Respiratory infections

1. Respiratory infections Dr. Tara Husain

5. Cough; results from stimulation of irritant receptors located in the airway mucosa including the ear

6. Causes of Acute Cough; • Acute respiratory infection. • pulmonary edema. • chemical irritation. • Foreign body aspiration

7. Causes of chronic cough; • Allergy ( asthma, allergic rhinitis) • Anatomical abnormality ( tracheo-esophageal fistula, Gastroesophageal reflux). • Chronic infection; cystic fibrosis Immunodeficiency. • Environmental exposure • Ticks.

8. Croup (Laryngotracheobronchitis) • It is acute infectious laryngotrachiobronchitits. • parainfluenza virus type 1 and 2 are the most common agents • Usually affects children between6 months-3 years,

9. Clinical presentation; • starts by symptoms of upper respiratory tract infection(common cold) , • then a brassy cough typically sounding like a barking seal • Then inspiratory stridor and respiratory distress • Symptoms are characteristically worse at night and often recur with decreasing intensity, until about 1 wk • Most cases are mild and self limited, • Rarely there may be very sever airway obstruction necessitating artificial airway

10. Examination; • suprasternal, intercostal and subcostal retractions,. • There may also be associated lower airway obstruction manifested by wheeze or expiratory rhonchi • PA XR ; (Steeple) sign of narrowed subglottic space.

12. Treatment; • Aerosolized raceme epinephrine reduces edema temporarily(about 2 hours), in sever cases it may need to be repeated every 20 minutes.A case needing this treatment needs hospital admission • Corticosteroids ; systemic or inhaled dexamethasone (0.15 mg/kg) single dose • helium-oxygen mixture (Heliox) may be effective in children with severe croup for whom intubation is being considered • Antibiotics not indicated • Over the counter cold medication not indicated

13. Indications for hospital admission; • progressive stridor • severe stridor at rest • respiratory distress • hypoxia • Cyanosis • depressed mental status • poor oral intake • need for reliable observation

14. Epiglottitis • Pediatric emergency • inflammation of the epiglottis and/or the supraglottic tissues surrounding the epiglottis predominantly bacterial ( H. influenzae type b). • Usually in children between 2-7 years • otolaryngologist or general surgeon and anesthesiologistshould be consulted

15. Clinical presentation; • sudden onset • high fever • Respiratory distress • fulminate progression • sever dysphagia and a muffled voice • Patients usually sit erect and they may drool from there mouth because of dysphagia

16. Diagnosis; • Thumb sign on lateral neck x-ray differentiates epiglottitis from sever croup • Laryngoscope examination to inspect the epiglottis which shows cherry red enlargement • Blood culture and culture from the surface of the epiglottis

18. Treatment; • 1-Endotracheal intubation is the preferred method of treatment. most patient can be safely extubated with in 48-72 hours • Antibiotics ( ceftriaxon) should be given. • All patients should receive oxygen unless the mask causes excessive agitation • Racemic epinephrine and corticosteroids are ineffective • Minor procedures, such as intravenous access, may cause respiratory distress and can be performed more safely after intubation • Examination of the tonsills by tounguedepresser is contraindicated unless in operative theater

20. Bronchiolitis; • Is predominantly a viral disease. • RSV is responsible for >50% of cases • Other agents include parainfluenza adenovirus, Mycoplasma. • occur in winter or early spring • Older family members are a common source of infection; they might only experience minor upper respiratory symptoms (colds) • Host anatomic and immunologic factors play a significant role in the severity • Co-infection with >1 virus can also alter the clinical manifestations and/or severity of presentation

21. Clinical presentation; • rhinorrhea, cough, and low grade fever, • followed in several days with the onset of rapid breathing and wheezing. • The child may feed poorly and may have sleeping disturbance. • Acute symptoms last for 5-6 days, • recovery is complete usually after 10-14 days

22. Examination; • dyspnea, • intercostal and subcostal retraction, • Tachypnea • prolonged expiratory phase, • in very sever cases there may be cyanosis

23. Differential diagnosis; • Congenital malformations; vascular ring, left ventricular enlargment, intrinsic abnormality • Foreign body aspiration • Gastroesophageal reflux • Trauma; aspirations, burns, or scalds of the tracheobronchial tree • tumors

24. Diagnosis; • CXR; typically shows air trapping and may show peribronchial, thickening, there may be atelectasis, or infiltrates • WBC count is usually normal • RSV may be isolated from nasopharyngeal secretions by PCR,culture • Hypoxemia may occur secondary to ventilation perfusion mismatch. • Hypercapnia is rare occurring in severely affected infants with sever airway obstruction and respiratory fatigued

27. Treatment; • Oxygen; Humidified oxygen should be given to maintain oxygen saturation of more than 93%. • Bronchodilators; such as aerosolized beta agonist or racemic epinephrine may be beneficial in selected patients • Corticosteroids; offer little benefit. • Antibiotics; are not indicated unless there is evidence of secondary bacterial infection • Ribavirin aerosol; a specific antiviral agent RSV it has been demonstrated to be mildly effective. It is considered in patients with high risk disease

28. Mechanical ventilation; required to treat respiratory failure or apnea. • monthly injections of RSV monoclonal antibodies for infants and toddlers under 2 years with bronchopulmonarydysplasia • Supportive measures; Intravenous fluid, if there is poor oral intake