Pulmonary Vascular Disease Flashcards
Chest CT findings associated with PVOD
Triad of findings
1. mediastinal lymph node enlargement
2. smooth thickening of interlobular septa
3. ground glass centrilobular nodules
Which pneumocyte makes up largest percent of the alveolar surface area?
90% of alveolar surface area is by type I pneumocytes
about 3% of surface area by type II pneumocytes
2 functions of type 2 pneumocytes
- produce surfactant to reduce surface tension
- mitosis/replicate to replace damaged type I pneumocytes (type I pneumocytes cannot multiply)
Main component of surfactant
90% lipids
hydrophilic heads and hydrophobic tails to reduce surface tension
Differentiate epithelial layer that makes up bronchi vs. bronchioles
Trachea and bronchi are ciliated, pseudostratified columnar
While bronchioles are ciliated simple cuboidal
At what level of airway do you lose
(a) Cartilage
(b) Smooth muscle
(a) Trachea and Bronchi have cartilage, while bronchioles (and alveoli) don’t
(b) Smooth muscle present in trachea, bronchi, and bronchioles. No smooth muscle at level of the alveoli (duh too thin!)
Which level of airway has ciliated epithelial cells?
Trachea, bronchi, and bronchioles have ciliated epithelial layer
Lose cilia only once down at the alveolar level
Describe mechanism by which heliox can reduce work of breathing
Same viscosity but much lower density => lower Reynolds number (dimensionless unit that can predict if flow will be laminar or turbulent) => increased probability of laminar flow
In a pt with a Hb of 6 and SpO2 95%, PaO2 80, which would increase tissue oxygen delivery more:
Hb increase to 8 or
PaO2 to 100
B/c of O2 delivery and arterial O2 content equations- Hb increase to 8 would bring more oxygen to tissues
Formula for lung compliance
Measuring both chest wall and lung together (w/o esophageal balloon no way to separate)
Compliance = ease at which lung expands = dV / dP
Diagnostic BAL finding for DAH (aside from continuously bloody aliquots)
Specifically over 20% hemosiderin-laiden macrophages
-will stain blue with special Prussian-blue stain (stains iron)
What type of transplant specifically carries high risk of DAH
Autologous (self) bone marrow transplant associated with DAH
List some etiologies of DAH that do not involve capillaritis (capillary inflammation)
DAH without capillaritis
-malignancy
-severe mitral stenosis (pressure backs up)
-PVOD/PCH (pressure backs up)
-severe coagulopathy
-idiopathic pulmonary hemosiderosis
While DAH that definitely involve capillarities are the ANCA and CTD- associated, then anti-GMI and APLS can be with or without capillaritis
Differentiate mechanism by which ANCA vasculitis and anti-GBM disease causes DAH
ANCA vasculitis- causes inflammation of small vessels = pulmonary capillaries
While anti-GBM deposits antibodies against type IV collagen into the basement membrane/extracellular matrix- so different part of the alveolar/capillary interface involved
Differentiate treatment/management of DAH due to ANCA vasculitis vs. anti-GBM disease
DAH treatment
ANCA vasculitis- steroids and immunosuppression (mainly cyclophosphamide or rituximab if severe enough that there’s DAH)
while anti-GBM responds better to PLEX so typically start with steroids + cyclophosphamide + PLEX
Clinical triad of EGPA
EGPA clinical triad
- asthma–like airwy disease (often preceeds other things by years)
then - eosinophilia in tissues and systemically then
- small vessel necrosis (vasculitis)
Differentiate ANCA detection by immunofluorescence vs. ELISA
Immunofluorescence detects the ANCA in cytoplasmic vs. perinuclear pattern
Then the ELISA detects the antibody
p-ANCA typically seen with anti-MPO, in EGPA and MPA
then c-ANCA pattern typically accompanied by anti-PR3 in GPA
Which ANCA vasculitis is most likely to have
(a) Kidney involvement
(b) Granulomas
ANCA vasculitides: GPA, MPA, EGPA
(a) Renal involvement (glomerulonephritis) in GPA and MPA (not EGPA)
(b) GPA and EGPA- it’s int he name! granulomatous polyangitis (neutrophilic inflammation) vs. EGPA (eosinophilic granulomatous)
Common clinical features of GPA
(a) Systems typically involved
(b) Typical pulmonary findings
Granulomatous polyangiitis- small vessel vasculitis
(a) ENT/sinus, kidneys (glomerulonephritis), eyes (mononeuritis multiplex)
(b) Typically pulmonary findings = cavitary masses/nodules
Which ANCA vasculitis expect to see p- vs. c-ANCA (and which Ab does this correlate with?)
p-ANCA (perinuclear pattern of ANCA positivity on immunofluorescene) typically with anti-MPO Ab detected on ELISA
-seen in MPA and EGPA
vs.
c-ANCA (cytoplasmic pattern of ANCA positivity on immunofluorescnece) typically seen with anti-PR3 Ab on ELISA
-GPA
Unique drug used in treatment of EGPA not used in the other two ANCA vasculitis (not used in GPA or MPA)
Anti-IL5 mepolizumab approved for EGPA
While GPA and MPA use steroids MTX, cyclophosphamide (typically start with those in EGPA too but then can use mepo)
Differentiate treatment of limited vs. severe ANCA-associated vasculitides
Limited (no life or organ threatening involvement): start with steroids and methotrexate
Severe (life or organ threatening, DAH, glomerulonephritis, any CNS or eye involvement): pulse steroids and then either rituximab or cyclophosphamide
Which leg more common for DVT during pregnancy? Why?
L leg DVT more common b/c of compression of the L iliac vein by the R iliac artery
Mechanism of tPA
tPA (alteplase) binds to fibrin on surface of the clot and converts trapped plasminogen to plasmin that then breaks down clot
Aside from bleeding, major adverse effect to monitor for with protamine
Protamine (reversal for heparin and lovenox)- beware of sudden/severe hypotension and bradycardia
Differentiate proximal and distal DVT
Proximal = iliac, femoral, or popliteal vein involved
Distal = below the knee involving the calf veins with NO proximal component, tibial and peroneal veins
Differentiate WHO FC II and III
FC II- dyspnea with normal activity
FC III- dyspnea with less than normal activity
Characteristic histopathologic lesion in severe PAH
Characteristic plexiform lesion in later stage arteriolar remodeling
Describe main histopathologic features of pulmonary vasculopathy in PH
Histopath features
-intimal proliferation
-thrombosis
-medial hypertrophy
-vasoconstriction
-plexiform lesions
Formulas and cutoffs for
(a) Transpulmonary gradient
(b) Diastolic pressure gradient
Helpful to differentiate group I and II PH
(a) TPG = mPAP - PCWP, abnormal if above 12-15
(b) Diastolic pressure gradient = PA diastolic - PCWP, abnormal if above 7
Mechanism/pathophysiology of DAH in
(a) ITP
(b) Severe MR
(c) ANCA vasculitis
Diffuse alveolar hemorrhage
(a) ITP (and other causes of severe thrombocytopenia) or coagulopathy causes bland hemorrahge- interstitium/capillary membrane intact but RBCS fill alveolar space
(b) Severe MR (and other causes of elevated LVEDP) cause bland hemorrhage
(c) ANCA vasculitis (and other systemic vasculitides) cause pulmonary capillaritis (breakdown/necrosis of alveolar/capillary membrane allowing RBC leakage)
Differentiate two histopath patterns of DAH
DAH has 3 distinct histologic patterns
- Bland hemorrhage (Left image): RBCs in alveolar space with normal interstitial space/alveolar septa
Etiologies: elevated LVEDP (severe MR), coagulopathy (ITP, antiplatelets) - Pulmonary capillaritis (Right image): interstitial neutrophilic infiltrate (red arrows), disruption of alveolar-capillary basement membrane => accumulation of RBC in alveolar space
Etiologies: systemic vasculitis (ANCA, HSP, IgA nephropathy), rheumatic disease (anti-GBM, MCTD, SLE) - DAD from drugs/toxins, infection (anything that can cause ARDS)
