Resp Flashcards
Is infective rhinitis viral or bacterial in origin?
Viral
what is infective rhinitis also known as?
common cold
what is allergic rhinitis also known as?
hay fever
causes of acute and chronic sinusitis
Acute:
Extension of acute / chronic rhinitis
Chronic:
Sequel of acute sinusitis
complications of sinusitis
In severe cases, infection can spread to meninges to cause meningitis (roof of paranasal sinuses is directly in contact with base of brain)
what are the 3 types of nasopharyngeal carcinoma?
Non-keratinising carcinoma (95% of NPCs)
Keratinising squamous cell carcinoma
Basaloid squamous cell carcinoma
what is nasopharyngeal carcinoma also known as?
cantonese cancer
risk factors for nasopharyngeal carcinoma
- EBV infection at young age
- salt-preserved food
- genetic factors
Smoking, alcohol - for keratinising squamous cell carcinoma
what percentage of NPCs are non-keratinising carcinomas?
95%
clinical features of NPC
- Largely asymptomatic until it spreads out of the nasopharynx
1. Obstruction of eustachian tube
2. Secretory otitis media leading to hearing loss and tinnitus
screening tests for NPC
- Screening test
- Antibody against EBV viral capsid antigen
- In Singapore
- annual screening (EBV IgA antibody test & nasoendoscopy) is recommended for people with strong family history
what are Squamous/laryngeal papilloma caused by
Caused by HPV infections
what is the most common malignant neoplasm of larynx and what is the percentage
Squamous cell carcinoma (most common: 95%)
what is a strongly associated cause of Squamous cell carcinoma of the larynx
smoking
3 types of Squamous cell carcinoma of the larynx
glottic, supraglottic, subglottic
presentation and prognosis of glottic Squamous cell carcinoma of the larynx
- Presents early with hoarseness, lower stage at presentation
- slow to metastasise, good prognosis
type 1 vs type 2 respiratory failure
Type 1 Respiratory failure:
- Hypoxaemia without hypercapnia
- Inability to maintain oxygen levels but able to ventilate hence carbon dioxide levels are normal
Type 2 Respiratory failure:
- Hypoxaemia with hypercapnia
- Component of poor ventilation resulting in retention of CO2
main cause of pulmonary oedema
pulmonary capillary congestion
clinical features of pulmonary oedema
- Frothy & pinkish phlegm
- Haemosiderin-laden macrophages
causes of pulmonary arterial hypertension
- Secondary to Left sided heart disease (most common)
- Congenital left-to-right shunts
- Chronic lungs disease
complication of pulmonary arterial hypertension
cor pulmonale - heart failure secondary to lung disease, esp. right heart failure
3 pathological classifications of pneumonia
lobar pneumonia, bronchopneumonia, atypical pneumonia
usual pathogens of lobar pneumonia
Streptococcus pneumoniae, Klebsiella
who is bronchopneumonia usually seen in?
Usually seen in infancy, old age & immunocompromised individuals
usual pathogens of atypical pneumonia
Mycoplasma, Chlamydia, Rickettsia, some viruses
morphology of lobar pneumonia
- Gross
- Consolidation of whole or part of a lobe, causing ‘hepatisation’ (firm, airless)
- Histology
- Red hepatisation
- Massive confluent exudation with neutrophils, red cells & fibrin filling the alveolar spaces
- Grey hepatisation
- follows red hepatisation
- Red hepatisation
morphology of bronchopneumonia
Gross:
Patchy areas of consolidation that may become confluent
morphology of atypical pneumonia
Gross:
No findings of consolidation
Histology:
No alveolar exudation/consolidation
5 clinical classifications of pneumonia and their causes
- Community-acquired pneumonia
- Usually caused by Gram + bacteria
- Streptococcus pneumoniae (most common)
- Hospital acquired pneumonia
- Usually caused by gram negative rods
- Viral pneumonia
- Aspiration pneumonia
- Usually due to unconsciousness or impaired swallowing
- Frequently leads to lung abscess
- Opportunistic pneumonia
- In immunocompromised patients
complications of pneumonia
Lung Abscess
Bronchopneumonia: focal fibrosis
Atypical pneumonia: interstitial fibrosis
lung abscess causes
- Aspiration pneumonia (most common cause)
- Infection by Staphylococcus aureus
lung abscess clinical features
- Cough with foul-smelling purulent sputum
- Clubbing
complications of lung abscess
- Rupture in pleural space, causing empyema and pneumothorax
- Haemorrhage from erosion into a pulmonary vessel
what is the pathogen that causes pulmonary tuberculosis
mycobacterium tuberculosis
risk factors for pulmonary tb
- Poverty, crowded, endemic areas
- immunocompromised: diabetes, HIV
- Alcoholism
- Chronic lung diseases
3 types of pulmonary TB
- Primary tuberculosis
- Occurs in individuals not exposed to mycobacteria before (unsensitized) or in immunosuppressed
- Secondary tuberculosis (post-primary tuberculosis)
- Occurs in previously exposed, sensitised people
- Main presentation in immunocompetent adults
- Miliary TB
- Occurs when the infection spreads through the bloodstream to other organs
important clinical features of tb
Cervical lymphadenopathy
Fever
Night sweats
Weight loss
Chronic cough
morphology of primary tb
formation of ghon focus
outcomes of primary tb
- Complete resolution via cell mediated immunity in 95% of cases
- Latent tuberculosis
- viable organisms may lie dormant in these foci for decades
- Progressive primary tuberculosis (uncommon)
- Latent tuberculosis
pattern of miliary tb
Distinctive pattern on chest X-ray with many tiny spots distributed throughout lung fields with appearance similar to millet seeds
morphology of secondary tb
apical lesion with formation of assman focus
outcome of secondary tb
Healing & Fibrocaseous TB
- in adults with vigorous immune responses, healing of the apical lesion occurs results in fibrocaseous TB
- May reactivate in later life if immune system is weakened, latent tuberculosis becomes a reactivated fibrocaseous TB
diagnostic tests for active tb
Microscopy:
Ziehl-Neelsen stain (for confirmation)
Auramine phenol fluorescence technique (for screening)
Gold standard:
Tb culture (more sensitive but takes 2 months)
diagnostic tests for latent tb
no gold standard diagnostic test for LTBI
2 imperfect tests:
TST (tuberculin skin test)
IGRA (Gamma Interferon (IFN-γ) Release Assay)
four first line drugs for Tb
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
difference between obstructive and restrictive lung disease
obstructive: Normal total lung capacity, reduced expiratory flow rate
FVC normal or slightly decreased, while FEV1 is greatly decreased leading to decreased FEV: FVC ratio
restrictive: Reduced total lung capacity, normal expiratory flow rate
examples of obstructive and restrictive lung disease
obstructive: COPD, bronchiectasis, asthma
restrictive: diffuse parenchymal lung disease
2 types of bronchial asthma
Allergic / atopic asthma:
- Type I hypersensitivity reaction (IgE-mediated)
- Triggered by allergens (e.g. certain food, drugs, animal allergens)
Non-atopic asthma:
- Hypersensitive airways can be triggered by irritants (e.g. URTI, strenuous exercise, air pollution, second hand smoke)
- Occupational and environmental triggers are important to ask about
What is the main abnormality in the pulmonary function test in COPD?
FEV1/FVC < 0.7, where FEV1 is the forced expiratory volume in the first second, while FVC is the forced vital capacity.
causes of COPD and what they are
Emphysema:
Permanent dilation of air spaces distal to the terminal bronchiole without fibrosis
Chronic bronchitis:
Clinically defined as persistent cough with sputum production for at least 3 months in at least 2 consecutive years
difference between the 2 types of patients pink puffers and blue bloaters
Pink puffers:
- patient has pink complexion, obvious breathing effort
- emphysema is primary underlying pathology
- no CO2 retention and there is adequate oxygenation of haemoglobin hence patients are pink
- patient compensates for less surface area for gaseous exchange by hyperventilating
Blue bloaters:
- chronic bronchitis is primary underlying pathology
- marked ventilation/perfusion mismatch → good perfusion but poor ventilation
- poor ventilation results in combined hypoxaemia & hypercapnia
morphology and histology of emphysema
Gross:
- Blebs & bullae (air-filled spaces)
Histological:
- Dilation of alveolar spaces
What are the complications of COPD
- Cor pulmonale leading to right ventricular failure
- Hypoxemia leading to respiratory failure
- Rupture of bullae leading to pneumothorax
what are diffuse parenchymal lung diseases and their clinical features
Group of disorders characterised by widespread inflammation predominantly in the interstitium
Clinical Features*
- Reduced compliance of lungs
- Oedema (in acute form) & Fibrosis (in chronic form) of alveolar walls
what is ARDS and its causes
Acute Respiratory Distress Syndrome (ARDS): Severe form of acute diffuse parenchymal lung disease
Causes:
- Systemic sepsis
- Severe trauma/ burns
- Inhalation of toxic fumes
what is the end stage of ALL interstitial lung disease and what is it known as
Chronic pulmonary fibrosis
- known as honeycomb lung
what is the most common cause of cancer related deaths worldwide
lung cancer
routes of spread and metastases of lung cancer
- Local spread to adjacent lung parenchyma
- Lymphatic spread to regional lymph nodes
- Transcoelomic spread to pleural space, pericardium
- Haematogenous spread to distant organs
classifications of lung cancer
non small cell lung carcinoma
- squamous cell carcinoma (central)
- adenocarcinoma (peripheral)
small cell lung carcinoma (central)
associations and histology of squamous cell carcinoma
associations:
- Commonest in males, often central
- High association with a history of smoking
histology:
- Squamous differentiation with keratin pearls
associations and histology of adenocarcinoma
association:
Not much association with smoking (equal incidence in smokers and non-smokers)
histology:
Bronchioalveolar carcinoma (BAC)
- looks like a consolidation rather than mass on chest X-ray
associations and clinical features of small cell lung carcinoma
associations: strong relationship with smoking
clinical features:
- Poor prognosis
- Tumour cells show neuroendocrine differentiation
prognosis of lung cancer and reasons for prognosis
All subtypes of lung cancer have a dismal prognosis: Majority diagnosed are stage IV
Reasons for poor prognosis
- No early symptoms
- Only way to pick up small lesions are by CT scan
- Metastatic spread is present in most (>50%) patients at presentation - Many patients present with symptoms caused by metastatic disease
transudate vs exudate in pleural effusion
- Transudate: Low protein fluid, due to high hydrostatic pressure, low oncotic pressure
- cardiac failure, hypoalbuminemia
- Exudate: High protein fluid, due to increased capillary permeability or inflammation
- bacterial infections (pneumonia, tb)
- carcinomas
