A case of acute chest syndrome complicated by diffuse cerebral infarcts in an adult with <scp>H</scp>b<scp>S</scp>β‐thalassemia<sup>+</sup>
Authors: Rehka Chandran, Amy Moran, Mark Barash, Brian Hopper, Amy Rankin, Joshua J. Field
Journal: American Journal of Hematology (2015)

To the Editor:Neurological events are a known complication of acute chest syndrome (ACS) episodes in adults with sickle cell disease (SCD) 1. Mental status changes and seizures account for most neurological events, whereas cerebrovascular accidents (CVA) complicate only about 1% of ACS episodes. The objective of this case study is to examine the course of an adult with HbSβ-thalassemia+ who developed severe ACS and diffuse cerebral infarcts after an admission for vaso-occlusive crisis (VOC). A 27 year-old female with HbSβ-thalassemia+, whose past history was only notable for osteonecrosis of the shoulders and hips, was admitted to the hospital for VOC. On admission, she was alert and oriented, with an unremarkable physical exam and normal vital signs. Intravenous fentanyl was started for pain management and, for the first 48 hours of the admission, the patient's clinical status remained stable. On hospital day 2, however, she abruptly developed a change in mental status, which was accompanied by respiratory failure with evidence of bilateral infiltrates on chest radiograph. She required intubation and underwent emergent exchange transfusion for ACS. Following exchange transfusion, her oxygenation gradually improved and, by hospital day 4, she was weaned off sedation in preparation for extubation. However, more than 24 hours after sedation was discontinued, she had not regained consciousness. Extensor plantar response (Babinski sign) was noted on exam, consistent with upper motor neuron damage which, along with poor mental status, prompted magnetic resonance imaging (MRI), and an electroencephalogram (EEG). MRI revealed diffuse supra- and infra-tentorial micro-infarcts and micro-hemorrhage (Fig. 1); EEG showed nonconvulsive status epilepticus. Seizure activity was successfully treated with antiepileptics, but unfortunately, her mentation did not improve. She remained minimally responsive until she was transferred to a long-term care facility on hospital day 20. MRI of the brain in a 29 year-old woman with poor mentation after an ACS episode. A. Diffusion-weighted images show areas of hyper-intensity consistent with acute infarct. B. Susceptibility-weighted images show micro-hemorrhages in the areas of end arterioles consistent with the infarcted tissue. The neurological insult in the present case was unusually severe. In the midst of an ACS episode, widespread cerebral microinfarcts devastated a woman who previously had few problems related to SCD. The sudden onset of her symptoms suggests fat emboli as the most likely cause of ACS and CVA. Fat emboli complicate VOC and can lead to severe ACS episodes, often with neurological complications 1. Twenty-two percent of ACS episodes in adults with SCD are associated with neurological findings 1. In the vast majority of these cases, however, neurological signs and symptoms resolve as the ACS episode is treated and improves. Because these events may have under-appreciated effects on long-term cognition, a formal cognitive assessment is warranted, especially after severe ACS episodes 2. More instructive than the severity of the case is that it occurred in a woman with a milder form of SCD. Descriptions of CVA complicating ACS events have largely been in patients with HbSS, likely, because neither ACS nor CVA are common in patients with HbSβ-thalassemia+ 3, 4. The incidence of ACS and CVA is more than 3-fold lower for patients with HbSβ-thalassemia+ compared to those with HbSS 3, 4. Even though severe complications occur less often in patients with milder phenotypes, they still happen. And when they do, prompt recognition and treatment with exchange transfusion is needed to reduce the chance of poor outcomes. Rekha Chandran,1,2 Amy Moran,1,2 Mark Barash,1,2 Brian Hopper,1,2 Amy Rankin,1,2 and Joshua J. Field1,2* 1Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin; 2Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin