respi patho Flashcards
defences against infection in lungs (3)
- large microbes trapped in mucus -> transported to throat by ciliary action -> swallowed
- cough reflex
- smaller organisms phagocytosed by alveolar macrophage/if enter bloodstream, will incite immune response
which parts of the aiway is sterile
- anywhere below the vocal chords (ie LOWER RESPIRATORY TRACT) -> due to defence mechanisms
main causative organism of acute URTI
viral infection
pathology of rhinitis (2)
INFECTIVE (mostly viral) -> surface epithelial cells necrosis -> exudation of fluid and mucous and swelling -> nasal obstruction
ALLERGIC -> hypersensitive to environmental agent, mast cell degranulation etc -> produce exudate and mucosal edema -> if antigenic stimulus persists, mucosa becomes swollen and polypoid -> formation of nasal polyps
which parts of the sinus is affected in sinusitis
- inflammation of the paranasal sinus linings of ANTERIOR GROUP of sinuses (maxillary, ethmoid and frontal sinuses)
complication of sinusitis
- mucosal edema (edema build up in mucosa forming a small lump) -> impair drainage of secretion -> secondary bacterial infection
clinical presentation of acute laryngitis and pharyngitis (3)
- sore throat (supraglottic)
- hoarseness (glottic)
- cough and tracheal soreness (subglottic)
acute laryngitis and pharyngitis is usually caused by:
viral infection
why is acute laryngitis and pharyngitis dangerous in young children
- children have small airways that are easy to collapse, mucosal & submucosal edema can cause airway obstruction easily
describe breathing sound in children with acute pharyngitis/ laryngitis
stridor
stridor + cough = coup
predisposing factor to chronic laryngitis + pathogenesis
- heavy smokers
- chronic irritation of epithelium cause squamous metaplasia
chronic laryngitis increases risk of:
dysplasia and squamous cell carcinoma
most common laryngeal carcinoma & location
SQUAMOUS CELL CARCINOMA (95%)
- mostly GLOTTIC (can be supraglottic/ subglottic)
risk factors for squamous cell carcinoma of LARYNX
- Smoking (alw associated with SCC)
- Alcoholism
- Asbestos
- Chronic laryngitis
describe benign lesions of the larynx (2)
- singer’s nodules -> stress vocal chords too much; cause HOARSENESS
- laryngeal papilloma/ squamous papilloma -> due to HPV INFECTION
patient presents with facial edema and bronchospasm
allergic pharyngolaryngeal edema
- life threatening Type I hypersensitivity
types of nasopharyngeal carcinoma (3)
- keratinizing NPC
- differentiated nonkeratinizing NPC
- UNDIFFERENTIATED NONKERATINIZING NPC (most common!!! 95% of NPCs)
main risk factors for keratinizing NPC (nasopharyngeal carcinoma) (2)
- EBV INFECTION (at nasopharyngeal epithelium) at young age -> presents as infectious mononucleosis
- family history -> esp SOUTHERN CHINESE
NPC clinical presentations
- hearing loss, tinnitus
- diplopia
- nasal obstruction
- cervical lymph node metastasis
what tests are recommended for people with fam history of NPC? (2)
- EBV IgA antibody -> IgA usually precedes tumour development by a few years
- nasoendoscopy
inhaling hot toxic fumes in a fire cause:
acute toxic laryngitis
three types of atelectasis and their causes (3)
- Resorption -> obstruction of alveoli, O2 in alveoli resorbed thus alveoli collapses
- Compression -> by pleural effusion/ haemothorax/ pneumothorax
- Contraction -> lung fibrosis cause loss of surfactant -> alveoli collapse
what does atelectasis predispose a patient to
- INFECTION due to mucus trapping
- and hypoxia
bronchiolitis pathogenesis
- inflammation of airway diameter <2mm (BRONCHIOLES)
- macrophage infiltrate airways, cause SCARRING & NARROWING -> obstruction of airway
bronchitis vs bronchiolitis (2)
- difference in region infected (bronchi vs bronchiole)
- bronchitis have MUCUS production (hyperplasia of mucus glands are seen in CHRONIC bronchitis)
causative organism for bronchitis/ bronchiolitis
VIRUSES
- eg influenza tracheobronchitis, respiratory syncitial virus (RSV) bronchiolitis
broncho pneumonia pathogenesis & complications
- bronchi infected -> spread to bronchioles & alveoli
complication: lung abscess
lobar pneumonia pathogenesis & complications
- Organisms begin infection from bronchioles & alveolar space (does not start from bronchi)
complication: bacteremia
common organism in lobar pneumonia
S pneumonia, Klebsiella
aspiration pneumonia pathogenesis & complication
- swelling or aninfectionof the lungs/ large airwaysdue tounconscious/ impaired swallowing
complication: lung abscess
aspiration pneumonia causative organisms
causative organisms: oropharyngeal bacteria, anaerobes
IMAGING: pneumonia
- basically opaque white block (usually at bottom of lung), no pulmonary vessels
- differentiate from pleural effusion: pneumonia still HAS costophrenic angle
- differentiate from mass: pneumonia has poorly defined margins
what is lung abscess
localized area of suppurative necrosis, usually forming large cavities
what causes lung abscess (6)
- broncho pneumonia
- aspiration pneumonia
- septic emboli (eg Staph aureus)
- trauma
- bronchiectasis -> bronchial obstruction -> accumulate mucus -> infection & necrosis
- pulmonary infarction -> necrosis
complications of lung abscess (4)
- Empyema (rupture into pleura)
- Bronchopleural fistula
- Haemorrhage from erosion into pulmonary vessel
- Septicaemia
lung abscess vs empyema
- lung abscess involves LUNG PARENCHYMA
- empyema involves PLEURAL SPACE
lung abscess contains mainly?
neutrophils
atypical pneumonia causative organisms
- Mycoplasma (#1), legionella, chlamydia, rickettsia
IMAGING & presentation: atypical pneumonia
- absence of consolidation on Xray due to minimal airspace exudate
- interstitial inflammation (pneumonitis) thus increase interstitial markings in Xray
presentation:
- symptoms of pneumonia
what type of hypersensitivity is hypersensitivity pneumonitis
- Acute exposure –> type III hyper sensitivity response –> respiratory 4-8 hours after exposure
- Repeated exposure -> sensitisation and type IV hypersensitivity reaction –> insidious development of dyspnoea and pulmonary fibrosis in a patient that has not experienced acute symptoms
IMAGING: pneumonitis
pneumonitis:
- inflammatory disease dominated by interstitial inflammation -> increase interstitial markings in Xray
TB histo presentations (3)
- Granuloma (epithelioid histiocytes surrounding area of central caseous necrosis)
- Multinucleated giant cells
- Lymphocytes
risk factors for TB
- poverty, crowded, endemic areas
- immunocompromised: diabetes, HIV
- alcoholic
- chronic lung diseases
complications of pri TB (uncommon)
progresses with severe pneumonia & dissemination
- continuing enlargement of the caseating granulomas in the lymph nodes
- spread occurs by the enlarging nodes eroding either
1) through wall of a bronchus (tuberculous bronchopneumonia) 2) into a thin-walled blood vessel (miliary TB)
primary vs secondary TB
- lymph node involvement more evident in pri TB -> secondary TB immune cells immediately activated to contain infection
- secondary TB found at apex of lung in CXR, pri TB at lymph nodes
- secondary TB cause increase tissue destruction (greater immune response)
complications of secondary TB
Vigorous immune response:
healing of apical lesion -> leave central area of caseous necrotic material (may contain bacteria) surrounded by dense collagenous wall -> calcifies (fibrocaseous TB)
* If immune response weakens and still have bacteria -> reactivated fibrocaseous tuberculosis
Poor immune response:
progressive enlargement of apical lesion -> continued destruction of lung tissue
* Bigger lesion -> increase risk of erosion into blood vessels or airways
IMAGING: secondary TB
- TB always found at APEX of lungs (highest pO2)
- little lymph node involvement (granuloma is contained in CXR) as immune system recognises and contains it
IMAGING: miliary TB
- millet seed appearance (many white spots all over lung)
bronchiectasis pathogenesis
permanent abnormal dilation of main bronchi -> cycle of inflammation, mucus secretion, infection, airway dilation/destruction
bronchiectasis clinical presentations (3)
- recurrent infection
- hemoptysis
- mucopurulent sputum production lasting months to years