Oncology Emergencies in the Critical Care Setting

An oncologic emergency is a life-threatening condition that results from either cancer or the patient’s treatment. When patients present with these emergencies, it may be the first suspicion that they have cancer. Treatment of patients with cancer can also trigger a metabolic emergency. Critical care nurses may see these patients on their units until the crisis resolves and they stabilize. Three of the more common oncologic emergencies can require intensive care unit (ICU) admission: tumor lysis syndrome, superior vena cava syndrome and disseminated intravascular coagulation.

Tumor Lysis Syndrome

What:

Tumor lysis syndrome (TLS) is an oncologic emergency that occurs when cancer cells lyse or die. Large amounts of potassium, uric acid and phosphate are released from inside the cells as the cancer cells lyse. The uric acid and phosphate/calcium crystals can deposit in the renal tubules, leading to kidney damage. Large amounts of potassium can lead to cardiac dysrhythmias.

Who:

Patients at highest risk for TLS include those with hematologic malignancies, in particular lymphomas and leukemias. Those with high tumor burden or aggressive disease in these cancer types are in jeopardy of developing TLS. TLS commonly develops once the patient has started chemotherapy, particularly in a patient who has chemosensitive tumors. However, newly diagnosed patients can present in TLS if they have a high burden of disease. Newer targeted agents for hematologic malignancies have been associated with an increase in TLS. TLS in solid tumors is rare but has been described in patients with aggressive breast cancers, among other types of cancer.

Signs and Symptoms/Other Predictors:

Clinical signs that patients will develop TLS include those who present with:

1. Hyperuricemia (serum uric acid > 7.5 mg/dL) or hyperphosphatemia (serum phosphate > 4.5 mg/dL)
2. A large tumor burden defined as either > 10 cm in diameter or a white blood cell count > 50,000 per microliter, an LDH two times the upper limit of normal, bone marrow involvement (with lymphoma) and/or organ infiltration
3. Chemosensitive tumors (for example, diffuse large B-cell lymphoma)
4. Oliguria and/or acidic urine
5. Dehydration or inadequate hydration during treatment
6. Preexisting nephropathy or if they are receiving nephrotoxic medications concurrently

Management:

Prophylaxis before or at the very start of chemotherapy for those at risk for TLS is a best practice and can help prevent complications. Aggressive hydration (2-3 L daily) at the start of treatment is recommended. Diuretics can be administered in case of fluid overload rather than decreasing the volume of hydration. If the patient has metabolic acidosis, administration of intravenous sodium bicarbonate can help prevent uric acid from precipitating in the kidneys. However, there is some risk with this practice, especially if the patient presents with high phosphorus, and sodium chloride is preferred over sodium bicarbonate.

Allopurinol is recommended to be started prior to chemotherapy for those patients not already in TLS. Allopurinol prevents the formation of new uric acid. Rasburicase (Elitek) is used for patients who present with TLS. Rasburicase makes uric acid more soluble; thus it is easily excreted by the kidneys.

Patients who present with TLS may need intensive care nursing. Cardiac monitoring, strict monitoring of fluid status, frequent lab work and renal replacement therapy may be needed. Patients at higher risk for the development of TLS at the start of treatment may be transferred to the ICU for monitoring and management of potential cardiac dysrhythmias and electrolyte imbalances.

Superior Vena Cava Syndrome

What:

Superior vena cava (SVC) syndrome occurs due to obstruction of the SVC. It occurs with tumors such as lymphomas or lung cancers that directly invade or impinge on the SVC. However, in patients with cancer who have indwelling central venous access devices (subcutaneous ports, for example), SVC syndrome can result from thrombosis in the catheter.

Who:

Patients with thoracic malignancies may develop SVC. Lung cancer (both non-small cell and small cell types) is the most common cause of SVC followed by non-Hodgkin’s lymphoma.

Signs and Symptoms:

Face and neck swelling, and dyspnea are the most frequent signs and symptoms of SVC syndrome. Distention of the neck and chest veins may be visible. Patients may also complain of head fullness, which makes it difficult to lie flat. They may have headaches and visual/auditory changes due to cerebral edema. In patients who have developed collateral circulation due to a slow-growing tumor, symptoms may be less severe.

Management:

The main principle for management of SVC syndrome is to address the underlying disease. In most cases, patients with SVC syndrome do not need to be treated urgently. Obtaining the correct diagnosis of cancer type is important in order to deliver the correct therapy. In a patient with severe symptoms, a stent may be placed into the SVC. Surgical resection can be performed in some cases.

Critical care admission is required for a patient with rapidly developing SVC syndrome and for those who present with tracheal deviation, decreased cardiac output, respiratory compromise, confusion or unresponsiveness due to cerebral edema. Once stabilized, the patient will require thrombus removal or stent placement. Patients with SVC generally have less than a six-month survival rate according to the type of malignancy.

Disseminated Intravascular Coagulation

What:

Disseminated intravascular coagulation (DIC) is an emergency in which bleeding and clotting occur simultaneously. DIC starts with excessive clotting. The clotting is caused by a procoagulant factor, which is a substance produced by cancer. The clotting continues without stopping due to continued stimulation from the procoagulant factor, often resulting in impaired circulation to vital organs and organ failure. As a result, platelets and clotting factors are depleted as more platelets go to the area of the clot. DIC results in bleeding when the platelets and clotting factors are consumed.

Who:

In individuals diagnosed with cancer, the most common causes of DIC are sepsis and certain types of tumors. Acute promyelocytic leukemia (APML) is the cancer most commonly associated with DIC. Mucin-producing tumors, such as gastric, ovarian and pancreatic cancers, can also be sources of DIC, as the cancer releases enzymes or necrotic tissue that can stimulate the clotting cascade (Leung, 2020). The development of cytokine release syndrome after therapy for chimeric antigen receptor T-cells (CAR-T cells) has also been associated with DIC. Procoagulant factors released from the vascular endothelium as part of inflammation are thought to be the reason for the development of DIC in this population.

Signs and Symptoms:

DIC is not a disease but a syndrome that is a result of a disease. In the cancer population, the diagnosis of DIC can be the first clue that a patient has cancer. Patients may present with unexplained bruising, bleeding gums, swelling of extremities and end-organ damage. No one lab test is diagnostic of DIC. Lab findings that assist in the diagnosis of DIC are thrombocytopenia, prolonged PT and aPTT, decreased fibrinogen and increased D-dimer. DIC is diagnosed by both the clinical presentation and abnormal lab results.

Treatment:

Treatment of the patient with an underlying condition will include treating DIC. For patients with cancer diagnoses, it is imperative to start chemotherapy or other treatment as soon as the diagnosis is confirmed. In sepsis, antibiotic therapy with broad-spectrum antibiotics is urgent. However, the coagulation abnormality can take several days to correct despite addressing the problem. For this reason, supportive care is necessary and consists of transfusions of FFPs, cryoprecipitate, red blood cells and platelets. Close hemodynamic monitoring of the patient with DIC is critical. Depending on the level of bleeding or the degree of coagulopathy, these patients may require transfer to the ICU. Frequent monitoring of vital signs and physical assessments are required. Nurses should also watch for end-organ dysfunction, including renal failure, hepatic failure and neurologic changes. Manifestations of DIC and the condition causing them can be frightening to patients and caregivers. Mortality in DIC can be as high as 80%. Caregivers are often the first to notice subtle changes in patients. Encourage both the patient and caregiver to alert the nurse to any new symptom or change. Early intervention is important to mediate this life-threatening condition.

Conclusion

Oncologic emergencies can occur because of the cancer’s pathophysiology or its management. As noted previously, three of the more common oncologic emergencies may be seen in the ICU. Until the patient’s cancer is controlled, these emergencies may require stabilization of the patient in the critical care arena. Even with new targeted therapies for the treatment of patients with cancer, these emergencies continue to be present. While treating patients with cancer, critical care nurses also need to recognize and manage oncologic emergencies.

Have you seen these or other oncologic emergencies in your setting?