Acute chest syndrome (sickle cell)
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This document defines and discusses acute chest syndrome (ACS) in patients with sickle cell disease. ACS is characterized by fever, respiratory symptoms, and new lung infiltrates seen on chest x-ray. It is commonly caused by infection, fat embolism, or hypoventilation. Clinical features include chest pain and symptoms like cough. Diagnosis can be challenging as symptoms may be mild and radiological signs lag behind. Treatment involves oxygen, IV fluids, pain management, respiratory support like bronchodilators, and antibiotics. Preventing recurrent ACS involves therapies like hydroxyurea and long-term blood transfusions. Distinguishing asthma from wheezing caused by sickle cell disease can also be difficult.
Acute chest syndrome (sickle cell)
- 1. Acute Chest Syndrome Atul Jindal (MD, DM) Assistant Professor AIIMS, Raipur
- 2. Overview Definition Pathophysiology Clinical features Challenges in the diagnosis of ACS Course & Outcome Monitoring & Investigations Treatment of ACS Chronic complications & Prevention
- 3. Definition Acute Chest Syndrome (ACS) is defined as an acute illness characterised by fever and/or respiratory symptoms, accompanied by a new pulmonary infiltrate on chest X-ray.
- 5. Etiology Pulmonary infection - identified in 38% who underwent extensive sampling Seasonal variation - 3 times more common in winter More common in children <10 years - Viral infection (commonest RSV) Mycoplasma pneumonia (14%), Staph, pneumococcus, H.influenzae
- 6. Etiology Fat embolism Microvascular pulmonary infarction Hypoventilation/atelectasis - rib pain, opiate narcosis, post-operative period Asthma
- 7. Clinical Features Second most common reason for hospitalisation Nearly half of patients present initially with a painful VOC ACS will often develop 24-72 hr after the onset of severe pain
- 8. Symptoms & Signs Data from Vichinsky et al, 1997, 2000 Clinical signs often precede the CXR findings. Sometimes Chest examination can be normal and hence it is important that the diagnosis is not excluded at this stage.
- 9. Challenges in the Diagnosis of ACS Pulmonary embolism - CT angio Fluid overload - Fluid balance chart Opiate narcosis - Monitoring of RR, sedation, and pain scores Alveolar hypoventilation due to pain
- 10. Monitoring and Investigations High Clinical suspicion + Clinical features = Straight forward diagnosis Diagnosis can be difficult clinical features may be few hypoxia is difficult to determine on clinical examination unless severe Radiological signs often lag behind the physical signs
- 11. Monitoring and Investigations Standard monitoring includes At-least 4 hrly SpO2 (on Air), HR, RR, BP Daily Clinical examination CBC, CXR, Cr, LFT, Blood C/S, Bld group and cross match, ABG, Sputum C/S and PCR if facilities available
- 13. Investigations - CBC Acute fall in Hb conc. or Platelet count are often seen Decreasing platelet count to <2lac is an independent risk factor for neurological complications and the need for mechanical ventilation Reticulocyte count - normal count excludes red cell aplasia by parvo B 19.
- 14. Investigations - Biochemical tests RFT & LFT - MODS as a consequence of Systemic fat embolism CRP - monitor progress ABG - on room air (if SpO2<94%) Patients in clear resp. distress or in whom SpO2 falls rapidly to <85% when O2 is removed need escalation of therapy. PaO2 < 82 mm hg (70% of cases)
- 15. Investigations - other Investigations CT - high sensitivity and specificity (84% and 97%) High radiation dose - not recommended Use in Pulm. Embolism Secretory Phospholipase A2 (sPLA2) - levels elevated in ACS
- 16. ACS - Treatment Oxygen - titrate to SpO2>95% or within 3% of patient baseline value IVF - Euvolemic (maintain I/O Chart) Pain relief - Adequate analgesia with frequent review and assessment of pain and sedation scores and cardiorespiratory monitoring Incentive Spirometry & Chest Physiotherapy Antimicrobials - treat for organisms for community acquired pneumonia + atypical organisms
- 17. ACS - Treatment Blood Transfusion -
- 18. ACS - Treatment Respiratory Support Bronchodilators - Demonstrable reversible airway disease History s/o asthma Acute bronchospasm
- 19. ACS - Treatment iNO - case reports , No RCT - insufficient evidence Corticosteroids - Significant variability in their efficacy Current evidence - mild to moderate ACS - not recommended due to its adverse effects If associated with Acute Asthma - Yes
- 20. ACS - Chronic complications Scarring Pulmonary fibrosis Chronic Sickle Lung Disease Poor Lung Function
- 21. ACS - Prevention Hydroxyurea - Significantly decrease the incidence of ACS in patients with recurrent severe pain and also in unselected children with HbSS. Long term transfusion - has been shown to decrease the incidence of ACS in patients who are being transfused for stroke prevention. Transfusion in preoperative period significantly reduces the incidence of post-operative ACS. Consider HSCT if both fails in preventing ACS episodes.
- 22. SCD - Wheeze or Asthma? Asthma in SCD - 17%-48% Challenge - Asthma or SCD? Wheezing: common in SCD and independently associated with morbidity Cooperative Study - out of 1722 ACS episodes - 11% were wheezing at admission and 26% ultimately had during the course.
- 24. SCD - Wheeze or Asthma? Episode of wheezing producing shortness of breath is associated increased risk of future episode of ACS (IRR 1.7, p=0.04)
- 25. SCD - Wheeze or Asthma? NHLBI guidelines 1) Assess for signs and symptoms of respiratory problems by history and physical examination; 2) In patients with signs or symptoms of respiratory problems, further assessment (including pulmonary function testing) is recommended.
- 26. SCD - Wheeze or Asthma? Knight-Madden and Greenough have termed “Recurrent Wheezing in Sickle Cell Disease (RWIS)”. Once we have a better understanding of the mechanisms underlying airway abnormalities in SCD we can begin to explore the impact of therapeutic interventions on recurrent wheezing, airway obstruction, and/or asthma on short and long term SCD outcomes. This is an important, understudied area that warrants further investigation in an attempt to reduce morbidity and mortality in these patients.