Pneumonia

Introduction

• 8^th leading cause of death in older people
• Leading cause of sepsis
• Environmental classification
  • CAP – Not hospitalised or in care facility for 14 or more days prior to presentation
  • Hospital-acquired pneumonia – New infection 48 hours or more after hospital admission
  • Ventilator-acquired pneumonia – new infection 48 hours or more after starting ventilation
  • Healthcare-associated pneumonia

• Patients hospitalised for 2 days or more in last 90 days
• Nursing home/long-term care facility
• Home IV therapy
• Dialysis patients
• Patients receiving chronic wound care, chemotherapy
• Immunocompromised patients

Risk factors

• High risk of aspiration
  • Swallowing/oesophageal motility issues
  • Stroke
  • NG tube
  • Intubation
  • Seizure
  • Syncope

• Impaired mucociliary clearance
• Debilitation
  • Alcoholism, extremes of age, neoplasia, immunosuppresion
• Risk of bacteraemia

• Indwelling devices
• Intrathoracic devices
• IVDU
• Chronic diseases
  • Diabetes, renal failure, liver failure, valvular heart disease, congestive cardiac failure
• Pulmonary disorders
  • COAD, chest wall disorders, skeletal muscle disorders, bronchial obstruction

• Bronchoscopy
• Viral infections

Pathophysiology

• 50% have no identifiable organism
• Pneumococcus is the most common isolated organism
  • Then viruses and atypicals (Mycoplasma, Chlamydia, Legionella)
• Most severe CAP is pneumococcus, Legionella, Haemophilus influenzae, Enterobacteriaceae, S. aureus and Pseudomonas
• 5% have more than one organism
• S. aureus and S. pneumonia can also arise from haematogenous spread

Clinical

• Cough (79-91%)
• Fatigue (90%)
• Fever (71-75%)
• Dyspnoea (67-75%)
• Sputum production (60-65%)
• Pleuritic chest pain (39-49%)
• Typical signs of consolidation (25%)
• Non-respiratory symptoms (50% of elderly)
• No signs of systemic infection (33%$
• Many patients will have antecedent coryzal-type illness making differentiation difficult

Typical characteristics

• S. pneumoniae
  • Sudden onset fever, rigors, pleurisy, productive cough, dyspnoea
  • Rust-coloured sputum; gram-positive encapsulated diplococci
  • Lobar infiltrate, occasionally patchy, occasional pleural effusion
• S. aureus
  • Gradual onset cough, fever, dyspnoea, especially after viral infection
  • Purulent, gram-positive cocci (grapes)
  • Patchy, multilobar infiltrate, empyema, lung abscess
• Klebsiella pneumoniae
  • Sudden onset rigors, fevers, dyspnoea, chest pain, bloody sputum (esp. alcoholics and nursing home residents)
  • Brown currant jelly
  • Upper lobe infiltrates, bulging fissure sign, abscess formation

• Pseudomonas
  • Recently hospitalised, debilitated or immunocompromised with fever, dyspnoea, cough
  • Gram-negative coccobacilli
  • Patchy infiltrate with frequent abscess formation
• Haemophilus influenzae
  • Gradual onset fever, dyspnoea, pleurisy; especially elderly and COAD patients
  • Short, tiny gram-negative encapsulated coccobacilli
  • Patchy, frequent basilar infiltrate with occasional pleural effusion

• Legionella
  • Fevers, chills, headache, malaise, dry cough, dyspnoea, anorexia, diarrhoea, nausea and vomiting
  • Few neutrophils and no predominant bacterial species
  • Multiple patchy non-segmented infiltrates, progressing to consolidation, cavitation and pleural effusion
  • Hyponatraemia is relatively common secondary to SIADH
• Moraxella catarrhalis
  • Indolent course of cough, fever, sputum and chest pain; mostly COAD patients
  • Gram-negative diplococci
  • Diffuse infiltrates
• Chlamydia pneumoniae
  • Gradual onset, fever, dry cough, wheezing +- sinus symptoms
  • Few neutrophils, no organisms visible
  • Patchy subsegmental infiltrates

• Mycoplasma
  • Upper and LRTI symptoms, coryzal, headaches
  • Few neutrophils, no organisms visible
  • Interstitial infiltrates (reticulonodular pattern), patchy densities
• Anaerobic organisms
  • Gradual onset, putrid sputum, especially in alcoholics
  • Purulent, mixed organisms
  • Consolidation of dependent portion of lungs; abscess formation

Typical CXR findings

• Cavitation – S. aureus, anaerobes (Fusobacterium, Bacteroides), aerobic Gram-negative bacilli (E. coli, Salmonella, Citrobacter, Enterobacter, Klebsiella, Morganella, Proteus, Serratia, Pseudomonas, Stenotrophomonas, Burkholderia cepacia, B. pseudomallei), TB, fungal
• Abscess – S. aureus, Klebsiella
• Empyema – S. aureus, Pseudomonas, Anaerobes (Fusobacterium, Bacteroides)
• Effusions – Bacterial, atypical, viruses, legionella, TB

Specific causes

Pneumococcal pneumonia

• Risk factors
  • Elderly
  • Children <2yo
  • Minorities
  • Day care
  • Immunosupression e.g. splenectomy, HIV, sickel cell disease)
• 25% have parapneumonic effusions
• Those with chronic lung disease, nursing home patients or elderly patients tend to have slower progression with malaise and minimal cough
• Lab findings – Leukocytosis, raised bilirubin/LFT and hyponatraemia
• Increasing incidence of penicillin, macrolide and fluoroquinolone resistance
• Patients with intermediate penicillin-resistant pneumococci may still be treated with penicillins as long as adequate doses are provided
• Highly penicillin-resistant strains require treatment with vancomycin, imipenem or ketolide

Staphylococcus aureus pneumonia

• Risk factors
  • Chronic lung disease
  • Laryngeal cancer
  • Immunosuppression
  • Nursing home patients
  • Those at risk of aspiration
• If leucocidin excretion accompanies infection, rapid progression and death occur even with adequate therapy
• Healthcare-associated pneumonia are at risk of MRSA
• May occur in concert with influenza
• If hx of furunculosis/folliculitis – suspect CA-MRSA
  • Mortality rate 37% within 48 hours with high propensity for necrotising infection

Klebsiella pneumonia

• Risk factors
  • Aspiration
  • Alcoholics
  • Elderly
  • Chronic lung disease

Pseudomonas pneumonia

• Risk factors
  • Prolonged hospitalisation
  • Who have received broad-spectrum antibiotics 
  • High-dose steroid therapy
  • Structural lung disease (e.g. CF)
  • Nursing home residents

Legionella pneumonia

• Range of illness from benign self-limiting to ARDS
• Risk factors
  • Cigarette smokers
  • Chronic lung disease
  • Transplant patients
  • Immunosuppressed
• No seasonality, making it more prominent in summer when other causes decline
• Commonly accompanied by abdo pain, vomiting, diarrhoea
• Can also cause sinusitis, pancreatitis, myocarditis and pyelonephritis

Mycoplasma

• Also occurs year-round
• Subacute respiratory illness with headache and retrosternal chest pain
• Usually no GI symptoms
• Occasionally causes rash, neurologic symptoms, arthralgia, haematological abnormalities and rarely AKI

Burkholderia pseudomallei

• Seen in tropical Australia
• Risk factors include:
  • Diabetes
  • Alcohol abuse
  • CKD
  • Chronic lung disease
  • Immunosuppression
• Also seen with Acinetobacter baumanii

Pneumocystis carinii pneumonia

• Usually insidious dry cough, dyspnoea, fever, fatigue and weight loss
• Crackles in chest are rare and classically hypoxia > CXR changes
• CXR
  • Classic diffuse bilateral perihilar interstitial shadowing 
  • Often subtle and missed early on
  • Normal in 10%
  • 10% show focal changes or coarse patchy shadowing
  • Pleural effusions, hilar or mediastinal lymphadenopathy are rare
• Often diagnosed by PCR of BAL sample
• Rx should be started once suspected with Bactrim 

CMV pneumonitis

• Risk highest following allogeneic stem cell transplant, lung transplant, pancreas transplant then liver, heart, renal, AIDS
• If recipient is seropositive, risk of infection is 70% but risk of disease only 20%
• If recipient is seronegative and donor is seropositive, risk of disease is 70%
• Steroid pulses and antilymphocyte globulin increase risk of disease substantially
• Diagnosis of infection vs. disease is difficult

Fungal pneumonia

• Cell-mediated immune controlled
  • Histoplasma, Blastomycosis, coccidioidomycosis, paracoccidioidomycosis, Cryptococcus
  • Can occur in healthy individuals (but more common  and severe in cell-mediated immunosuppression e.g. HIV, organ transplant)
• Non-immune phagocyte control
  • Aspergillus and Mucor spores
  • Rarely present in patients with normal neutrophil number and function

Fungal pneumonia

• Candida
  • Both impaired cell-mediated immunity (predisposes to mucosal overgrowth) and impaired phagocyte function (required before deep invasion occurs)
  • Primary Candida pneumonia is uncommon and is more often a manifestation of disseminated Candida infection
  • More common than this is benign colonisation of airway
  • Amphotericin B is most often used for disseminated Candida

Fungal pneumonia

• Invasive Aspergillosis
  • Highly lethal in immunocompromised patients 
  • Need histological diagnosis of hyphae and cultures from biopsy
  • Recovery from sputum in immunocompromised (but not immunocompetent) patients indicates invasive disease with 80-90% PPV
  • CXR
    • Wedge-shaped pleural based densities/cavities
  • CT
    • Halo sign (low attenuation surrounded by nodular lung lesion) is an early CT finding
    • Crescent sign (air crescent near periphery of lung nodule) is a late CT sign
  • Voriconazole is first-line therapy

Pertussis

• Macrolides only reduce infectivity (after 5 days of therapy) and do not change outcome
• Need to collect sample from ciliated epithelium so NPA required (not just swab)
• IgG serology positive after immunisation but IgA specific for infection
• PCR most sensitive and specific

Diagnosis

• When symptoms suggest pneumonia, treat empirically (do not need CXR findings for diagnosis)
• In otherwise healthy, mildly ill, ambulatory patients, no further ancillary testing may be necessary
• For patients over 50 or more than mildly ill
  • FBC, Chem20 should be done to risk stratify (e.g. CURB-65)
• Pulse oximetry for all as SpO2 <91% is associated with complications
• ABG for those appearing ill, with underlying lung disease, desaturation or respiratory distress
• Most patients do not require identification of specific organism

• Non-hospitalised patients
  • Incidence of positive BC in CAP is very low
  • Pathogen identification usually does not alter therapy
  • Majority of patients respond to empiric therapy
  • Sputum culture <15% adequate samples and helpful results

• Hospitalised CAP
  • Incidence of positive BC rises with disease severity
  • BC positive in 5-16% of all patients and 15-30% of S. pneumoniae
  • Sputum culture positive in only 40%
  • Who gets BC? 
    • Admitted to ICU and in those with leukopaenia, cavitary lesions, severe liver disease, alcohol abuse, asplenia or pleural effusions
    • eTG states all patients requiring hospitalisation
  • All admitted patients should have sputum culture and Gram stain if adequate sample can be obtained
    • Adequate = >25 PMN/LPF and <10-25 squamous cells/LPF
    • Single or predominant organism on Gram stain of fresh sputum or heavy growth on culture of purulent sputum is likely to be causative
    • The finding of many PMN’s with no bacteria in a patient who has NOT received antibiotics can reliably exclude typical bacterial pathogens
  • Legionella serology tests for other sub-types also
  • Pneumococcal urinary antigen assay
    • Can be taken before or after antibiotics initiated and can be useful (especially if bacteraemic)
    • Test all adults with severe disease
    • 50-80% sensitive and >90% specific
  • Legionella urine antigen
    • Useful in ICU, alcoholics, those with classic findings and those with recent (within 2 weeks) travel history
    • Detects Legionella pneumonila type 1 only
    • >95% specific and 88-100% sensitive
    • Test all patients with severe disease (eTG)
  • Nose and throat swab PCR
    • For respiratory viruses, Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella if available
    • Test all severe cases
    • Testing for influenza is warranted if it will alter management
      • Oseltamivir may be indicated (moderate-to-severe CAP, high-risk group, admitted to hospital or RACF resident/high-risk household contacts
      • Cohorting if being admitted to hospital
  • IgM serology
    • For Mycoplasma acute diagnosis (difficult to interpret though)
  • Acute and convalescent IgG serology
    • For Mycoplasma, Legionella, Chlamydia and influenza
    • Only provides retrospective diagnosis
    • Chlamydia titre 1:16 is significant
  • Bronchoalveolar lavage
    • If other tests not identified a pathogen and severe case
  • Pleural fluid for Gram stain, pH, culture and leukocyte count
    • If pleural effusion >1cm thick on lateral decubitus CXR

Pneumonia in special populations

Pneumonia in alcoholics

• Higher risk of pneumonia, TB, pleurisy, bronchitis, empyema and COAD
• More likely to be undernourished, to suffer aspiration pneumonitis, to be heavy smokers and to have alcoholic cirrhosis and portal hypertension
• Greater oropharyngeal colonisation with gram-negatives
• Depressed granulocyte and lymphocyte counts with impaired neutrophil delivery
• S. pneumonia is most common but Klebsiella and Haemophilus are important agents
• Higher mortality rates

Pneumonia in diabetics

• 4x more likely to suffer pneumonia and influenza
• 2-3x more likely to die with pneumonia or influenza
• More common
  • S. aureus, gram-negative bacteria, mucormycosis (mucormycete fungal infection) and Mycobacteria
• S. pneumonia, Legionella and influenza have higher morbidity and mortality in diabetic patients

Pneumonia in pregnancy

• Viral pneumonia has higher morbidity and mortality in pregnancy
  • Often use antiviral therapy in this group

Pneumonia in the elderly

• Mortality rate approaches 40%
• Increased susceptibility due to:
  • COAD, aspiration risk, CCF, cardiovascular disease, cerebrovascular disease, lung cancer, dementia, diminished gag reflex
• 3x risk of pneumococcal pneumonia
• Post-viral bacterial pneumonia is common and usually due to S. pneumoniae, S. aureus or H. influenzae
• Often present with non-pulmonary symptoms such as falls, weakness, tremulousness, functional decline, abdominal complaints, delirium or confusion
• More likely to be afebrile on presentation but more likely to have SBI if temp >38.3
• Age alone confers poor prognosis above 85yo
• Up to 1/3 will not develop leukocytosis
• Poor prognostic indicators
  • Hypothermia or temp >38.3
  • Leukopaenia, immunosuppression
  • Gram-negative or staphylococcal disease
  • Cardiac disease
  • Bilateral infiltrates
  • Extrapulmonary disease
• 10% receive ICU

Pneumonia in nursing home residents

• Eight independent predictors of pneumonia in NH residents:
  • Increase HR
  • RR >30
  • Temp >38
  • Somnolence or decreased alertness
  • Acute confusion
  • Lung crackles on auscultation
  • Absence of wheeze
  • Leukocytosis
• 1 of above = 33% chance of pneumonia
• 3 or more features = 50% chance of pneumonia
• Most commonly S. pneumoniae, gram-negative bacilli and H. influenzae
• Prone to outbreaks of influenza
• Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella are uncommon
• Therapy should include coverage for gram-negative and MRSA
• Consider impaired renal fx, increased vulnerability to drug side effects/interactions

Pneumonia in high-care NH

• Mild
  • Amoxicillin q8h PO for 7 days
  • If patient does not improve or Gram-negative on stain – Augmentin for 7 days
  • Add doxycycline if high suspicion of atypical 
• Moderate
  • Always consider aspiration pneumonia
  • BenPen 1.2g IV q6h then switch to amoxicillin when able
  • If fails to improve, Gram-neg on stain or known recent sputum colonisation with Gram-negative – Ceftriaxone 1g IV then switch to augmentin
  • If risk factors for atypicals or fail to improve by 48 hours, add doxycycline
• Severe
  • As for severe CAP

Pneumonia in HIV

• CAP accounts for ¾ of bacteral pneumonia diagnosed in patients hospitalised with HIV
• S. pneumoniae is most common cause
• Pseudonomas is common

Pneumonia in transplant patients

• First 3 months
  • More common following transplant of liver, heart or lung
  • Gram-negative (especially Pseudomonas in ventilated patients), S. aureus, Legionella predominate
    • Klebsiella, E. coli and fungi also seen in early nosocomial stage
  • 33% mortality rate
• First 6 months
  • CMV, P. jiroveci and Aspergillus
• After 6 months
  • Typical CAP are common and less often fatal than earlier infections

Pneumonia in the immunosuppressed

• Lungs are the most frequent target organs
• Bacterial over 1-2 days vs. fungal/protozoal less fulminant
• Diffuse infiltrate
  • CMV, herpesvirus, PCP, Aspergillus, Bacterial, Cryptococcus
• Focal infiltrate
  • Gram-negative rods, Staphylococcus aureus, Aspergillus, Cryptococcus, Nocardia, Mucormycosis, PCP (uncommon), TB, Legionella

Aspiration pneumonia

• 50% of healthy adults aspirate during sleep
• Silent aspiration is more common in patients with CAP (71% vs. 10% of normal population)
• 5-15% of CAP occur due to aspiration
• 30% of those with pneumonia in nursing homes are due to aspiration
• NH aspiration pneumonia 28% mortality vs. CA aspiration pneumonia 19%

• Risk factors
  • Intoxications – Alcohol, drugs, therapeutic drug overdose, sedatives, procedural sedation, GA
  • Neurological – Stroke (esp. brainstem), seizure, head trauma, dementia, chronic neurological condition
  • Oropharyngeal – Impaired glottic function, emergent intubation, periodontal disease and poor oral hygiene
  • GI – High gastric pressures, BVM, GORD, oesophageal dysmotility/obstruction, NG/OG/percutaneous gastric tube, tracheobronchial fistula
  • Other – Chronic supine position, RSI, advanced age, chronic debility, extension neck contractures

• 1/3 of aspirations are silent
• Pathophysiology
  • pH <2.5 and volume >0.3-0.4mL/kg required for aspiration pneumonitis
  • Direct caustic effect followed by inflammation peaking at 4-6 hours
  • Clinical cough, pleurisy, fever and CXR findings
  • Community-acquired aspiration pneumonia
    • Typical organisms include ß
  • Hospital-acquired aspiration pneumonia
    • Pseudomonas
    • Gram-negatives
  • Both need coverage for anaerobes
  • Recumbent patients – Posterior portions of upper lobes and upper portions of lower lobes
  • Upright patients – Basal segments of lower lobes

• Clinical features
  • Historical features that suggest chronic silent aspiration include general debility, chronic cough, hoarseness, dysphagia and previous episodes
  • Usually present early with CXR findings
• Diagnosis
  • CXR – Unilateral focal or patchy consolidations in dependent lung portions
    • Occasionally bilateral or interstitial pattern seen
    • Right lower lobe is most common site when upright
• Treatment
  • Large amounts of aspirate may require suctioning or BAL
  • Bronchodilators useful for aspiration-induced bronchospasm
  • See below
• Disposition
  • If healthy and small aspiration – observe and discharge
    • Do not need antibiotics if mild symptoms resolve within 24-48 hours
  • Stable patients at risk of deterioration e.g. diabetic, advanced age, chronic disease) should be admitted and observed
  • Start antibiotics in ED if definite evidence of infection

Aspiration pneumonitis

• Most severe form of pulmonary aspiration
• Can progress to ARDS within hours
• Indications for antibiotics in suspected aspiration:
  • Failure to improve despite symptomatic therapy
  • Clinical deterioration
  • CXR suggesting aspiration pneumonia
  • Aspiration of contaminated fluid e.g. bowel obstruction

Hospital-acquired pneumonia

• 0.5-5% of all hospitalised patients
• Diagnosis difficult as many other pathologies may mimic (atelectasis, PE, aspiration, CCF, cancer)
• High-incidence of oropharyngeal colonisation with Gram-negative makes isolation of causative organism difficult
• Blood cultures positive in only 6%
• VAP is HAP after 48-72 hours of intubation with increased risk of multidrug resistance

• Pathogenesis
  • Microaspiration of upper respiratory tract flora
• Diagnosis
  • New/change in infiltrate on CXR and growth of pathogenic organism on sputum + one of:
    • WCC >12
    • Temp >38.3
    • Sputum Gram stain with >2+ PMN and bacteria
• Tracheal aspirates may yield multiple organisms and represents upper airway colonisers but if a bacterium is absent from this, then highly unlikely to be present in LRT given microaspiration pathogenesis
  • Certain bacteria if identified are almost always pathogenic also i.e. Legionella, Chlamydia, TB, influenza, para-influenza, RSV, Strongyloides, Toxoplasma, PCP, Histoplasma, Coccidioides, Blastomycoses, Cryptococcus
• Current guidelines suggest 7 days therapy unless Pseudomonas
• Clinical improvement usually takes at least 48-72hrs

• CXR
  • Improvement lags behind clinical status
  • Increase of 50% in consolidation in 48 hours, new cavitation or significant new pleural effusion should raise concern for deterioration

Assessing severity

• Red flags
  • RR >30
  • SBP <90
  • SpO2 <92%
  • Acute onset confusion
  • HR >100
  • Multilobar involvement
• Age, comorbidities, social situation, ability to tolerate oral therapy and need for supportive oxygen therapy play a key role in deciding between inpatient vs. outpatient care
• SMART-COP, CORB are based on predictors for ICU and vasopressor support + mortality as opposed to PSI and CURB-65 that are based on mortality risk and less applicable to deciding on outpatient vs. inpatient care

SMART-COP

• S – Age >50
• Multilobar
• Albumin <35
• RR >25
• Tachy >125
• Confusion (new)
• O2 – PaO2 <70, SpO2 <93, P/F <333
• pH <7.35
• SBP <90

Smart-cop

• Score 0-2: Low risk
• Score 3-4: Moderate risk. 1/8 risk of intensive respiratory or vasopressor support (ICU)
• Score 5-6: High. 33% risk of ICU
• Score >=7: Very high. 77% risk of ICU

CORB

• Confusion (acute)
• O2 <90%
• RR >30
• BP <90/60
• Severe = 2 or more of above and sensitivity of 81% and specificity of 69% for predicting ICU
• Abbreviated version of SMART-COP

Pneumonia severity index

• Pneumonia Severity Index is the most well validated score
  • Non-hypoxaemic (91% or greater) with PSI I to III have <4% mortality and are candidates for outpatient therapy
• Class I (No predictors)
  • <50yo with no comorbidities and minimal X-ray or vital signs need no further testing
  • All others need labs at least
  • 0.1% mortality
• Class II (<70 points)
  • 0.6% mortality
• Class III (71-90 points)
  • 2.8% mortality
  • Non-hypoxaemic patients may be candidates for outpatient care
• Class III may require brief observation or hospitalisation
• Class IV and V warrant admission (+- ICU)
• Not designed for use in severe HIV, non-CAP or pregnant patients
• One profound derangement may also warrant admission

CURB-65

• Confusion, Uraemia >7mmol/L, RR >=30, Age >=65 or Abnormal BP <90 or <60
• 1 point for each factor
• Those with score <2 have a low mortality rate and are candidates for outpatient care

Treatment

eTG rationale

• Doxy or macrolides used for CAP treat atypicals and are active against some Strep pneumoniae but due to increasing resistance of S. pneumoniae, should only be used as monotherapy in mild CAP with early review
• If oral cephalosporin is used for CAP due to penicillin allergy, cefuroxime is preferred to cephalexin or cefaclor as higher antipseudomonal activity
• At recommended doses, BenPen remains active against intermediate penicillin resistant S. pneumoniae
• Strains of H. influenzae that produce beta-lactamase and high-level S. pneumoniae resistance to penicillins is uncommon

eTG treatment of CAP

• If outpatient
  • Mild disease:
    • Amoxicillin 1g PO q8h for 5-7 days OR
      • With early review in case of atypical pneumonia
    • Doxycycline 100mg PO q12h for 5-7 days
      • Preferred if atypical pathogen suspected (e.g. young adult Mycoplasma)
      • With early review in case of resistant S. pneumoniae
    • Use both if not improving after 48 hours or from the outset if clinical review not possible
  • Moderate disease
    • Collect blood and sputum samples prior to antibiotic therapy +- additional Ix
    • Always consider influenza and take nasopharyngeal swab PCR + consider empirical antiviral
    • Non-tropical: BenPen 1.2g q6h IV + Doxycycline 100mg PO BD for 7 days
      • Change BenPen to Amoxicillin 1g PO q8h once able
    • Tropical: Same as above unless risk factors for Burkholderia pseudomallei, or Gram-negative bacilli on culture, in which case:
      • Ceftriaxone 2g daily IV + Gentamicin 5mg/kg IV
      • If atypicals considered likely (e.g. non-Indigenous, urban) add doxycycline

• Severe disease
  • Non-tropical
    • Ceftriaxone 1g IV daily OR Cefotaxime 1g IV q8h + Azithromycin 500mg IV daily
    • Add antistaphylococcal if suspected (rapid progression to sepsis, cavitatory or Gram-positive cocci in clusters)
    • Always consider influenza
    • Gram-negative bacilli identified
      • Change Cef to antipseudomonal e.g. Cefepime or PipTaz
      • If severe sepsis also, add gentamicin as second antipseudomonal
    • Switch to oral regime as per moderate CAP once able
    • 7 day course usually adequate (but 8 if aerobic gram-negative bacilli e.g. Klebsiella; 14 if S. aureus or Acinetobacter; 15 if Pseudomonas)
  • Tropical
    • Meropenem 1g IV q8h (wet season)
    • PipTaz 4,5g q6h (dry season)
    • + Azithromycin 500mg IV daily
  • Always consider influenza and/or staphylococcus
• Resistant Strep. Pneumoniae
  • MIC <4 mg/L allows ongoing use of usual penicillins
    MIC >4mg/L means add vancomycin, antipneumococcal fluoroquinolone, teicoplanin or linezolid

Treatment (Tintinalli)

• Outpatient CAP for uncomplicated pneumonia
  • Azithromycin 500mg day 1 then 250mg OD for 5 days
  • Doxycycline 100mg BD for 10-14 days
• Outpatient CAP with significant comorbidities (chronic organ failure, diabetes, alcoholism, malignancies and asplenia)
  • Moxifloxacin 400mg OD for 7-14 days OR
  • Augmentin + Azithromycin
• Inpatient CAP
  • Moxifloxacin 400mg IV OR
  • Ceftriaxone + Azithromycin
• Inpatient HAP
  • Ceftazidime (Pseudomonas) + Ciprofloxacin + Vancomycin (MRSA) OR
  • Meropenem (Pseudomonas) + Ciprofloxacin + Vancomycin (MRSA) OR
  • PipTaz + Ciprofloxacin + Vancomycin
  • Can substitute aminoglycoside for ciprofloxacin and lincomycin for vancomycin
• Inpatient ICU
  • Ceftriaxone + Azithromycin OR
  • Ceftriaxone + Moxifloxacin OR
  • Moxifloxacin + Clindamycin 
  • + Vancomycin (if HCAP or MRSA risk)
• Inpatient with higher Pseudomonal risk
  • PipTaz + Ciprofloxacin OR
  • Aztreonam + Moxifloxacin
  • + Vancomycin if MRSA or HCAP risk

Treatment 

• Fluoroquinolones should not be used in myaesthenia gravis
• Newer fluoroquinolones (e.g. moxifloxacin) cover typical bacterial and atypical agents but should only be used if other agents have failed or documented pneumococcal resistance
• Patients who have received broad-spectrum antibiotics in the last 3 months are at risk of drug-resistant infection
  • Consider a respiratory fluoroquinolone or combination therapy using an aminopenicillin or third-generation cephalosporin with a macrolide
• For patients at risk of Pseudonomas, use two active agents e.g. anti-pseudomonal beta-lactam (PipTaz) or cefepime with a respiratory fluoroquinolone
  • Consider adding an aminoglycoside for dual coverage

Treatment (MetroSouth)

• Mild CAP
  • Amoxicillin 1g q8h PO 5-7 days OR
  • Doxycycline 100mg BD 5-7 days (if atypical suspected or penicillin allergy)
  • If patient not improving at 48 hours or clinical review at 48 hours not possible, consider using both
• Moderate CAP
  • BenPen 1.2g IV q6h followed by amoxicillin 1g q8h PO +
  • Doxycycline 100mg PO BD for 5-7 days
  • If non-immediate penicillin allergy use Ceftriaxone 1g IV daily followed by Cefuroxime 500mg BD PO for 5-7 days
  • If immediate penicillin allergy use moxifloxacin 400mg PO daily for 5-7 days
• Severe CAP
  • BenPen 1.2g IV q4h
  • Gentamicin 4-5mg/kg (7mg/kg in critically unwell patients
  • Azithromycin 500mg IV daily for up to 3 days
• Community-acquired aspiration pneumonia
  • Amoxicillin 1g PO q8h
  • For more severe disease
    • BenPen 1.2g q6h + Metronidazole PO or IV
  • If penicillin allergic use Clindamycin PO or lincomycin IV
• Hospital-acquired pneumonia (>48 hrs in hospital) [including aspiration]
  • Augmentin if mild
  • Ceftriaxone  + Metronidazole if severe for 5-7 days
  • Seek ID advice if known MRSA, previous PipTaz resistance, penicillin allergic or immunocompromised

Gentamicin dosing

• Actual body weight in non-obese patients
• Adjust body weight in obese patients
  • Ideal body weight + 0.4x (Actual-Ideal)
• Daily dosing if CrCl >60 over max 48 hours
• 36 hourly dosing if CrCl 40-60 over max 48 hours

Relative indications for ICU

• Septic shock, mechanical ventilation
• Markedly elevated RR
• P:F ratio <=250
• Multilobar infiltrates
• Confusion
• Uraemia with Urea >20mg/dL
• Leukopaenia, thrombocytopaenia, hypothermia, hyponatraemia, lactic acidosis, asplenia
• PSI Class V or CURB-65 >=3

Oh’s ICU admission criteria

• 3 or more of:
  • SBP <90
  • Multilobar disease
  • P/F <250
  • Confusion
  • Urea >7
  • Leukopaenia
  • Thrombocytopaenia
  • Hypothermia
  • Aggressive fluid resuscitation

Duration of antibiotic therapy

• Courses as short as 5 days should be sufficient
• Should continue until afebrile for 48-72 hours and organ dysfunction largely resolved
• Average time to defervescence
  • 7 days in elderly
  • 2.5 days in young patients with pneumococcal pneumonia
  • 6-7 days in bacteraemic patients with pneumococcal pneumonia
  • 1-2 days in Mycoplasma 
  • 5 days in Legionella
• P. aeruginosa and Mycoplasma may persist in sputum despite effective therapy

If fails to respond?

• Is it pneumonia?
• Complication – Empyema, superinfection, BOOP
• Right drug by correct route?
• Host factors – Obstruction of bronchus, immunosuppression
• Organism resistance?
• Other organisms?
• Is the fever a drug fever?

Treatment of influenza

Neuraminidase inhibitors (such as oseltamivir) have been associated with lower rates of hospitalisations, complications and deaths in systematic reviews of observational studies.

Systematic reviews of RCT’s however, have not demonstrated such benefits.

The conclusion drawn is that the RCT’s recruited mostly healthy young individuals while observational studies included patients at increased risk of morbidity and mortality from influenza pneumonia.

As such, the recommendation in eTG is to offer treatment to patients:

• With established complications
• Who need to be admitted to hospital for management of influenza
• With moderate-to-severe community-acquired pneumonia during influenza outbreaks

The recommendation is to consider treatment in patients at higher risk of poor outcomes including:

• Pregnant women
• Age >65 or <5
• Heart disease
• Down syndrome
• Obesity
• COAD
• Severe neurological conditions
• Immunocompromised
• Aboriginal and Torres Strait Islander peoples
• Homeless
• Residents of aged-care or long-term residential facilities

Treatment can also be considered for patients who are being admitted to hospital or who reside in an aged-care or long-term residential facility or have household contacts who are in the above high-risk groups for prevention of transmission.

Parapneumonic effusions

• May be uncomplicated which resolves with treatment of pneumonia OR
• Complicated
  • Develop over 7-14 days after initial fluid formation
  • Increasing pleural fluid volume
  • Continued fever
  • Pleural fluid pH <7.3
  • Large number of neutrophils
  • May show organisms on Gram stain or culture
• Rx
  • If >1cm thick on lateral decubitus CXR – Aspirate
  • If organisms, turbid or purulent – treat as empyema
  • If not turbid, purulent or organisms
    • If pH <7.0 treat as empyema
    • If pH 7.0-7.2 – serial thoracocentesis
    • If pH >7.2 – Observe

Empyema

• Anaerobic bacteria, usually Streptococci or Gram-negative rods, are responsible for 76% of cases
• Drainage +- surgical therapy is warranted
• If not loculated and no fibrinous peel formed – simple aspiration
  • Intrapleural fibrinolysis may be of benefit
• If loculated or fibrinous peel – surgical decortication (open or thoracoscopic)
• CXR will often show complex shapes abutting the pleura
• Antibiotics with anaerobic cover are required until drainage possible

Disposition

• Up to 50% of patients are still symptomatic at day 30
• Educate about smoking cessation, alcohol moderation, nutrition, hydration, follow-up and pneumococccal/influenza vaccination
• Follow-up CXR
  • Guidelines suggest restricting follow-up CXR at 6 weeks to those at increased risk of malignancy (smokers and those age >50)

Chest X-ray interpretation

• Left upper lobe pneumonia obscures the left heart border (lingula portion)

• Left lower lobe pneumonia obscures the aorta up to the arch and the diaphragm
• ‘More black sign’ – Thoracic vertebrae should get darker as you descend on a lateral CXR. If they do not, this suggests overlying consolidation
• Left upper lobe collapse
  • Collapses anteriorly from top to bottom giving a veiled appearance and loss of left heart border
  • Also look for volume loss (mediastinal shift towards the collapse, diaphragm shift up to collapse and rib space narrowing)

• Right upper lobe collapse
  • Clock arm with Golden S sign

Last Updated on July 15, 2024 by Andrew Crofton