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Clinical Pearls & Morning Reports

Posted by Carla Rothaus, MD

Published November 29, 2023

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What factors increase the risk of infection in a patient with sickle cell disease, apart from hyposplenism and functional asplenia?

An important challenge faced by both patients with sickle cell disease and the providers caring for them is determining whether a patient’s pain is the result of an uncomplicated painful vaso-occlusive event or a symptom of another complication associated with sickle cell disease. Read the NEJM Case Records of the Massachusetts General Hospital here.

Clinical Pearls

Q: How common is osteonecrosis among patients with sickle cell disease?

A: Osteonecrosis, which results from infarction of the bone trabeculae and marrow cells, can lead to focal severe pain that often does not resolve as quickly as the systemic pain associated with vaso-occlusive events. Among patients with sickle cell disease, the lifetime risk of osteonecrosis is 30 to 50%, and recurrent or untreated osteonecrosis can give rise to fractures, joint collapse, and osteomyelitis. Older age, male sex, a high BMI, leukopenia, frequent vaso-occlusive events, a history of acute chest syndrome, and hemoglobin SS disease with concurrent α-thalassemia trait have all been associated with an increased risk of osteonecrosis.

Q: What factors increase the risk of infection in a patient with sickle cell disease, apart from hyposplenism and functional asplenia?

A: Sickle cell disease is also associated with irregular IgG and IgM antibody responses, defects in the alternative complement pathway, a reduction in circulating CD4+ and CD8+ T cells, and aberrant activation of regulatory T cells, all of which are thought to contribute to increased morbidity and mortality from infection. The prevalence of osteomyelitis in patients with sickle cell disease is as high as 12%, and the bacteria that most commonly cause osteomyelitis are salmonella species, Staphylococcus aureus, and gram-negative enteric bacilli.

Morning Report Questions

Q: What are some of the causes of acute chest syndrome?

A: Among patients with sickle cell disease, the lifetime risk of acute chest syndrome is 30 to 50%; it is the second most common cause of hospitalization and a leading cause of death in patients with sickle cell disease. Clinically defined as the presence of a new infiltrate on chest imaging with accompanying pulmonary symptoms and fever in a patient with underlying sickle cell disease, acute chest syndrome can be caused by pneumonia, infarction from in situ thrombosis, or fat embolization from bone marrow infarction. It is important to note that acute chest syndrome can often occur in the context of a painful vaso-occlusive event, and patients sometimes report pain that is worse than their typical pain. Given the high mortality associated with acute chest syndrome, it is always an important consideration in a patient with sickle cell disease who describes atypical pain.

Q: Is Campylobacter fetus frequently isolated in patients with acute enteritis?

A: The primary reservoir of C. fetus is the gastrointestinal tract of cattle and sheep, and the organism spreads to humans through contaminated food and water. Although C. fetus is infrequently isolated in patients with acute enteritis, it is the campylobacter species most commonly associated with bacteremia and invasive disease, which can lead to endocarditis, pericarditis, osteomyelitis and spondylodiscitis, cellulitis, and other end-organ complications. Invasive infection occurs primarily in immunocompromised hosts.

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