Tumor lysis syndrome and the metabolic emergencies

At room temperature the enzyme in the sample keeps destroying uric acid, so the level reads falsely low and can hide ongoing tumor lysis.

Blood from an infusion line can be diluted or carry drug into the sample; it is drawn from a site without an infusion.

Every hour of delay lets the drug lower uric acid in the tube; the sample must reach the lab and be run within 4 hours.

Rasburicase keeps breaking down uric acid inside the tube at room temperature, so the label calls for a prechilled heparin tube, an ice-water bath, and analysis within 4 hours; otherwise the result reads falsely low.

An antihistamine may ease itching but continuing the culprit drug risks organ involvement and death.

A severe allopurinol reaction is not dose-limited; any continued exposure keeps it going.

Rash, fever, and eosinophilia weeks after starting allopurinol suggest a severe hypersensitivity reaction such as DRESS; the drug is stopped at once and not restarted.

Fever with eosinophilia and rash after a new drug points to a drug reaction; waiting for cultures lets the reaction progress.

Potassium at this level can trigger a fatal arrhythmia within minutes, so it outranks every other abnormality on the panel; continuous ECG monitoring starts at once.

Low calcium explains the cramps and tingling, which makes it tempting, but at this level it is less immediately lethal than the potassium.

High uric acid injures the kidneys over hours to days; it matters, but it does not stop the heart.

Kidney injury drives the rising potassium and may lead to dialysis, but the creatinine itself is not the immediate threat.

Clearer thinking shows the calcium is coming down; it is a sign of response, not a problem.

A falling calcium is the goal of hydration and needs no urgent report.

Rapid saline restores volume and calcium excretion, but older adults can develop fluid overload; crackles and falling saturation call for slowing fluids and reassessing.

Brisk urine output is expected during saline diuresis and shows the kidneys are clearing calcium.

Bleeding points to a platelet or clotting problem; neither calcium nor digoxin causes it.

High calcium adds to digoxin's effect on cardiac conduction, so dangerous dysrhythmias can appear even at a usual digoxin level.

Hearing loss is linked to drugs such as cisplatin or aminoglycosides, not to calcium or digoxin.

Neither hypercalcemia nor digoxin lowers blood glucose.

For bone metastases and myeloma, the label calls for withholding zoledronic acid when creatinine rises 0.5 mg/dL or more from a normal baseline, until it returns to near baseline.

Faster infusion raises kidney toxicity; zoledronic acid runs over no less than 15 minutes.

Giving another nephrotoxic dose to a kidney that is already worsening can cause lasting injury.

Extra fluid does not offset the drug's direct kidney toxicity once creatinine has risen.

Calcium in malignancy comes from bone and PTH-related protein, so cutting dietary calcium does little and can worsen nutrition.

Weight bearing slows bone resorption, while immobility releases more calcium from bone and worsens hypercalcemia.

Bed rest speeds calcium release from bone and adds clot and pressure risks.

High calcium makes the kidneys lose water; fluids are encouraged, not restricted.

Fluid restriction is avoided during the first 24 hours of tolvaptan, because combined with the drug it can overcorrect sodium.

Grapefruit inhibits CYP3A and raises tolvaptan levels, so it is avoided.

Tolvaptan is started in a hospital because sodium can rise too fast and cause osmotic demyelination; sodium is checked closely in the first days.

Tolvaptan is limited to about 30 days because of liver injury, and sodium and liver tests are followed.

A high urine sodium is part of both pictures, which is exactly why volume status is the deciding sign.

Both conditions produce hypotonic hyponatremia, so serum osmolality does not separate them.

Concentrated urine occurs in both; it does not tell salt wasting from SIADH.

Cerebral salt wasting loses sodium and water together, so the patient is dry; SIADH keeps the patient euvolemic. This matters because the treatments are opposite.

Sports drinks hold far less sodium than plasma, so they mainly add free water and lower sodium further.

Hard candy stimulates saliva and eases dry mouth without adding free water, so the restriction is kept.

Hourly sips add up across the day and quietly exceed the 1-L limit.

Ice chips are water and count toward the restriction; taken without limit they undo it.

Tingling around the mouth and cramps point to low calcium, as in tumor lysis, rather than low sodium.

Seizures and stupor are late signs of severe or rapidly falling sodium, not the first ones.

Early hyponatremia causes vague symptoms such as nausea, headache, and malaise; confusion and seizures come with lower or faster-falling sodium.

Large volumes of dilute urine and thirst describe diabetes insipidus, the opposite water problem.

Aspirin is not an adequate venous thromboprophylaxis for hospitalized medical patients with cancer.

ASCO (2023) recommends drug prophylaxis for hospitalized patients with active cancer and acute illness when there is no bleeding or other contraindication; pancreatic cancer adds risk.

Full-dose anticoagulation treats a clot; it is not prophylaxis and adds bleeding risk.

Mechanical methods are for patients who cannot receive anticoagulants; this patient has no contraindication.

Sinus tachycardia is the most frequent ECG change in pulmonary embolism, although it is not specific.

S1Q3T3 is the classic textbook sign of right heart strain, but it appears in only a minority of patients.

Beat-to-beat changes in QRS height suggest a large pericardial effusion, not a pulmonary embolism.

A slow rate is unusual in PE; the heart speeds up to keep output as the right ventricle strains.

Malignancy itself raises D-dimer, which is the reason it is less useful in this group.

An elevated D-dimer shows only that fibrin is being broken down somewhere, which is common in cancer without any clot.

D-dimer rises with small clots too, and with many conditions that are not clots at all, so its level does not measure clot size.

Cancer, recent surgery, chemotherapy, and infection all raise D-dimer, so a high value cannot confirm PE; imaging decides.

Marrow replacement lowers platelets in any acute leukemia, but it does not explain consumption of clotting factors.

In APL fibrinogen is typically low, because it is being consumed and broken down.

Promyelocyte granules release tissue factor and other procoagulants that switch on clotting throughout the body, consuming platelets and factors and driving fibrinolysis.

Antibody-mediated factor loss, such as an acquired inhibitor, is a different disorder and not how APL causes bleeding.

Microthrombi in the kidney lower urine output, so oliguria, not diuresis, is the warning sign.

Small clots in fingers, toes, and organ vessels cut off flow, causing dusky digits and failing kidneys, lungs, or brain alongside the bleeding.

Warm extremities show good perfusion, the opposite of what microthrombi cause.

DIC is linked with shock and poor perfusion, not with a lone rise in blood pressure.

The WBC will not fall without treatment; delaying cytoreduction lets the brain and lung injury progress.

Red cells add to blood viscosity in leukostasis, so transfusion is avoided or delayed until the count falls.

Diuresis concentrates the blood and raises viscosity further; hydration is used instead.

Symptomatic leukostasis needs the blast count lowered quickly; cytoreduction with hydroxyurea or induction is definitive, and leukapheresis may be added.

Suspected PE with hypotension is high-risk (massive) embolism and can progress to arrest; this patient needs assessment and escalation now.

A flare reaction along the vein is a local, self-limited histamine response, not an extravasation.

Grade 1 CRS is fever alone; it needs monitoring and supportive care but is not unstable.

Mild hypercalcemia in an alert, eating patient is stable and can wait.