Pulmonary Sepsis Flashcards
components of the upper respiratory tract
- nose
- sinus
- larynx
- trachea
components of the lower respiratory tract
- bronchi
- terminal bronchi
- lung parenchyma
characteristics of lower pulmonary sepsis
- serious
- mortality/morbidity risk
- secondary to irritants
name the defense mechanisms of the respiratory tract
- nasal hair
- saliva
- filtering function of nasopharynx
- cough reflex
- mucociliary apparatus
- secretion of IgA
- phagocytic activity by alveolar macrophages
- alveolar fluid
- cell mediated immunity
causes of primary infection
- viral
- bacterial
- atypical bacteria
- fungi
causes of secondary infection
- irritants
- bacterial following a viral infection
- long-standing cold
commonest viral organisms to cause upper respiratory tract sepsis
- rhinovirus
- adenovirus
- influenza
- RSV
characteristics of rhinovirus
- no cross immunity between different serotypes
infections caused by adenovirus
- pharyngitis (sore throat)
- conjunctivitis
infections caused by influenza virus
- upper resp tract
- fever
- lassitude
- depression
- primary influenzal pneumonia
what infection does croup cause?
- laryngotracheobronchitis
- bronchiolitis in children
what kind of virus causes croup?
RSV
characteristics of URT bacterial sepsis
- uncommon in developed countries
- secondary to viral infections
- 2 main bacteria: strep pyogenes, haemophilus influenzae
characteristics of bacterial acute laryngitis
- HIB or strep pyogenes
- swellling
- inability to breath (mechanically)
what kind of infection is trigged from irritative occupational hazards
- acute laryngitis and tracheitis
- irritation by smoke, corrosives, noxious gases
- oedema with obstruction
what is pneumonia?
infection of the alveolar spaces, causing alveolar exudates, polymorph infiltration, fibrin, oedema fluid resulting in consolidation
morphological classification of pneumonia
- bronchopneumonia
- lobar pneumonia
infective causes of bronchopneumonia
- strep pneumoniae
- haemophilus influenzae
- moraxella catarrhalis
- staph pneumonia
- klebsiella
- pseudomonas aeruginosa
- coliform bacteria
- chlamydia
- legionella pneumophilia
- tuberculosis
- mycobacterium avium-intercellulare
how does bronchopneumonia develop?
- inflammation centred onto the bronchi
- spreads out to cause inflammation in the alveoli
histological characteristics of bronchopneumonia
- polymorphs and fibrin infiltration
- spread to adjacent alveoli
- patchy foci coalsce
- frequently widespread and bilateral
- rarely heals with fibrosis
how does lobar pneumonia develop?
- starts in the alveoli
- spreads to the bronchioles luminally as the exudate flows out
histological characteristics of lobar pneumonia
- polymorphs, fibrin, oedema fluid in alveoli
- all or most of the lobe is affected here
- consolidation present
aetiology of pneumonia
- bacterial
- fungal
- viral
- aspiration
- radiation (like radiotherapy)
- allergic mechanisms
which bacteria are associated with smokers and COPD?
- strep pneumoniae
- haemophilus influenzae
- moraxella catarrhalis
which organisms are associated with HAP?
- klebsiella
- pseudomonas aeruginosa
- coliform bacteria
which organisms are associated with immunosuppression?
- mycobacterium avium-intercellulare
- pneumocystis jirovecii
- aspergillus fumigatus
which bacteria causing pneumonia are gram positive?
- strep pneumoniae (diplococci)
- staph aureus (cocci)
which bacteria causing pneumonia are gram negative?
- haemophilus influenzae (coccobacillus)
- moraxella catarrhalis (diplococci)
- klebsiella (rods)
- pseudomonas aeruginosa (rods)
- legionella
infective causes of CAP
- strep pneumoniae
- haemophilus influenzae
- moraxella catarrhalis
- staph aureus
- legionella
- klebsiella
- pseudomonas
- mycoplasma
- chlamydia
- coxiella
- viruses
cause of aspiration pneumonia
anaerobes
pathogenesis of pneumonia
- suppression of the cough reflex
- impaired ciliary function
- impaired phagocytic activity
- pulmonary oedema and congestion
- secretions
- low host resistance
- virulent infections
how can the cough reflex be suppressed?
- coma
- anaesthesia
- drugs
- aspiration
how can the ciliary function be impaired?
- cigarette smoke
- hot gases
- corrosives
- viruses
how can phagocytic activity be impaired?
- alcohol
- tobacco
- smoke
- excess oxygen
how can host resistance be depleted?
- chronic disease
- immune deficiency
- immunosuppression
- leucopenia
- chemotherapy
which populations are more vulnerable to pneumococcal infections?
- chronic disease
- immunodeficiency syndromes
- poor splenic function
clinical/investigative characteristics of CAP
- either morphological pattern
- sputum: gram-positive diplococci, neutrophils
- some are penicillin-sensitive
stages of an acute pneumonia
- congestion
- red heparisation
- gray heparisation
- resolution
characteristics of red heparisation
- lung becomes like a liver
- alveoli packed with polymorphs, red cells, fibrin
characteristics of gray heparisation
- dry, gray firm lung
- lysis of red cells
- fibrinouus exudate persists
characteristics of resolution
- digestion of exudates
- resolution of pleura
- formation of adhesions
what stages do pneumonia patients go through nowadays?
if the correct treatment is given, they go directly into the resolution phase
complications of pneumonia
- pleurisy/pleural adhesions (due to fibrin formation in the lung)
- lung abscess
- alveolar fibrosis
- empyema
- bacteraemia
what is septicaemia?
when bacteria and their toxins circulate in the blood
causes of lung abscesses
- aspiration of infected material, gastric contents
- necrotising or suppurative pneumonia
- bronchiectasis
- bronchial obstruction
- septic emboli
- haematogenous spread
contents of lung abscesses
- anaerobic bacteria from mouth commensals
- staph aureus and B-haemolytic streptococci, nocardia and gram negative organisms
how do you treat lung abscesses?
drainage and antibiotics
pathological characteristics of viral pneumonia
- interstitial pneumonia
- interstitial infiltrate
- no alveolar exudate
causes of viral pneumonia
- influenza virus type A+B
- RSV
- adenovirus
- rhinovirus
- coronavirus (yep)
what is bronchiectasis?
- abnormal permanent dilatation
- happens in the lower limbs, distal bronchi and bronchioles
- associated chronic infection
causes of bronchiectasis
- localised obstruction (tumours, foreign bodies, mucus, chronic bronchitis)
- congenital (CF, immunodeficiency, immotile cilia)
- necrositing or suppurative pneumonia (virulent organisms - staph aureus, klebsiella, tuberculosis)
- symptoms precipitated by URTI or new pathogens
pathogenesis of bronchiectasis
- obstruction - air resorbed from distal airways
- atelectasis - loss of elastic tissue in interstitium - fibrosis attaches lung to pleura
- dilatation of proximal airways due to pressure of inspired air
- becomes irreversible if:
- obstruction persists especially during growth
- persistent infection - bronchial wall ulceration, inflammation and further dilatation
complications of bronchiectasis
- lung abscess
- cor pulmonale
- metastatic brain abscesses
what is cor pulmonale?
abnormal enlargement of the right side of the heart as a result of disease of the lungs or the pulmonary blood vessels
