A 14-year-old boy presents to the emergency department by ambulance complaining of significant chest pain. He reports that the pain started suddenly one hour ago and is exacerbated by taking deep breaths. He describes it as a diffuse ache throughout is chest and rates it an 8/10 in severity. He has a history of sickle cell disease and describes a long history of transient joint pains, usually in his fingers. He is unsure of his immunization status. Vital signs are temperature 38.6°C (101.5°F), blood pressure 140/90 mm Hg, heart rate 120 beats/minutes, and respirations 24/minute. Physical examination reveals conjunctival pallor, tachycardia with normal heart sounds, and wheezes in the posterior right chest. A chest x-ray reveals consolidation in the right lower lobe.
This patient has a higher susceptibility to infection with which of the following pathogens?
- A) Acid-fast rods
- B) Gram-negative, comma-shaped bacilli
- C) Gram-negative diplococci
- D) Gram-positive, catalase-positive cocci
- E) Gram-positive, obligate anaerobic bacilli
C) Gram-negative diplococci
This is a presentation of acute chest syndrome in a patient with sickle cell disease. The presence of acute onset chest pain, fever, wheezes, and consolidation on x-ray are suggestive of acute chest syndrome, a feared complication of sickle cell disease caused by vaso-occlusion of sickling red cells. Patients with sickle cell disease become functionally asplenic in early childhood. Individuals with functional or anatomic asplenia are at higher risk of infection by encapsulated bacteria because they do not possess a spleen capable of clearing encapsulated bacteria from their bloodstream.
Answer choice A: Acid-fast rods, is incorrect. This describes mycobacteria, which are not encapsulated organisms.
Answer choice B: Gram-negative, comma-shaped bacilli, is incorrect. This describes campylobacter, which is not an encapsulated organism.
Answer choice D: Gram-positive, catalase-positive cocci, is incorrect. This describes staphylococcal species, which are not encapsulated.
Answer choice E: Gram-positive, obligate anaerobic bacilli, is incorrect. This describes clostridia species, which are not encapsulated.
Key Learning Point
Patients with sickle cell disease become functionally apslenic in early childhood, making them more susceptible to serious infection by encapsulated bacteria.