Oncologic Emergencies¶
Chapter 80 | Part 4: Oncology and Hematology
KEY CLINICAL POINTS¶
- Superior vena cava syndrome (SVCS) is a critical oncologic emergency caused by malignant tumors (85% of cases) or benign causes (15% of cases).
- Neoplastic meningitis is a life-threatening complication with poor prognosis (median survival 10–12 weeks) but can be managed with intrathecal chemotherapy, radiation, and targeted therapies.
- Tumor lysis syndrome (TLS) is a chemotherapy-related emergency requiring aggressive hydration, allopurinol/febuxostat, and dialysis to prevent renal failure and electrolyte imbalances.
1. DEFINITION & OVERVIEW¶
Oncologic emergencies encompass acute complications arising from cancer or its treatment, including structural obstruction, metabolic derangements, and treatment-related toxicities. These emergencies require rapid diagnosis and intervention to prevent morbidity and mortality.
Table 80-1: Management of Cancer Patients with Back Pain¶
| Clinical Feature | Action | Outcome |
|---|---|---|
| Suspicious for myelopathy | MRI of spine | Determine level of cord compression |
| Normal neurologic exam | Symptomatic therapy | Monitor for progression |
| Pain crescendo pattern | High-dose dexamethasone | Reduce inflammation |
| Lhermitte’s sign | MRI of spine | Identify epidural metastases |
| Pain aggravated by supine position | Symptomatic therapy | Rule out spinal cord compression |
1.1 Structural-Obstructive Emergencies¶
SVCS, pericardial effusion, intestinal obstruction, urinary obstruction, and spinal cord compression are common structural obstructions. These often result from tumor mass, metastases, or treatment-related complications.
1.2 Metabolic Emergencies¶
Hypercalcemia, SIADH, lactic acidosis, and hypoglycemia are paraneoplastic syndromes or treatment-related metabolic crises. These require prompt correction to prevent organ failure.
1.3 Treatment-Related Emergencies¶
TLS, hypersensitivity reactions, and immune-mediated pneumonitis are chemotherapy- or immunotherapy-related emergencies. Prophylactic measures and early intervention are critical.
2. EPIDEMIOLOGY¶
SVCS occurs in 10–30% of patients with malignant tumors (e.g., lung, lymphoma). Neoplastic meningitis affects 3–8% of cancer patients. TLS occurs in 5–13% of AML and 10–30% of ALL. Hypercalcemia is the most common paraneoplastic syndrome.
2.1 Risk Factors¶
Advanced cancer stage, immunosuppressive therapies (e.g., checkpoint inhibitors), chemotherapy (e.g., gemcitabine, mitomycin), and radiation therapy increase emergency risks.
2.2 Demographics¶
SVCS is more common in males (lung cancer). Neoplastic meningitis is prevalent in patients with breast, lung, and lymphoid malignancies. TLS is more frequent in patients with high tumor burden.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
SVCS results from SVC obstruction by tumors or thrombosis. Neoplastic meningitis arises from leptomeningeal spread of cancer cells. TLS occurs due to rapid tumor cell lysis, releasing intracellular contents into circulation.
3.1 SVCS Pathogenesis¶
Malignant tumors (e.g., lung, lymphoma) or thrombosis cause SVC obstruction. Tumor infiltration leads to collateral venous circulation and edema.
3.2 TLS Mechanism¶
Rapid destruction of tumor cells (e.g., chemotherapy) releases uric acid, potassium, phosphorus, and calcium. Renal failure and electrolyte imbalances ensue.
4. CLINICAL FEATURES¶
SVCS presents with neck swelling, dyspnea, and cyanosis. Neoplastic meningitis causes multifocal neurological deficits. TLS manifests as hyperuricemia, hyperkalemia, and acute renal failure.
4.1 SVCS Symptoms¶
Neck/face swelling, dyspnea, cough, hoarseness, and hemoptysis. Severe cases may present with proptosis or obtundation.
4.2 Neoplastic Meningitis¶
Headache, gait abnormalities, seizures, cranial nerve palsies, and cognitive changes. CSF analysis reveals malignant cells.
5. DIFFERENTIAL DIAGNOSIS¶
SVCS must be differentiated from benign causes (e.g., thoracic aortic aneurysm, fibrosing mediastinitis). Neoplastic meningitis requires distinction from infectious meningitis and other CNS tumors.
5.1 SVCS Differential¶
Benign causes include aortic aneurysm, thyromegaly, and fibrosing mediastinitis. Malignant causes include lung, lymphoma, and metastatic tumors.
5.2 Meningitis Differential¶
Infectious meningitis, brain metastases, and leptomeningeal carcinomatosis must be ruled out via CSF analysis and imaging.
6. INVESTIGATIONS & DIAGNOSIS¶
Chest X-ray, CT, and MRI are essential for SVCS. CSF analysis and imaging (MRI/CT) confirm neoplastic meningitis. TLS is diagnosed via electrolyte panels and uric acid levels.
Table 80-2: Diagnostic Criteria for Tumor Lysis Syndrome¶
| Parameter | Threshold |
|---|---|
| Serum uric acid | >8.0 mg/dL |
| Serum potassium | >6.0 mEq/L |
| Serum phosphate | >10 mg/dL |
| Serum calcium | <8.0 mg/dL |
| Creatinine | >1.6 mg/dL |
6.1 SVCS Diagnosis¶
Chest X-ray (widening superior mediastinum), CT (collateral veins, thrombosis), and MRI (sensitivity for SVC obstruction).
6.2 Meningitis Diagnosis¶
CSF analysis (malignant cells, elevated protein), MRI (leptomeningeal enhancement), and lumbar puncture.
7. MANAGEMENT & TREATMENT¶
SVCS is managed with steroids, radiation, and stents. Neoplastic meningitis requires intrathecal chemotherapy. TLS is treated with hydration, allopurinol, and dialysis.
Table 80-3: Management Algorithm for Tumor Lysis Syndrome¶
| Step | Action | |
|---|---|---|
| 1 | Hydrate with 1/2 normal saline 3000 mL/m²/day | |
| 2 | Administer allopurinol 300 mg/m²/day | |
| 3 | Monitor serum electrolytes every 6–12 h | |
| 4 | If uric acid >8.0 mg/dL or creatinine >1.6 mg/dL | Start rasburicase or hemodialysis |
| 5 | If potassium >6.0 mEq/L | Initiate hemodialysis |
7.1 SVCS Treatment¶
Radiation (non-small-cell lung cancer), chemotherapy (small-cell lung cancer), and stenting (intravascular self-expanding stents).
7.2 TLS Management¶
Aggressive hydration (1/2 normal saline 3000 mL/m²/day), allopurinol/febuxostat, and dialysis for severe electrolyte imbalances.
8. PROGNOSIS & COMPLICATIONS¶
SVCS mortality is related to underlying cancer. Neoplastic meningitis has a median survival of 10–12 weeks. TLS can lead to acute renal failure and death if untreated.
8.1 SVCS Outcomes¶
Prognosis depends on tumor type and response to treatment. Early intervention improves survival.
8.2 TLS Complications¶
Acute renal failure, cardiac arrhythmias, and metabolic acidosis are life-threatening complications requiring immediate intervention.
9. SPECIAL CONSIDERATIONS¶
Pregnancy, pediatric, and elderly patients require tailored approaches. Chemotherapy and immunotherapy risks must be balanced against potential benefits.
9.1 Pregnancy¶
Avoid live vaccines; manage infections with caution. Radiation and chemotherapy may be delayed until postpartum.
9.2 Pediatric Patients¶
Neutropenic enterocolitis and TLS are more common. Dose adjustments and supportive care are critical.
10. KEY POINTS & CLINICAL PEARLS¶
- SVCS is a medical emergency requiring immediate imaging and intervention. 2. Neoplastic meningitis is managed with intrathecal chemotherapy and radiation. 3. TLS prevention includes hydration and allopurinol. 4. Immune checkpoint inhibitors may cause pneumonitis and hypophysitis. 5. Early recognition and treatment of metabolic emergencies are vital to prevent organ failure.