RESPIRATORY DISORDERS & THEIR MANAGEMENT III: FIBROSIS & OSA

what is interstitial lung disease (ILD)

a group of disorders that cause fibrosis (scarring) of the lung parenchyma

• primarily the interstitial space surrounding the alveoli

what are the types of ILD

• Idiopathic pulmonary fibrosis (IPF)

• Drugs - amiodarone, methotrexate, radiotherapy/ radiation

• External antigen

• Autoimmune ILD - rheumatoid arthritis, SLE (lupus), systemic sclerosis, Sjogren’s syndrome, idiopathic inflammatory myopathies

• Sarcoidosis

what are examples of external antigen ILDs

• hypersensitivity pneumonitis - Bird Fancier’s lung (bird feathers)/ Farmer’s lung (fungal spores)

  • reversible and steroid-responsive

• pneumoconiosis (dust related) - asbestosis, silicosis, coal-miner’s lung

  • common in South Yorkshire

outline the pathophysiology of interstitial lung disease

what are symptoms of ILD

• dyspnoea especially on exertion

• dry cough (not productive unless infection)

• reduce exercise tolerance

what are signs of ILD

• increased work of breathing

• cyanosis

• low oxygen saturations

• auscultation - fine crackles (so rule out other causes of crackles like heart failure, bronchiectasis)

• systemic signs

what is a sign of ILD that is only present in idiopathic pulmonary fibrosis

clubbing is only present in IPF

what are some systemic signs of ILD

• rashes in SLE (lupus) or sarcoidosis

• cervical lymphadenopathy in sarcoidosis

• polyarthritis with deformities in rheumatoid arthritis

image showing classic butterfly rash in lupus

image showing classic rheumatoid arthritis hands

sarcoidosis: tender red patches on skin

sarcoidosis: redness in eyes

what investigations can be done for interstitial lung disease (ILD) (3)

• spirometry including transfer factors (DLCO)

• chest x-ray (CXR)

• high resolution CT chest

what is the DLCO test

Diffusing Capacity of the Lung for Carbon Monoxide (DLCO)

• measurement of alveolar gas exchange

• measures amount of CO bound to haemoglobin after 10s breath hold with small amount of CO in inhaled gas

normal healthy CT scan

ILD CT scan

spirometry flowchart

volume/ time and flow-volume loops

outline the management of idiopathic pulmonary fibrosis (IPF)

• pulmonary rehabilitation

• long term oxygen therapy (LTOT)

• anti-fibroblast therapies (only work for some people)

  • nintedanib used if FVC >80%

  • pirfenidone used if FVC 50-80%

• lung transplantation referral if someone is young and healthy

what is the median survival for IPF

≈ 3yrs

• so often best supportive care (BSC) is given at diagnosis

how effective is mechanical ventilation at treating IPF

mechanical ventilation has poor outcomes

which treatment is universal in interstitial lung disease

pulmonary rehabilitation is useful in all ILD

• other types of ILD treatments vary

what is the main treatment for drug-induced and/ or external allergens ILD

• removing or reducing exposure to the offending antigen

  • in Bird Fancier’s lung (type of hypersensitivity pneumonitis) people need to get risk of carpets/ furniture and sometimes even move house

• hypersensitivity pneumonitis: allergy-based response steroids are effective

what would be the treatment for systemic ILD

treatment of the underlying condition would be the main aim and hopefully the ILD will improve

what does OSA stand for

obstructive sleep apnoea

define OSA

• sleep-related breathing disorder

• characterised by transient, partial or complete obstruction of the upper airways

• leading to frequent and/ or prolonged apnoeas or hypopneas and resultant temporary hypoxias

how common is OSA

• common

• prevalence of 0.5-4% of the population (as common as type I diabetes)

apnoea VS hypopnea

• apnoea: complete airflow obstruction with temporary cessation of breathing for >10s

• hypopnea: decreased airflow of >30% for >10s

what are the different types of apnoea (3)

• obstructive (peripheral apnoea)

  • most common

• central (brainstem related)

• mixed

what structure controls breathing

the brain stem

what are night-time symptoms of OSA

• constant stertor (snoring)

• choking/ gasping episodes

• apnoeas

• enuresis (bed wetting)

  • particularly common in paediatric OSA patients

what are paediatric day-time symptoms of OSA

• ADHD
  aggression

• learning difficulties

• mouth breathers

• hyponasality (sounds congested)

what are adult day-time symptoms of OSA

• excessive sleepiness (might think they have narcolepsy)

• loss of libido

• irritability

what are signs of OSA

• obesity (main risk factor in adults)

• adenotonsillar hypertrophy (main cause in children)

• syndromes (esp. in paediatrics)

give examples of syndromes that can result in OSA

general examination to rule out syndromes which cause craniofacial abnormalities

• Down’s - associated with naso and oropharyngeal narrowing and adenotonsillar hypertrophy

• Pierre Robin sequence - cause retro and micrognathia » glossoptosis

• Treacher Collin’s - cause retro and micrognathia » glossoptosis

(paediatrics!)

what investigations can be done for OSA

bold = main two investigations

• Epworth sleepiness score/ STOP-Bang score

• Overnight Pulse Oximetry (image)

• Polysomnography (PSG) - full sleep study (expensive)

is an adult is suspected of having OSA what should be done

• refer to sleep clinic to prove it is sleep apnoea

• unless specific ENT cause may be contributing

is a child is suspected of having OSA what should be done

• refer to ENT clinic

• because majority have large tonsils so they need removing

what else can a polysomnography be used for

if someone is unsure whether a patient has central sleep apnoea or peripheral sleep apnoea

what can be done if a more distal cause of OSA/ failed CPAP

• can consider drug-induced sleep endoscopy (DISE) in specialist centres

how are apnoeas/ hypopneas graded

outline management for OSA in adults

outline management for OSA in children

why is OSA such a problem (5)