Pneumonia in a Patient With MF: Clinical Manifestations and Concern for Disease Progression

Diagnosis and Presentation

B.H. is a 73-year-old female with chronic kidney disease, chronic heart failure with preserved ejection fraction, and post-PV myelofibrosis (MF). She was diagnosed with polycythemia vera (PV) in 2000, and in 2016 she had transformation to post-PV myelofibrosis. B.H. has high-risk disease with leukocytosis, peripheral blasts, increased lactate dehydrogenase (LDH), splenomegaly, thrombocytopenia, anemia, and constitutional symptoms. Her next-generation sequencing molecular panel was positive for JAK2, TET2, and SRSF2 mutations on the most recent bone marrow analysis. Due to comorbidities and overall performance status, B.H. is not a transplant candidate.

B.H. was enrolled on a clinical trial in 2019, and since that time she has had fairly stable disease. She presented for semi-urgent evaluation due to new onset of fevers and cough. At the time of presentation, she had temperature of 101°F and was complaining of a productive cough with yellow/green sputum. She was dyspneic with exertion, yet without dyspnea at rest. Walking oxygen saturations remained >90%. Aside from a fever, vital signs remained largely at baseline. Work-up included a complete blood cell count (CBC) with differential, comprehensive metabolic panel (CMP), B-type natriuretic peptide (BNP), lactate, procalcitonin, blood cultures, chest x-ray (CXR), and respiratory viral panel (including COVID-19).

Results

The CBC with differential showed acute increase in leukocytosis from baseline of 60–70,000/μL to 125,000/μL, peripheral blasts 2%. Hemoglobin and platelets were stable and 9.3 g/dL and 43,000 /µL, respectively. CMP was without acute changes, and renal function was at baseline with a glomerular filtration rate (GFR) of 54. Lactate was initially elevated at 4.9, yet improved to 1.6 with 1-liter normal saline bolus. Procalcitonin was not elevated. BNP was minimally elevated, yet not above baseline. Respiratory viral panel was negative for identifiable viruses and 2-view CXR consistent with right lower lobe pneumonia. Blood cultures remained without growth.

Treatment

B.H. was deemed appropriate for outpatient management given her overall clinical stability, lack of hypoxia, and identified etiology for the fever. She started on treatment for pneumonia with Levaquin 750 mg/day with plans for a 7-day course.

Follow-up Assessment

B.H. returned for close monitoring 3 days later, at which time she had significant improvement in her cough and dyspnea. Her fevers had resolved, and she was feeling better overall. Repeat CBC showed a decrease in white blood cells (WBC) from 125,000 to 109,000/µL, with other cell lines remaining stable. Another 4 days later, B.H. returned yet again with continued improvement in symptoms. Her WBC count continued to improve and was back to her baseline of 62,400/µL.

Considerations

The clinical scenario of extreme leukocytosis is encountered from time to time when a patient with myelofibrosis presents with an infection. Disease progression is appropriate when creating a differential; however, the advanced practitioner must also take into consideration the possibility that the underlying infection is responsible for the dramatic increase in WBC count. One must evaluate the entire clinical scenario and assess response to treatment of the infection. In this patient’s case, peripheral blasts remained at baseline and there was no progressive anemia or thrombocytopenia, which would likely be present in the setting of disease progression to blast phase myelofibrosis or acute myeloid leukemia. B.H.’s WBC count responded nicely to the appropriate antibiotic therapy, which was largely reassuring.