Leukemoid reaction



Leukemoid reaction



Leukemoid reaction


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USMLE® Step 1 questions

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Leukemoid reaction

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USMLE® Step 1 style questions USMLE

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A 47-year-old man comes to the office due to 2 days of sore throat, purulent nasal discharge and facial pain. Past medical history is significant for several sinus infections over the past 6 months, all of which resolved with oral antibiotics. Temperature is 38.5°C (101.4°F), pulse is 80/minute, respirations are 19/minute, and blood pressure is 130/70 mmHg. Physical examination shows pharyngeal erythema and maxillary sinus tenderness. There is no lymphadenopathy. Laboratory results are as follows:    
Laboratory value  Result
Complete blood count 
Hemoglobin   10 g/dL 
 Platelets   600,000/mm3 
 Leukocytes   100,100/mm3 
 Neutrophils  40% 
 Myelocytes  32% 
 Metamyelocytes  10% 
 Band forms  1% 
 Blast cells  1% 
 Lymphocytes  7% 
Fluorescence in situ hybridization (FISH) analysis reveals a bcr-abl fusion gene. Which of the following additional findings is most likely to be seen in this patient?

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Leukemoid reaction p. 211

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Leukemoid reaction refers to an increase in white blood cell count, specifically above 50,000 cells/mm �, due to causes other than leukemia. Leukemoid reactions can occur as a response to stress or infection, and can mimic symptoms of leukemia, such as fatigue, weight loss, and bruising. Distinction between the two needs lab tests, which show elevated neutrophils (suggestive of an acute inflammatory process) in case of leukemoid reaction, and the absence of dysplastic cells (seen in leukemia).


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