Pulmonary complications of sickle cell disease.
The purpose of this symposium is to update pediatricians and family practitioners
on the most current research and clinical guidelines related to pediatric sickle cell
disease, particularly in the school-aged child, and to discuss key considerations
when caring for these patients.
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Patients with sickle cell disease (SCD) suffer from intense pain that can start during infancy and increase in severity throughout life, leading to hospitalization and poor quality of life. A unique feature of SCD is vaso-occlusive crises (VOCs) characterized by episodic, recurrent, and unpredictable episodes of acute pain. Microvascular obstruction during a VOC leads to impaired oxygen supply to the periphery and ischemia reperfusion injury, inflammation, oxidative stress, and endothelial dysfunction, all of which may perpetuate a noxious microenvironment leading to pain. In addition to episodic acute pain, patients with SCD also report chronic pain. Current treatment of moderate to severe pain in SCD is mostly reliant upon opioids; however, long-term use of opioids is associated with multiple side effects. This review presents up-to-date developments in our understanding of the pathobiology of pain in SCD. To help focus future research efforts, major gaps in knowledge are identified regarding how sickle pathobiology evokes pain, pathways specific to chronic and acute sickle pain, perception-based targets of "top-down" mechanisms originating from the brain and neuromodulation, and how pain affects the sickle microenvironment and pathophysiology. This review also describes mechanism-based targets that may help develop novel therapeutic and/or preventive strategies to ameliorate pain in SCD.
The mechanism by which hydroxyurea reduced the frequency of vaso-occlusive crises is unclear. The proportion of F cells rose between 8 and 24 weeks ( and ), and changes in the mean corpuscular volume also occurred at this time. Since the results in the hydroxyurea and placebo groups began to diverge at about eight weeks ( and ), it is possible that the increase in fetal hemoglobin is only one way in which hydroxyurea can affect sickle cell anemia. The increase in mean corpuscular volume during hydroxyurea treatment is primarily due to an increase in the hemoglobin content of the cells, but it may also reflect altered properties of red-cell membranes. Other explanations of the antisickling effect of hydroxyurea are increased water content of red cells, with secondarily increased deformability, and decreased adhesion of red cells to endothelium.
Pneumonia and pulmonary infarction in sickle cell anemia.
Acute chest syndrome (ACS) is a common and serious lung complication in sickle cell disease. A retrospective medical chart review was performed over a 6-year period in all pediatric ACS patients to investigate whether factors during the initial hospitalization were associated with recurrent ACS episodes. There were 386 episodes of ACS: 149 had only 1 episode of ACS, and 76 had >1 episode of ACS; 172 (76.4%) had hemoglobin SS, and 39 (17.3%) had hemoglobin SC. The most common presenting features were fever (83%), pain (70%), and cough (61%), which changed with the number of ACS episodes. Children
Acute chest syndrome in sickle-cell disease.
Hydroxyurea is the first clinically acceptable drug shown to prevent painful crises in adults with sickle cell anemia; it has no role in the treatment of crises in progress. It is not approved by the Food and Drug Administration for the prevention of crises, and short-term and long-term use of this drug is potentially dangerous. Our data support the use of hydroxyurea therapy for the prevention of painful crises in adult patients who are able to follow directions about dosages and monitoring and can appreciate the still unclear long-term risks of such treatment.
Liver involvement in sickle cell disease.
In 12 patients who did not receive transfusions (11 in the hydroxyurea group), hemoglobin levels repeatedly exceeded 12.8 g per deciliter, a potentially adverse effect because of increased blood viscosity (if fetal hemoglobin levels in red cells were not high enough to inhibit sickling in vivo). Four patients assigned to hydroxyurea and five patients assigned to placebo had platelet counts of more than 800,000 per cubic millimeter. In no case was morbidity associated with a high hemoglobin concentration or platelet count.
ASH Sickle Cell Disease Initiative Website at
Community health workers can assist individuals with sickle cell disease in a variety of ways. They may be asked to help identity and overcome barriers to care, such as transportation or childcare, navigate the healthcare system, assist with obtaining health insurance, conduct health education, reinforce healthy behaviors, or assist clients with other needs, as they arise.