504	A. Kulkarni and V. Agarwal

•It should be used cautiously in patients with renal impairment. It has many drug interactions and may cause skin hypersensitivity reactions.

•Febuxostat may be used if the patient is hypersensitive to allopurinol.

Step 7: Consider rasburicase (recombinant urate oxidase)

•Urate oxidase—present in most mammals, but not in humans—oxidizes preformed uric acid to allantoin, which is 5 to 10 times more soluble than uric acid in acid urine.

•When exogenous urate oxidase (uricase, rasburicase) is administered, serum and urinary uric acid levels decrease markedly within approximately 4 h.

•This should be used especially if the uric acid level is above 8 mg/dL.

•Uric acid levels should be monitored regularly to adjust dosing.

•Rasburicase degrades uric acid within the blood samples at room temperature, thus interfering with accurate measurement.

•Therefore, samples should immediately be placed on ice until the completion of assay.

Step 8: Treat associated electrolyte disorders

•Hyperkalemia—hemodialysis may be needed if renal insufficiency or volume overload is present.

•Hypocalcemia—if asymptomatic, no therapy is required.

•Hyperphosphatemia—restrict phosphate intake and increase loss with phosphate binders such as aluminum hydroxide or calcium carbonate, sevelamer hydroxide, and lanthanum carbonate.

Step 9: Consider hemodialysis

•This modality should be considered in specific situation such as:

–Volume overload

–Uric acid of more than 10 mg/dL despite rasburicase

–Uncontrolled hyperkalemia and hyperphosphatemia

–Renal failure (Table 63.2)

63.3Superior Vena Cava Syndrome

A 19-year-old patient with lymphoma presented with dyspnea, swelling of the head and the neck, and upper limbs, and distended veins on the neck and the upper chest.

Step 1: Resuscitate

•Compression of the tracheobronchial tree causing airway compromise is an airway emergency, needing intubation (with a small endotracheal tube) and ventilation till definitive treatment (refer to Chap. 78)

Table 63.2 Treatment for tumor lysis syndrome
Intervention	Dosage	Comment
Fluids	3 L/m2/day (200 mL/kg/day if £10 kg)	Exercise caution if congestive heart failure
Allopurinol	Oral dose: 50–100 mg/m2 every 8 h orally (maximum 300 mg/m2/day) or	6-Mercaptopurine, azathioprine, cyclophosphamide,
	10 mg/kg/day divided every 8 h (maximum 800 mg/day)	and methotrexate require dose reduction
	IV: 200–400 mg/m2/day in 1–3 divided doses (maximum 600 mg/day)	Renal impairment—50% dose reduction
		Drug interaction with thiazide diuretics, ampicillin/
		amoxicillin
Rasburicase	IV infusion 0.1–0.2 mg/kg/day in 50 mL normal saline over 30 min, for	Contraindicated in glucose-6-phosphate dehydrogenase
	5 days	deficiency
		Adverse reactions—anaphylaxis, rash, hemolysis, and
		methemoglobinemia
Hyperkalemia	Calcium gluconate: 10 ml of 10% solution or calcium chloride (5–10 ml	ECG monitoring
	of 10% solution) by slow IV infusion for life-threatening arrhythmias
	Albuterol nebulizer	Avoid PR route in neutropenics
	Regular insulin: 0.1 U/kg IV + 25% D (2 mL/kg) IV	Sodium bicarbonate and calcium not to be administered
	Sodium bicarbonate: 1–2 mEq/kg IV, push only if pH <7.2	through the same line
	Sodium polystyrene sulfonate: 1 gm/kg/day in 1–4 doses with 50%
	sorbitol PO/PR
	Dialysis: if severe
Hypocalcemia	Calcium gluconate: 10 ml of 10% solution IV administered slowly or	ECG monitoring
	calcium chloride
Hyperphosphatemia	Hydration	Limit aluminum hydroxide use to 1–2 days to avoid
	Aluminum hydroxide: 50–150 mg/kg/day in divided doses PO or	cumulative aluminum toxicity
	nasogastrically every 6 h
	Dialysis: if severe

emergencies-Onco 63

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506	A. Kulkarni and V. Agarwal

Step 2: Do imaging

•Computed tomography (CT) scan of chest with or without venography is diagnostic

•These patients may not be able to lie supine for CT chest

•They have to be intubated prior to CT or empirical therapy needs to be started

•Upper extremity venogram or duplex ultrasound for patients with a central venous catheter in upper extremity to exclude venous thrombus.

Step 3: Confirm diagnosis

•Obtain biopsies before instituting therapy if diagnosis is uncertain

Proper hemostatic measures should be taken while performing invasive

procedures

Step 4: Chemotherapy and corticosteroids

• These can be used, especially in tumors that are chemosensitive

Step 5: Radiotherapy

•This is a standard treatment modality for sensitive tumors but may take a few weeks to show effect

Step 6: Stenting of the superior vena cava

•It has been shown to be effective and feasible in relieving the symptoms of superior vena cava syndrome

63.4Malignant Spinal Cord Compression

A 68-year-old patient with carcinoma of prostrate developed worsening back pain progressively with radiating pain down the right leg associated with weakness and difficulty in walking and loss of bladder and bowel function.

Step 1: Resuscitate (see Chap. 78)

(a)Pain relief with adequate analgesics is a priority in these patients.

(b)Urgent neurosurgical, radiotherapy, oncology consultation for limb salvage is necessary.

(c)Special precaution needs to be taken while transporting these patients.

Step 2: Do imaging

•In patient with high index of suspicion and symptoms suggestive of metastatic bone disease, magnetic resonance imaging is gold standard for diagnosis.

•Alternative is CT scan of spine.

•It is important to image the entire spine as more than one area of compression may be present.

63 Onco-emergencies	507

Step 3: Start glucocorticoids

(a)Dexamethasone is indicated in patients with motor deficits or radiologic evidence of neural compression.

(b)It is given as an initial intravenous dose of 10–16 mg followed by 4 mg every 4 h.

(c)This is later administered orally and tapered over 10–12 days.

(d)Use proton pump inhibitors or H2 blockers along with high dose of corticosteroids.

Step 4: Consider radiation therapy

•This has been the mainstay of the treatment in patients with and without motor deficit.

•This is usually combined with surgery for spine stabilization.

Step 5: Consider surgery

•It is indicated in most cases, especially in patients with a good performance status. Indications are the following:

–Gross instability of the spine

–Rapidly progressive symptoms

–Progressive symptoms during radiation therapy

–When tissue for diagnosis is needed

–Radioresistant tumors

Step 6: Consider chemohormonal therapy

•Hormonal chemotherapy and zoledronic acid should be considered in sensitive tumors such as prostate cancer, testicular tumor, or lymphoma.

Suggested Reading

1.Coiffier B, Altman A, Pui CH, Younes A, Cairo MS. Guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review. J Clin Oncol. 2008;26:2767–78.

2.Halfdanarson TR, Hogan WJ, Moynihan TJ. Oncologic emergencies: diagnosis and treatment. Mayo Clin Proc. 2006;81(6):835–48. www.mayoclinicproceedings.com.

This review covers the complete spectrum of oncologic emergencies with their etiopathogenesis and initial therapy, a must read for those caring for cancer patients. It does not require subscription.

3.Abrahm JL. Assessment and treatment of patients with malignant spinal cord compression. J Support Oncol. 2004;2:377–401.

A very comprehensive evidence-based review on malignant spinal cord compression.

Part IX

Trauma and Burn

M.C. Mishra and Prasad Rajhans