PNEUMONIA. Dr. A.Torossian, M.D., Ph. D. Department of Respiratory Diseases

Transcription

1 PNEUMONIA Dr. A.Torossian, M.D., Ph. D. Department of Respiratory Diseases

2 Definition Pneumonia is an infection of the lungs caused by bacteria, viruses, fungi and other microorganisms.

3 Classifications (based on various criteria) Anatomic or radiologic distribution The pathogen responsible aetiological classification The setting or mechanism of acquisition

4 Community-acquired pneumonia (CAP) Pneumonia that develops in the outpatient setting or within 48 hours of admission to a hospital

5 Hospital-acquired pneumonia (HAP) Pneumonia that develops at least 48 hours after admission to a hospital and is characterized by increased risk of exposure to multidrug-resistant (MDR) organisms, as well as gram-negative organisms

6 Health care-associated pneumonia (residents of nursing home or other long-term facility) Ventilator-associated pneumonia Nursing home patients with pneumonia are less likely to present with classic signs and symptoms of the typical pneumonia presentation, such as fever, chills, chest pain, and productive cough, but instead often have delirium and altered mental status VAP may occur in as many as 10-20% of patients who are on ventilators for more than 48 hours.

7 Aspiration Pneumonia Caused by the aspiration of oropharyngeal secretions into the lung Patients with increased risk of aspiration and development of aspiration pneumonia: Decreased ability to clear oropharyngeal secretions - poor cough or gag reflex, impaired swallowing mechanism (eg. stroke patients), etc. Unconsciousness - seizures, coma, anesthesia Presence of other comorbidities - anatomic abnormalities, gastroesophageal reflux Intubation/extubation others

8 Because the episode of aspiration is usually not witnessed, the diagnosis is inferred when a patient at risk of aspiration develops evidence of a radiographic infiltrate in characteristic anatomic pulmonary locations The classic findings are in the right lower lobe

9 Typical Community- acquired Pneumonia The most common bacterial pathogens Streptococcus pneumoniae Haemophilus influenzae Moraxella catarrhalis These 3 pathogens account for approximately 85% of CAP cases

10 Some clues about the pathogen Underlying chronic obstructive pulmonary disease (COPD): H influenzae or M catarrhalis Recent influenza infection: Staphylococcus aureus Alcoholic patient presenting with currant jelly sputum : Klebsiella pneumoniae

11 Atypical Community- acquired Pneumonia Atypical organisms are generally associated with a milder form of pneumonia, the so-called "walking pneumonia." A feature that makes these organisms atypical is the inability to detect them on Gram stain or to cultivate them in standard bacteriologic media.

12 Atypical pathogens Mycoplasma pneumoniae: Mycoplasmas are the smallest known free-living organisms in existence; they lack cell walls (and therefore are not apparent after Gram stain) but have protective 3-layered cell membranes. Chlamydophila species (Chlamydophila pneumoniae, Chlamydophila psittaci): Psittacosis, also known as parrot disease or parrot fever, is caused by C psittaci and is associated with the handling of various types of birds.

13 Atypical pathogens Legionella species: Legionella species are gram-negative bacteria found in freshwater; they are known to grow in complex water distribution systems; Legionella species are the causative agent of Legionnaires disease. Coxiella burnetii: C burnetii is the causative agent of Q Fever. It is spread from animals to humans; person-to-person transmission is unusual. Animal reservoirs typically include cats, sheep, and cattle.

14 Hospital-acquired pneumonia Gram-negative bacteria Pseudomonas aeruginosa Klebsiella pneumoniae Haemophilus influenzae Escherichia coli Acinetobacter baumannii and others Staphylococcus aureus Viruses, fungi, anaerobic bacteria and combinations of these

15 Anaerobic organisms Pneumonia due to anaerobes typically results from aspiration of oropharyngeal contents. These infections tend to be polymicrobial and may consist of the following anaerobic species: Peptostreptococcus, Bacteroides, Fusobacterium, and Prevotella They are often combined with aerobic species

16 Viruses Common causes of viral pneumonia are: Influenza virus A and B (subtypes of Influenza A - swine influenza - A (H1N1) virus, avian influenza - A (H5N1) virus) Rhinovirus Respiratory syncytial virus (RSV) Human parainfluenza viruses (in children) Adenoviruses (in military recruits) Severe acute respiratory syndrome virus (SARS coronavirus) others Viruses that primarily cause other diseases, but sometimes cause pneumonia include: Herpes simplex virus (HSV), mainly in newborns Varicella-zoster virus (VZV) Cytomegalovirus (CMV), mainly in people with immune system problems

17 Fungal pneumonia Endemic fungal pathogens (eg, Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis, Paracoccidioides brasiliensis) cause infection in both healthy and immunocompromised hosts in defined geographic locations of the Americas and around the world Opportunistic fungal organisms (eg, Candida species, Aspergillus species, Mucor species, Cryptococcus neoformans) tend to cause pneumonia in patients with congenital or acquired defects in their host defenses

18 Parasitic pneumonia The most common parasites involved: Toxoplasma gondii (in HIV-infected/AIDS patients) Ascaris lumbricoides Schistosoma species others

19 Ethiology of CAP (European region) cause percentage (%) Typical pathogens Streptococcus pneumoniae Haemophillus inflienzae 2-10 Moraxella catarrhalis 0-5 Atypical pathogens Mycoplasma pneumoniae 1-10 Chlamydophila pneumoniae 5-15 Legionella pneumophila 0-15 Others 5-25 Viral agents 2-15 Pneumocystis carinii 0-10 Unknown pathogen 30-60

20 CAP is usually acquired via inhalation Less commonly, CAP results from secondary bacteremia from a distant source, such as Escherichia coli urinary tract infection CAP may be due to aspiration of oropharyngeal contents in patients with certain risks

21 Anamnesis Determining the presence of pneumonia Assessing disease severity at the time of presentation Identifying the causative agent

22 Anamnesis Symptoms - Pulmonary Cough - the presence of cough, particularly cough productive of sputum, is the most consistent presenting symptom Sputum - the character of the sputum may suggest a particular pathogen, for example: Rust-colored sputum - S. pneumoniae Currant jelly sputum K. pneumoniae Foul-smelling or bad-tasting sputum - anaerobic infections Chest pain, dyspnea, hemoptysis

23 Anamnesis Symptoms Non-pulmonary Nonspecific - fever, rigors or shaking chills, malaise Other nonspecific symptoms - myalgia, arthralgia, headache - often seen in cases with atypical pneumonia Sometimes nausea, vomiting, diarrhea, and altered sensorium, others

24 Anamnesis Additional host factors Comorbid conditions Possibility of immunosuppression Social history Family history Medication history Allergy history

25 Anamnesis Potential exposures Exposure to contaminated air-conditioning or water systems - Legionella species Exposure to overcrowded institutions (eg. jails, homeless shelters) S pneumoniae, Mycoplasma pneumoniae Exposure to various types of animals - cats, sheep, goats (C burnetii) or birds (C psittaci), etc.

26 Anamnesis Aspiration risks Alcoholism Altered mental status Anatomic abnormalities, congenital or acquired Dysphagia GERD (gastro-esophageal reflux disease) Seizure disorder, unconsciousness Anesthesia others

27 Risk Factors for severe disease Age over 65 years Recent antibiotics Immune compromised host (e.g. HIV Infection) Chronic respiratory illness (COPD, Asthma) Diabetes mellitus Chronic liver and kidney disease Cancer

28 Physical examination Hyperthermia (fever, typically >38 C) or hypothermia (<36 C) Tachypnea (>18 respirations/min) Use of accessory respiratory muscles Tachycardia (>100 bpm) or bradycardia (<60 bpm) Central cyanosis Altered mental status

29 Physical examination Adventitious breath sounds, such as rales/crackles, rhonchi or wheezes Decreased intensity of breath sounds, bronchial breath sound Bronchophony, whispering pectoriloquy Dullness to percussion

30 HOW TO DIFFERENTIATE BETWEEN PNEUMONIA AND OTHER RESPIRATORY TRACT INFECTIONS? A patient should be suspected of having pneumonia when the following signs and symptoms are present: an acute cough and one of the following: new focal chest signs, dyspnoea, tachypnoea, fever > 4 days. If pneumonia is suspected, a chest X-ray should be performed to confirm the diagnosis.

31 Imaging methods Chest X-ray Radiology is generally helpful in detecting suspected pneumonia and identifying the presence of complications only occasionally can imaging suggest specific pathogens

32

33

34

35 Computed tomography CT scanning may identify pulmonary infections earlier than plain radiography. In most cases, it can be helpful in the analysis of more complex lung findings and evaluation of other intrathoracic structures. Ultrasonography Ultrasonography is useful in evaluating suspected parapneumonic effusions, especially if septations are present within the fluid collection

36 Laboratory tests The amount of laboratory and microbiological work-up should be determined by the severity of pneumonia C-reactive protein In patients with a suspected pneumonia a test for serum-level of C-reactive protein (CRP) can be done. A level of CRP <20 mg/l at presentation, with symptoms for >24 h, makes the presence of pneumonia highly unlikely; a level of >100 mg/l makes pneumonia likely Complete Blood Count Sputum Gram stain Sputum Culture

37 Urine antigen testing for pneumococcus and Legionella pneumophila Immunological tests IgM antibody, complement fixation test PCR

38 In more severe cases: Blood culture, prior to antibiotic therapy Endotracheal aspirate for culture in intubated patients Culture and study of pleural fluid if effusion is present Arterial blood gas (if serious dyspnea is present)

39 Procedures Bronchoscopy with or without bronchoalveolar lavage (BAL) Thoracocentesis: in patients with a parapneumonic pleural effusion

40 Treatment Where? And how? initial assessment of severity need for hospitalization level of care (outpatient, medical ward care, or medical ICU care)

41 Severity mild moderate severe Place of treatment Out-patient hospital ICU Gr.1 Gr. 2 Gr. 3 Gr. 4 Gr. 5 Ramirez, Dis Manage Heart Outcomes 2003; 11 (1) 33-43

42 Various systems to assess the severity of disease and risk of death exist and are in wide use, including the PSI/PORT (ie, Pneumonia Severity Index/Patient Outcomes Research Team score), CURB- 65 and others

43 CURB-65 CURB-65 One point is given for the presence of each of the following: Confusion of new onset - Altered mental status Uremia - BUN greater than 7 mmol/l Respiratory rate - Greater than or equal to 30 breaths per minute Blood pressure - Systolic less than 90 mm Hg or diastolic less than 60 mm Hg Age older than 65 years

44 Patients are stratified for risk of death as follows: 0 or 1: low risk (less than 3% mortality risk) 2: intermediate risk (3-15% mortality risk) 3 to 5: high risk (more than 15% mortality risk)

45 BTS guidelines Thorax 2009;64(Suppl III):iii1 iii55. doi: /thx.2009

46 Treatment of mild CAP Amoxicillin or tetracycline should be used as the antibiotic of first choice Macrolide such as azithromycin, clarithromycin, or roxithromycin is a good alternative in countries with low pneumococcal macrolide resistance Treatment with levofloxacin or moxifloxacin may also be considered

47 Duration of medication Usually 8-10 days Atypical pathogens - min 14 days (usually 2-3 weeks) Clinical improvement is expected during the first 2-3 days The patients should be instructed to contact the physician if there is no improvement

48 Treatment options for hospitalized patients with communityacquired pneumonia (no need for intensive care treatment) (in alphabetical order) Aminopenicillin ± macrolide Aminopenicillin/beta-lactamase inhibitor ± macrolide Non-antipseudomonal cephalosporin Cefotaxime or ceftriaxone ± macrolide Levofloxacin Moxifloxacin Penicillin G ± macrolide

49 Start empiric antibiotic treatment within 4 hours of hospitalization Decreases mortality Decreases length of stay

50 Treatment of HAP Offer antibiotic therapy as soon as possible after diagnosis, and certainly within 4 hours Choose antibiotic therapy in accordance with local hospital policy (which should take into account knowledge of local microbial pathogens) and clinical circumstances for patients with hospital-acquired pneumonia

51 Treatment options for patients with HAP Piperacillin-tazobactam Cefepime Ceftazidime Levofloxacin Ciprofloxacin Imipenem Meropenem Aztreonam Amikacin Gentamicin Tobramycin Vancomycin Linezolid

52 Additional supportive care measures: Analgesia and antipyretics Intravenous fluids (and, conversely, diuretics) if indicated Oxygen supplementation Respiratory therapy, including treatment with bronchodilators, mucolytics/antitussives Chest physiotherapy, early mobilization

53 Low molecular heparin in patients with acute respiratory failure Steroids have no place in the treatment of pneumonia unless septic shock is present! Suctioning and bronchial hygiene Mechanical ventilation

54 Clinical response to antibiotic therapy should be evaluated within h of initiation. With appropriate antibiotic therapy, improvement in the clinical manifestations of pneumonia should be observed in h Because of the time required for antibiotics to act, antibiotics should not be changed within the first 72 hours unless marked clinical deterioration occurs

55 WHEN SHOULD IV BE USED AND WHEN SHOULD THE SWITCH TO ORAL OCCUR? In mild pneumonia, treatment can be applied orally from the beginning In patients with moderate pneumonia, sequential treatment should be considered i.v. during the first days, then switching to oral The optimal time to switch to oral treatment is unknown - it seems reasonable to target this decision according to the resolution of the most prominent clinical features at admission

56 The timing of radiologic resolution of pneumonia varies with patient age and the presence or absence of an underlying lung disease. The chest radiograph usually clears within 4 weeks in patients younger than 50 years without underlying pulmonary disease.

57 If patients do not improve within 72 hours, an organism that is not susceptible to the initial empiric antibiotic regimen should be considered. Lack of response may also be secondary to a complication such as empyema or abscess formation Consider broadening the differential diagnosis to include noninfectious etiologies such as malignancies, congestive heart failure, etc., or other pathogens - M.tuberculosis

58 Further Outpatient Care When treated in an outpatient setting, arranging adequate follow-up evaluations for the patient is mandatory. Patients also should be instructed to return if their condition deteriorates Patients should have a follow-up chest radiograph to ensure resolution of consolidation.

59 Complications Necrotizing pneumonia/pulmonary abscess Fibrosis/organization of lung parenchyma Bronchiectasis Empyema Respiratory failure Acute respiratory distress syndrome

60 Differential diagnosis Pulmonary Thromboembolsm Heart failure Tuberculosis Lung cancer Metastatic lung Fibrosis Collagenosis Others

61

62

63

64

65

66 Prognosis Generally, the prognosis is good in otherwise healthy patients with uncomplicated pneumonia Advanced age, aggressive organisms (eg, Klebsiella, Legionella, resistant S.pneumoniae), comorbidity, respiratory failure, neutropenia, and features of sepsis, alone or in combination, increase morbidity and mortality

67 Guidelines for the management of adult lower respiratory tract infections M. Woodhead, F. Blasi, S. Ewig, J. Garau, G. Huchon, M. Ieven, A. Ortqvist, T. Schaberg, A. Torres, G. van der Heijden, R. Read and T. J. M. Verheij, Joint Taskforce of the European Respiratory Society and European Society for Clinical Microbiology and Infectious Diseases, 2011