Interstitial lung disease (ILD) Flashcards
(22 cards)
Describe the difference between an obstruction and a restriction in breathing
An obstruction refers to a reduction in flow e.g., a blockage
examples: COPD, asthma
Restriction refers to a reduction volume
examples: ILD, Musculoskeletal,
neuromuscular, obesity & pregnancy
What are the 3 types of
restrictive lung diseases?
Extrapulmonary: obesity (reduces compliance, fat limits expansion of the chest), scoliosis & ascites (fluid in abdomen)
Neuromuscular: Motor neuron disease & Diaphragmatic paralysis, myasthenia gravis (failure in signalling to contract properly)
Lung parenchyma: Interstitial lung disease (ILD)
Define ILD
refers to over 200 different conditions e.g., drug induced lung disease, connective tissue disorders or occupational lung diseases. The most common ILD is idiopathic pulmonary fibrosis (IPF)
Most common ILDs: 1/3 has a known cause
Sarcodosis
IPF (5,500 people die annually)
Hypersensitivity pneumonitis
Connective tissue disease
Drug-induced lung disease
Occupational lung disease
Define IPF
IPF: results in scarring of pulmonary intersititium, bronchovascular and septal tissues, there may be inflammation present. Distal airways and alveolar spaces may also be affected. The cause is idiopathic which means UNKNOWN.
What are the 4 categories in ILD
- IIP
- ILD due to specific causes
- Granulomatous
- Rare causes
Define IPF/IIP
IIP is a group of lung diseases characterized by inflammation and scarring (fibrosis) of the tissue around the small air sacs (alveoli) in the lungs. The term “idiopathic” means the cause of the condition is unknown. “Interstitial” refers to the tissue between the air sacs, and “pneumonitis” refers to inflammation of the lungs
There is no known cause, but there is increasing evidence that suggests that exposure to metals such as brass, lead and steel can be a risk factor.
Describe the radiographic findings when diagnosing IPF/IIP
can be made using an X-ray of the chest or CT scan, it can be diagnosed without a biopsy of the lung.
1. Honeycombing: found in lower lobes, in cystic spaces within lung walls, CT images give a mix of healthy lung tissue and damaged lung tissue, there is little inflammation. it suggests irreversible fibrosis and structural distortion.
2. reticular opacity: shows net-like shadows on CT scan, a thickening of intersitial spaces due to fibrosis
3. Ground class opacification: hazy areas where the beam of radiation is not great enough to pass through a substance, it reflects inflammation and early fibrosis, can be seen in active areas of inflammation or in early stages of the disease
4. Posteriorly concentration: The fibrosis and reticular opacities typically affect the lower and peripheral regions of the lungs, particularly in the posterior segments.
Describe the treatment and prognosis of IPF/IIP
Prognosis: Poor prognosis, as disease remains ‘dormant’ and then patient experiences rapid clinical detieoration.
Survival rate of 5 years (10-50%)
Median survival rates after diagnosis: 2.5yrs
There is a higher prevalence & mortality rates for men aged 50-70
Treatment: Little effective treatment, steroids and immunosuppressive drugs DO NOT WORK
Describe the difference between IPF vs non-usual intersitial pneumonitis
IPF has poor prognosis and little effective treatment compared to Non-UIP.
IPF shows no improvements in lung function by quitting smoking unlike non-UIP
Describe the use of VAT
A keyhole syndrome used to collect a piece of lung tissue during a lung biopsy.
Performed under general anaesthetic
Procedure is carried out to take out lymph nodes, growth or lumps from the lungs
A small incision is made close to the ribs & a thorascope is inserted to view the lungs.
Describe the drug induced causes of Non-UIP (specific cause)
It can be caused by
1. Cancer drugs e.g., bleomycin
2. heart drugs (amiadone)
3. Anti-inflammatory drugs e.g., methotrexate
4. Antibiotics e.g., nitrofuratonin
5. Recreational drugs e.g. cocaine & heroin
6. Paraquat (weed killer)
7. Radiation
Drugs can diffuse into the parenchyma, if lung damage is detected in using drugs as treatment then it should be stopped immediately.
Damage may be irreversible & also treatable with steroids in some cases
Describe hypersensitivity as a cause of Non-UIP
(specific cause)
also known as extrinsic allergic alveolitis, creates inflammation by initiating a immune response due to inhalation of substances such as dust, mold or chemicals.
Diseases include farmers lung (molds from hay) & bird fanciers’ lung (hypersensitivity reaction to bird droppings or antigens on bird feathers). BFL results in symptoms of weight loss, fatigue, fever and chills, SOB & pulmonary fibrosis.
Describe connective tissue disease as a cause of Non-UIP
(specific cause)
It involves a range of autoimmune conditions that attack the connective tissue, e.g., rheumatoid arthritis, scleroderma & Sjogren’s syndrome
RA: affects joints causing inflammation, can also affect lungs, heart & eyes. Treatment of RA may induce ILD
SJ: a chronic autoimmune condition that destroys salivary and tear glands causing dryness
SC: an autoimmune condition that causes hardening of the skin, it can also affect the lungs in severe cases. It can cause ILD and pulmonary hypertension.
Describe occupational lung disease as a cause of Non-UIP
(specific cause)
OLD refers to inhalation of mineral dusts from working in construction/mines. Inhalation of substances such as coal. asbestos or silica. It has a cytotoxic effect on the lungs
Define granulomatous ILD
A granuloma refers to clumps of macrophages (histocytes), this forms because of an inflammatory response brought on by an immune response, most common ILD granulomatous is sarcoidosis.
Define sarcoidosis
An idiopathic disease (no known cause) that causes multiple inflammatory disorders, granulomas form in lungs and lymph nodes enlarge at the hilum.
Symptoms: cough, fatigue, swollen lymph nodes
It can affect more organs e.g., heart, eyes etc
It can give obstructive or restrictive effects.
Define rare cases that cause ILD, e.g., Amyloidosis
Rare diseases e.g., amyloidosis, positive HIV or histiocytosis, can cause ILD
Amyloidosis: where disruptive proteins accumulate and fold to make up larger organs, this can affect normal function
Symptoms: SOB. fatigue, swelling & weight loss
Diagnosis: biopsy, urine & blood tests, CT scan
Describe the symptoms of IPF and the changes in radio imaging
symptoms: SOB, fatigue, weight loss, joint pain, finger clubbing, persistent cough, lung crackling & decreased exercise tolerance
X-ray changes
Abnormal chest x-ray
Lower lung lobe changes
CT may indicate glass changes (opacity)
CT scan is vital for diagnosing
Describe the diagnosis of ILD
- Take a patient history and perform a full body exam
- complete a resp test e.g., spirometry
- X-ray/ biopsy
- VAT biopsy
- Blood tests to look for inflammatory mediators, infections and antibodies
How does ILD affect lung function?
ILD reduced compliance, lungs struggle to inflate properly due to increased inflammation or fibrotic tissue.
As the compliance is reduced, the lung volume is too. This requires an increased effort for the patient to breathe, placing more strain on the respiratory muscles which may lead to fatigue.
Patients can be identified by being SOB
What are the possible treatment options for ILD?
- Antitussive meds to reduce coughing
- Pain relief e.g., morphine
- N-acetylcysteine to restore oxidant/antioxidant balance, it has anti-fibrotic effects, helps thin mucus
- Steroids (not for IPF)
- Antifibrotic agents e.g., Pirfenidone, expensive, used to treat mild-moderate cases
- Immunosuppressants e.g., methotrexate (used for pateints that don’t respond to steroids, can be a cause of ILD, Azathioprine is less toxic than methotrexate)
Describe the treatment options for lung diseased patients
- Pulmonary rehabilitation (give patient empowerment, educated on diet and exercise, given an exercise routine)
- Long-term O2 therapy ( needs prescription)
- Lung transplant (if eligible, not possible in IPF)
- Palliative care (ensuring the patient is aware of the pathway of the disease, make the most of treatment available)
- Drug treatments
