Oncologic Emergencies (Case 36: A Problem Set of Three Common Cases)

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Oncologic Emergencies (Case 36: A Problem Set of Three Common Cases)

Minal Dhamankar MD and Zonera Ali MD

Case 1: A 77-year-old man with history of CLL presents with severe fatigue, nausea, and mild abdominal discomfort. He is found to have an elevated white count, splenomegaly, and bulky lymphadenopathy. He is admitted and started on chemotherapy. His basic metabolic panel is as follows: potassium 6.8 mEq/L, calcium 8.1 mg/dL, phosphate 7.0 mg/dL, LDH 28,900 U/L, uric acid 14.3 mg/dL, and creatinine 2.6 mg/dL (baseline creatinine before treatment was 1.0 mg/dL).

Differential Diagnosis

Renal Failure in Cancer Patients

Tumor lysis syndrome (TLS)

Infiltration of kidneys by the underlying neoplastic process

Renal failure secondary to nephrotoxic chemotherapeutic agents

Prerenal azotemia from volume depletion

Ureteral obstruction due to adenopathy

Case 2: A 56-year-old man with history of osteoarthritis presents with a 1-month history of back pain that radiates down his legs. Pain wakes him at night and is more severe with recumbency. On physical exam, there is point tenderness at the level of the first lumbar vertebra, but range of motion is normal. The straight leg–raising test on the right side is positive. A radiograph of his lumbar spine reveals age-related degenerative changes. He receives a presumptive diagnosis of lumbosacral strain and is advised to take NSAIDs. A month later, he wakes up with leg weakness. Clinical exam reveals bilateral leg weakness, an enlarged, nodular prostate, and a PSA of 45 ng/mL.

Differential Diagnosis

Low Back Pain and Leg Weakness in a Cancer Patient

Brain metastasis

Asthenia

Lambert-Eaton myasthenic syndrome

Spinal cord compression (SCC)

Case 3: A 55-year-old man with a history of acute myelogenous leukemia (AML) presents for a scheduled routine red blood cell (RBC) transfusion and reports fatigue. He is also receiving outpatient chemotherapy via a peripherally inserted central venous catheter (PICC). His temperature is 101°F, and blood pressure is 82/58 mm Hg with orthostatic changes. He is given 1 L of IV fluids and has routine laboratory samples drawn as he is transferred to the hospital. Upon admission, he is having rigors. His lab work shows a white blood cell count of 200 cells/µL and an absolute neutrophil count of 60 cells/µL.

Differential Diagnosis

Fever in a Cancer Patient

Tumor fever

Neutropenic fever

Transfusion reaction

Catheter-related sepsis

Drug fever

 

Speaking Intelligently

Patients with cancer are subject to developing a unique set of complications that require emergent evaluation and treatment. These oncologic emergencies can be broadly classified as those resulting from the disease itself and those resulting from therapy directed against the cancer; however, they can also be classified according to organ systems to facilitate recognition and management as follows (selected emergencies are discussed in more detail in the Clinical Entities section).

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PATIENT CARE

Clinical Thinking

• Oncologic emergencies may manifest over hours, causing devastating outcomes such as paralysis and death, while some are insidious and may take months to develop.

• Various clinical symptoms often are evident before an emergency occurs; therefore, a patient-focused approach that includes education and cancer-specific monitoring is needed.

• Ability to recognize these conditions, a focused initial evaluation, and institution of appropriate therapy can be lifesaving and may spare patients considerable morbidity.

• The approach to definitive therapy is commonly multidisciplinary, involving surgeons, radiation oncologists, medical oncologists, and other medical specialists.

History

• In patients with TLS, symptoms largely reflect the underlying metabolic derangements, including nausea, vomiting, diarrhea, anorexia, lethargy, and fatigue. Urine output may decrease, and the patient may manifest symptoms of uremia or volume overload. Hypocalcemic tetany and seizures can occur. Muscular symptoms may include muscle weakness, cramps, and parasthesias. Life-threatening arrhythmias in the form of ventricular tachycardia or fibrillation can lead to syncope and sudden death.

• New back pain that is not responding to routine pain medication, worsens when the patient lies down, or is associated with the development of leg weakness, urinary incontinence, and loss of sensory function warrants consideration of epidural SCC.

• Fever can be the only symptom in patients with neutropenic fever. A focused history to identify any localizing symptoms should be obtained. Presence of rigors is usually indicative of bacteremia. Diarrhea is usually associated with a gastrointestinal source, and persistent headaches might prompt a workup to rule out meningitis. It is important to know when the patient received his last chemotherapy, as the neutrophil nadir typically occurs 5 to 10 days after the last dose. Usually, white blood cell recovery occurs within 5 days of this nadir.

Physical Examination

• In TLS, physical exam may reveal signs of renal failure and acidosis. In cases of severe renal failure, there may be signs of fluid overload secondary to aggressive hydration in the setting of oliguria/anuria.

• In patients presenting with epidural SCC, symmetrical motor weakness is typical. If the lesion is at or above the conus medullaris, extensors of the upper extremities are affected. Lesions above the thoracic spine cause weakness from corticospinal dysfunction and affect flexors in the lower extremities. Patients may be hyperreflexic below the lesion and have extensor plantar responses. There may be absent sensation below the level of spinal cord involvement.

• In patients with neutropenic fever, the oral cavity should be examined carefully, looking for erythema and mucosal ulcers. All sites of IV catheters and tunneled catheters should be inspected, looking for erythema, tenderness, and purulent exudates. The perianal area should be inspected and palpated gently.

Tests for Consideration

Laboratory studies include:

CBC with differential count: Neutropenia is usually defined as an absolute neutrophil count (ANC) of less than 500 cells/µL or less than 1000 cells/µL with a predicted nadir of less than 500 cells/µL.

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Basic metabolic profile: Tumor lysis syndrome leads to a large number of metabolic derangements.

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Serum uric acid levels: Large amounts of uric acid are released when tumor cells lyse and should be closely monitored whenever there is a high suspicion of TLS.

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Microbiologic evaluation: Blood cultures should be obtained as soon as possible. Urine should be collected for culture, and sputum should be sent for cultures if there is a productive cough. Stool and cerebrospinal fluid should be collected and cultured, if there is clinical suspicion of infections of these sites.

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IMAGING CONSIDERATIONS

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→ Plain radiographs: Chest radiographs should be obtained but are commonly normal or show nonspecific findings in patients with neutropenic fever. In patients with back pain where there is a concern for epidural SCC, radiographs of the spine are simple and inexpensive but have high false negative rates.

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→ CT scan: High-resolution CT may be helpful in febrile neutropenic patients with suspected lung infection and a normal chest radiograph. The role of CT scan in diagnosing epidural SCC is limited, as focused CT imaging can miss clinically inapparent lesions; CT myelography is useful but involves a lumbar puncture and hence is contraindicated in patients with brain metastases, thrombocytopenia, or coagulopathy.

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