Respiratory Tract Infections In the Emergency Department

1. Respiratory Tract Infections In the Emergency Department

2. Lecture Objectives • Review presentation and diagnosis of respiratory tract infections seen in the emergency department (E.D.) • Discuss and compare different antibiotic treatment regimens for respiratory tract infections

3. Respiratory Tract Infections • > 200 million cases per year in U.S.A. • 10 % of office visits to primary care M.D.'s • Rx uses 1/2 of outpt. & 1/3 of inpt. antibiotics • Direct Rx costs $15 billion per year • Indirect Rx costs $9 billion per year • Upper tract infections: • Rhinitis, pharyngitis, sinusitis, otitis, epiglottitis, croup • Lower tract infections: • Tracheitis, bronchitis (acute & chronic), pneumonia

4. Lower Respiratory Tract Infections • Incidence • 2.5 to 3 million cases per year in U.S. • 25 % require hospitalization • ? 50,000 deaths per year in U.S. • Account for 28 % of E.D. patients with respiratory symptoms

5. Acute Bronchial Infections • Most common etiologic agents: • Hemophilus influenzae (24 %) • H. parainfluenzae (17 %) • Streptococcus pneumoniae (20 %) • Branhamella catarrhalis (11 %) • Neisseria species Note the top 4 account for 74 %

6. Acute Bronchial Infections • Less common etiologic agents: • Klebsiella • Pseudomonas • Staphylococcus aureus • Serratia marcescens • Other streptococci • ? % role for mycoplasma & chlamydia

7. General Etiologies of Non-Viral Community- Acquired Pneumonias • Strep. pneumoniae 60 to 75 % • Legionella sp. 5 to 15 % • Mycoplasma pneumoniae 5 to 18 % • Hemophilus influenzae 2 to 5 % • Chlamydia pneumoniae 2 to 5 % • Staph. aureus 1 to 5 % • Branhamella catarrhalis 1 to 5 %

8. Risk Factors for Additional Pathogens (besides Strep. pneumoniae) • COPD • Alcoholism • Diabetes • Institutionalized • "Active cancer" • Bronchiectasis

9. Conditions Predisposing to Anerobic Lung Infections • Aspiration • Esophageal dysfunction • Suppressed consciousness • EtOH, drug OD, CVA, Seizure, Anesthesia • Gingival infections • Underlying lung conditions • Bronchiectasis, pulmonary infarction, neoplasms, other obstructive lesions • Subphrenic abscess • Penetrating chest trauma • Thoracotomy

10. Classical aspiration pneumonia infiltrate (apical posterior segment of the right upper lobe)

11. Infiltrates six hours after aspiration

12. Causes of Pneumonia Associated with Hilar Adenopathy • Plague • Psittacosis • Tularemia • Tuberculosis • Sporotrichosis • Rubeola • Varicella • Anthrax • Blastomycosis • Coccidiomycosis • Histoplasmosis • Mycoplasma • Pertussis • Echovirus

13. Histoplasmosis with 2 to 5 mm nodules

14. Varicella pneumonia in a 24 year old female renal transplant patient

15. Bilateral upper lobe cavitary tuber-culosis

16. Miliary tuberculosis

17. Exudative right upper lobe infiltrate from tuber-culosis

18. Tuberculous pneumonia in the left upper lobe with consolidation and cavitation

19. Implanted Lucite plastic balls to collapse the upper lobes (old treatment for tuberculosis prior to antibiotics)

20. Viruses Causing Pneumonia • Most common: • Influenza • Adenovirus • RSV • CMV • Varicella-Zoster • Measles • Less common: • Parainfluenza • Rhinovirus • Coxsackie • Echovirus • Herpes simplex • Rubella

21. Pneumocystis carinii pneumonia

22. Pneumocystis carinii pneumonia

23. Pneumocystis pneumonia 4 days after a normal chest film

24. Sputum silver stain of Pneumocystis carinii

25. Pulmonary Kaposi’s sarcoma in an A.I.D.S. patient

26. Differential diagnosis of focal infiltrates in immuno-compromised patients A G L S S

27. Differential diagnosis of diffuse interstitial infiltrates in immuno-compromised patients A P C C D P Malignancy

28. Clinical Features of Pneumonia in the Elderly • Main symptoms may be malaise, weakness, stupor, "failure to thrive" • Cough may not be present • Fever may not be present • Tachypnea/tachycardia may be only signs • Leucocytosis may not be present • X-ray findings may be obscured by CHF, COPD, old Tuberculosis • Resolution often prolonged • Sepsis and death more frequent

29. Indications for Pulse Oximetry when Pneumonia Suspected • Just about everybody !

30. Indications for Getting Arterial Blood Gases if Pneumonia Suspected • O2 saturation < 90 % on O2 • Pulse oximeter unable to track • Altered mental status • Patient appears to be tiring • Intubated • Subjective respiratory distress

31. Pneumococcal Pneumonia • Sudden onset • Sx: chills, rigors, fever, pleuritic chest pain • Cough may be initially absent • Lung consolidation occurs early • 25 % of patients develop bacteremia • 5 % overall mortality

32. Left upper lobe infiltrate and CHF from Pneumococcal pneumonia

33. Sputum gram stain showing Streptococcus pneumoniae

34. Sputum gram stain of Streptococcus pyogenes

35. Complications of Pneumococcal Pneumonia • ARDS • Empyema • Purulent pericarditis • Purulent arthritis • Meningitis • Endocarditis

36. Legionnaire's Disease General Risk Factors • Ususally summer to early fall • Occurs in all age groups • Middle-aged males : most frequent • 1/2 of patients have underlying illness • Immunosuppression (renal transplants) • Diabetes mellitus • COPD • Renal disease • Neoplasms

37. Legionella outbreak at Chambersburg Hospital in Pennsylvania

38. Legionnaire's Disease Social and Occupational Risk Factors • Smoking • EtOH use • Construction work • Excavation of soil nearby • Overnight travel during incubation period • Person to person transmission very rare ; resp. isolation of case not needed

40. Legionella Pneumonia • Incidence • 0.5 to 15 % of community-acquired pneumonias • Up to 30 % of nosocomial pneumonias ( if present in water supply) • If identified in hospital water supply, should attempt to eradicate organism : • Use superheated (> 70 degrees C) water to flush distal outlets • Hyperchlorination of hospital water to 4 to 6 ppm

41. Legionnaire's Disease (Legionella pneumophila) • Associated clinical findings: • Fever (continuous, not spiking; > 39.4 C in 80 %) • Malaise (100 %) • Weakness (100 %) : may be chief complaint • Anorexia (100 %) • Cough (92 %) : initially non-productive • Shaking chills (78 %) : usually begin on day 2 to 3 • Bradycardia (60 %) : relative to temperature • Diarrhea (50 %) : watery, non-bloody, no abd. pain • Confusion, lethargy (33 %) : may be other CNS sx • Pleuritic chest pain (33 %) O

42. Legionnaire's Disease • Less common clinical findings: • Hemoptysis (25 %) : usually minor • Headache • Myalgias • Arthralgias • Rhinitis & pharyngitis usually absent

43. Legionnaire's Disease • Lab and CXR findings: • Few to moderate polys on sputum gram stain • No bacteria on sputum gram stain • Leucocytosis • Elevated SGOT, LDH, Alk phos, bili (50 %) • Hyponatremia (50 %) • Hypophosphatemia • Proteinuria (50 %) • CXR: early patchy infiltrate, later lobar infiltrate

44. Legionella pneumonia in left upper and mid lung fields

45. Legionnaire's Disease Confirmation of Diagnosis • Culture • Charcoal yeast extract agar • Growth evident in 48 to 72 hours • Stains • Direct flourescent antibody (DFA) : best • Gimenez & Dieterla stains : not specific • Serologic • Indirect flourescent antibody (IFA) • Takes 3 to 6 weeks for IFA titer to increase • Dx by 4X increase in titer

48. Mycoplasma Pneumonia • Incidence greatest in 10 to 30 year olds • Incubation period 2 to 3 weeks • Headache, malaise, low fever, nonproductive cough • Erythema multiforme may occur : confirms diagnosis • Bullous myringitis : diagnostic • May also have otitis or non-exudative pharyngitis • Elevated cold agglutinin titers in second week

49. Complications of Mycoplasma Pneumonia • Hemolytic anemia • Thrombocytopenia • DIC • Stevens Johnson Syndrome • Myocarditis / pericarditis • Meningoencephalitis • Polyneuritis / myelitis • Pancreatitis • Glomerulonephritis • Asthma

50. Chlamydia Pneumonia • Fever, cough, mucoid sputum • Pharyngitis common • May have laryngitis • Chest pain / hemoptysis unusual • Diagnosis by serology (microimmunofluorescence)