[French guidelines for the management of adult sickle cell disease: 2015 update]

Sickle cell disease is a systemic genetic disorder, causing many functional and tissular modifications. As the prevalence of patients with sickle cell disease increases gradually in France, every physician can be potentially involved in the care of these patients. Complications of sickle cell disease can be acute and chronic. Pain is the main symptom and should be treated quickly and aggressively. In order to reduce the fatality rate associated with acute chest syndrome, it must be detected and treated early. Chronic complications are one of the main concerns in adults and should be identified as early as possible in order to prevent end organ damage. Many organs can be involved, including bones, kidneys, eyes, lungs, etc. The indications for a specific treatment (blood transfusion or hydroxyurea) should be regularly discussed. Coordinated health care should be carefully organized to allow a regular follow-up near the living place and access to specialized departments. We present in this article the French guidelines for the sickle cell disease management in adulthood.

[Acute chest syndrome in adult sickle cell patients]

Sickle cell disease is a frequent genetic condition, due to a mutation of the β-globin gene, leading to the production of an abnormal S hemoglobin and characterized by multiple vaso-occlusive events. The acute chest syndrome is a severe complication associated with a significant disability and mortality. It is defined by the association of one or more clinical respiratory manifestations and a new infiltrate on lung imaging. Its pathophysiology is complex and implies vaso-occlusive phenomena (pulmonary vascular thrombosis, fat embolism), infection, and alveolar hypoventilation. S/S or S/β⁰-thalassemia genotype, a history of vaso-occlusive crisis or acute chest syndrome, a low F hemoglobin level (<5%), a high steady-state hemoglobin level (> 10 g/dL), or a high steady-state leukocytosis (>10 G/L) are the main risk factors. Febrile chest pain, dyspnea, sometimes cough with expectorations are its main clinical manifestations, and bi-basal crackles are found at auscultation. Inferior alveolar opacities with or without pleural effusions are identified on chest X-ray or CT-scan. Management of the acute chest syndrome should be prompt and implies, besides the recognition of severity signs, a multimodal analgesia, oxygen supplementation, sometimes a parenteral antibiotic treatment and the frequent use of blood transfusions especially in the most severe cases. Prevention is important and includes a regular monitoring of hospitalized patients and the use of incentive spirometry.

[Acute respiratory distress syndrome complicating an acute chest syndrome: potential benefit of early combination of exchange transfusion and prone positioning]

We report the case of an 8-year-old sickle cell anemia child admitted for acute respiratory failure complicating acute chest syndrome. Because of threatening respiratory failure, tracheal intubation was performed immediately after ICU admission. The patient met the criteria for ARDS with a PaO2/FiO2 ratio of 94mmHg. An exchange transfusion was performed immediately after admission. HbS fraction failed from 69 % to 30 %. Fluid resuscitation with crystalloids and continuous norepinephrine infusion was needed because of arterial hypotension. Due to persistent severe hypoxemia with PaO2/FiO2 ratio below 100, the patient was placed in prone positioning 16hours after admission, for a total duration of 14hours. A second 12-hour session of prone positioning was performed 41h after admission and PaO2/FiO2 ratio reached 300mmHg after. Treatment also included transfusion of two red-cell pack on day 1 and 2 after admission in order to maintain hemoglobin level above 8g/dL, and a daily folic acid supplementation. The control of hyperthermia was achieved by a systematic parenteral administration of paracetamol. Cefotaxime and erythromycine were continued until day 7 despite the negative results of all bacteriological samples. The outcome was favorable from day 3 and the patient met the criteria for extubation on day 5. A first attempt of extubation was performed on day 5, but re-intubation was required because of laryngeal edema. Steroids were given for 48h and the patient was successfully extubated on day 7. She was discharged from the ICU on day 8, and from the hospital on day 12. We discuss the various treatments available for the management of acute chest syndrome and their actual relevance in acute respiratory distress syndrome in the absence of strong evidence-based guidelines in pediatric ARDS.

[Lung manifestations of sickle-cell disease]

Sickle-cell disease is an autosomal recessive genetic disorder of hemoglobin that causes systemic damage. Hypoxia is the main actor of sickle-cell disease. It initiates acutely the pathogenic cascade leading to tissue damages that in turn induce chronic hypoxia. Lung lesions represent the major risk of morbidity and mortality. Management of sickle-cell disease requires a tight collaboration between hematologists, intensivists and chest physicians. Recurrent episodes of thrombosis and hemolysis characterize the disease. New therapeutic protocols, associating hydroxyurea, transfusion program and stem cell transplantation in severe cases allow a prolonged survival until the fifth decade. However, recurrent pain, crisis, frequent hospital admissions due to infection, anemia or acute chest syndrome and chronic complications leading to organ deficiencies degrade the patients' quality of life. In low-income countries where the majority of sickle-cell patients are living, the disease is still associated with a high mortality in childhood. This paper focuses on acute chest syndrome and chronic lung manifestations.