Sickle cell disease: Pulmonary management options

High risk and low prevalence diseases: Acute chest syndrome in sickle cell disease

INTRODUCTION

Acute chest syndrome (ACS) in sickle cell disease (SCD) is a serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of ACS in SCD, including diagnosis and management in the emergency department (ED) based on current evidence.

DISCUSSION

ACS is defined by respiratory symptoms and/or fever and a new radiodensity on chest imaging in a patient with SCD. There are a variety of inciting causes, including infectious and non-infectious etiologies. Although ACS is more common in those with homozygous SCD, clinicians should consider ACS in all SCD patients, as ACS is a leading cause of death in SCD. Patients typically present with or develop respiratory symptoms including fever, cough, chest pain, and shortness of breath, which can progress to respiratory failure requiring mechanical ventilation in 20% of adult patients. However, the initial presentation can vary. While the first line imaging modality is classically chest radiograph, lung ultrasound has demonstrated promise. Further imaging to include computed tomography may be necessary. Management focuses on analgesia, oxygen supplementation, incentive spirometry, bronchodilators, rehydration, antibiotics, consideration for transfusion, and specialist consultation. Empiric antibiotics that cover atypical pathogens are necessary along with measures to increase oxygen-carrying capacity in those with hypoxemia such as simple transfusion or exchange transfusion.

CONCLUSIONS

An understanding of ACS can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

A Differential Approach to an Uncommon Case of Acute Anemia in a Child With Sickle Cell Disease

Introduction: Hyperhemolytic crisis is a rare and dangerous complication of sickle cell disease where the hemoglobin level drops rapidly. This can quickly lead to organ failure and death. In the literature, most cases of hyperhemolysis in sickle cell patients followed a red cell transfusion. Case Summary: In this article, we report a case of a 6-year-old African American boy with sickle cell disease who presented with fever, increased work of breathing, and consolidation in the left lower lobe of the lung on chest X-ray. He initially improved with oxygen, fluids, and antibiotics but his hemoglobin acutely dropped from 7.6 to 6 g/dL the next day of admission. He was not previously transfused, and his reticulocyte count remained high. Subsequent transfusion recovered his hemoglobin. Conclusion: This case demonstrates that in the background of the chronic hemolysis of sickle cell disease, an acute anemia should warrant exploration of aplastic crisis (parvovirus infection), immune hemolytic anemia, hepatic sequestration crisis, splenic sequestration crisis, and hyperhemolytic crisis as possible etiologies. Ongoing reticulocytosis and a source of infection may direct suspicion especially toward hyperhemolytic crisis even without preceding red cell transfusion. We propose that the optimum management should include full supportive care (including transfusions if necessary) and treatment of the underlying cause of hemolysis (such as infections or drug exposure).

Asthma Screening in Pediatric Sickle Cell Disease: A Clinic-Based Program Using Questionnaires and Spirometry

A clinician diagnosis of asthma is associated with increased morbidity and mortality in people with sickle cell disease (SCD). We hypothesized that a screening program would help identify children with asthma needing referral to pulmonary clinic. We conducted a single-center project to screen patients with SCD for asthma using a previously validated questionnaire (Breathmobile) and for pulmonary function abnormalities with portable spirometry. Participants with a positive questionnaire and/or abnormal spirometry were referred to pediatric pulmonary clinic. We evaluated clinical associations with abnormal spirometry and questionnaire responses. Of the 157 participants, 58 (37%) had a positive asthma screening questionnaire. Interpretable spirometry was available for 105 (83% of those eligible) and of these, 35 (34%) had abnormal results. The asthma questionnaire was 87.5% sensitive [95% confidence interval (CI) 74.8-95.3] and 85.3% specific (95% CI 77.3-91.4) to detect a clinician diagnosis of asthma. Participants with positive questionnaires were older (mean age 12.2 vs. 9.9 years, P = 0.012). Spirometry identified 16 additional participants who had normal asthma questionnaires. Seventy-four participants (47%) were referred to pediatric pulmonary clinic and 25 (34%) of these participants scheduled clinic appointments; however, only 13 (52%) were evaluated in pulmonary clinic. Clinic-based asthma screening and spirometry frequently identified individuals with asthma and pulmonary function abnormalities. Only 22% of those referred were eventually seen in pulmonary clinic. The impact of improved screening and treatment on the pulmonary morbidity in SCD needs to be defined and is an area for future investigation. In addition, case management or multidisciplinary clinics may enhance future screening programs.

Clinical correlates of acute pulmonary events in children and adolescents with sickle cell disease

OBJECTIVES

We aimed to identify risk factors for acute pulmonary events in children and adolescents in the Pulmonary Hypertension and the Hypoxic Response in SCD (PUSH) study.

METHODS

Patients with hemoglobin SS (n = 376) and other sickle cell genotypes (n = 127) aged 3-20 yrs were studied at four centers in a cross-sectional manner. A subgroup (n = 293) was followed for a median of 21 months (range 9-35).

RESULTS

A patient-reported history of one or more acute pulmonary events, either acute chest syndrome (ACS) or pneumonia, was obtained in 195 hemoglobin SS patients (52%) and 51 patients with other genotypes (40%). By logistic regression, history of acute pulmonary events was independently associated with patient-reported history of asthma (P < 0.0001), older age (P = 0.001), >3 severe pain episodes in the preceding 12 months (P = 0.002), higher tricuspid regurgitation velocity (TRV) (P = 0.028), and higher white blood cell (WBC) count (P = 0.043) among hemoglobin SS patients. History of acute pulmonary events was associated with >3 severe pain episodes (P = 0.009) among patients with other genotypes. During follow-up, 43 patients (15%) had at least one new ACS episode including 11 without a baseline history of acute pulmonary events. History of acute pulmonary events (odds ratio 5.0; P < 0.0001) and younger age (odds ratio 0.9; P = 0.007) were independently associated with developing a new episode during follow-up.

CONCLUSIONS

Asthma history, frequent pain, and higher values for TRV and WBC count were independently associated with history of acute pulmonary events in hemoglobin SS patients and frequent pain was associated in those with other genotypes. Measures to reduce pain episodes and control asthma may help to decrease the incidence of acute pulmonary events in SCD.

Acute chest syndrome: sickle cell disease

Acute chest syndrome (ACS) is a common complication and reason for hospital admission in patients with sickle cell disease (SCD). It is also the most common cause of death in this patient population. Most of the time, the trigger for ACS in an individual patient cannot be identified. However, although infection is the most common identifiable cause for ACS, other important triggers are vaso-occlusive crisis (VOC) and asthma. This comprehensive review will focus on the pathogenesis, clinical characteristics, complications and treatment available to manage ACS. But importantly, this review will highlight new possible etiologies, with the goal of improving oxygenation and, therefore, a reduction in sickling and lung damage in this patient population.

Asthma and chronic sickle cell lung disease: a dynamic relationship

Chronic lung disease is a significant source of morbidity and mortality in patients with sickle cell disease. Asthma and sickle cell lung disease share many of the same clinical features and pathophysiological mechanisms. Though there is growing evidence of an association between sickle cell disease and airway hyper-reactivity, there is still no consensus on the definition of asthma in sickle cell lung disease. This review will explore what we know about asthma and airway hyper-reactivity in sickle cell disease and whether currently available asthma therapies may be beneficial in delaying or averting the progression of sickle cell lung disease.

Improving care for children with sickle cell disease/acute chest syndrome

BACKGROUND

Acute chest syndrome (ACS) is a leading cause of hospitalization and death of children with sickle cell disease (SCD). An evidence-based ACS/SCD guideline was established to standardize care throughout the institution in February 2008. However, by the summer of 2009 use of the guideline was inconsistent, and did not seem to have an impact on length of stay. As a result, an implementation program was developed.

OBJECTIVE

This quality-improvement project evaluated the influence of the development and implementation of a clinical practice guideline for children with SCD with ACS or at risk for ACS on clinical outcomes.

METHODS

Clinical outcomes of 139 patients with SCD were evaluated before and after the development of the implementation program. Outcomes included average length of stay, number of exchange transfusions, average cost per SCD admission, and documentation of the clinical respiratory score and pulmonary interventions.

RESULTS

Average length of stay decreased from 5.8 days before implementation of the guideline to 4.1 days after implementation (P = .033). No patients required an exchange transfusion. Average cost per SCD admission decreased from $30 359 before guideline implementation to $22 368. Documentation of the clinical respiratory score increased from 31.0% before implementation to 75.5%, which is an improvement of 44.5% (P < .001). Documentation of incentive spirometry and positive expiratory pressure increased from 23.3% before implementation to 50.4%, which is an improvement of 27.1% (P < .001).

CONCLUSIONS

Implementation of a guideline for children with SCD with ACS or at risk for ACS improved outcomes for patients with SCD.

Respiratory Symptoms and Acute Painful Episodes in Sickle Cell Disease

The authors examined the prevalence of respiratory symptoms and determined whether respiratory symptoms were associated with prevalence of chest pain and number of acute painful episodes in children and adolescents with sickle cell disease. Participants ( N = 93; 44 females, 49 males; mean age 9.8 ± 4.3 years) reported coughing in the morning (21.5%), at night (31.2%), and during exercise (30.1%). Wheezing occurred both when they had a cold or infection (29.0%) and when they did not have (23.7%) a cold or infection. Sleep was disturbed by wheezing in 20.4%. Among the 76 patients who were school-age (>5 years), 19.7% of patients missed more than 4 days of school because of respiratory symptoms. The majority of patients reported having acute painful episodes (82.8%), and most (66.7%) reported having chest pain during acute painful episodes in the previous 12 months. Participants with acute pain episodes greater than 3 during the previous 12 months had significantly higher reports of breathing difficulties ( P = .01) and chest pain ( P = .002). The high number of respiratory symptoms (cough and wheeze) among patients with sickle cell disease may trigger acute painful episodes. Early screening and recognition, ongoing monitoring, and proactive management of respiratory symptoms may minimize the number of acute painful episodes.