Lower Respiratory tract infections

1. Lower Respiratory Tract
Infections : an overview

6. Acute Bronchitis

9. Lower Respiratory Tract Infections
 Every year about 5 million people die of acute respiratory infections.
 Among these, pneumonia represents the most frequent cause of mortality,
hospitalization and medical consultation.
 Several factors (age, underlying disease, environment) influence mortality,
morbidity and also microbial aetiology.
 LRTI incidence increased with fluctuations over time, was higher in men
than women aged ≥70 and increased with age from 92.21 episodes/1000
person-years (65-69 years) to 187.91/1000 (85-89 years)

10. Epidemiology
 Respiratory infections are a significant cause of mortality worldwide.
 Twenty-five percent of deaths globally are due to infectious diseases, with
respiratory infections ranked as the leading infectious disease cause of mortality.
 Considering global deaths from all causes, lower respiratory tract infections
(LRTIs) are ranked third.
 Global mortality due to respiratory infections exceeds the total mortality from
HIV infection, malaria and diarrheal diseases combined.

20. Bronchitis
 Bronchitis can be classified as either acute or chronic.
 Acute bronchitis can be defined as acute bacterial or viral infection of the larger
airways in healthy patients with no history of recurrent disease.
 It affects over 40 adults per 1000 each year and consists of transient inflammation
of the major bronchi and trachea.
 Most often it is caused by viral infection and hence antibiotic therapy is not
indicated in immunocompetent individuals.

21. Acute Exacerbations of Chronic
Bronchitis
 Most common cause :AECB
 Respiratory viruses are associated with 30% of cases.
 Atypical bacterial (mostly Chlamydophila pneumoniae) infections are
implicated in less than 10%.
 Bacterial pathogens in approximately 40–50% of exacerbations.

22. Acute Exacerbations of Chronic
Bronchitis
 Viral pathogens associated with AECB include influenza, parainfluenza, rhinovirus,
coronavirus, adenovirus and respiratory syncytial virus.
 The three major bacterial causes of AECB in mild COPD exacerbations include -
Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae.
 In one study, patients undergoing mechanical ventilation for their AECB/COPD
exacerbations were frequently found to have Pseudomonas aeruginosa and
Stenotrophomonas spp.

23. Acute Exacerbations of
Chronic Bronchitis
 Patients who were less severely ill tended to have S. pneumoniae and other Gram-
positive cocci isolated from sputum, while more severe baseline
airway obstruction was associated with H. influenzae and M. catarrhalis.
 The most severely obstructed AECB/COPD patients tended to have
Pseudomonas and Enterobacteriaceae spp. cultured from sputum.
 Mycoplasma pneumoniae is thought to be a rare cause of AECB, while C.
pneumoniae may be isolated in as many as 5–10% of cases.

24. Bronchiectasis

26. Bronchiectasis

27. Bronchiectasis
 Bronchiectasis patients also frequently have non-enteric Gram-negative bacteria
isolated from sputum during exacerbations.
 H. influenzae has been isolated in 30–47% of cases,
 P. aeruginosa (including mucoid species) in 12–31%,
 M. catarrhalis in 2.4–20%,
 S. pneumoniae in 7–10%,
 Staphylococcus aureus in 4–14%,
 Mycobacterium (primarily Mycobacterium avian intracellular complex) in 2–17%,
and no organisms in 21–23% of sputum cultures obtained during exacerbations

30. Community acquired Pneumonia : Incidence
 CAP is the second most common cause of hospitalization and the most
common infectious cause of death.
 Community-acquired lower respiratory tract infections (LRTI) and pneumonia
(CAP) are common causes of morbidity and mortality among those aged ≥65
years; a growing population in many countries.
 CAP incidence increased more markedly with age, from 2.81 to
21.81 episodes/1000 person-years respectively, and was higher among men.
 Pneumonia is also a very common case of nosocomial infections ranking third
in occurrence behind urinary tract infections and surgical wound infections
(33% of the infections acquired in the hospital).
 In the United States, CAP accounts for over 4.5 million outpatient and
emergency room visits annually, corresponding to approximately 0.4 percent
of all encounters.

31. Risk factors
 ●Older age
 ●Chronic comorbidities -chronic obstructive pulmonary disease (COPD), include
other forms of chronic lung disease (eg, bronchiectasis, asthma), chronic heart
disease (particularly congestive heart failure), stroke, diabetes mellitus,
malnutrition, and immunocompromising conditions .
 ●Viral respiratory tract infection –This is most pronounced for influenza virus
infection.
 ●Impaired airway protection – Conditions that increase risk of macro-aspiration of
stomach contents and/or micro-aspiration of upper airway secretions predispose to
CAP, such as alteration in consciousness (eg, due to stroke, seizure, anaesthesia, drug
or alcohol use) or dysphagia due to esophageal lesions or dysmotility.
 ●Smoking and alcohol overuse – Smoking, alcohol overuse (e.g., >80 g/day), and
opioid use are key modifiable behavioural risk factors for CAP.
 ●Other lifestyle factors – Other factors that have been associated with an increased
risk of CAP include crowded living conditions (eg, prisons, homeless shelters),
residence in low-income settings, and exposure to environmental toxins (eg,
solvents, paints, or gasoline) .

32. Community acquired Pneumonia
 The most commonly identified causes of CAP can be grouped into three
categories:
 ●Typical bacteria
 •S. pneumoniae (most common bacterial cause)
 •Haemophilus influenzae
 •Moraxella catarrhalis
 •Staphylococcus aureus
 •Group A streptococci
 •Aerobic gram-negative bacteria (eg, Enterobacteriaceae such
as Klebsiella spp or Escherichia coli)
 •Microaerophilic bacteria and anaerobes (associated with aspiration)

33. Community acquired Pneumonia
 ●Atypical bacteria ("atypical" refers to the intrinsic resistance of these
organisms to beta-lactams and their inability to be visualized on Gram stain or
cultured using traditional techniques)
 •Legionella spp
 •Mycoplasma pneumoniae
 •Chlamydia pneumoniae
 •Chlamydia psittaci
 •Coxiella burnetii

34. Community acquired Pneumonia
 ●Respiratory viruses
 •Influenza A and B viruses
 •Rhinoviruses
 •Parainfluenza viruses
 •Adenoviruses
 •Respiratory syncytial virus
 •Human metapneumovirus
 •Coronaviruses (eg, Middle East respiratory syndrome coronavirus)
 •Human bocaviruses

35. Symptoms and Signs
 Symptoms include malaise, chills, rigor, fever, cough, dyspnoea, and chest
pain.
 Cough typically is productive in older children and adults and dry in infants,
young children, and the elderly.
 Dyspnoea usually is mild and exertional and is rarely present at rest.
 Chest pain is pleuritic and is adjacent to the infected area.
 Pneumonia may manifest as upper abdominal pain when lower lobe infection
irritates the diaphragm.
 GI symptoms (nausea, vomiting, diarrhoea) are also common.
 Symptoms become variable at the extremes of age. Infection in infants may
manifest as nonspecific irritability and restlessness; in the elderly,
manifestation may be as confusion and obtundation.

36. Symptoms and Signs
 Signs include fever, tachypnoea, tachycardia, crackles, bronchial breath
sounds, egophony (E to A change—said to occur when, during auscultation, a
patient says the letter “E” and the examiner hears the letter “A”), and
dullness to percussion.
 Signs of pleural effusion may also be present.
 Nasal flaring, use of accessory muscles, and cyanosis are common among
infants.
 Fever is frequently absent in the elderly.

38. Risk Stratification for Community-Acquired
Pneumonia (the Pneumonia Severity Index)
Factor : Patient demographics
 Men
 Women
 Nursing home resident
Points
 Age (in years)
 Age (in years) −10
 10

39. Risk Stratification for Community-Acquired
Pneumonia (the Pneumonia Severity Index)
Factor : Coexisting illness
 Cancer
 Liver disease
 Heart failure
 Cerebrovascular disease
 Renal disease
Points
 30
 20
 10
 10
 10

40. Risk Stratification for Community-Acquired
Pneumonia (the Pneumonia Severity Index)
Factor : Physical examination
 Altered mental status
 Respiratory rate ≥ 30 breaths/min
 Systolic blood pressure <90 mm Hg
 Temperature ≥ 40° C or <35°C
 Heart rate ≥ 125 beats/min
Points
 20
 20
 20
 15
 10

41. Risk Stratification for Community-Acquired
Pneumonia (the Pneumonia Severity Index)
Factor : Test results
 Arterial pH < 7.35
 Blood urea nitrogen ≥ 30 mg/dL (11 mmol/L)
 Sodium < 130 mmol/L
 Glucose ≥ 250 mg/dL (14mmol/L)
 Haematocrit < 30%
 PaO2< 60 mm Hg or Oxygen saturation <90%*
 Pleural effusion
Points
 30
 20
 20
 10
 10
 10
 10

42. Risk Stratification for Community-Acquired
Pneumonia (the Pneumonia Severity Index)
Points Mortality Recommendation
≤70 < 1% Outpatient treatment
71−90 <5% Outpatient treatment
91−130 5−15% Admit
>130 >15% Admit
Many consider hypoxemia an absolute
indication for admission.

43. CURB – 65 RISK SCORE
 In CURB-65, 1 point is allotted for each of the following risk factors:
 Confusion
 Uremia (BUN ≥19 mg/dL [6.78 mmol/L])
 Respiratory rate > 30 breaths/min
 Systolic Blood pressure < 90 mm Hg or diastolic blood pressure ≤ 60 mm Hg
 Age ≥ 65 years
Scores can be used as follows:
0 or 1 points: Risk of death is < 3%. Outpatient therapy is
usually appropriate.
2 points: Risk of death is 9%. Hospitalization should
be considered.
≥ 3 points: Risk of death is 15 to
40%.
Hospitalization is
indicated.
with 4 or 5 points, Risk of death is >50%. ICU admission should be
considered.

46. Community-Acquired Pneumonia in
Adults : Treatment
Group I Likely Organisms Empiric Treatment
Outpatients—no
modifying factors
present†
Streptococcus pneumoniae, Mycoplasma
pneumoniae, Chlamydia
pneumoniae, Haemophilus influenzae,
respiratory viruses, miscellaneous
organisms
(eg, Legionella species, Mycobacterium
tuberculosis, endemic fungi)
Macrolide (azithromycin 500
mg orally once, then 250 mg
once a
day; clarithromycin 250 to
500 mg orally twice a day; or
extended-
release clarithromycin 1 g
orally once a day)
or
Doxycycline 100 mg orally
twice a day (if allergic to
macrolide)

47. Community-Acquired Pneumonia in
Adults : Treatment
Group II Likely Organisms Empiric Treatment
Outpatients—
modifying factors
present
S. pneumoniae, including antibiotic-
resistant forms; M. pneumoniae; C.
pneumoniae; mixed infection (bacteria +
atypical pathogen or virus); H. influenzae;
enteric gram-negative organisms;
respiratory viruses; miscellaneous
organisms (eg, Moraxella catarrhalis,
Legionella sp, anaerobes [aspiration], M.
tuberculosis, endemic fungi)
Beta-lactam (cefpodoxime 200 mg
orally every 12 hours; cefuroxime 500
mg orally every 12 hours; amoxicillin 1
g orally every 8
hours; amoxicillin/clavulanate 875/125
mg orally every 12 hours)
plus
Macrolide orally
or
Antipneumococcal fluoroquinolone
orally or IV (alone;
eg, moxifloxacin [400 mg po/IV every
24 hours], gemifloxacin [320 mg po/IV
every 24 hours], levofloxacin [750 mg
po/IV every 24 hours] )

48. Community-Acquired Pneumonia in
Adults : Treatment
Group III Likely Organisms Empiric Treatment
Inpatient—not in intensive
care unit (ICU)
S. pneumoniae, H.
influenzae; M.
pneumoniae; C.
pneumoniae; mixed infection
(bacteria + atypical
pathogen or virus);
respiratory
viruses; Legionella species,
miscellaneous organisms
(eg, M. tuberculosis,
endemic
fungi, Pneumocystis
jirovecii)
Azithromycin 500 mg IV
every 24 hours
plus
Beta-lactam IV
(cefotaxime 1 to 2 g every 8
to 12 hours; ceftriaxone 1 g
every 24 hours)
or
Antipneumococcal
fluoroquinolone orally or
intravenously (alone)

49. Community-Acquired Pneumonia in
Adults : Treatment
Group IV A Likely Organisms Empiric Treatment
ICU patient—
no Pseudomonas risk
factors
S. pneumoniae, including
antibiotic-resistant
forms; Legionella species; H
. influenzae; enteric gram-
negative
organisms,;Staphylococcus
aureus; M. pneumoniae;
respiratory viruses
miscellaneous organisms
(eg, C. pneumoniae, M.
tuberculosis, endemic fungi)
Beta-lactam IV
(cefotaxime 1 to 2 g IV every
8 to 12 hours; ceftriaxone 1
g IV every 24 hours)
plus either
Antipneumococcal
fluoroquinolone IV
or
Azithromycin 500 mg IV
every 24 hours

50. Community-Acquired Pneumonia in
Adults : Treatment
Group IV B Likely Organisms Empiric Treatment
ICU patient—
Pseudomonas risk
factors present
Same as those for category IVA
(above)
plus Pseudomonas species
Antipseudomonal beta-
lactam‡ or aztreonam (if allergic to
or intolerant of beta-lactams) 1 to 2
g every 8 hours
plus either
Ciprofloxacin 400 mg IV every 12
hours or levofloxacin 750 mg orally
or IV every 24 hours
Alternatively:
Antipseudomonal beta-lactam‡
plus
An aminoglycoside
plus either
Ciprofloxacin 400 mg IV every 12
hours or levofloxacin 750 mg po or
IV every 24 hours

51. PROGNOSIS
 With empiric treatment, 90% of patients with bacterial pneumonia improve.
 Improvement is manifested by decreased cough and dyspnoea,
defervescence, relief of chest pain, and decline in white blood cell count.
 Failure to improve should trigger suspicion of
 An unusual organism
 Resistance to the antimicrobial used for treatment
 Empyema
 Coinfection or superinfection with a 2nd infectious agent
 An obstructive endobronchial lesion
 Immunosuppression
 Metastatic focus of infection with reseeding (in the case of pneumococcal
infection)
 Nonadherence to treatment (in the case of outpatients).

54. THANK YOU