3. Interstitial Lung Disease Flashcards
What is the function of the interstitium
For gas exchange
What ILD is cause by exposure to birds
Hypersensitivity penumonitis
What is the most common CTD assoc ILD
Rheumatoid ILD
What are the two main idiopathic ILDs
UIP/IPF and Sarcoidosis
Most common two Sx of ILD
Breathlessness and cough
Drugs associated with ILD
Amiodarone, methothrexate, Rituximab, nitrogurantoin, sulfsalazine, Bleomicyi and Leflunamide
What are common examinations in most ILDs
Clubbing (esp common in IPF and asbestosis)
and mid and late inspiratory bibabsal fine crackles
NOT common in Sarcoidosis
What are the infiltrates in ILD like
Bilateral diffuse nodular or reticular infiltrates
Are pleural effusions common in ILD
No
What is the pathological pattern of disease in IPF
Subpleural dominant disease
Honeycomb fibrosis
Grossly distorted lung architecture
Temporal and spatial heterogeneity
Fibroblastic foci
risk factors for IPF
Male, smoker
Is sputum produced in IPF
Usually no, only dry cough
BUT smokers may have chronic bronchitis also (respiratory bronchiolitis ILD)
Pathogenesis of IPF- what cells are involved
Fibroblasts transdiff into myofibroblats, secrete excess collagen and also accumulate and form fibroblastic focus
TII AEC hypertorphy and can’t transdiff to TI AEC
FEV1/FVC ratio in IPF
Normal (early disease) or increased due to disprop decrease in FVC
What does it mean if FVC less than 80
Likely to be RESTRICTIVE
FGold standard biomarker for IPF disease progression
> 10% decline in FVC over 6 -12 mo
What is one common observation on exercise tests for IPF pts
Destauration
CXR changes in IPF
Usually occur earliest in CPA - reticular and nodular opacification- left heart border more shaggy and diffuse, same for hemidiaphragm
Critical Inv in suspected IPF
HRCT
- Reticular patter made of intra-lobular lines (all) - due to intralob septal thickening
- Traction Bronchiectasis/ bronchiolectasis (almost all)
- Honeycomb cyst formation ( Most)
- ALL changes supleural and bnasally dominant
What is a possible UIP pattern
Sub pleural basal predominance and reticular abnormality , and no features inconsistent with UIP but no honeycombing
What to do if possible UIP pattern
Consider doing Surgical lung biopsy, if SLB shows UIP then confirmed, otherwise dx possible UIP
Tx fot UIP
Pirfenidone and Nintedanib
Non pharmalogical Tx of IPF
Smoking cessation, ambularotu and domicillary oxugen if prone to hypoxaemia, pulm rehabiliatation, maybe lung transplant
What characterises Sarcoidosis
Non-caseating granuloma
How can sarcoidosis affect the heart, liver and spleen, nerves
Myopathy or arrhythmias
Cirrhosis and splenomegaly
Facial nerve palsy
What are general Sx of sarcoidosis and what are the resp Sx
Fatigue, malaise, fever, weight loss, hypercal (eg. polyuria, constipation, confusion, renal stones, polydipsia), lymphodenopathy, night sweats
cough, dyspnea, and chest pain
Chest examination in Sarcoidosis
Infreq crackles, often normal chest exam
what Ix to stage sarcoidosis
and how to divide stages
CXR
Stage 1 - Bilat hilar lymphadenopathy with normal parenchyma. May also present with erythema nodosum ( typically on shins)
Stage 2 - BHL with lung infiltrates ( spare LZ)
Stage 3- Lung infiltrates without BHL]
PFT in sarcodiosis
Normal in stage 1 disease or mild 2 or 3 disease, but will have restrictive defect with more extensive disease
If endobronchial disease, may have obstructive defect
What is a possible observation in sarcoidosis blood tests
Serum angiotensin converting enzyme raised
What skin test for sarcoidosis
Tuberculin skin test- usually negative in pts with sarcoidosis due to anergy ( originally positive due to TB infxn or BCG vaccine)
Similarity and diff between TB and Sarcoidosis
Both have infiltrates but only CXR has hilar lymphadenopathy?? Non-caseatinng granuloma in sarcoid vs caseating in TB
How to confirm sarcidosis dx
Stage 1- usually don’t need histology if have erythema nodosum
Stage 2 and 3- biopsy. Skin lesion or lymph nodes if have. In lungs, transbronchial if possible, SLB sometimes
Tx for pulm sarcoidosis
Corticosteroids eg. predni
Complication of VTE
Chronic thromboembolic pulmonary hypertension
Where do bloot clouts usually arise
deep veins of legs, but thrombi may also originate in pelvis, arms, or right heart
Leg sx of DVT
Calf pain, tightening, swelling
What is Virchow;s triad, examples of what can affect it
Blood flow, vessel wall, coagulability
- Surgery can induce trauma to blood vessels
- Venous stasis and dehydration can affect blood flow
- Inflammatory healing process makes blood hypercoagulable
How does a large settled central PE cause shock
- Right ventricle pushes blood through circulation, will dilate due to increased afterload
- This generates hormonal activation and myocardial inflammation
- In due cause can drive RV ischaemia due to increased O2 demand
- RV contractiluty will drop and will not load LV
- Reduced LV stretch reduces stroke value and CO, resulting in hypo T and shock
- Shock is main cause of death rather than hypoxaemia
High risk factors for PE
Fracture of lower limb, hospitalisation for HF or AF, hip or knee replacement, major trauma, MI, previous VTE, spinal cord injury, family history,
Moderate risk factors for VTE
Many, including CCF, HRT, RF, stroke, cancer, thrombophillia, porstpartum and many inflammatory causes eg. IBD
Weak risk factors for VTE
DM, HTN, bed rest, immobility due to sitting on car/plane, old, surgery (laparo), obesity, pregancy, varicose veins
Px complain of PE
Dyspnoea, pleuritic chest pain, cough, substernal chest pain, haemoptysis, fever, syncope, unilateral leg swelling
Ix for PE
CXR may show distal wedge infarction
ECG changes - S1Q3T3 possible, or may just be sinus tachy
Echo- right ventricle larger than left, septum may go into LV, suggesting acute RV stress
Simplified wells score
2 or more means PE likely
Previous PE/DVT, HR>100, surgery or immobilzation within past 4 weeks, haemoptysis, active cacner, clinincal signs of DVT, alternative Dx less likely than PE - 1 pt each
What is D-dimer
Breakdown product of crosslinked fibrin
Specificity and sensitivity of D-dimer
High sensitivity but low specifity
+ve doesn’t mean PE, high false +ve, just use to rule out
Gold standard to dx PE
CTPA
Are pts with distal or central infarction in PE at higher risk of death
central
cardiac biomarker for PE
Troponin
Acut Tx for high risk PE pts
Alteplase Bolus + 2hr infusion
Subsequent IV unfractionated heparin
Diff High risk and intermediate risk VTE pts
Shock in high risk
Diff Intermediate and low risk PE pts
Low risk have PESI Class II or below and sPESI =0
If pt cannot have thrombolysis, what should be done for high risk acute PE
Cathether directed lysis under ultrasound
What does fibrinolysis target
Plasminogen, which is converted into active plasmin that breaks down fibrin into FDPs
Tx of low risk PE
New approach - just give DOACs (apix, rivarox) immediately
Give LMWH like dalteparin subcut for at least 5 days until INR therapeutic for 2 days, then give warfarin (overlap until INR stable)
Mech of heparin
Potentiates antithrombin III which inactivates thrombin (factor IIa), and many other factors
Difference between LMWH and UFH
LMWH preferentially inactivates factor Xa, little to no monitoring
Mech of action of warfarin
Vit K antagonist- inhibits epoxide reductase ( affects synthesis of factors II, VII, IX and X)
featurdd of intermediate risk PE
May have large clot load in pulm artery or saddle embolism
Tx of intermediate risk PE
Indv case basis
But consider IV unfractionated heparin instead of LMWH as can stop if need thrombolysis
When should thrombolysis not be given in PE
If there is haemodynamic stability
When should chronic thromboembolic pulmonary hypertension be checked for
If pt describes onset of RH failure such as progressive breathlessness despite treatment, and peripheral oedema
When may indefinte doacs be considered
Young male with unprovoked event w/o any known cause
What should be used to determine stopping of anticaog in PE
DASH score - Dodimer elevated, Age (<50), Sex male, H- not hormone assoc ( female)
If 1 or lower can consider stopping
If on oestrogen containing hormones and now off it, -2 points
Do crackles in IPF clear on coughing
NOOOOOO
Ix for hypersensitivity pneumonitis
CXR, CT, avian precipitins abs
What pattern is found in hypersensitivity pneumonitis on HRCT
Mosiac distr, with ground glass shadowing
Ix for dequative interstitial pneumonia
HRCT followed by transbronchial biopsy +BAL if HRCT atypical
Is clubbing common in hypersensitivity pneeumonitis
no
Does sacrcoidosis cause hypo or hypercalcaemia
Hyper
