interstitial lung disease Flashcards
(27 cards)
INTERSTITIAL LUNG DISEASE
(I.E. PULMONARY FIBROSIS)
* Multitude of diseases that cause — of the — / — , resulting in restrictive defect on
pulmonary function
▪ Occupational / environmental:
o Inorganic
o Organic
▪ Idiopathic:
o — , — , Langerhans cell —
▪ Drug / treatment:
o E.g. amiodarone, bleomycin, radiotherapy etc.
▪ Connective tissue disorder associated
o SLE, Rheumatoid arthritis, scleroderma, dermatomyositis
▪ Post infectious:
o TB
fibrosis
pulmonary parenchyma / interstiitum
IPF , sarcoidosis , histocytosis
INTERSTITIAL SPACE:
The interstitial space is defined as — connective tissue throughout the lung ( — walls and — ) composed of
three subdivisions:
* Bronchovascular: area surrounding the — , – and — from the – of the — to the respiratory —
* Parenchymal: situated between the — and — membranes
* Subpleural: situated — the pleura, as well as the —
loose connective tissue
alveolar wall and septa
bronchi , artries , veins
root of lungs
resp bronchiole
alveolar and capillary basement membrane
beneath
interlobular septa
DIAGNOSIS REQUIRES
CLINICOPATHOLOGICAL CORRELATION:
* Interstitial lung disease is diagnosed by a combination of — features in combination with clinical signs and symptoms, but can be diagnostically and therapeutically challenging!!
* The interstitium of the lung is not normally visible radiographically; it only becomes visible when it involved in a disease process, which increases its — and —
* Hallmark of this disease is — or —
radiologically
volume or attenuation
fibrosis or scarring
FIBROTIC LUNG :
* As the alveolar walls become fibrotic and scarred, — of oxygen and carbon dioxide is impaired, resulting in lack of oxygen transfer to blood, causing — and —
CLASSIFICATION OF INTERSTITIAL LUNG
DISEASE:
* Many ways, some confusing!
* Aetiology
* Radiology
▪ Based on zones of fibrosis
- Upper, mid, lower, widespread
* Histology
diffusion
hypoxiema and dyspnoea
AETIOLOGY
* Occupational / environmental:
▪ —
▪ —
* — :
▪ IPF, sarcoidosis, Langerhans cell histiocytosis
* Drug / treatment
▪ E.g. amiodarone, bleomycin, radiotherapy etc.
* Connective tissue disorder associated
▪ SLE, Rheumatoid arthritis, scleroderma, dermatomyositis
* Post infectious:
▪ –
1- OCCUPATIONAL / ENVIRONMENTAL
* Inhalation of dusts, fibres (i.e. air contaminants)
*— : defined as a disease of the lungs due to
inhalation of dusts / particles; often related to occupation
* Inorganic (mineral dust pneumoconisoses):
▪ — , — , — , –
* Organic
▪ Extrinsic — alveolitis / —
pneumonitis
▪ Mouldy — , bird — , –
organic and inorganic
idiopathic
tb
Pneumoconiosis
Asbestosis( mining , fabrication , instal or remove ) , silicosis,( sand blasting and ceramics , stone cutting ) coal, Beryllium ( nucelar eenegry and aircraft )
allergic , hypersensitivity
Mouldy hay, bird faeces, cotton fibres
NATURE OF DUST INFLUENCES TYPE OF
LUNG DISEASE:
* Some dusts do little harm
* Others cause widespread lung – and —
* Factors that influence pathogenicity include:
▪ —
▪ –
▪ — composition
▪ —
▪ –
▪ Particle —
▪ — of exposure
▪ Co-existence of other lung diseases
▪ Particle size and shape
* Particles — um may reach alveoli – most dangerous size
* Particles >— um are unlikely to reach distal alveoli
* <– um tend to act like gases and move into and out of alveoli without causing —
* Shape - > Long and thin e.g. asbestos
destruction and fibrosis
size shape
chemical composition
concentration and solubility
particle reactivity
duration
1-5
>5-10
<0.5
doest cause damage
COAL WORKERS PNEUMOCONIOSIS
* Coal: carbon, trace metals, inorganic minerals, crystalline silica
* Spectrum of disease is wide
▪ Pulmonary anthracosis:
- Most — coal induced pulmonary lesion
- Commonly seen in urban — and —
- Inhaled carbon pigments taken up be alveolar — , accumulate in — along lymphatics and in lymph nodes
▪ Simple coal workers’ pneumoconiosis (CWP)
▪ Complicated CWP
▪ — syndrome
innocuous ( not harmful )
urban dwellers and smokers
macrophages
connective tissue
Caplan syndrome
SIMPLE COAL WORKERS
PNEUMOCONIOSIS:
* — dust accumulation around respiratory —
* Characterised by coal — and larger coal —
* Macules consist of dust —
* Nodules are a collection of —
* — zone predominant
* Can eventually cause — of alveoli leading to
—-
* Usually not functionally —
COMPLICATED COAL WORKERS
PNEUMOCONIOSIS:
* Also called —
* Develops after — years
* Occurs on a background of — CWP by coalescence of the coal —
* Intensely — ; usually multiply
* Microscopically the lesions consist of dense — and — , often with — due to —
* — zone predominant
* Massive confluent —
* Minority of cases lead to increasing pulmonary — , pulmonary — and —
* Progression of CWP to PMF linked to coal dust — level and total dust —
focal dist
resp bronchioles
coal macules and larger coal nodules
dust laden macrophages
collagen fibres
upper
dilation
centrilobular emphysema
disabling
progressive massive fibrosis
10-20
simple
coal nodules
black scar
dense collagen and pigement
central necrosis bc of ishcemia
upper
fibrosis
dysfunction , hypertension , cor pulmonale
exposure and burden
COAL WORKERS PNEUMOCONIOSIS
CAPLAN SYNDROME
* Definition: Co-existence of
—- with a pneumoconiosis leading to the
development of distinctive –
pulmonary lesions that develop fairly
rapidly
* Nodules exhibit —-
surrounded by pallisading fibroblasts,
plasma cells, macrophages containing coal dust and collagen
* This syndrome also occurs in — and –
rheumatoid arthritis
nodular
central necrosis
asbestosis and silicosis
SILICOSIS
* Caused by — of —
* Silica occurs in crystalline and amorphous forms, but — forms (quartz, cristobalite, tridymite) are more
toxic and fibrogenic
* Occupations:
▪ Rock cutting
▪ Mining
▪ Drilling
▪ Tunnelling
▪ Stonemasons
▪ Sandblasters
▪ Glass and pottery making
inhalation of crystalline silica
crystalline
Several forms of Silicosis
* Acute silicosis:
▪ Exposure to very — levels of silica; develops — after exposure
▪ Rapid onset — , cough, — and
respiratory failure
▪ Histology: Interstitial — and accumulation of — fluid in alveolar spaces
* Chronic ( — ) silicosis:
▪ Inhalation over a — period of time
▪ Formation of characteristic — nodules
▪ — zone and — predominant
* Complicated (conglomerate) silicosis:
▪ Progression of — silicosis
▪ Expansion and coalescence of nodules, destruction of lung parenchyma (PMF)
* Other pulmonary disease associations
▪ Increased risk of —
▪ – syndrome
▪ Lung —
▪ Clinical course: Progressive respiratory failure, pulmonary hypertension and cor pulmonale
high
quickly
tachypnea m cynosis
interstitial inflammation
proteinacoeis fluid
nodular
prolonged
fibrotic silicotic nodules
upper and sub pleural
chronic
tb
Caplan
carcinoma
ASBESTOSIS
* Due to — of —
* Asbestos is a family of —
* Sources of asbestos:
▪ Construction materials
▪ Insulation products
▪ Cement
▪ Roofing material
▪ Electric motor components
▪ Textiles
* Different fibre types -> Two distinct forms:
▪ Serpentine ( – , — fibre)
▪ Amphibole ( — , – and — fibre; and are — pathogenic)
▪ Chrysotile (serpentine fibre; — used in industry)
▪ Amosite
▪ Crocidolite
inhalation of asbestos fibres
crystalline hydrated silicates
curly flexible
straight still brittle more
most
ASBESTOS RELATED DISORDERS:
* — , commonest:
▪ — circumscribed plaques of dense collagen, most frequently on —
* Pleural effusions
* Asbestosis:
▪ Interstitial — of lungs
▪ — zone predominant
* — (pleural and peritoneal)
* — carcinoma
▪ Concomitant smoking greatly increases risk —
pleural plaques
well
pariteal Pleura
interstitial fibrosis
lower
mesothelioma
bronchogenic
smoking
ASBESTOSIS:
* The fibres are — , are surrounded in — and coated in — , producing a — shaped fibre
* The iron coating has also resulted in the fibres being called “ — bodies”
* Latency period of — years
* Asbestosis: diffuse pulmonary interstitial — with asbestos bodies
* Begins as — around respiratory — and
— and extends to involve adjacent — and —
* Results in – air spaces enclosed with thick fibrous walls -> —
* Begins in — lobes and — , but spread– to involve — and — lobes as the fibrosis progresses
inhaled
macrophages
iron
dumbbell shaped
ferruginous bodies
10-30
fibrosis
fibrosis
resp bronchioles and alveolar ducts
alveolar sac and alveoli
emlarged
honeycombing
lower and subpleuarally
upwards
middle and upper
HYPERSENSITIVITY PNEUMONITIS
(PREVIOUSLY CALLED — )
* Inhaled — antigens cause a type — hypersensitivity immune reaction (in contrast to the inorganic dusts that we
talked about earlier, this is a major point to understand)
* Circulating antibodies react with antigen with precipitation in lung of antigen/antibody complex.
* Acute, but may progress to chronic disease (Type – hypersensitivity –> pulmonary — in — zones)
* — lung, — fanciers lung etc.
extrinsic allergic ALVEOLITIS
organic antigens
type iii
type iv–> pulmonary fibrosis in upper
farmers lung and pigeon fanciers
HYPERSENSITIVITY PNEUMONITIS
(PREVIOUSLY CALLED EXTRINSIC ALLERGIC ALVEOLITIS)
CLINICAL FEATURES:
* Acute febrile episodes
* Headache, malaise, cough dyspnoea
* Bibasal crepitations
* Symptom onset 6-8 hours after antigen exposure
▪ e.g. mouldy hay with thermophilic actinomyces, aspergillus, avian antigens etc.
* Acute setting: symptoms last 24 hours
* May progress to chronic disease via type IV
hypersensitivity reaction, causing pulmonary fibrosis (upper zone)
* Alveolar walls infiltrated by lymphocytes, plasma cells,
macrophages, granulomas
* Chronic phase is associated with fibrosis - clinical
findings often subtle
* Investigations:
▪ — is essential (exposure to Ag, timing and onset of symptoms, repeat episodes etc.), serum precipitins, specific IgE
* Management:
▪ Avoidance of allergen; air driven mask, steroids
▪ Good prognosis overall
history
— CAUSES OF PULMONARY
FIBROSIS
* Includes:
▪ Sarcoidosis
▪ Langerhans cell Histiocytosis
1- SARCOIDOSIS
* — lung disease
* — disease of — aetiology
characterised by — granulomata in many
tissues.
* Many diseases (including TB and berylliosis) cause granulomatous inflammation, thus sarcoidosis is a diagnosis of exclusion, requiring the correct — and — context
* Always requires — (CPC)
* Involves — in 90-95% of cases
idiopatheic
resitecitve
mutlisystem
non caveating
clinical and radiological
clinic-pathological correlation
lungs
aetiology of scardiosis:
*— !
* Disordered immune regulation in genetically predisposed
individuals
* – cells play a central role; may propagate an excessive cellular immune reaction. There is an accumulation of —
T lymphocytes accompanied by release of —
* Possible exposure to environmental antigens; no unequivocal evidence to suggest that sarcoidosis is caused
by an — agent
epidemiology:
* 11/100,000 in whites
* 36/100,000 African Americans
* — > — (2:1)
* Age of onset: 25-40 years
* High incidence in Sweden and Denmark and also among
US African Americans
* Higher prevalence in —
unknown
T cells
cd4
il-2
infectious agent
females ? males
non smokers
SITES INVOLVED BY SARCOIDOSIS:
* Lungs: 90-95% of patients
▪ Bihilar —
▪ Interstitial inflammation progressing to diffuse interstitial
fibrosis -> pulmonary hypertension -> cor pulmonale
* — : 25% patients:
▪ Erythema nodosum
▪ Lupus pernio
* Eyes: 20-50%:
▪ Iritis
▪ Iridocyclitis
▪ Retinitis
▪ Optic nerve involvement
* Parotid gland: 10%
▪ Painful enlargement
* Spleen: 10%
* Liver
* Heart
* Brain
* Bone marrow: 40%
* Kidneys, musculoskeletal, cranial nerves
adenopathy
skin
clinical features of scaridosis :
CLINICAL FEATURES
* Asymptomatic / incidental finding
▪ E.g. screening CXR
* 30% present with respiratory symptoms
▪ SOB, dry cough
▪ Other non-specific: fever, fatigue, weight loss, night sweats,
anorexia
* Peripheral lymphadenopathy
* Cutaneous lesions
* Eye involvement
* Neurosarcoid
*—- syndrome: fever, erythema nodosum, polyarthritis
(often ankles) and bilateral hilar lymphadenopathy
* — syndrome: combined uveoparotid involvement
* Bilateral hilar
lymphadenopathy
* Right paratracheal
strip enlargement
* Bilateral infiltrates
involving
predominantly the
mid z o n e s
lofgrens
mikulicz
INVESTIGATIONS AND DIAGNOSIS
* CXR
* CT thorax
* PFT’s (restrictive defect)
* ECG
* Bloods:
▪ Calcium often raised
▪ Alkaline phosphatase
▪ Serum ACE
▪ Renal / liver / bone profile
* Sampling of nodes: most common site is —
* Procedure: —TBNA (endobronchial ultrasound, transbronchial needle aspiration)
* Non caseating granulomatous inflammation
* Must send sample to microbiology for— , to exclude
infectious aetiologies of granulomatous inflammation
* Case should be discussed at a multidisciplinary meeting, as
this is a diagnosis of exclusion, and clinicopathological
correlation is essential
* Exclude:
* Other causes of granulomatous inflammation
* Infection (TB), foreign body, hypersensitivity pneumonitis,
silicosis, berylliosis, vasculitic disorders involving lung,
malignancies (e.g. lymphoma / carcinomas can shows
adjacent granulomatous inflammation)
hilar nodes
EBUS
C&S
CLINICAL COURSE
* — course
* May remain —
* Progressive chronicity
* Periods of – interspersed with periods of –
* Respiratory involvement may progress to diffuse interstitial
fibrosis (10-15%), and lead to pulmonary hypertension andcor pulmonale
* — impairment
* Usually steroid —
unpredictable
asymptomatic
activity anf remission
visual
steroid responsive
IDIOPATHIC PULMONARY FIBROSIS
* Pulmonary disorder of— aetiology characterised histologically by —- interstitial fibrosis
* – > —
* 2/3rds > – years
* Similar clinical, radiological and pathologic findings can be seen in well-defined entities such as asbestosis and
connective tissue disorders etc.
* Therefore other potential causes should be ruled out
before the appellation of “idiopathic” is used
* Another term Usual Interstitial Pneumonia (UIP) is used to describe the histological or radiological appearances of this
condition
PATHOGENESIS:
* — wall injury -> interstitial —- and accumulation of inflammatory cells (alveolitis)
* If the injury is — , cellular interactions involving lymphocytes, macrophages, neutrophils and alveolar
epithelial cells, leading to proliferation of fibroblasts and progressive interstitial fibrosis
* Possible immune mechanism trigger
diffusre
m > f
>60
alveolar wall
oedema
presistent
pathologic features of IPF:
* Inflammatory response that heals by —
* Early stage: Interstitial — / —
* IPF is — called usual interstitial pneumonia
* The hallmark for UIP is — appearance of areas of — and — alternating with areas of
normal lung. The inflammation is usually —
* Advanced stage: lung spaces are separated by inflammatory fibrous tissue giving “ — change”
x ray:
Bilateral interstitial shadowing
Patchy or nodular
CT: Honeycombing and traction bronchiectasis
Reticular opacities
Subpleural, lower zone predominant in IPF
fibrosis
inflammation and penumoitis
histologically
heterogeneous
fibrosis and inflammation
patchy
honeycomb
