may demonstrate a spectrum from peaked T waves, PR and QRS prolongation, loss of P-wave and T-wave flattening, and finally a sine wave. Hypocalcemia causes a prolonged QT

 

CHAPTER 70

hypocalcemia. These electrolyte and metabolic disturbances

can progress to clinical toxic effects, including renal insufficiency, cardiac arrhythmias, seizures, and death due to organ

failure. It is most common in cancers with high cell turnover

(leukemia and lymphoma).

One of the most common hematologic emergencies is

neutropenic fever, which is the presence of a fever >38°C

with an absolute neutrophil count of <500/!lL. Febrile neutropenia is a result of bone marrow suppression, a common

side effect of chemotherapy. Patients with neutropenia are

susceptible to life-threatening bacterial infections. Older

age has been shown to be an independent risk factor for the

development of neutropenia and febrile neutropenia. A history of previous chemotherapy-induced neutropenia predicts recurrent neutropenia and neutropenic fever.

CLINICAL PRESENTATION

..... History

Pain is the presenting symptom of spinal cord compression

in 90-95% of patients. The pain is usually constant and

close to the site of the lesion. Patients complain of a band

or girdle of pain/tightness radiating from back to front,

exacerbated by recumbency, movement, coughing and

sneezing. Symptoms may include numbness and tingling,

which usually precedes weakness. Weakness often presents

with "stiffness," dragging of a limb, or unsteadiness.

Facial edema is the most common symptom of SVC

syndrome with patients often describing feeling bloated.

Other symptoms include dyspnea, cough, chest and shoulder pain, and hoarseness. Dyspnea may be worse when

leaning forward or lying down. Arm swelling and lymphedema are other common symptoms of SVC syndrome.

In both acute and chronic hypercalcemia of malignancy, the major manifestations affect gastrointestinal,

renal, and neuromuscular function. Patients with acute

hypercalcemia commonly present with anorexia, nausea,

vomiting, polyuria, polydipsia, dehydration, weakness, and

confusion. Patients with tumor lysis syndrome may have

similar symptoms often related to acute renal failure.

Neutropenic patients, usually on chemotherapy, often

present to the ED with fever and no clear source of infection. Tachycardia and hypotension may accompany fever

and may indicate severe sepsis or septic shock. Weakness

and dehydration are usually present.

..... Physical Examination

Patients with cancer who present to the ED require a thorough physical examination to identify potential life threats

associated with malignancy. Vital signs and general assessment including mental status will often reveal whether an

acute medical emergency such as neutropenic sepsis or

arrhythmia exists. A thorough head-to-toe examination

should follow. Head, eyes, ears, nose, and throat examination should assess for a patent airway, oropharyngeal

infection, facial plethora, and cranial neuropathies. Neck

examination should assess for cervical spine tenderness and

dilated neck veins. Cardiovascular and respiratory exams

should assess breath sounds and cardiac rhythm. Decreased

breath sounds or distant heart sounds may indicate pleural

or pericardia! effusions. Abdominal exam should assess for

masses and possible source of occult infection. Back exam

should assess for any localized tenderness or masses, and

neurologic exam should identify any focal neurologic deficits. Extremities and skin should be assessed for hydration

status and edema, possibly related to acute renal failure.

DIAGNOSTIC STUDIES

..... Electrocardiogram

An electrocardiogram should be performed in all patients

with suspected electrolyte abnormalities. Patients with hypercalcemia may have a shortened QT interval due to the

increased rate of cardiac repolarization. Arrhythmias such as

bradycardia and first -degree atrioventricular b lock may occur.

Tumor lysis syndrome may result in multiple electrolyte

abnormalities that may manifest as arrhythmias. Hyperkalemia

may demonstrate a spectrum from peaked T waves, PR and

QRS prolongation, loss of P-wave and T-wave flattening, and

finally a sine wave. Hypocalcemia causes a prolonged QT

and may result in ventricular arrhythmias.

..... Laboratory

Serum basic metabolic panel (BMP) with calcium, magne ­

sium, and phosphorous should be assessed on all patients

with vague complaints, vomiting, or dehydration. BMP

should also be ordered for those at risk for hypercalcemia

(bony metastasis) and tumor lysis syndrome (recent cancer

treatment). Patients with tumor lysis syndrome present

with acute renal failure in the presence of hyperuricemia

(> 15 mg/dL), hyperphosphatemia (>8 mg/dL), hyperkale ­

mia, and hypocalcemia. A complete blood count should be

obtained on all patients to assess for neutropenia (absolute

neutrophil count <500/!lL), anemia, and thrombocytopenia. The absolute neutrophil count is determined by mul ­

tiplying the total white blood cell count times the

percentage of neutrophils plus bands. Multiple sets of

blood cultures and a urine culture should be collected in

all febrile neutropenic patients in the ED.

..... Imaging

Patients with signs or symptoms suggestive of spinal cord

metastasis should have their spine imaged. Plain radiographs may identify bony metastasis or pathologic fractures

but are not sufficiently sensitive to rule out the presence of

spinal disease. Computed tomography ( CT) scan of the

spine is more sensitive than plain films; however, magnetic

resonance imaging of the spine is the test of choice to

assess for spinal metastasis and cord involvement. Similarly,

chest radiograph may be used as an initial test for patients

with suspected SVC syndrome, but CT chest with contrast

is the test of choice for identification.

ONCOLOGIC EMERGENCIES

MEDICAL DECISION MAKING

Identification of common emergencies associated with

malignant disease is key to the expeditious ED care of the

cancer patient. Patients with acute shortness of breath

should be assessed for malignant pleural or pericardia! effusions or pulmonary embolus. Generalized weakness may be

from dehydration, electrolyte abnormalities associated with

tumor lysis syndrome or renal failure, or an occult infection

owing to immunosuppression from chemotherapy. Brain

or spinal cord metastasis should be considered for any focal

neurologic sign or symptom, and appropriate imaging

should be performed in the ED (Figure 70-1).

TREATMENT

For patients with acute spinal cord compression from spinal

metastasis, IV corticosteroids relieve pain, reduce edema,

and may improve neurologic function. They may also ternporarily prevent the onset of cord ischemia. Radiation

therapy provides more definitive treatment in most patients.

Indications for radiation therapy include known radiosensitive tumor with no spinal instability and palliative therapy

in patients who present with paraplegia.

SVC syndrome is treated in the ED with IV steroids

(dexamethasone 10 mg IV) and furosemide IV in an

attempt to reduce venous pressures. Patients with cardiac

or respiratory compromise or central nervous system

dysfunction may require emergent endotracheal intubation or radiation therapy. Vascular surgery should be consulted for possible SVC stenting.

Hypercalcemia is treated in the ED with IV fluid

administration. Levels > 13 mg/ dL usually require

treatment. An initial bolus of 1-2 L of normal saline (NS)