A 65-year-old man is brought to the emergency department due to high fevers and confusion. He has had 2 days of cough productive of greenish sputum. He has a history of well-controlled type 2 diabetes mellitus and was treated for bronchitis twice in the last 4 months. The patient received the influenza vaccine this year. He has smoked a pack of cigarettes daily for the past 27 years and drinks alcohol occasionally. Temperature is 38.4 C (101.2 F), blood pressure is 118/74 mm Hg, pulse is 98/min, and respirations are 24/min. His pulse oximetry reading is 92% on room air. The patient is obese. His anterior cervical lymph nodes are enlarged and nonpainful. His lungs are clear to auscultation except for scattered rales at the right lung base. Abdominal examination reveals a palpable liver edge and spleen tip. Chest-x ray shows a developing right lower lobe infiltrate. Laboratory studies are as follows: Blood cultures are sent to the laboratory; antibiotics and supportive care are initiated. What is the best next step in management of this patient?

Question

A 65-year-old man is brought to the emergency department due to high fevers and confusion.  He has had 2 days of cough productive of greenish sputum.  He has a history of well-controlled type 2 diabetes mellitus and was treated for bronchitis twice in the last 4 months.  The patient received the influenza vaccine this year.  He has smoked a pack of cigarettes daily for the past 27 years and drinks alcohol occasionally.  Temperature is 38.4 C (101.2 F), blood pressure is 118/74 mm Hg, pulse is 98/min, and respirations are 24/min.  His pulse oximetry reading is 92% on room air.  The patient is obese.  His anterior cervical lymph nodes are enlarged and nonpainful.  His lungs are clear to auscultation except for scattered rales at the right lung base.  Abdominal examination reveals a palpable liver edge and spleen tip.  Chest-x ray shows a developing right lower lobe infiltrate.  Laboratory studies are as follows:  Blood cultures are sent to the laboratory; antibiotics and supportive care are initiated.  What is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d411_195d_bc81_1babcaaca3da_MD0003_00 This patient with a fever, productive cough, and right lower lobe infiltrate likely has bacterial pneumonia. Most bacterial infections cause a mild to moderate leukocytosis with a predominance of neutrophils. This patient's complete blood count demonstrates a dramatic leukocytosis, primarily with lymphocytes. In an elderly patient, severe lymphocytosis combined with hepatosplenomegaly, lymphadenopathy, and bicytopenia (anemia, thrombocytopenia) strongly suggests underlying chronic lymphocytic leukemia (CLL). Although patients with CLL have high white blood cell counts, their immune systems are abnormal; hypogammaglobulinemia and defects in cell signaling increase the risk and severity of infections (a major complication of CLL). CLL is diagnosed by flow cytometry (showing a clonality of mature B cells). (Choice A) Bronchoscopy with biopsy is sometimes used to determine the pathology of a lung mass, but it does not play a role in the diagnosis of CLL. This patient's lung infiltrate is likely pneumonia; bronchoscopy is not indicated at this time. (Choice B) Epstein-Barr virus serology can be used to diagnose infectious mononucleosis (IM). IM typically affects young adults and presents with fever, lymphadenopathy, malaise, and pharyngitis. Although splenomegaly, lymphadenopathy, and lymphocytosis can occur with IM, leukocytosis is generally mild (12,000-18,000/mm³) and cytopenias are rare. (Choice D) The JAK2 mutation is associated with myeloproliferative diseases, particularly polycythemia vera (PV). PV can lead to splenomegaly but usually causes an elevated hematocrit (>50%), thrombocytosis, and thrombotic complications. (Choice E) Lymph node (LN) biopsy is not generally needed to diagnose CLL. Flow cytometry is the test of choice. LN biopsy is useful in diagnosing some lymphomas (eg, Hodgkin lymphoma, non-Hodgkin lymphoma). (Choice F) Serum protein electrophoresis can detect elevated levels of monoclonal proteins. It is typically used to diagnose multiple myeloma (MM). MM often presents with anemia and bone pain; peripheral smear shows rouleaux formation (red blood cells that appear stacked) and leukopenia. This patient has dramatic leukocytosis. Educational objective: Infections are a common complication of chronic lymphocytic leukemia (CLL). CLL is diagnosed by flow cytometry (clonality of mature B cells).

A 65-Year-Old Man Is Brought to the Emergency Department Due