L11 Lower Respiratory Tract Infections Flashcards
Pneumonia Pathogenesis?
Colonized by pathogen => inflammatory response => Fluid buildup in alveoli
Typical Causes of Community Acquired Pneumonia?
Streptococcus pneumoniae (Most Common)
- Haemophilus influenzae*
- Moraxella catarhalis*
- Staphylococcus aureus*
- Klebsiella pneumoniae*
Clinical Features of Typcial Community Acquired Pneumonia (CAP)
Clinical Features:
Acute onset
Fever
Rigors
Dyspnoea
Cough
Sputum
Pleuritic chest pain
Atypical causes of Community-Acquired Pneumonia (CAP)
Atypical Causes:
Nonzoonotic:
Legionella pneumophilia (Hotels/Gyms/Cruises)
Mycoplasma pneumoniae
Chlamydophilia pneumoniae
Zoonotic:
Chlamydophila psittaci
Coxiella burnetti (Q fever)
TB
Respiratory Viruses
Clinical Features of Atypical Community-Acquired Pneumonia (CAP)
Clinical Features:
Subacute onset
Fever
Dry cough
Extrapulmonary symptoms
Fatigue
Headache
Confusion
Nausea
Vomiting
Diarrhoea
Myalgia
Investigations for Pneumonia?
Investigations for Pneumonia?
Blood Tests:
Full blood count (FBC) - check for elevated WBC
Urea and electrolytes (U&E)
C-reactive protein (CRP) - increases in pneumonia
ABG - oxygenation of radial artery
Microbiology:
All patients w/ Pyrexia (fever) :
Blood culture (BEFORE antibiotics)
Sputum Culture** **Appearance: (Less effective for elderly w/ poor cough reflex)
Mucopurulent: bacterial pneumonia or bronchitis
Rusty: pneumococcal pneumonia
Scant or watery: mycoplasma or viral pathogens
Malodorous: aspiration
Pneumococcal/legionella Urinary Antigen
Pleural fluid culture
XRAY:
Lobar - bacterial
Diffuse Bilateral Infiltrates – viral, pneumocystis, atypical pathogen
Lower lobes are most commonly involved regardless of etiology
Radiology lags behind clinical improvement- Must repeat X-Ray 6 weeks after release
Invasive TestInvasive Test
Broncho-alveolar lavage (BAL): Only for those w/ severe Pneoumia and failure to respond to treatment
Sputum Culture Appearance for Pneumonia?
Sputum Culture** **Appearance for Pneumonia
Mucopurulent: bacterial pneumonia or bronchitis
Rusty: pneumococcal pneumonia
Scant or watery: mycoplasma or viral pathogens
Malodorous: aspiration
X RAY for Pneumonia:
Most Commonly Impacted?
When to Repeat scan?
XRAY for Pneumonia:
Lobar - bacterial
Diffuse Bilateral Infiltrates – viral, pneumocystis, atypical pathogen
Lower lobes are most commonly involved regardless of etiology
Radiology lags behind clinical improvement- Must repeat X-Ray 6 weeks after release
Blood Tests for Pneumonia?
Blood Tests:
Full blood count (FBC) - check for elevated WBC
Urea and electrolytes (U&E)
C-reactive protein (CRP) - increases in pneumonia
ABG - oxygenation of radial artery
Assessment of Pneumonia Severity?
CURB65 score: Determine Admission to hospital and Empiric Treatment
1 Point for each parameter
Confusion
Urea >7mmol/L
Respiratory rate >30/min
Blood pressure sBP<90mmHg and/ or dBP <60mmHg
Age >= 65years
+ Clinical judgment:
Hypoxia, hypercapnia, acidosis
Stability of underlying illness
Social circumstances
Empiric Treatment for Community-Acquired Pneumonia?
Typical: Typically treat with Co-Amoxiclav => Flucloxacillin if resistant
Atypical: Penicillin not effective, Clarithromycin/Doxycycline
Complications of Pneumonia?
Complications of Pneumonia:
Pleural effusion=> Empyema
Bacteremia (bloodstream infection)
Lung Abscess
Obstruction (Sputum plug => atelectasis)
Sepsis, severe sepsis, septic shock
Adult Respiratory Distress Syndrome (ARDS)
Renal Failure
Metastatic infection: Meningitis, septic arthritis, endocarditis
Prevention of Pneumonia?
Prevention of Community:
- Pneumococcal vaccination
- Influenza vaccination
- Smoking cessation
Prevention of HAP:
- Good infection prevention and control practice
- Yearly staff Influenza vaccination
- Maintain upright position and mobility
- Avoid sedatives if possible
Most common Nossicomal Disease contributing to death?
Hospital-Acquired Pneumonia (HAP)
Pneumonia develops >48 hours post-admission
Transmission of Hosptial Acquired Pneumonia
Aspiration of contaminated oropharyngeal secretions
Inhalation of contaminated respiratory droplets (influenza) or Aersol (TB)
Contaminated Water => Legionella spp.
Risk Factors for Hosptial Acquired Pneumonia
4 common Causes of Hospital-Acquired Pneumonia?
Gram Negative and Resistant Bacilli more common, often multidrug resistant
E. coli
Klebsiella pneumoniae
Enterobacter spp.
Pseudomonas aeruginosa
Treatment for hospital acquired pneumonia
Agent with activity against Gram negative bacilli (Piperacillin/Tazobactam)
__________________: Fluid or food aspirated into the lung => secondary inflammation
4 Potential Outcomes?
Patients at risk?
Microbiology?
Aspiration Pneumonia: Fluid or food aspirated into the lung => secondary inflammation
Outcomes of aspiration:
- Chemical pneumonitis (gastric acid)
- Obstruction of airway secondary to particulate matter (food)
- (Bacterial) aspiration pneumonia
- Lipid Pneumonia (From inhaled mineral oil => lipid-laden macrophages fill alveoli)
Patients at risk:
Elderly
Neurological impairment: stroke, dysphagia, cerebral palsy, motor-neuron disease, cranial nerve palsy, dementia
Impaired conscious level: Sedative medication, post seizure
Gastric disorders eg. GORD
Microbiology
Anaerobic bacteria
Staphylococcus aureus
Streptococci
Enterobacteriaceae
Pneumonia in the Immunocompromised?
Pneumonia in the Immunocompromised
- Regular pathogens in community / hospital setting
- Reactivation of latent / dormant infections (TB)
- Opportunistic infections (Fungi => Concerning if pyrexia after a few days )
Pleural Effusion vs. Empyema
Pleural Effusion= Buildup of fluid in Pleural Space, Lungless able to expand
Empyema = Pus in the pleural space
Epidemiology/Risk Factors for Pleural Effusion
Epidemiology:
Mostly pediatric or elderly
57% of patients w/ pneumonia develop pleural effusion => risk of development to empyema w/ inappropriate therapy
Risk Factors
Extremes of age
Diabetes mellitus
Alcohol misuse
Immunosuppression
Corticosteroids
Gastroesophageal reflux disease
Clinical Features and Diagnosis of Pleural Effusion
Clinical Features
Pneumonia with unresolving features of infection persistent
Pyrexia
Dyspnea
Raised inflammatory markers WCC, CRP
Pleuritic chest pain
Diagnosis
Clinical suspicion
Chest XR: Pleural effusion
Pleural Fluid Aspiration: Appearance of fluid: clear/purulent
Most common Lower Respiratory Tract Infection during first year of life?
Bronchiolitis
