Pulmo Flashcards
Innervation of the diaphragm
Phrenic nerve
Nerve roots of origin of phrenic nerve
C3,4,5
Most common location of Morgagni hernia
Right anterior
Most common site of Bochdalek hernia
Left posterior
Most common congenital diaphragmatic hernia
Bochdalek
Neutrophil-derived elastase that destroy lung parenchyma is inhibited by
α1-antitrypsin
Source of resistance in inspiration that is being reduced by surfactant
Compliance resistance
Pathology of adult RDS
Diffuse alveolar damage
Most common cause of adult RDS
Sepsis
Type of pneumocytes affected in adult RDS
Type I pneumocytes
Lung volumes (4)
1) IRV
2) TV
3) ERV
4) RV
Lung capacities
1) Inspiratory capacity
2) Functional residual capacity
3) Vital capacity
4) Total lung capacity
Capacity-associated volumes: Inspiratory capacity
IRV + TV
Capacity-associated volumes: Functional residual capacity
ERV + RV
Capacity-associated volumes: Vital capacity
IRV + TV + ERV
Equilibrium point at which the elastic recoil of the lungs is equal and opposite to the outward force of chest wall
FRC
Best zone of ventilation in children
Mid to lower lung fields
Ghon’s focus is usually found at which lung fields
Mid to lower lung fields
States that partial pressure exerted by a gas in a mixture of gases is proportional to the fractional concentration of that gas
Dalton’s law
Most common cause of V/Q mismatch
Hypoxemia
Fick’s law of diffusion states that diffusion rate of oxygen across pulmonary membrane depends on
1) Pressure gradient
2) Surface area
3) Diffusion distance
Processes that impair O2 diffusion
1) Decreased O2 gradient (high altitude)
2) Decreased surface area (emphysema)
3) Increased diffusion distance (pulmonary fibrosis)
Cardiac output at rest
5L/min
V/Q ratio at zone 1
3.3
V/Q ratio at zone 2
1.0
V/Q ratio at zone 3
0.6
CO2 is converted to carbonic acid: Inside the RBC vs outside the RBC
Inside
Direction of flow of Cl in chloride shift
Into RBC
Direction of flow of HCO3 in chloride shift
Out of RBC
Dorsal and ventral respiratory groups are found in
Medulla
Pneumotaxic and apneustic centres are found in
Pons
Controls basic rhythm of respiration
DRG
Stimulates expiratory muscles
VRG
Most preventable cause of death among hospitalized patients
Pulmonary embolism
Embolus that occlude the main pulmonary artery, impact across bifurcation
Saddle embolus
Embolus that pass through inter arterial and inter ventricular defect to gain access to the systemic circulation
Paradoxical embolus
Most common cause of PE
Proximal leg DVT
T/F Majority of deep leg vein thrombi are clinically silent
T
% of deep leg vein thrombi that cause infarction
10
Lobe most commonly affected by PE
Lower lobe
% of pulmonary circulation that has to be obstructed to cause sudden death
> 60
% chance of having a second embolus in PE survivors
30
Virchow’s triad
SHE
1) Stasis
2) Hypercoagulability
3) Endothelial injury
Natural anticoagulants in the body
1) Protein C
2) Protein S
3) AT III
Most commonly inherited thrombophilic condition
Factor V Leiden mutation
Major risk factors for PE (5)
1) Post op
2) Prior VTE
3) CVA
4) Estrogen treatment
5) APAS
PE: Most common history
Unexplained breathlessness
PE: Most common symptom
Dyspnea
PE: Most common sign
Tachypnea
Symptoms of massive PE (4)
1) Dyspnea
2) Hypotension
3) Cyanosis
4) Syncope
Symptoms of small PE (3)
1) Pleuritic pain
2) Cough
3) Hemoptysis
Most common history of DVT
Cramp in the lower calf
Most common signs and symptoms of DVT (4)
1) Swelling
2) Pain
3) Erythema
4) Warmth
Classic findings/signs in PE (3)
1) Homans sign
2) Moses sign
3) Palpable cord sign
Pain elicited when calf muscle is compressed against the tibia but none when compressed from side to side
Moses sign or Bancroft sign
Pain of the calf muscle on compression either by squeezing or forced dorsiflexion
Homans sign
Asymmetry in tolerance to pressure of 180mmHg applied on each calves simultaneously
Lowenberg sign
Gold standard for diagnosis of DVT
Contrast venography
Most reliable criterion for DVT on contrast venography
Constant intraluminal filling defect
Natural history of DVT (3)
1) Progressive proximal extension
2) Complete/partial dissolution
3) Embolization
PE on ECG
S1Q3T3
PE: Most common ECG abnormality
T wave inversion in leads V1-V4
Primary criterion for DVT on venous ultrasonography
Loss of vein compressibility
PE on x-ray: Focal oligemia
Westermark sign
PE on x-ray: Peripheral wedge-shaped density above the diaphragm
Hampton hump
PE on x-ray: Enlarged right descending pulmonary artery
Palla sign
PE on x-ray: Prominent central artery
Fleischner sign
Principal imaging test for diagnosis of PE
Chest CT with IV contrast
RV enlargement on chest CT with contrast indicates
Increase likelihood of death within the next 30 days
Most common radiographic abnormalities of PE (2)
1) Atelectasis
2) Pulmonary opacities
PE on ABG
1) Hypoxemia
2) Hypocarbia
PE on 2D echo
RV pressure overload
The Great Masquerader
PE
Virchow’s triad is a predisposing factor to
DVT
PE: Prevention
Heparin
PE: Acute management
Unfractionated heparin
PE: Long-term prevention of recurrence
Warfarin
Substance used in lung scanning
Albumin-labeled gamma-emitting radionuclide
PE: High-probability lung scan
2 or more segmental perfusion defects in the presence of normal ventilation
Best known indirect sign of PE on 2D Echo
McConnell sign
Hypokineses of RV free wall with normal motion of RV apex
McConnell sign
Definitive diagnosis of PE
Pulmonary angiography
Finding of PE on pulmo angio
Intraluminal filling defect in more than 1 projection
Target aPTT in unfractionated heparin therapy for PE
2-3x upper limit of laboratory normal value
Major disadvantage of unfractionated heparin therapy
Repeated blood sampling for dose adjustment every 4-6 hrs
Unfractionated heparin therapy for PE increases the risk for
Heparin-induced thrombocytopenia
Advantage of low molecular weight heparin over unfractionated heparin
No monitoring or dose adjustment needed unless patient is markedly obese or has CKD
Monotherapy for symptomatic VTE patients with cancer
Dalteparin
Anti-Xa
1) Fondaparinux
2) Rivaroxaban
Advantages of Fondaparinux (2)
1) Once-daily subcutaneous injection
2) No lab monitoring
Novel drugs for prevention of VTE after total hip and total knee replacement
1) Rivaroxaban
2) Dabigatran
Dabigatran MOA
Direct thrombin inhibitor
Most serious complication of anticoagulation
Hemorrhage
Management for life-threatening or intracranial haemorrhage due to heparin or LMWH
Protamine sulfate
Anticoagulant for patients with renal insufficiency
Argatroban
Anticoagulant for patients with hepatic failure
Lepirudin
2 principal indications for IVC filter insertion
1) Active bleeding that precludes anticoagulation
2) Recurrent venous thrombosis despite intensive anticoagulation
Lower rate of death and recurrent PE
Fibrinolysis
Preferred fibrinolytic regimen for PE
100mg rtPA as continuous IV infusion over 2 hours
Patient with PE respond to fibrinolytics up to ___ after PE has occurred
14 days
Contraindications to fibrinolysis
1) Intracranial disease
2) Recent surgery
3) Trauma
Mode of transmission of pTB
Droplet nuclei
Most common and important agent of human disease
MTb
T/F Majority of inhaled MTb bacilli reach the alveoli
F
Survival of MTb in macrophages depend on
Reduced acidification due to lack of accumulation of proton-adenosine triphosphate
Why MTb do not die in macrophages
Inhibits intracellular release of Ca resulting in impaired Ca/calmodulin pathway that lead to phagosome-lysosome fusion
T/F Primary PTB may be asymptomatic
T
Lesion formed in PTb after initial infection that heals spontaneously into a small calcified nodule
Ghon focus
The Ghon focus is pathologically
Subpleural granuloma
Most common site of extra pulmonary TB in children
Hilar LN
Clinical finding of PTb in young children and impaired immunity
Pleural effusion
Most common population of post primary disease
Public school teachers
Responsible for the acid-fastness of MTb
Mycolic acid
Caseous necrosis in MTb infection is due to
Phosphatides
Common location of secondary PTb lesion
1) Apical and posterior segment of upper lobes
2) Superior segments of lower lobes
Pneumonia in PTb that results from massive involvement of pulmonary segments or lobes
Caseating pneumonia
Gold standard for diagnosis of PTb
Mycobacterial culture
Duration required for expected growth in mycobacterial culture
4-6 weeks
Medium for PTb culture
Egg- or agar-based medium, Lowenstein-Jensen or Middlebrook 7H10
Temp for PTb culture
37C
CO2/O2 for Middlebrook medium in PTb culture
5% CO2
Decreases the time for bacteriologic confirmation of TB to 2-3 weeks
Immunochromatographic lateral flow assay
Most useful for the rapid confirmation of TB in persons with AFB-positive, AFB-negative, and extrapulmonary smears
Nucleic acid amplification
MTb isolates should be tested for susceptibility to which drugs to detect MDR Tb
1) Isoniazid
2) Rifampin
When MDR-Tb is found, expanded susceptibility testing should be done against which drugs
Fluoroquinolones and injectable drugs
Tuberculin reaction is what type of hypersensitivity
Type IV
Positive tuberculin reaction size in mm: HIV infected
> =5
Positive tuberculin reaction size in mm: On immunosuppressive therapy
> =5
