A 66-year-old woman comes to the office due to 2 days of increasing productive cough and low-grade fever. She was treated for community-acquired pneumonia 4 months ago and sinusitis 2 months ago. Her review of systems is positive for fatigue, generalized weakness, and right-sided chest pain. The patient is otherwise healthy and takes no medications. She has never smoked cigarettes and drinks alcohol only on rare social occasions. Temperature is 38.4 C (101.2 F), blood pressure is 126/72 mm Hg, pulse is 98/min, and respirations are 16/min. Pulse oximetry is 96%. She is well-appearing. There is mucosal pallor. There is no lymphadenopathy in her cervical or supraclavicular chains. Bronchial breath sounds and crackles are present in the left lower lung field. There is point tenderness over the right seventh and eighth ribs at the midclavicular line. The abdomen is soft with no hepatosplenomegaly. Laboratory results are as follows: Chest x-rays shows consolidation in the left lower lung and right-sided osteolytic lesions with fractures at the seventh and eighth ribs. This patient is at increased risk for recurrent infections due to which of the following abnormalities?

Question

A 66-year-old woman comes to the office due to 2 days of increasing productive cough and low-grade fever.  She was treated for community-acquired pneumonia 4 months ago and sinusitis 2 months ago.  Her review of systems is positive for fatigue, generalized weakness, and right-sided chest pain.  The patient is otherwise healthy and takes no medications.  She has never smoked cigarettes and drinks alcohol only on rare social occasions.  Temperature is 38.4 C (101.2 F), blood pressure is 126/72 mm Hg, pulse is 98/min, and respirations are 16/min.  Pulse oximetry is 96%.  She is well-appearing.  There is mucosal pallor.  There is no lymphadenopathy in her cervical or supraclavicular chains.  Bronchial breath sounds and crackles are present in the left lower lung field.  There is point tenderness over the right seventh and eighth ribs at the midclavicular line.  The abdomen is soft with no hepatosplenomegaly.  Laboratory results are as follows:  Chest x-rays shows consolidation in the left lower lung and right-sided osteolytic lesions with fractures at the seventh and eighth ribs.  This patient is at increased risk for recurrent infections due to which of the following abnormalities?

Quizplus · Accepted Answer

11ec25c8_d423_b729_bc81_6d3832cbc49b_MD0003_00 Multiple myeloma (MM) is a monoclonal plasma cell neoplasm. Bone marrow infiltration by neoplastic cells causes osteolytic lesions, fractures, hypercalcemia (from bone destruction), and anemia. In addition, the excessive production of monoclonal protein can clog the renal tubules, resulting in renal insufficiency. Patients with MM are prone to infection. Neoplastic infiltration of the bone marrow alters and impairs the normal lymphocyte population, resulting in ineffective antibody production and hypogammaglobulinemia. Respiratory (eg, streptococcal pneumonia) and urinary tract infections are the most common infections seen in MM. (Choices A and B) The complement system helps form the terminal membrane attack complex. Deficiencies in this system cause problems with the innate immune system, making patients particularly vulnerable to encapsulated bacteria (eg, Neisseria meningitides). These are relatively rare disorders and would not account for this patient's osteolytic lesions and fractures. (Choice C) CD4+ T lymphocytes are destroyed by HIV. HIV increases infection risk but would not account for this patient's osteolytic lesions and pathologic fractures. (Choice D) Defective chemotaxis may contribute to recurrent infections in patients with rare genetic conditions, HIV, and bone marrow transplants. It does not contribute significantly to the predisposition to infection in patients with MM. (Choice F) Defects in phagocytic oxidative metabolism impair the ability of phagocytes to produce reactive oxygen intermediaries that aid in the destruction of pathogens and cancerous cells. This may be seen in chronic granulomatous disease. These defects would not explain this patient's osteolytic lesions and laboratory abnormalities. Educational objective: Patients with multiple myeloma are at increased risk for infection due to bone marrow infiltration by neoplastic cells, which alters the normal leukocyte population and causes hypogammaglobulinemia.

A 66-Year-Old Woman Comes to the Office Due to 2