive diagnostic test for tamponade?
echocardiogram
if a bowel obstruction is suspected, what findings are suggestive of a perforation?
fever, tachycardia, hypotension, peritoneal signs, ascites
what physical exam finding should not be relied on to rule out bowel obstruction?
bowel sounds, as they can continue early in the obstruction
what is the imaging/lab test workup for a suspected bowel obstruction?
CT AP with contrast, CBC, CMP, lactate
type of obstruction which is due to insufficient or absent peristalsis
functional bowel obstruction
what descriptors signify whether the obstruction is inside or outside the bowel?
intraluminal or extraluminal.
what descriptor signifies that the obstruction is located within the bowel wall?
intramural
tumor involvement of the enteric nervous system or the celiac plexus, paraneoplastic syndrome, or drug induced ileus can result in what type of bowel obstruction?
functional bowel obstruction
what are the most common causes of bowel obstruction in patients with cancer?
adhesions and tumors
what is the term for a bowel obstruction caused by two distinct points of obstruction?
closed-loop obstruction
what is the term for a bowel obstruction with compromised blood flow to the bowel causing ischemic necrosis?
strangulated obstruction
when is a strangulated obstruction most likely to occur?
in setting of complete bowel obstruction, and more common in closed-loop obstructions.
in adults, an intussusception is usually due to what conditions?
instrinsic bowl tumor/metastases
what is the most common cause of large bowel obstruction?
colorectal cancers. 60% are due to this.
what is the usual treatment for large bowel obstruction?
stent and/or resection
how is bowel perforation diagnosed
free air seen on imaging studies
what is the treatment priority in bowel obstruction and peritonitis?
sepsis management. Can include microbiologic evaluation, fluid resuscitation, broad spectrum antibiotics to cover enteric pathogens, and source control (drainage of infected fluid collections and colonic resection)
in the initial management of malignant bowel obstruction, what lab finding should raise the suspicion for bowel necrosis?
persistent acidosis
what common complication of bowel obstruction makes it important to monitor urine output?
dehydration
what intervention can be considered for nausea and vomiting to decrease the risk of aspiration?
nasogastric tube placement
for malignant small bowel obstruction with concern for perforation, necrosis, or ischemia, what other features should prompt surgical consideration?
closed-loop obstruction, volvulus, intussusception, or small bowel tumor
in medical management of malignant bowel obstruction, why is IV hydration important?
prevent dehydration and correct electrolyte abnormalities
T or F: opioids may be used for pain control with bowel obstructions
True, a meta-analysis showed there is no difference in the rate of spontaneous resolution between patients who are treated with opioids and those who are not.
in medical management of malignant bowel obstruction, what is recommended in addition to antiemetics to help control nausea?
dexamethasone to reduce bowel edema, inflammation, and distension
in medical management of malignant bowel obstruction, what agents can be considered to reduce secretions?
scopolamine, h2 blockers, glycopyrrolate ( muscarinic receptor antagonist), octreotide ( mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone)
what is the role of the NG tube in medical management of malignant bowel obstruction?
decompress the stomach which may facilitate resolution of the obstruction, and may prevent aspiration from gastric contents
why monitor NG tube output?
to replace fluid losses, and low output (<100 mL in 4 hours) may suggest obstruction has resolved
what are the signs and symptoms of a bowel obstruction?
nausea, vomiting, abdominal pain, obstipation, abdominal tenderness
small bowel malignant bowel obstructions including closed loop, intussuception, volvulus, and small bowel tumors should all be considered for what treatment?
surgical resection
malignant bowel obstruction is often a harbinger of what?
the transition into the terminal phase of the illness and rapid deterioration of clinical status
