Respiratory MCQs Flashcards
What is the best measure of clinical progression in Interstitial pulmonary fibrosis ?
FVC in lung function testing
In patients with apical emphysema but basal fibrosis what pattern would we see on spirometry ?
May have a normal loop but a majorly impaired diffusion capacity
Radiological features of definite usual interstitial pneumonia
Honeycombing, traction bronchiectasis and reticulation
Architectural distortion
How to confirm diagnosis of usual interstitial pneumonia?
If HRCT displays features, there is no need for biopsy
What are the names of anti-fibrotics approved for use in Australia
Nintedanib and Pirfenadone
Bronchodialator respose required in spirometry for dx. asthma
> 12% and >200mls
Name drug used and guide used in prevocation testing
Stop the challenge after the patient drops their FEV1 >20% - then you check the dose of methacholine that is required to give them this drop by >20% (PD20 provocation dose) = the smaller the number the more sensitive their airways are.
<8mg/ml is diagnostic
Indirect provocation testing
Detects the presence of inflammatory cells in the airways and is more indicative of current asthma (than direct method)
Positive if > or = 15% reduction in FEV1
More specific but less sensitive than direct challenge
Mannitol, exercise, hypertonic saline all used
Omalizumab MOA
Recombinant, DNA derived, monoclonal anti-IgE antibody
Binds circulating IgE and limits allergic response
Side effects
Mainly nasopharyngitis (28%), URTIs 16%), headaches
- Patients need to cary epipens ?
Only used as last line- FEV1 less than 80 - high IgE
Mepolizumab MOA
Monoclonal antibody against interleukin 5
Eosinophilia
Two types of asthma
Atopic and non-atopic. Both caused by IgE production. However atopic asthma is systemic IgE whereas non-atopic is local IgE production
Histological changes in asthma
Increased goblet cells and mucous production in pseudostratified columnar epithelium, thickened basement membrane, increased histamine from mast cells in the lamina propria as well as increased neutrophils and helper T cells. Smooth muscle hypertrophy is also present.
Pathophysiology of atopic asthma
Allergen inhaled –> taken up by columnar cells –> thymic stromal lymphocytes secreted –> activated dendritic cells in the lamina propria produce chemo-attractant conditioned to attract T-2 helper T cells –> activated t-helper 2 cells stimulate plasma cells via IL13 and IL4 promoting IgE production in plasma cells –> T helper 2 also produce IL9 to stimulate mast cells –> finally IL5 prodiuced by helper T 2 cells stimulates eosinophil production from the bone marrow
IgE also attaches to mast cells to produce histamine, leukotrienes and prostaglandins which in turn activates smooth muscle
Stem cell factor produced by columnar cells maintains mast cells in the area
T helper 1 - normally found in lungs
T helper 2 cells, not normally found in the lungs are upregulated and systemically cause an overproduction of antibodies.
How to assess severity of asthma on presentation
Mild/moderate –> able to speak whole sentences in one breath
Severe –> any of: unable to speak in sentences, visibly breathless, sats 90-94% or increased work of breathing
Life threatening –> drowsy, collapsed, exhausted, cyanosed, sats less than 90, poor inspiratory effort
Management of asthma by severity
Mild-moderate 4-12 puffs of salbutamol via MDI (100 microg/puff)
Severe –> 12 puffs of salbutamol (100 microg/puff) every 20 mins for 1 hour (i.e. 3 cycles) and 8 x puffs of ipatropium bromide (21 microg/actuation)
OR
nebs: 5 mg salbutamol and 500 microg ipatropium
drive with air is possible, but other wise oxygen, then commence oxygen post.
AIM 93-95% SATS
Life threatening –> continuous 5mg salbutamol nebs prepare to intubate or ventilate
REASSESS
After first reassessment in asthma what is the next management step ?
If poor response at any level –> Magnesium sulphate 10 mmol over 20 mins
If no improvement or worsening –> corticosteroids
Oral pred 37.5 mg -50mg for 5-10 days. If oral not available then IV Hydrocortisone 100 mg 6 hrly.
Post 1 hour of treatment REASSESS and transfer home vs. ward vs. ICU depending on treatment requirements
Usual interstitial pneumonia (UIP)
Subpleural reticulation, apical basal gradient, traction bronchiectasis, honeycombing
Non-specific interstitial pneumonia (NSIP)
Ground glass change, apical to basal gradient, subpleural sparing, traction bronchiectasis
Organising pneumonia (OP)
Consolidation, bronchovascular in distribution
Desquamative interstitial pneumonia
Ground glass change with small cysts
Respiratory bronchiolitis interstital lung disease
Centrilobular ground glass nodularity
Lymphocytic interstital pneumonia
Ground glass changes with cysts
Hypersensitivity pneumonitis
Acute: Ground glass nodularity
Chronic: Fibrotic changes akin to UIP but with mosaicism, ground glass and gas trapping
Description of terms used such as “UIP”, DIP, NSIP
These are radiological terms use in lung disease to describe the pattern of disease, however lots of diseases can fit the single pattern
Pattern seen in Idiopathic pulmonary fibrosis and treatment
UIP pattern of disease
Anti-fibrinolytics: Pirfenidone or nintedanib
Describe IPF
Chronic inexorably progressive fibrosing lung disease of unknown cause.
Other causes of fibrosing disease need to be excluded
Radiological UIP is a strong surrogate for histology - lung biopsy seldom needed.
Typical patient: older man in their 6-7th decade, past smoking history, GORD, family history.
Unlikely patients to have IPF
Exposure to known HP antigen, Squarks on auscultation, rheumatological signs, pneumotoxic drugs
pirfenidone MOA
ACTs through TGF-B to reduce fibroblast proliferation
Slows rate of disease progression.
Improves survival
Photosens. rash and GIT upset
Nintedanib MOA
Inhibits multiple Tyrosine kinases - slows disease progress. Major SE diarrhoea and weight loss. Small bleeding risk - avoid if anticoag,.
Improved progress in Systemic sclerosis too
Genes associated with Pulmonary fibrosis
TERT, TERC, RTEL1, PARN
associated with disease anticipation
Association with telomerase complex genetic mutation
IPF and dyskeratosis congentia - leading to aplastic anaemia. When inherited in child, anticipation is noted.
Autosomal dominant inheritance
Clinical features of telemere shortening
Affects any rapid turn over cells - i.e. greying of hair, liver cirrhosis, opportunistic infection, emphysema, osteoporosis, coronary artery disease
Gene mutation associated with RA-ILD and Pulm. fibrosis
MUC5B ~50% of ILD patients
Which immmunosuppressant is contraindicated in SS related ILD
Methotrexate - can cause ILD
Which immunosuppression is contraindicated in IPF
Aza and mycophenolate
Antibody assicated with Dermatomyositis and lung disease
anti-MDA5, often have negative myopathic screen- pneumomediastinum is the most common presentation in this micro-population
Differentiated Langerhans cell histiocytosis vs. LAM
Langerhans - irregularly shaped cysts and sparing of the costophrenic recess. Langerhans cells are dendritic cells
LAM cysts are typically found in the costophrenic recess ‘LAMbsall to the gullies’. Typically smooth cysts.
(LAM = lymphangioleiomyomatosis)
Drugs that cause pulmonary fibrosis
BackCountry MAN
Biologics
Chemo
Methotrexate
Amiodarone
Nitrofuantoin
CVID classic presentation
Recurrent sinusitis
Associated with Granulomatous lymphocytic interstitial lung disease GLILD can mimic sarcoidosis in producing ACE
Diagnosed with Bronchioalveolar lavage
LAM classic presentation
Pulmonary cysts and renal angiomyolipoma in a young woman.
There may also be sporadic tuberous sclerosis associated
High VEG-F levels may assist with dx.
Management is with Rapamycin (Sirolimus) an mTOR inhibitor
Pulmonary alveolar proteinosis presentation
Chronic cough and dyspnoea - crazy paving on CT in lower zones. Milky fluid on BAL with periodic acid Schiff positivity. Anti-GM-CSF antibody is expected.
whole lung lavage, immunomodulation and inhaled GM-CSF management.
At which level of flow volume loop is the pulmonary vascular resistance at its lowest ?
FRC (Functional residual capacity)
I.e. the bottom of the tidal volume in normal respiration
Starlings law and how it relates to pulmonary circulation
Fluid movement out of capillary by the difference in hydrostatic and oncotic gradients. Oncotic gradient in pulmonary physiology is low but favours reabsorption. Hydrostatic pressure is NIL. Therefor a slight increase in pulmonary pressure leads to large volume extravasation.
Thin walled vessels without much smooth muscle means that vessels are highly compliant and accomodate large volumes with small pressure changes
Lung volumes affect on PVR
Large extra-alveolar vessel pressure decreases as the vessels are pulled open at large pulmonary volumes, small vessels are compressed and pressure increases.
At small lung volumes the opposite occurs.
Sarcoidosis syndromes
Loftgrens: Bilateral hilar lymphadenopathy, erythema nodosum, fever and polyarthralgia
Mikulicz syndrome: enlargement of the parotic and lacrimal glans
Heerfordts: Parotid enlargement, fever, uveitis and hilar involvement. Occasionally facial nerve palsy
All typified by non-caseating granulomas with hypercalcaemia (Macrophages inside granulomas cause an increased conversion of Vit D to 1,25 dihydroxycholecalciferol
