Weakness, DOE, and WBC > 100K: What's Your Diagnosis?

A 75-year-old man with a past medical history of hypertension presents to the emergency department complaining of 2 weeks of gradually worsening generalized weakness and dyspnea on exertion. He denies any cough, fever, chest pain, or other complaints.

Examination: Vital signs: BP: 112/73 mm Hg, HR: 118 beats/min, RR: 28 breaths/min; O₂ Sat 98% on room air.

Other than tachycardia and tachypnea, the remainder of the physical examination was essentially normal.

Testing:

Chest X-ray: Mild pulmonary vascular congestion.

CBC: WBC 192,000 with 7% blasts, hemoglobin 8.8, platelets 90

Chemistry: K 5.8, Na 128, Cr 2.6, Phos 5.7, Uric acid 19.7, Lactic acid 13.5

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Questions:1. What is the most likely diagnosis? Is more than one diagnosis likely?

2. What should you do to properly manage this patient?  

3. What is this patient's prognosis?

Please click here for answer and discussion.

Answers:

1. This patient has acute leukemia with blast crisis, tumor lysis syndrome, and probable leukostasis.

2. He should be admitted with STAT renal and hematology/oncology consultations and q 4 hour CBC and chemistry labs. He should be emergently treated with high-dose hydroxyurea, rasburicase (due to the uric acid >10), allopuirnol and aggressive IV fluids.

3. His prognosis is poor.
 

Discussion

Acute leukemia is caused by a malignant leukocyte clone that overproduces non-functioning white blood cells and takes over the bone marrow, leading to underproduction of normal blood cells. Presentation varies but is often the result of anemia, low platelets, or immune suppression. In acute leukemic blast crisis, the WBC count is often >100,000, a condition that is often rapidly fatal even with proper treatment, which includes hydroxyurea, aggressive IV fluids, and cytapheresis. For additional details, see the Table 1, below.

Complications of acute leukemia include tumor lysis syndrome (TLS) and leukostasis. TLS is caused by rapid turnover of the malignant WBCs, a result of their absolute numbers and short life span. Chemotherapy can trigger or worsen TLS. TLS causes elevated levels of potassium, phosphorus, uric acid, and LDH and can lead to renal failure. Treatment is with IV fluids, allopurinol, and rasburicase. See Table 2, below, for more details.

Leukostasis from elevated leukocyte levels often presents with dyspnea and/or confusion secondary to vascular occlusion in the lungs and/or brain caused by the elevated WBC levels. This patient’s initial symptoms were likely from leukostasis. See Table 1 for details.

The patient was admitted and treated as above. Soon after admission he became more tachycardic then hypoxic and within 8 hours had a cardiac arrest. He was given additional treatment for hyperkalemia with D50, insulin, bicarb and calcium but resuscitative efforts were unsuccessful.

Excerpt on LEUKEMIA & CANCER COMPLICATIONS from The Emergency Medicine 1-Minute Consult Pocketbook

Hematology & Oncology

Table 1. Oncology: Hematologic Malignancies

Leukemia

Malignant clone that overproduces nonfunctional WBCs, harms normal marrow function

      ALL/AML

Bone pain, pallor, LAN, HSM, easy bruising, bleed, fever/infection, angina, CHF

Labs

WBC often >100k, anemia, ↓platelets. If tumor lysis:  ↑↑LDH, ↑uric, ↑Cr, ↑K, ↑phos, ↓Ca

Crisis

Blast crisis often rapidly fatal via leukostasis, tumor lysis and/or infection

Rx

Cytapheresis & high-dose hydroxyurea, aggressive IVF, allopurinol +/- rasburicacse, (ABX)

Table 2. Oncology: Complications

Leukostasis

WBC usually >100K, unlikely if mostly lymphocyte: block vessels in lungs>heart & brain

Clinical

SOB, drowsy, CNS, MI, death

Treatment

CNS radiation therapy, leukopheresis + Cytoxan or hydroxurea. Avoid transfusion initially

Tumor Lysis Syndrome

Usually from lymphoma or acute leukemia, often after Rx started

Lab

↑↑WBC, ↑uric acid, ↑K, ↑phos, ↑↑LDH, ↓Ca, renal failure

Treatment

NS or DW5 w/ bicarb as 2x maintenance, allopurinol, rasburicase

For more information, click on image.

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