LRTI

1. LRTI Bella. Week 12

2. LRTI’s • Bronchitis • Bronchiectasis • Bronchiolitis • CF • Aspergillosis • TB

3. Acute Bronchitis • Bronchitis is inflammation of the main air passages to the lungs • Generally follows viral resp. infection, upper airways  lower airways. occ. Secondary bacterial infection (Strep. pneumoniae, H. influenzae) • At risk: elderly, infants & children, smokers, underlying heart or lung disease (COPD)

4. Chronic Bronchitis • Chronic bronchitis is a long-term condition. People have a cough that produces excessive mucus. • To be diagnosed with chronic bronchitis, you must have a cough with mucus most days of the month for at least 3 months of 2 successive years.

5. Bronchitis cont. • Illness begins with an irritating, unproductive cough & discomfort behind sternum  progresses to productive cough w/ yellow/green sputum • SYMPTOMS: Chest discomfort, productive cough, fatigue, fever (usually low), SOB worsened on exertion, wheeze • TREATMENT: in otherwise healthy adults the disease improves spontaneously in 4-8 days. Antibiotics – amoxycillin 250mg 3xdaily

6. Bronchiectasis • Defined as permanent dilation of the airways arising from chronic bronchial infection, described as a syndrome • CAUSE: mostly idiopathic, associated w/ mucociliary clearance (CF), post-infectious complications (TB, mycobacterium, pertussus), immune disorders (hypogammaglobulinaemia, IgG def., HIV), aspiration, rheumatic and chronic inflam conditions (RA, IBD) • SYMPTOMS: chronic cough with purulent sputum (copious), chronic fatigue, chest pain, haemoptysis, rhinosinusitis, haemoptysis • SIGNS: bilateral basal lung crackles (60%), clubbing (uncommon)

7. Bronchiectasis cont. • INVESTIGATIONS: high-resolution CT scanning is the standard test used for diagnosis, spirometry ( FEV1, normal FVC, FEV1:FVC), sputum microscopy • MICRO: Haemophilusinfluenzae, pseudomonas aeruginosa, Strep pneumoniae, Staph aureus

8. 36-year-old male HIV-positive patient with recurrent bronchitis. Thin section CT demonstrates extensive segmental and subsegmentalbronchiectasis (straight arrows) with diffuse air trapping and several centrilobular nodules due to plugging of small airways (curved arrow).

9. Bronchiectasis cont. • TREATMENT: antibiotics (dependant on the sensitivity of the microbe/s), physiotherapy and postural drainage, bronchodilators, corticosteroids, surgery, vaccination • PROGNOSIS: despite treatment patients tend to have ongoing symptoms. 5-year mortality rate =13%

10. Bronchiolitis • Viral bronchiolitis is the commonest lower respiratory tract infection in children less than 12 months of age and is the most frequent cause of hospitalisation in infants under 6 months of age • Caused by viral infections of the lower respiratory tract (usually RSV),  widespread small-airway narrowing due to airway oedema, resulting in air trapping. Secondary bacterial infection is rare. • CLINICAL FEATURES: • Nasal obstruction ± rhinorrhoea and an irritating cough • After 1–3 days there follows increasing tachypnoea and respiratory distress. The chest is often overexpanded. • Auscultatory signs are very variable: fine inspiratry crackles are often heard early, becoming coarser during recovery; expiratory wheeze is often present, initially high-pitched, with prolonged expiration. • Respiratory distress may be mild, moderate or severe. • Fever of 38.5°C or greater is seen in about 50% of infants with bronchiolitis. • Apnoea may be the presenting feature, especially in very young, premature or low-birthweight infants. It often disappears, to be replaced by severe respiratory distress.

11. Bronchiolitis cont. • DIAGNOSIS: bronchiolitis is a clinical diagnosis. The hallmark is crackles on auscultation, wheeze is usually present (Hx of atopy makes asthma more likely) • DIFFERENTIAL DIAGNOSIS: pulmonary aspiration, bacterial or viral pneumonia, cardiac failure, cystic fibrosis, sepsis (with apnoea), primary ciliarydyskinesia, airway malacia (tracheomalacia and/or bronchomalacia), inhaled FB in an older infant, and pneumothorax. • INVESTIGATIONS: only indicated in moderate-severe illness; oximetry, nasopharyngeal aspirate for RSV and viral culture, CXR, FBC, U&E, MSC if temperature > 38.5°C, blood gasses • MANAGEMENT: Mild bronchiolitis requires explanation and reassurance, but no specific pharmacological or other therapy. Moderate/severe illness: oxygen, bronchodilators

12. Cystic Fibrosis • Most common, lethal, inherited condition in the western world. Autosomal recessive, incidence 1 in 2800 live births in Australia, median survival 38 years • Caused by mutation in the CFTR gene on chromosome 7, ion channel regulator. Results in impaired chloride transport and enhanced sodium absorption across airway epithelial cell, increasing water absorption and dehydrating airway secretions  thick viscous secretions and impaired mucociliary clearance  bacterial colonisation and recurrent infections  irreversable airway damage, bronchiectasis, eventual chronic respiratory failure

13. CF cont. • DIAGNOSIS: newborn screening (heel prick), FHx, high sweat [Na]>60mmol/L, DNA, blood immunoreactivetrypsin levels MICRO: Pseudomonas aeruginosa, Staph aureus, H. influenzae

14. CF cont. • Clinical features that may indicate pulmonary exacerbation in CF • Change in sputum • New or increased haemoptysis • Increased cough • Increased dyspnoea • Malaise and lethargy • Temp >38 • Anorexia or weight loss • Change in physical examination of the chest (tachypnoea, accessory muscle use, coarse crackles, wheeze) • Decreased pulmonary function • Radiographical changes indicative of pulmonary infection • TREATMENT PULM: antibiotics (dependant on culture and sensitivity, ciprofloxacin is the only oral Ab pseudomonas is sensitive to, usually 2 IV Ab are used – an aminoglycoside and a penicillin), anti-inflamatories, mucolytics, physiotherapy • MANAGING EXTRA-PULMONARY: pancreatic enzyme replacements, nutritional therapy, vitamins etc

15. Aspergillosis • Aspergillus species are ubiquitous moulds found in organic matter. The majority of human illness is caused by Aspergillusfumigatus and Aspergillusniger and, less frequently, by Aspergillusflavus and Aspergillusclavatus. The transmission of fungal spores to the human host is via inhalation. • EFFECTS ON THE LUNG • Asthma: type 1 hypersensitivity (atopic) reaction to fungal spores • Allergic bronchopulmonaryaspergillosis (ABPA):type 1 and 3 hypersensitivity reaction to A. fumigatus. Bronchoconstriction bronchiectasis (permanent damage) • Aspergilloma (mycetoma): fungus ball within a pre-existing cavity • Invasive aspergillosis: rapidly progressive, often fatal infection that occurs in patients who are severely immunosuppressed, multi-organ dissemination may occur • Extrinsic allergic alveolitis (EAA): sensitivity to A. clavatus(‘malt workers lung’)

16. TB • Pulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs, but may spread to other organs • Caused by the bacteria Mycobacterium tuberculosis • Airborne transmission • Increased risk of infection with HIV

17. TB cont. • Primary infection: mid to upper lobe lung infection via M. tuberculosis. Ingested by alveolar macrophages, organisms replicate initiating an inflammatory response. TH1 cell response occurs 3 weeks later leading to hypersensitivity reaction with granuloma formation and caseous necrosis (tissue destruction) • Primary progressive TB: initial infection is not contained • Secondary TB: latent infection is reactivated or via re-infection • Miliary TB: massive haematogenous dissemination (esp. liver, bone marrow, spleen, adrenals, meninges, kidneys, fallopian tubes, and epididymus)

18. There is a small tan-yellow subpleuralgranuloma in the mid-lung field on the right. In the hilum is a small yellow tan granuloma in a hilar lymph node next to a bronchus. This is the "Ghon complex" that is the characteristic gross appearance with primary tuberculosis. In most persons, the granulomatous disease will not progress. Over time, the granulomas decrease in size and can calcify, leaving a focal calcified spot on a chest radiograph that suggests remote granulomatous disease.

19. References • http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002078/ (Bronchitis) • How To Treat – Bronchiectasis • http://www.mja.com.au/public/issues/180_08_190404/fit10649_fm.html (Bronchiolitis) • How to treat – CF • http://emedicine.medscape.com/article/296052-clinical (aspergillosis)