A 76-year-old man comes to the office due to worsening shortness of breath over the past 10 days. He has had a nonproductive cough for several months. The patient appears ill. Neck veins are nondistended. There is decreased chest expansion on the right side. Auscultation reveals decreased breath sounds over the right lung base. Chest imaging reveals loculated pleural fluid on the right side. Thoracentesis is performed. Laboratory analysis reveals the following: Blood cell counts were normal a month ago at the time of hospital discharge. Which of the following is the most likely underlying cause of this patient's increased platelet count?

Question

A 76-year-old man comes to the office due to worsening shortness of breath over the past 10 days. He has had a nonproductive cough for several months. The patient appears ill.  Neck veins are nondistended.  There is decreased chest expansion on the right side.  Auscultation reveals decreased breath sounds over the right lung base. Chest imaging reveals loculated pleural fluid on the right side.  Thoracentesis is performed.  Laboratory analysis reveals the following:  Blood cell counts were normal a month ago at the time of hospital discharge.  Which of the following is the most likely underlying cause of this patient's increased platelet count?

Quizplus · Accepted Answer

Eductional Objective: Reactive thrombocytosis is the most common cause of elevated platelet count in all age groups.  It is generally caused by high levels of inflammatory cytokines (eg, IL-6), which prompt the liver to release thrombopoietin.  Reactive thrombocytosis is seen in chronic infection, rheumatologic disease, and burns; it can also occur with hemolysis and iron deficiency anemia.

A 76-Year-Old Man Comes to the Office Due to Worsening