INFECTIOUS PULMONARY DISEASES

1. INFECTIOUS PULMONARY DISEASES Module H Pneumonia -Chapter 15 (pp. 224-241) Lung Abscess - Chapter 16 (pp. 242-249) Tuberculosis – Chapter 17 (pp. 250-259) Avian Flu SARS Fungal Diseases - Chapter 18 (pp. 260-271)

2. Pneumonia • Inflammatory Process • Gas Exchange areas of the lung. • Alveolar Consolidation • Alveoli become filled with fluid, RBC, WBC and macrophages. • 2 million cases/year with 40,000 to 70,000 deaths. • 6th leading cause of death • “Old Man’s Friend”

4. Etiology • Bacteria • Viruses • Fungi • Rickettsia • Protozoa • Anaerobic organisms

5. Pneumonia vs. Pneumonitis • Pneumonia is an infection with an inflammatory response and consolidation of the lung parenchyma. • Pneumonitis is an inflammatory response due to a non-infectious agent.

6. Aspiration Pneumonitis • Etiology • Strokes • Neuromuscular disease • Decreased level of consciousness • Alcoholics • Drug Abuse • Head Injury • Chemical (Mendelson’s Syndrome) • Inhalation of gastric acid

7. Types of Pneumonia • Lobar Pneumonia • Involves the entire lobe • Segmental (Lobular) • Bronchopneumonia • Alveoli contiguous to an bronchi • Interstitial Tissues • Double Pneumonia: Both lungs • Walking Pneumonia: Mild form of pneumonia • Mycoplasma Pneumoniae • Necrotizing Pneumonia

8. At Risk Patients • Elderly • Chronic Disease • Diabetes, Renal Disease, Alcoholics • Immunosuppressed Patients • Cancer patients • AIDS • Transplant patients • Malnutrition • Patients on steroids • Burn victims • Leukemia • Drug abuse

9. Classification of Pneumonia • Nosocomial • Diagnosed 48 hours after hospital admission. • Ventilator Associated Pneumonia (VAP) is a subset of nosocomial infections. • Community –Acquired Pneumonia • Outside a health care setting.

10. Pneumonia during Mechanical Ventilation • Use of a modified Clinical Pulmonary Infection Score (CPIS) • If score is above 6, pneumonia is likely.

11. Bacterial Etiology – Gram + • Streptococcal (Pneumococcal) Pneumonia • Most common (80%) • 80 different types • Pneumococcal Vaccine • Staphylococcal Pneumonia • Staphylococcal aureus • Primary causative agent • Methicillin-resistant (MRSA) • Staphylococcal epidermidis • Normal flora

12. Bacterial Etiology – Gram - • Rare in “healthy” hosts • Klebsiella pneumoniae (Friedlander’s Bacillus) • Lobar Pneumonia • Older men and alcoholics • Pseudomonas aeruginosa • Chronically ill, tracheotomized patients • Haemophilus influenzae • Second most common community acquired pneumonia (CAP) to Streptococcus pneumoniae • Secondary to viral infection • Type B is pathogenic • HIB vaccine has reduced incidence

13. Bacterial Etiology – Gram - • Legionella pneumonphila • American Legion in 1976 • 30+ species • Escherichia coli • GI tract normal flora • Enterobacter sp. • Enterococcus sp. • Normal flora in GI tract • Vancomycin Resistant Enterococcus (VRE) • Proteus sp. • Serratia marcesens

14. Antibiotic Resistant Respiratory Bacterial Pathogens • Methacillian Resistant Staphylococcus Aureus (MRSA) • Treated with Vanomycin • Vancomycin Resistant Enterococcus(VRE) • Normally found in GI tract • Nearly impossible to treat • Treated with teicoplanin & Synercid

15. Viral Pneumonia • 90% of acute upper respiratory tract infections are caused by viruses. • 50% of lower respiratory tract infections are due to viruses.

16. Types of Viral Pneumonias • Influenza Virus • Types A and B are the most common • Winter months • Respiratory Syncytial Virus (RSV) • Bronchiolitis in infants & pneumonias in elderly • Parainfluenza Viruses • 5 types • Type 1, 2, 3, 4A and 4B • Type 1 is associated with croup infections • Adenovirus

17. Types of Viral Pneumonias • Varicella • Chickenpox & pneumonia • Rubella • German Measles & pneumonia • Rubeola • Measles • Cytomegalovirus (CMV) • Member of the herpes virus • Usually seen in AIDS patients

18. Other Causes of Pneumonia • Mycoplasma Pneumoniae (Primary Atypical Pneumonia) • Walking Pneumonia • Young (5 to 35 years of age) • Rickettsiae • Rocky Mountain Fever, Typhus, Q fever • Transmitted by fleas, ticks, mites • Chlamydia Psittaci (Psittacosis) • Found in respiratory tract and feces of a variety of birds • Parrots, parakeets, cockatoos, chickens, pigeons • Transmitted to humans via aerosol or direct contact • Chlamydia Pneumoniae

19. Other Causes of Pneumonia • Pneumocystis carinii • Opportunistic, often fatal, form of pneumonia seen in immunocompromised patients. • Has been thought to be a protozoa but more recently, information suggests a fungus. • Major cause of pneumonia in AIDS patients.

20. Fungal Infections • AIDS patients and patients on steroids • Histoplasma capsulatum • Coccidioides immitis • Blastomyces dermatitidis • Candida albicans • Oral thrush • Aspergillus • Treatment • Amphotericin B (IV) • Nystatin • Fluconazole

21. Aspergilloma

22. Tuberculosis • One of the oldest diseases – 4,000 B.C. • 1.5 Billion cases worldwide • 15 million of these are active • TB is still prevalent in US • 15,000 cases/year – 50% occur in patients born outside the US • Highest incidence in SE US, inner cities, homeless & jails • HIV infection is the greatest single medical risk factor (no defense mechanism) • Age has traditionally been considered an independent risk factor (greater chance of exposure)

23. Tuberculosis • Chronic disease requiring months of treatment. • Suboptimal treatment can result in drug-resistant TB. • TB can affect many organs in the body but most common location is the lungs. • Brain Kidneys • Bones Genital tract • TB is caused by mycobacterium tuberculosis. • Produces a tubercle (lesion) that undergoes caseation. • Highly aerobic & like to grow in areas with high oxygen tension • Brain, lung apex • TB has airborne mode of transmission • Transmitted within aerosol droplets from cough/sneeze & can remain suspended in the air for several hours

24. Tuberculosis • Initial infection results in no sickness, no symptoms, and the individual is not contagious (Latent TB). • Active TB occurs with immunosuppression. • AIDS, Young, Old, Cancer, substance abuse • Treatment is multiple first line drug therapy for 6 or 9 months • There is an emergence of drug resistant strains of TB (MDR-TB) • Cure rate is poor

25. Categories of Tuberculosis • Primary TB • Post-primary TB • Disseminated TB

26. Primary TB • First exposure to the pathogen • Bacilli implant in the alveoli & multiply over 3-4 weeks • Inflammatory reaction • Leukocytes, macrophages move into the area to engulf (but not kill) the bacilli • Alveolar Consolidation • Positive TB reaction • WBC normal

27. Protective Cell Wall 2-10 weeks Neutrophils TB Bacilli & Macrophages Fibroblasts Lymphocytes Tubercle or granuloma

28. Caseous Lesion • Necrosis • Cottage Cheese • Caseation

29. Healing • Fibrosis • Calcification • Retraction of lung tissue

30. Post-primary Tuberculosis • Reactivation of the tuberculosis months or years after the initial infection • Most patients recover completely but the live tubercle bacilli can remain dormant for decades • May reactivate in patients with weakened immunity • Positive TB test • Cavity formation and possible rupture

31. Disseminated Tuberculosis • Bacilli escape from the tubercle and rapidly disseminate to other parts of the lung or other organs • Move via the lymphatics or bloodstream • Miliary Tuberculosis • Small tubercles scattered throughout the body via blood stream.

33. Symptoms • General malaise • Cough with sputum production • Minimal initially, gradually increasing • Night sweats • Chills • Increasing dyspnea • Chest pain • Loss of appetite • Weight loss CONSUMPTION

34. Chest x-ray • Initial Lung Lesion is called a Ghon nodule • Ghon nodule + involvement of lymph nodes in the hilar region is the Ghon Complex • Multiple Nodules (supra- or retroclavicular) • Pleural Effusions • Cavity Formation

35. Diagnostic Testing • TB skin test • Mantoux Test • 5 m of purified protein derivative (PPD) in 0.1 mL of solution is injected. • Induration of 10 mm or greater is positive test • Sputum Cultures and Acid fast stain • Ziehl-Neelsen & Fluorescent Stain • Culture will differentiate M. Tuberculosis from other acid fast organisms (6-8 weeks) • Sputum may show AFB but negative for TB • Chest x-rays

36. Drug Therapy for Tuberculosis • First Line • R – rifampin (Rimactane) (*) • I – isoniazid (INH) (+) • P – pyrazinamide (Tebrazid) • E – ethambutol (Myambutol) • R – rifapentine (Priftin) (*) • R – rifabutin (Mycobutin) • Use if patient receiving antiretroviral • Second Line • Streptomycin • (*) Reduces efficacy of oral contraceptives. • (+) Liver toxicity when alcohol is used.

37. Treatment • If a patient does not respond to treatment in 2-3 weeks, suspect: • Non-compliance with drug regimen • Multiple drug resistant organisms (MDR-TB) • Oxygen

38. Prophylactic Treatment • Isoniazid if often prescribed as a daily dose for one year in individuals exposed to TB • Positive TB skin Test

39. Safety Precautions • Isolation • Keep door closed • National Institute for Occupational Safety and Health (NIOSH) recommends particulate filter respirators for HCWs • Surgical masks are not very effective against TB