Respirology Flashcards
A-a gradient
150 - PCO2/0.8 - PaO2
Normal = Age/4 + 4
Differential Diagnosis normal A-a gradient
Hypoventiliation - Drug intoxication - OHS/OSA - Neuromuscular dysfunction - Diaphragm injury (phrenic nerve / myopathy) - Brain bleed/stroke/tumor/meningitis High altitude
Differential Diagnosis wide A-a gradient
1) VQ Mismatch (improves w/ 100% FiO2) - COPD, PE
2) Shunt (does not improve completely with O2) - intracardiac (PFO/ASD/VSD), intrapulmonary (AVM), physiologic (severe PNA)
3) Diffusion Abnormality - ie. ILD
Diagnosis of asthma
- History of variable resp symptoms that vary over time & intensity
- PFT: variable expiratory airflow obstruction
a) Airflow obstruction: FEV1/FVC < LLN
b) Variability, any of:
- FEV1 >12% and 200 cc improvement post bronchodil OR after 4 wks anti-inflm tx OR between visits
- Diurnal peak flow variability of >10%
- Positive methacholine challenge test = Decrease FEV1 by 20% with <4mg/ml methacholine
- Positive exercise challenge test = Decrease in FEV1 by >=10% and 200 cc from baseline with exercise
Asthma Control Criteria
Control implies all criteria present:
Daytime symptoms <2 days/week
Nighttime symptoms <1 per week and mild
Reliever (SABA or bud/fom) <2 doses per week
Physical activity NORMAL
NO absence from work/school
Exaggerations infrequent and mild (no steroids/ED/admission, any one = severe)
Peak flow >= 90% personal best
<10-15% peak expiratory flow diurnal variation
Sputum eos <2-3%
Definition Uncontrolled Asthma
- Poor symptom control defined by lack of any one of asthma control criteria
- Frequent exacerbations (>=2 /year) req steroids
- One exacerbation in past year requiring hospitalization/ICU/MV
- Sustained airflow limitation of FEV<80% personal best
Definition severe asthma
- Asthma requiring use of HIGH dose ICS + 2nd controller for previous year
- Requiring oral steroid for >50% of the year for control
Work-up for severe asthma
Total IgE Peripheral and sputum eosinophil count FeNO where available Skin testing for aspergillus \+/- CT chest to evaluate for alternate pathology
Treatment algorithm asthma
Poorly controlled = daily ICS + prn SABA
Well controlled + risk of severe exacerbation = daily ICS or prn bud/form
Well controlled with NO risk of severe exacerbation = prn bud/form or prn SABA
- Low dose ICS-formoterol PRN (ie. symbicort)
- Low dose ICS-formoterol OD + PRN +/- add LTRA (esp if exercise/NSAID induced or allergic rhinitis)
- Medium dose ICS-formoterol OD + PRN +/- add LTRA
- High dose ICS-formoterol OD + PRN +/- add LTRA
- Refer for phenotypic ax +/- tiotropium, biologics, Macrolides (dec exacerbations), low dose steroids, bronchial thermoplasty
*sx control x2 mo + low risk of exacerbation = consider stepping down
Indications for anti-IgE (Omalozumab)
Serum IgE 30-700 and sensitive to 1+ perennial allergen, severe despite high dose ICS and one other controller
Indications for anti-IL5 (mepolizumab) or IL4/13 (dupilumab)
Serum eosinophils >300 and recurent exacerbation despite high dose ICS and one other controller
- Dupilumab also for those w nasal polyposis or mod/severe atopic dermatitis
Treatment asthma exacerbation
Ventolin + Atrovent PO or IV solumedrol/pregnisone \+/- MgSO4 Treat reversible triggers D/C home if PEF >70% personal best after 1 hr monitoring
Budesonide doses
Low = 200-400 Med = 400-800 High= >800
Fluticasone doses
Low = 100-250 Med = 250-500 High = >500
RADS vs occupational asthma
RADS = develops after single high dose exposure to vapour, gas or fumes
Occupational asthma = asthma that gets worse at work due to presence of some allergen
Spirometry - flattened inspiratory and expiratory curve
Fixed upper airway obstruction - eg goitre
- Glottic stenosis (prolonged intubation)
- Subglottic stenosis - GPA, sarcoid, polychondritis
Spirometry - flattened inspiratory curve, normal expiratory curve
Variable extra-thoracic obstruction - ie. vocal cord paralysis
Spirometry - flattened expiratory curve, normal inspiratory curve
Variable intra-thoracic obstruction - ie. tracheomalacia
Spirometry- scooped expiratory curve, normal inspiratory curve
Obstructive lung disease (asthma, COPD, CF)
Spirometry - small (but normal shaped) inspiratory and expiratory curves
Restrictive lung disease
If curves more rounded - think neuromuscular cause
Restrictive PFTs with 10% VC decline supine
Diaphragmatic dysfunction (eg post-op/CABG, mech vent, NMD eg ALS/MG) --> test MIP/MEP (decreased MIP = most sensitive for B/L diaphragm involvement; most specific - FVC)
RV/TLC > ULN
Gas trapping
TLC > ULN
TLC < ULN
TLC > ULN: Hyperinflation
TLC < ULN: Restriction
Isolated reduced DLCO with otherwise normal PFTs
Anemia (eg GIB) Pulmonary HTN Early ILD/emphysema (don't yet have restriction) PE Sarcoid
High DLCO, otherwise normal PFTs
Diffuse alveolar hemorrhage
Left sided HF
Polycythemia
Contra-indications to PFTs
Unstable cardiovascular pathology (ACS, arrhyth, HF) Hemoptysis Pneumothorax Aneurysm (thoracic, abdo, cerebral) Recent eye/lung/intra-abdominal surgery Acute illness
Contra-indications to methacholine
Severe asthma or COPD (FEV1<50% or <1L)
Stroke, MI within last 3 months
BP >200/100
Aortic Aneurysm
Relative: Pregnancy, use of cholinesterase inhib, FEV<60% or 1.5L
Diagnosis COPD
FEV1/FVC < 0.7 or LLN with NO significant bronchodilator response
*if diagnosed, test for A1T1 if <65yo OR <20py hx
COPD - Severity of airflow limitation - grading
Mild - FEV1>=80%
Moderate - FEV1 50-79%
Severe - FEV1 30-50%
Very Severe - FEV1<30%
MRC scale for grading dyspnea
0 - not troubled by symptoms 1- SOB with heavy exertion 2- SOB with normal exertion 3- SOB with light exertion (ie. walking 1 block) 4- SOB with basic ADLs
Nonpharm treatments for all patients with COPD
- Smoking cessation (slows progression, improves SURVIVAL) - use varenicline +/- patch x12+ weeks asap >e-cig/ buproprion
- Pulmonary rehab (improves QoL/exercise capacity in all) - improves SURVIVAL and exacerbation risk if within 4 wks AECOPD
- Supplemental O2 if eligible (increase SURVIVAL in severe hypoxemic)
- Vaccinations (pneumovax, yearly flu, TdAP pertussis is missed as teen)
- PRN SABA
- Palliative/Dyspnea Mx
Treatment for mild COPD (MRC 0-1)
SABA PRN –>
LAMA or LABA (Lama preferred)
Treatment for moderate-severe COPD (MRC >1) at low risk exacerbation (<2 exacerbations in last yr, no hospitalizations)
LAMA or LABA –>
LAMA + LABA –>
LAMA + LABA + ICS (low dose)
*If stable symptoms, can step back treatment
Treatment for moderate-severe COPD (MRC >1) at high risk exacerbation (2+ exacerbations in last yr, 1+ COPDe requiring hospitalization)
LAMA + LABA –>
LAMA + LABA + ICS (low dose) –>
Add on therapies to reduce exacerbation risk: Roflumilast (wt loss/diarrhea), NAC (for bronchitis), Azithromycin (R/o NTM 1st; S/E: QTC, hearing impairment) . NO theophylline
*Never step back treatment (unless started inapprop)
Indications for continuous oxygen in COPD
PaO2 <55 (SaO2<88%) or
PaO2 <60 if: Cor pulmonale, peripheral edema, Hct >56% (erythrocytosis)
Advanced treatments in COPD
Non-invasive ventilation:
- Indications: pCO2 >=52 and hx admissions for hypercapnic respiratory failure
Lung reduction surgery (increase survival** in severe predom upper lobe emphysema)
Transplant if: Bode score 7-10 + one of :
- FEV1<25% with DLCO <20%
- COPDe hospitalization with PCO2>50mmHg
- pHTN or cor pulmonale despite O2
Treatment Dyspnea in advanced COPD
Oral opioids (NOT nebulized)
Neuromuscular stimulation/chest wall vibration
Walking aids
Pursed lip breathing
Continuous O2 if meets criteria (may dec dyspnea, no significant QoL improvement)
Diagnosis Asthma/COPD Overlap syndrome
- Dx COPD based on rf, hx, PFTs
- Past Hx/dx asthma with bronchodilator reversibility
- Spirometry: postbronchodilator fixed FEV1/FVC<0.7
*Supportive criteria: Sp Eos >3%, peripheral eos >300, documentation of bronchodilator improvement (FEV1 by 200cc or 12%)
Treatment Asthma/COPD overlap
ICS/Laba = 1st line
Add LAMA if refractory
Treatment of AECOPD
Supplemental O2 NIVV (BIPAP) SABA/SAAC (eg ipratroprium) Steroid x5-7 days (Pred 40) ABX x5-7d if 2/3: inc sputum purulence/vol/dyspnea OR req NIV/MV Re-initiate LABA/LAAC prior to D/C
Indications for NIV or MV in AECOPD (NIV > MV if no excessive secretions and LOC permits)
pH <= 7.35
pCO2 >=45
Severe dyspnea or persistent hypoxemia despite med tx
Causes of bronchiectasis
CF, primary ciliary dyskinesia, Humoral immunodeficiency (dx: immunoglobulins)
Post-infectious (TB, NTM, pertussis, recurrent PNA)
Aspiration (dx: swallow study)
ABPA
A1AT deficiency
Autoimmune: RA, SLE, IBD
Congenital malformations (bronchiomalacia, lung sequestration)
Idiopathic
Clues to CF
Onset of symptoms <45 History malabsorption Pancreatitis History of staph, pseudomonal or NTM infxns Male infertility \+sweat chloride and CFTR gene testing
Clues to A1AT
Emphysema/obstruction on PFTs/CT
Liver disease
Panniculitis
Clues to primary ciliary dyskinesia
Recurrent URTIs and otitis media
Male infertility
Low nasal nitric oxide
Dx and Tx of ABPA
History of asthma with brown casts in sputum
Eos >1000 peripherally
Total IgE
Central bronchiectasis
Infiltrates on imaging
Sensitization to aspergillus (IgE spec AB or skin prick)
Tx: pred +/- itraconazole
Treatment non-CF bronchiectasis
Airway clearance techniques (breathing technique)
Mucoactive agents (hypertonic saline) *DNAse ONLY if CF
Inhaled colistin/gent if pseudomonas colonized
Azithro if recurrent exacerbations
Pulmonary rehab (if mMRC>1)
Vaccines (Flu, pneumococc, Tdap)
Supplemental O2
NIV if resp failure w/ hypercapnea w/ recurrent hospitalization
Sx/lung resection
Transplant if poor lung fcn and 1 of: massive hemoptysis, severe PH, ICU admission or resp failure req NIV
- NO DNAse unless CF,
- don’t offer steroid, PDE4i, or ICS routinely
Treatment bronchiectasis exacerbation
Obtain sputum Cx
ABX empirically (based on past Cx) x 14 days min
If bleeding TXA +/- embolization (1st line)
Causes of ILD
Idiopathic (IPF, NSIP, COP, AIP, LIP, DIP, RBILD)
CTD-related:
- SSc, DM, Sjogrens, RA, MCTD, Sarcoid
Exposure:
- Hypersensitivity pneumonitis (organic exposure)
- Pneumoconiosis (inorganic exposure)
- Drugs: MTX, macrobid, amio, bleomycin, vaping
- Radiation-induced
Others
Diagnosis IPF
- Progressive fibrotic ILD +
- UIP pattern or positive histology +
- Other causes excluded (CTD, meds, exposures)
Definite UIP Pattern
- Reticular changes
- Basal/subpleural predominant
- Honeycombing
- Absence of inconsistent features
Inconsistent CT features of etiologies of ILD that are not IPF
GGOs Mosaic attenuation Cysts Micronodules or centrilobar nodules Consolidation
Work-up for ILD
CT Chest
PFTs
ANA, RF, CCP, +/- myositis panel
*If hx mould/water/bird feather exposure or mosaic attenuation/upper lobe on CT–> precipitating Abs for HP
Consider BAL or biopsy if inconsistent features
Treatment IPF
Nonpharm:
- Smoking cessation, O2 (criteria as per COPD),
- Vaccines, Rehab
Pharm:
- Anti-fibrotics: Nintendanib, Pirfenidone (reduce FVC decline and mortality benefit)
- NO steroids/immunosuppression (increases mortality in chronic IPF)
- Steroids ok for NON-IPF eg HP, CTD, D-induced
- Dyspnea Mx (low dose opioid)
- Cough Mx
Transplant:
- Refer if FVC <80%, DLCO <40% despite med tx
- Transplant if FVC <60-65%
Supportive / Transplant for Pneumoconiosis
Treatment of acute IPF exacerbation
R/O infection, PE, HF
Steroids 1g/day x3 then taper + ABX
(Will see new GGO on CT)
Treatment CTD associated ILD
Steroid
MMF/Aza , if fails, ritux/cyclo
+/- Antifibrotics (new evidence: Nintedanib)
When to do diagnostic thoracentesis
- indication to repeat
- dx that can’t be dx by fluid
Suspect EXUDATIVE effusion >1cm in lateral decubitus
- Can repeat ONCE for sensitivity for cytology
- Mesothelioma CANNOT be dx by fluid and req pleural biopsy
Light’s Criteria
Exudative if any of the following:
Pleural protein:Serum protein >0.5
Pleural LDH:Serum LDH >0.6
Pleural fluid LDH > 2/3 ULN
JAMA - Is this pleural effusion exudative?
clue cholesterol, ldh cutoffs
+ LR:
High cholesterol >55mg/dL
LDH >200
Pleural cholesterol:Serum cholesterol > 0.3
-LR:
All 3 lights criteria absent
Causes of chylothorax (Tg >1.24, chylomicrons +)
Cancer (lymphoma highest likelihood) Trauma Surgery TB LAM (young woman w/ PTX/cystic lung dz)
Causes of eosinophilic exudative effusion
Asbestos related (BAPE) Drugs (macrobid) Lung CA PE eGPA Parasitic infection
Causes of low glucose in exudative effusion
<1mmol: RA or empyema
1-3: Cancer, SLE, TB
Indications for chest tube insertion in parapneumonic effusion
Frank pus or blood
Positive gram stain or culture from pleural fluid
pH <7.2 of pleural fluid (of gluc<3.4 if pH unavail)
Effusion >50% hemithorax or is loculated
Indications for chest tube insertion for pneumothorax
Spontaneous and >2cm or symptomatic –> needle aspiration and tube
Secondary (ie. COPD, CF, TB, PCP) - bc lung abN and risk of air leak
Surgery if persistent
Extra-pulmonary Sarcoidosis - Manifestations
Ocular - anterior uveitis (optho)
CNS - CN palsies, HA, ataxia, weakness, LP = nonspec lymphocytic inflammation
CVS: Heart block, restrictive cardiomyopathy, pHTN rare
GI: liver/splenic lesions, cholestasis, liver failure (rare)
Blood: HyperCa/hypercalciuria, lymphopenia, thrombocytopenia
Skin: erythema nodosum, lupus pernio
Logfren’s Syndrome - Sarcoid
Erythema nodosum
Arthralgias/Arthritis (migratory)
Bilateral hilar adenopathy
*High % spontaneous remission
Heerfordt’s Syndrome - Sarcoid
Anterior uveitis
Parotid enlargement
Facial palsy
Sarcoid biopsy: indication and approach
ALL except clear lofgren’s, Heerfordt’s, or lupus pernio
*EBUS guided LN sampling > mediastinoscopy
Indications to treat PULMONARY sarcoid +tx options
-Bothersome dyspnea/cough affecting QoL
-Decreasing lung function (obstructive or restrictive)
-pHTN
*If mild - tx with ICS
If mod-sev tx with Pred 20-40 mg OD x1-3 mo then taper to 10mg/d x1 yr
- MTX if relapse/steroid tox for QoL/preserve FVC
- pulm rehab for fatigue
Indications to treat extra-pulmonary sarcoid
CNS/Ocular/CVS disease - all require oral prednisone
Severe skin dz, hyperCa, symptomatic liver dz also tx
-Skin refractory to steroids –> infliximab
Indications for cardiac imaging (PET or MRI) in sarcoid
Symptoms or abn ECG (blocks or low voltages)
Diagnosis of OSA
Symptoms (choking/snoring/daytime somnolence) +
>5 apnea/hypopnea episodes on monitoring
*mild (5-15/hr), mod 15-30, severe >30
Indications for CPAP for OSA
Excessive daytime somnolence or poor sleep rltd QoL
Asymptomatic with HTN, AHI>30 (severe), critical occupation
*other tx: oral appliance (mild/mod), tonsillectomy/uvulopalatopharyngoplasty (rare)
How / Who to screen for Pulmonary Hypertension
TTE
- esp in:
- Scleroderma (yearly w/ DLCO),
- Portal HTN undergoing transplant w/u,
- Residual dyspnea/exercise intol s/p 3mo AC post-PE (+/-VQ to r/o CTEPH)
Diagnosis Pulmonary Hypertension
Right heart cath demonstrating mean pulm artery P >20 and pulm vascular resistance >3WU on R-heart cath
other clues: isolated reduced DLCO
Categories: Pulmonary Hypertension
1- PAH: Idiopathic, Drug/Toxin, CTD, HIV, schisto, portal HTN, heritable, PVOD
2- Secondary to L heart disease: systolic/diastolic dyscn, valvulopathy
3- Secondary to hypoxemia/lung dz (COPD, ILD, etc)
4- CTEPH –> thromboendarterectomy, AC
5- Unclear mechanism (MPNs, splenectomy, sarcoid, LAM)
Screening and diagnosis of CTEPH
Screening = VQ Scan Diagnosis = CTPE
Work-up for all PH
CBC, lytes, LFTs, TSH, BNP HIV, HBV, HCV ANA, ENA TTE PFTs 6MWT VQ scan - screen for CTEPH Abdo US \+/- sleep study Right heart cath
Treatment PAH
- Diuretics for volume
- Vasoreactivity to determine if CCB candidate
- Influenza/pneumococcal vaccines
- PDE-5 inhibitors (sildenafil. tadalafil)
- Endothelin receptor antags (bosentan, masetentan)
- Prostanoids
- Pulmonary/Physical rehab
- OCP/contraception
- Transplant: for NYHA III/IV
Treatment CTEPH
Anticoagulation +/- pulmonary endarterectomy
Work-up chronic cough
1- CXR, exclude ACEi
2- Treat UACS empirically with antihistamines and oral decongestants +/- intranasal corticosteroid
3- If no response - methacholine test to dx asthma
4- if suspect GERD based on sx, empiric tx with lifestyle, PPI, H2RA, prokinetic, 24h pH monitor if persists
Follow-up of solid lung nodules
If <6mm - no follow-up
If 6-8mm - repeat CT at 6-12 months
If >8 mm - repeat CT @ 3 mo or proceed to bx
Follow-up subsolid lung nodules
If < 6mm - no follow-up (unless multiple, in which case rpt in 6 mo)
If >6mm - repeat CT between 3-12 months or bx
Differential diagnosis of clubbing
- Cancer: NSCLC, mesothelioma, bronchogenic
- Purulent: Abscess, empyema, CF, bronchiect
- Hypoxia: ILD, Cyanotic CHD or IE
- AI: IBD
- Graves
Management of complicated empyema
1) Insert chest tube
2) Intrapleural tPA + DNAase (better than TPA or streptokinase alone)
3) If still no drainage, then VATS with decortication
Antibiotics for purulent COPD exacerbation without pneumonia (clinically or radiographically)
If simple/no RFs for complications:
- Amoxicillin
- Doxycycline
- Macrolide (ie. Azithro)
- Septra
- 2nd/3rd gen cephalosporin
If complicated:
- Amox-Clav
- Fluoroquinolone
Complicated, any of:
- FEV1<50%,
- 4+ exac/yr,
- Home o2,
- Chronic steroid,
- Abx w/i 3 mo,
- Comorbid ischemic heart dz
Appearance of NSIP pattern on CT
Diffuse GGOs
Peripheral reticulations
No honeycombing
RF for severe asthma exacerbation
Any 1 of:
- Hx of previous severe exacerbation (ED/hospitalized/steroids)
- Poorly controlled asthma per CTS
- > 2 SABA inhalers per year
- Current smoker
Asthma yellow zone
If on nothing: take daily ICS or prn bud-form
If on prn bud/form: take it up to 8x/d
If on daily symbicort/advair/(ics or LTRA + severe asthma in past year): increase baseline x4 for 1-2 weeks OR take pred 30-50mg x5d
Nonpharm for asthma
- Confirm Dx, educate, and give action plan
- Weight loss + exercise train
- Avoid trigger, allergens +/- allergen immunotherapy
- Stop smoking + Vaccinations
- Avoid NSAIDs (and maybe BB)
- Tx comorbidities: GERD, PND, Obesity
Tx Vocal cord dysfcn
- Education, behav mod
- SLP
- Treat GERD
Causes of lymphocytic pleural effusion
- Lymphoma, carcinoma
- TB,
- Sarcoid
- RA
- Yellow nail
RF for primary spontaneous PTX
Smoking
Fam Hx
Marfan
Thoracic endometriosis
Sarcoid stages
1 - bilateral adenopathy
2 - adenopathy w/ parenchymal lesions
3 - parenchymal lesions with NO adenopathy
4 - fibrosis
Hemoptysis Ddx
- Infection: bronchitis, TB, bronchiectasis
- Tumor: carcinoid (young smoker w/ lung collapse), malignancy (SCLC/NSCLC)
- CTD: Goodpasture, GPA, SLE
- D/Toxin: Cocaine, anticoag
- Vascular: pulm AVM, bronchial art. aneurysm, PE
Massive Hemoptysis
-Def’n and Mx
~200-600cc/24hrs
Bleeding side down
IR for arterial embolization
Rehab for Long COVID
If:
New/ongoing resp SOB/cough/exercise intolerance w/ functional limitations after resolution of COVID
AND
New/ongoing need for O2
OR at least 1 of:
-Persistent imaging changes
-PFT showing reduced lung vol, airflow, DLCO
OSA driving guidelines
Disqualify if:
- Sleepiness while driving,
- Crash in past 5y from sleeping and not on/compliant to tx (>4hrs >70% nights in past 30d)
FITNESS FOR SURGERY, FEV1 for:
- Pneumonectomy
- Lobectomy
- Poor outcomes
Pneumonectomy - FEV1 >2L or 80% Predicted
Lobectomy - FEV1>1.5L
Poor perioperative outcomes:
- FEV1 <60% predicted
- DLCO ≈ Mortality
Restriction with normal DLCO
Extraparenchymal lung disease (e.g. obesity, chest wall pathology, neuromuscular disease
