Review Question - QID 212720

This patient’s presentation of acute left-sided abdominal pain, a shrunken spleen on abdominal ultrasound, and a peripheral blood smear featuring Howell Jolly bodies is indicative of autosplenectomy due to sickle cell anemia, which predisposes patients to infection with Streptococcus pneumoniae and other encapsulated organisms.

Patients with chronic sickle cell disease commonly experience autosplenectomy, in which the spleen undergoes fibrosis and shrinkage. Splenic dysfunction results in decreased complement activation and thus decreased opsonizing ability, thereby increasing the susceptibility to infections with encapsulated organisms. Sickle cell patients with functional asplenia are especially predisposed to infection with Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis.

Figure A shows a peripheral blood smear featuring Howell-Jolly bodies, left-over nuclear remnants that are normally removed in the spleen.

Incorrect Answers:
Answer 1: Staphylococcus aureus is a Gram-positive, catalase-positive, coagulase-positive bacteria; it is not an encapsulated organism.

Answer 2: Staphylococcus epidermidis is a Gram-positive, catalase-positive, coagulase-negative bacteria; it is not an encapsulated organism.

Answer 3: Staphylococcus saprophyticus is a Gram-positive, catalase-positive, coagulase-negative bacteria; it is not an encapsulated organism.

Answer 5: Streptococcus viridans is a Gram-positive, alpha-hemolytic bacteria; it is not an encapsulated organism.

Bullet Summary:
Sickle cell anemia patients are highly susceptible to infection from Streptococcus pneumoniae due to functional asplenia.