Pulm Flashcards
What are complications of systemic miliary TB
- Kidneys
- Meninges in Brain
- Lumbar vertebrae - POTT disease
- Adrenal glands: Addison’s disease
- Liver: hepatitis
- Cervical lymph nodes:
Treatment for active TB
RIPE:
Treatment - combination of rifampin, isoniazid,
Pyrazinamide, ethambutol 6-9 months
Prophylaxis - Rifampin or isoniazid - 9 months
TLC IRV TV IC ERV RV FRC VC
- TLC- Total Lung Capacity- Volume of gas present in lungs after a maximal inspiration
- IRV-Inspiratory reserve volume (not labeled)- Air that can still be breathed in after normal inspiration
- TV- Tidal Volume- Air that moves into lung with each quiet inspiration, typically 500 mL
- IC-Inspiratory Capacity- IRV+TV
- ERV- Expiratory Reserve Volume- Air that can still be expelled after normal expiration
- RV- -Residual Volume- Air in lung after maximal expiration; cannot be measured on spirometry
- FRC-Functional Residual Capacity- RV+ERV (volume in lungs after normal expiration)
- VC-Vital Capacity-TV+IRV+ERV
FEV1
FEV1, which is the amount of air forcibly exhaled in the first second after maximal inspiration, is a good measure of airflow. When expressed as a % of the forced VC (FVC), it can be used to diagnose obstructive diseases such as COPD and asthma. Normal FEV1% > 80.
Restrictive lung disease patients demonstrate a normal or increased FEV1%. FVC and FEV1 are both decreased.
How do each of these parameters change for
obstructive (emphysema)
restrictive (fibrosis)
TLC FEV1 FVC FEV1/FVC Peak flow FRC RV
Obstructive: TLC - increases *FEV1 - really decreases FVC - decreases FEV1/FVC - decreases Peak flow - decreases FRC - increases RV - increases
Restrictive: *TLC - really decreases FEV1 - decreases *FVC - really decreases FEV1/FVC - increases/normal Peak flow - decreases FRC - decreases RV - decreases
Where is the most of airway resistance and autonomic control
Resistance = 1/radius4
In the branching airway system of the lungs, the first and second order bronchi represent most of the airway resistance:
Sympathetic adrenergic neurons activate β2 (Gs) receptors on bronchial smooth muscle, leading to relaxation and dilation of the airways via increases in cAMP. Parasympathetic cholinergic neurons (vagal branches) activate muscarinic receptors (M3- Gq), which lead to contraction and constriction of the airways via increases in intracellular [Ca2+].
- Asthma and COPD (chronic bronchitis and emphysema)- Many inflammatory mediators also cause bronchoconstriction by acting on specific receptors, all of which are linked to increases in intracellular Ca2+ and contraction via the PLC and DAG pathway. Short and long-acting β2 agonists are used to counteract bronchoconstriction. Vagal tone to the lungs can also be reduced with anti-cholinergic drugs.
What is minute ventilation (VE) and formula
What is alveolar ventilation (VA) and formula
Normal values for RR, Vt, Vd
Ve=total volume of gas entering the lungs per minute
Vt x RR
Alveolar ventilation - VA - volume of gas per unit time that reaches the alveoli
(Vt - Vd) x RR
INcreases in Va results in decrease in PCO2 while a decrease in Va results in PCO2
Normal values: Respiratory Rate=12-20 breaths/min
VT = 500 mL/breath
Vd = 150 mL/breath
There are two ways to increase respiration. One way is to increase the respiratory rate (RR). The other way is to increase tidal volume (VT). Assume a baseline RR of 15, a VT of 500 ml, and a dead space volume of 150 mls. Then double minute ventilation by one of the above methods. To increase alveolar respiration, which method is superior or are they equivalent?
A. Increased RR better
B. Increased VT better
C. Methods equivalent
Answer B - better to breath deeper than faster
Minute ventilation goes from 7,500 ml/min to 15,000 ml/min in either case
Va with increase in RR
Va = (Vt-Vd) x RR = 350 x 30 = 10,500 ml/min
Alveolar ventilation with increase Vtidal
Va = (Vt - Vd) x RR = 1000 x 15 = 15,000 ml/min
What is physiological deadspace?
Ventilated but not perfused.
Vd = anatomic deadspace (conducting airways + functional dead space in alveoli
Apex of healthy lung is largest contributor of functional dead space. An ideal lung has no functional dead space.
PaCO2 = arterial PCO2 PECO2 = expired air PCO2
Vd = Vt x [(PaCO2 - PECO2)/PaCO2]
If no alveoli participate in gas exchange (not perfused) then there is no expired CO2 (PeCO2) and Vd = Vt and everything is deadspace. If expired Co2 equals arterial CO2 then Vd = 0 and there is no dead space. Neither extreme exists in life .
In the measurement of physiologic dead space using Bohr’s method, the arterial and expired pCO2 were 40 and 30 respectively. What is the ratio of deadspace to tidal volume?
Vd = Vt x [(PaCO2-PeCO2)/PaCO2]
0.25 is answer
A man who has a tidal volume of 500 mL is breathing at a rate of 15 breaths/min. The PCO2 in his arterial blood in 40 mm Hg and the PCO2 in his expired air is 30 mm Hg. Whwat is his minute ventilation?
What percentage of each tidal volume is dead space? What percentage of each tidal volume reaches functioning alveoli? What is his alveolar ventilation?
What is his minute ventilation?
500 x 15 = 7500 ml/min
What percentage of each tidal volume is dead space?
Vd= Vt x (PaCO2- PECO2)/PaCO2= 500 x 10/40 = 125 ml or 25%
What percentage of each tidal volume reaches functioning alveoli? 75%
What is his alveolar ventilation? (500-125) x 15 = 5625 ml/min
Describe structure of hemoglobin- what is special about fetal
4 polypeptide units (2 α and 2 β) and 2 forms;
1) T (taut) form has low affinity for O
2) R (relaxed) has high affinity for O
Taut in Tissues, Relaxed in Respiratory
Fetal hemoglobin (2α and 2F subunits) has lower affinity for 2,3-BPG than adult Hb and thus has a higher affinity for O2, driving diffusion of oxygen across placenta to fetus. Hemoglobin acts as a buffer for Hydrogen ions.
Why is the dissociation curve of oxygen-hemoglobin sigmoidal shaped.
WHat factors shift towards left
What factors shift toward right?
Sigmoidal shape due to positive cooperativity (higher affinity for each subsequent oxygen molecule bound). Myoglobin is monomeric > no positive cooperativity and not sigmoidal. (hyperbolic)
When curve shifts to the right, decreased affinity of hemoglobin for O2 (t form). An increase in all factors listed causes a shift of the curve to the right.
Left:
- decreased temperature
- decreased 2-3, BPG
- increase in pH (decreased (H+),
- CO
Right shift
- increased temp
- increased CO2
- increased 2,3 BPG
- decrease in pH - acidosis
Equation of Oxygen content and oxygen delivery.
also normal values for
O2 content, Hb content, binding ability.
O2 content = 1.34 x SaO2 x Hb + (PaO2 x .0003)
The .0003 shows that very little oxygen can be dissolved in blood.
normally 1 g Hb can bind 1.34 mL O2
Normal Hb amount in blood is 15 g/dL
O2 binding capacity is normally around 20
O2 delivery to tissues = cardiac output x O2 content of blood.
How do each of these affect
Hb level
% O2 saturation
Dissolved O2
Total O2 content
- CO poisoning
- Anemia
- Polycythemia
1. CO poisoning Hb level - normal % O2 saturation - decreases Dissolved O2 - normal Total O2 content -decreases
2. Anemia Hb level - decreases % O2 saturation - normal Dissolved O2 - normal Total O2 content -decreases *reduced O2 content, normal saturation
3. Polycythemia Hb level - increase % O2 saturation - normal Dissolved O2 - normal Total O2 content -increase
Describe CO2 transport - pulm
Carbon dioxide is transported from tissues to the lungs in 3 forms:
1) Bicarbonate (90%)- vast majority is generated in RBCs and put into plasma in exchange for chloride. H+ buffered in RBCs by Hb
2) Carbaminohemoglobin or HbCo2 (5%) Co2 bound to Hb at N-trminus of the globin (not heme). Co2 binding favors taut form (O2 unloaded)
3) Dissolved CO2 (5%) contributes to serum pH.
Ficks Law’s of diffusion
Depends on
- surface area
- thickness
- Solubility of gas
- Pressure difference
Even though Co2 has a greater MW than O2, its diffusion is about 20x greater because CO2 is highly soluble in blood!
What are normal values for the following
Tracheal PO2
Alveolar PO2
Alveolar PCO2
at end of gas exchange
Tracheal PO2 - 150 mm Hg (atmospheric)
Alveolar PO2 - 100 mmHg
Alveolar PCO2 - 40 mmHg
Poor alveolar perfusion would increase PO2 and decrease PCO2.
Equation for PaCO2
PaCO2 = [VCo2 x .863]/V
Alveolar ventilation is inversely related to alveolar PCO2.
What are the effects on
pH
Bicarb
PaCO2 and compensation in
Metabolic acidosis
Metabolic alkalosis
Respiratory acidosis
Respiratory alkalosis
- Metabolic acidosis - pH goes down, bicarb goes down
Compensation - PaCO2 decreases - hyperventilation - Metabolic alkalosis - pH goes up, bicarb goes up,
Compensation: PaCo2 increases -hypoventilation - Respiratory acidosis - pH decreased, increased PaCO2,
Compensation: increased bicarb - Respiratory alkalosis - pH increased, decreased PaCo2,
Compensation: drop in bicarb - Respiratory alkalosis
What are the values for
in acute respiratory acidosis
pH-7.4, PCO2 = 40, HCO3 = 24
For every 10 PaCO2 increase
- pH decrease
- HCO3 increase
Chronic respiratory acidosis
For every 10 PaCo2 increase
- pH decrease
- bicarb increase
For every 10 PaCO2 increase
- **-pH decrease - 0.08
- HCO3 increase - 1
Note if bicarb is above 30 look for another process like chronic respiratory acidosis
Chronic respiratory acidosis
For every 10 PaCo2 increase
- **-pH decrease - 0.03
- bicarb increase - 3-4 (renal compensation)
-Renal compensation maximum in 4 days, PH never normalized
What are the values for
in acute respiratory acidosis
pH-7.4, PCO2 = 40, HCO3 = 24
For every 10 PaCO2 decrease
- pH increase
- HCO3 decrease
Chronic respiratory acidosis
For every 10 PaCo2 decrease
- pH increase
- bicarb decrease
For every 10 PaCO2 decrease
- **-pH increase- 0.08
- HCO3 decrease - 2
Relationship is true down to a PCO2 of 20
Chronic respiratory acidosis
For every 10 PaCo2 decrease
- **-pH increase - 0.03
- bicarb decrease - 5 renal compensation)
Holds down to a PCO2 of 20, can be complete - renal compensation unlike acidosis
What is winters formula?
Applies to metabolic acidosis
Expected PCO2 = (1.5 x serum HCO3-) + (8+/- 2)
If PCO2 is lower than expected there is a concomitant respiratory alkalosis.
Compensation for a metabolic alkalosis
PCO2 would increase by 5 mm Hg for every 10 increase in HCO3 but PCO2 rarely increases above 50 mm Hg
Diffusion capacity - A/T x D x change in pressure
What factors increase and decrease these values
Decreased by:
- lung fibrosis (increase T),
- emphysema (decreased A),
- pulmonary hypertension/embolism (decreased blood flow from increased resistance),
- CHF (decreased blood flow) and
- anemia (decreased RBCs)
Increased (all increase change in P) by 1. polycythemia (more RBCs),
- exercise (increased pulmonary blood flow),
- intracardiac L to R shunts (increased pulmonary blood flow)
How do PO2 levels affect pulmonary and systemic circulations?
PO2 exerts opposite effects on pulmonary and systemic circulation. In the lungs, a decrease in PO2 causes hypoxic vasoconstriction, shifting blood away from poorly ventilated to well-ventilated regions. In the systemic circulation, hypoxia promotes vasodilation not vasoconstriction
hypoxia promotes vasodilation to get oxygen to tissues. Constriction is to divert blood away.
It is important for the blood to be distributed to those segments of the lungs where the alveoli are best oxygenated. When the oxygen tension of the alveoli decreases below normal, the adjacent blood vessels constrict causing their resistance to increase as much as fivefold at extremely low oxygen levels. This is opposite to the effect observed in systemic vessels, which dilate in response to low oxygen (opposite of pulmonary vessels).
Why do high and low lung volumes raise PVR
At high volumes, pressure on alveolar vessels causes them to collapse, raising PVR.
At low volumes, traction on extra- alveolar vessels is absent and vessels collapse, raising PVR.
The lowest PVR is at FRC.
How to calculate PAO2
PAO2 = .21 (Patm - 47 mmHg) - (PaCO2/.8)
V/Q mismatch in the lung - normal
Pa, Pv, Pa for all three zones
Ideally, ventilation is matched to perfusion (V/Q=1) for adequate gas exchange
Lung zones:
Apex of lung- V/Q=3 (wasted ventilation)
Base of lung- V/Q=0.6 (wasted perfusion)
V/Q > 0 = airway obstruction (shunt). In shunt, 100% O2 does not improve PO2 (eg A-v malformations)
V/Q > infinity = blood flow obstruction (physiological dead space). 100% O2 does improve PO2 assuming <100% deadspace
Zone 1 - PA> Pa>Pv (no blood flow -alveolar is better)
Zone 2 - Pa>PA > Pv
Zone 3 - Pa > Pv > Pa
What are the signs and symptoms of high altitude pulmonary edema aka HACE
When do symptoms occur?
Symptoms: shortness of breath, dry cough, fever, reduced exercise performance, weakness and lethargy
36-72 hours after arrival.
Physical signs -tachypnea -tachycardia -cyanosis \+/- rales -loud P2, RV heave
What are the three compensatory mechanisms for high altitude
- Immediate -Hyperventilation leading to respiratory alkalosis - decreased atmospheric pressure decreases alveolar oxygen tension. To compensate, decrease alveolar carbon dioxide levels would correspond to an increase in PAO2. The alkalosis, increased pH, favors oxygen loading at the alveoli
- Days: Increased 2,3 DPG - doesn’t shift the whole curve but shifts the setpoint to the right. Increases oxygen unloading in tissues
- Days to weeks
Kidneys increase level of erythropoietin, which stimulates he bone marrow to increase RBC and hemoglobin levels> thereby increasing oxygen content of blood.
What are three classes of drug for high altitude prophylaxis
- Nifedipine
- Sildenafil
* *3. Acetazolamide - two days before a hike. It gives you a metabolic acidosis so when you are on the hike you can exceed levels of ventilation you could’ve had without it.
- inhibiting bicarb reabsorption
Tracheobronchial source is most common for hemoptysis - what are the 3 B’s?
- Bronchitis (acute or chronic) - 60-70% of cases
- *(Bronchogenic carcinoma), endobronchial metastatic tumor, Karposi’s sarcoma, bronchial carcinoid
- 23% of cases - Bronchiectasis (inflammation of airways; cystic fibrosis)
What is Kussmaul’s breathing?
Increased rate and DEPTH of breathing
This is associated with *ACIDOSIS
Hyperpnea
What is Cheyne Stokes breathing?
FA: May be associated with Central Sleep apnea
Constant rate of breathing with variable depth include apneic period (aka suspension of breathing)
Causes:
- neurologic disorder (cerebral hemorrhage)
- **Congestive heart failure (around 40% of CHF patients will have this kind of breathing at night
- High altitude and normal aging
What are the accessory muscles of respiration
Expiration
- Abdominal muscles (rectus abdominis)
- INternal intercostals
Inspiration:
- Sternocleidomastoid
- Scalenes
- Trapezius
- EXternal intercostals
In COPD, it is difficult for air to get out. Therefore you need to use these accessory muscles.
If a patient is using their accessory muscles and has obstructive pattern on pulmonary test they likely have COPD.
What is paradoxical breathing?
Associated with respiratory fatigue or diaphragmatic weakness
So basically with normal breathing the abdomen extends outwards with chest expansion.
In this case the abdomen goes inward. The accessory muscles are pulling allowing the chest to rise but pulled with it is the diaphragm, pulling the abdominal contents up with it.
Emphysema “pink puffer”
- α1-Antitrypsin deficiency results in excess elastase activity, which can cause emphysema. (can be congenital or from free radicals of tobacco smoke or neutrophils)
- In lungs, reduction in α1-antitrypsin leads to uninhibited elastase in alveoli leading to reduced elastic tissue > panacinar emphysema. - Centriacinar—associated with
smoking. Frequently in
upper lobes (smoke rises up). Panacinar—associated with
α1-antitrypsin deiciency.
Frequently in lower lobes. - Enlargement of air spaces, decreased recoil, increased compliance, decreased DLCO from destruction of alveolar walls.
INcreased elastase activity > increasedloss of elastic fibers >increasedlung compliance.
CXR: increase AP diameter, flattened diaphragm, increasdlung ield lucency. Barrel-shaped chest Exhalation through pursed lips to increase airway pressure and prevent airway collapse.
[class notes]
Trapped air—hyperinflation and overdistention
• As more alveoli coalesce, blebs and bullae may develop
• Destruction of alveolar walls and capillaries—reduced surface
area for O2 diffusion (hence the major difference with asthma which is that emphysema has a diffusion problem too)
• Compensation is done by increasing respiratory rate to
increase alveolar ventilation
• Hypoxemia and hypercapnea usually develops late in disease - results from hypoventilation and increase airway resistance and problems with alveolar gas exchange)
• Minimal coughing with no to small amounts of sputum
• Overdistention of alveoli causes diaphragm to flatten and AP
diameter to increase
Complications
• Pulmonary hypertension (pulmonary vessel constriction d/t
alveolar hypoxia and acidosis)
• Cor pulmonale (Rt heart hypertrophy +- RV failure)
• Pneumonia
• Acute Respiratory Failure
• V/Q mismatch
• Emphysema: increase ventilation of poorly perfused lung units (high V/Q ratio) increased physiological dead space.
*-the area is getting destroyed so blood flow will not be sent there with vasoconstriction. You are ventilating areas without blood flow, this is why pulmonary hypertension comes later in the disease
• Chronic bronchitis: perfusion of under-ventilated areas, low V/
Q ration and subsequent physiological shunt.
*mucus pus in alveolar space, what is happening to your ventilation and perfusion. You are having areas poorly ventilated but still perfusing. That is what we call a shunt like hypoxia.
If you hear bronchial breath sounds, what should you think of?
Pneumonia
What conditions do you think of when you hear
Fine crackles
***interstitial lung disease
also pneumonia, CHF
How do fine crackles and coarse crackles differ
Fine crackles
- altered by body position change but remains unaltered by coughing
- it is not transmitted to mouth
- produced by sudden inspiratory opening of small airways which were held closed during a previous expiration
- *interstitial lung disease
Coarse crackles
- it is altered by coughing but not by body position changes
- it can be transmitted to mouth
- produced by gas passing through airways which undergo intermittent opening and closing.
Describe what would be seen with each of the physical findings for:
- Breath sounds
- Percussion
- Fremitus
- Tracheal deviation
Pleural effusion Atelectasis Simple pneumothorax Tension pneumothorax Consolidation (lobar pneumonia, pulmonary edema)
- Pleural effusion
1. Breath sounds -decreased
2. Percussion -dull
3. Fremitus - decrease
4. Tracheal deviation: either none or away from side of lesion - Atelectasis
1. Breath sounds - decreased
2. Percussion -dull
3. Fremitus - decrease
4. Tracheal deviation -toward side of lesion - Simple pneumothorax
1. Breath sounds - decreased
2. Percussion -hyper-resonant
3. Fremitus - decrease
4. Tracheal deviation - none - Tension pneumothorax
1. Breath sounds - decreased
2. Percussion - hyper-resonant
3. Fremitus - decrease
4. Tracheal deviation - away from side of lesion - Consolidation (lobar pneumonia, pulmonary edema)
1. **Breath sounds - bronchial breath sounds, late inspiratory crackles, - egophony: Eee > Aaa change, associated with pleural effusion,
- bronchophony: 99 if heard with increased clarity and distinction,
- whispered pectoriloquy: whispered sounds heard clearly and distinctly
2. Percussion - dull
3. Fremitus - increase
4. Tracheal deviation - none
The critical feature of her case is that Mrs. Smith, age 35, has been having “asthma attacks” since her early childhood. Her attacks are characterized by the relatively sudden onset of dyspnea; they are more frequent in the spring and fall, when they are often preceded by symptoms of rhino-conjunctivitis. If untreated, an attack will last for a few days, but if she is treated with a subcutaneous injection of adrenaline, as you have administered at your office, she often has relief from acute symptoms, and the attack may or may not recur. Recently, her attacks have been more frequent, and she does not feel that her breathing is improved to the point where she can carry out her responsibilities as a wife and mother.
Asthma
Following transfusion, oxygen delivery will improve leading to a rise in arterial and mixed venous oxygen content (so OK, I think we are all good with that idea!) Transfusion will not change the arterial PO2 (OK, makes sense) and not change tissue oxygen consumption
I said low O2 delivery, low mixed venous oxygen (MVO2) content- this is true and I may have said the tissues take more O2 etc. but to clarify- LOW O2 DELIVERY results in an INCREASE IN O2 EXTRACTION not in the use or consumption of oxygen, which reflects the metabolic rate of the tissue. The removal of an increased fraction of the O2 from the blood will result in LOW MVO2.
To summarize, there are two main concepts linked to the idea of O2 content in mixed venous blood (MVO2).
The first concept is related to oxygen delivery. ANY decrease in O2 delivery to the tissue will increase the extraction of oxygen from the blood (and by doing so, will decrease MVO2). The tissue will extract more oxygen from the blood in order to meet its metabolic needs (i.e. its rate of oxygen utilization)- so in fact, the RATE of O2 USE does not change, but % of O2 removed from the blood per 100 ml WILL INCREASE because less O2 is coming in. Thus, if you RESTORE O2 delivery, O2 extraction rate will return to baseline- but the use of O2 by the tissue- its metabolic rate, remains the same. We can make up some math for this: Let’s say I NEED 32 oz. of coffee a day- and 64 oz. is regularly delivered- so I routinely take 50% of all the coffee coming to me. Well, one day, someone takes some of my coffee (grrrr! probably Dr. Foty)- and only 48 oz. gets to me- well, I still need my 32 oz- but if I take my regular 50%- I won’t get what I need- so I take 75% this time. My needs haven’t changed- but I need to increase my “extraction” of coffee-then, if the next day, the whole 64 oz. comes- I will go back to my 50%. So my coffee consumption does not change- only the fraction that I remove from the pot. I hope that makes sense. To problem solve for things that change MVO2 in this way, you want to think about what would be the causes of low oxygen delivery - think about the equation: DO2 (delivery) = Cardiac Output X O2 content of the blood (CaO2). As we have discussed, CaO2 is dependent on the the Hgb, O2 SAT and PaO2. So decreased CO, Hgb, O2 SAT and PaO2 will all result in a decrease in MVO2.
The other main concept linked to MVO2 is oxygen consumption by the peripheral tissue (this is O2 USAGE- not to be confused with EXTRACTION)- so anything that increases (e.g. fever, exercise) or decreases (e.g.cyanide, hypothermia) tissue oxygen consumption (that is the USE of O2) will ALSO change the mixed venous O2- in this case, an increase in tissue O2 USE (i.e. metabolic rate) will decrease MVO2, while a decrease in tissue O2 use will increase MVO2. (so that is like, I am getting my 64 oz. delivered, but I decide to drink 40 oz today!)
The mechanism of pulmonary cystic fibrosis (sweat glands)
FA:
Autosomal RECESSIVE defect in CFTR gene on chromosome 7; commonly a deletion of Phe508.
Most common lethal genetic disease in Caucasian population.
__________________________
Patho:
CFTR encodes an ATP-gated Cl− channel that secretes Cl− in lungs and GI tract, and reabsorbs
Cl− in sweat glands. Most common mutation > misfolded protein > protein retained in RER and not transported to cell membrane, causing reduced Cl− (and H2O) secretion; increased intracellular Cl− results in compensatory increased Na+ reabsorption via epithelial Na+ channels > increased H2O reabsorption > abnormally thick mucus secreted into lungs and GI tract. increased Na+ reabsorption also causes more negative transepithelial potential difference.
___________________________
Diagnosis:
Increased Cl− concentration (> 60 mEq/L) in sweat is diagnostic. Can present with contraction alkalosis
and hypokalemia (ECF effects analogous to a patient taking a loop diuretic) because of ECF
H2O/Na+ losses and concomitant renal K+/H+ wasting. Increasedimmunoreactive trypsinogen (newborn screening).
__________________
Complications:
1. Recurrent pulmonary infections (eg, S aureus [early infancy], P aeruginosa [adolescence]), chronic bronchitis and bronchiectasis > reticulonodular pattern on CXR, opaciication of sinuses.
2. Pancreatic insuficiency, malabsorption with steatorrhea, fat-soluble vitamin deiciencies (A, D, E,
K) leading to foul smelling feces
3. biliary cirrhosis, liver disease. Meconium ileus in newborns. Infertility in men (absence of vas deferens, spermatogenesis may be unaffected) and subfertility in women (amenorrhea, abnormally thick cervical mucus).
Nasal polyps, clubbing of nails.
_____________
Treatment:
Multifactorial: chest physiotherapy, albuterol, aerosolized dornase alfa (DNAse), and hypertonic
saline facilitate mucus clearance. Azithromycin used as anti-inlammatory agent. Ibuprofen slows
disease progression. Pancreatic enzymes for insuficiency.
Sweat glands
With the lungs, CFTCR is secreting chloride. What follows the chloride? Sodium. What follows sodium? Water. That is why the mucus is so sticky and thick because no water.
Lung epithelial cells - CFTCR
(cystic fibrosis transmembrane conductance regulator)
The two ions are chloride and sodium but CFTCR is a chloride channel.
Has a big role in the sweat glands. when sweat is secreted there is a lot of sodium and chloride in the lumen. As it goes through the lumen, there are channels along the way to reabsorb. CFTCR are the chloride channels here, chloride will be reabsorbed into the body (as sodium does through their channels, balanced). So there are few sodium and chloride ions remaining in sweat, when we sweat alot the sweat becomes actually saltier because we its faster.
CF - no problem with sodium channel, chloride channels are not open so it can’t leave and keeps going towards the skin, Negative and positive want to stay together. Sodium is pulled by the chloride so alot more is in the sweat now. Salty skin is a symptom of CF.
Describe how flow volume loop changes in these situations
Obstructive Restrictive Fixed Obstruction Variable extrathoracic Variable intrathoracic
Obstructive - In obstructive disease, flow is reduced during expiration (scooped out curve) resulting in air trapping and an increase in RV.
-due to premature closing of those airways, loop shifts to the left. Inspiration is relatively normal
Restrictive - In restrictive disease, flow is normal during expiration resulting in a normal or increased slope in the expiratory phase. The problem here is the lung is stiff and all lung volumes are reduced. Loop shifts to right and is smaller everywhere
Fixed Obstruction - Fixed obstruction somewhere in large airways affecting flow in both the inspiratory and expiratory phases
-flat inspiration and expiration, looks like a rectangle sort of
Variable extrathoracic - Obstruction is extrathoracic and only occurs in inspiration when pressure in trachea becomes negative relative to atmospheric pressure
Variable intrathoracic - Obstruction is intrathoracic and only occurs during expiration when pressure in lung becomes greater than internal large airway pressure
What is flail chest?
Flail chest is a life-threatening condition that occurs when the rib cage is broken in several places due to trauma and becomes detached from the rest of the chest wall. Classic cause of paradoxical chest movement.
Inspiration - broken chest wall goes in due to negative pressure
Expiration
A 26-year-old female has the following arterial blood findings:
PO2 - 94 mmHg
%O2 saturation - 50
Oxygen content - 13 ml/dL
Which of the following is the most likely cause of the findings described above? A. Cyanide intoxication B. Morbid obesity C. High altitude D. Chronic blood loss E. Asthmatic attack F. carbon monoxide
F. carbon monoxide
Cyanide effectively and rapidly halts mitochondrial oxidative phosphorylation by binding to the ferric iron (Fe3+) of cytochrome oxidase a3. Affected cells can’t use oxygen for aerobic respiration, resulting in high anion-gap lactic acidosis - and as we have already discussed, one of the clues will be a RISE in the mixed venous oxygen content.
While cyanide does bind to the ferrous form (Fe2+) of iron found in oxyhemoglobin - it DOES NOT bind to the Fe2+ in oxyhemoglobin very well; it prefers Fe3+ (ferric form; methemoglobin)- which circulates in the blood in small amounts (range is 0-3% of total hemoglobin)- and therefore WHEN cyanohemoglobin IS measured in the blood, it really reflects the binding of cyanide to the ferric form of iron in methemoglobin primarily. For this reason, you would not expect cyanide to cause the O2 sat to drop in such a large way- Step 1 wants you to know that the problem with cyanide is in the periphery with the ability of the tissues to USE the oxygen that is delivered. I also attached a cyanide cartoon- it is a “sketchy”.
When it comes to metabolic acidosis check anion gap. What are the values to note and how to calculate?
MUDPILES
HARDASS
Anion gap = (Na+) - (Cl- + HCO3-)
> 12 mEq/L is elevated anion gap
8-12 is normal anion gap
MUDPILES - metabolic acidosis with elevated anion gap
- methanol (formic acid)
- uremia
- diabetic ketoacidosis
- propylene glycol
- iron tablets or INH
- lactic acidosis
- ethylene glycol
- salicylates
Normal anion gap metabolic acidosis HARDASS Hyperalimentation (Addison disease - primary adrenal insufficiency/hypocortisolism) Renal tubular acidosis Diarrhea Acetazolamide Spironolactone Saline infusion
RIPE for assessing image quality?
Rotation
• The medial aspect of each clavicle should be equidistant from the spinous
processes • The spinous processes should also be in vertically orientated against the
vertebral bodies.
should be visible
projected within the chest, it’s PA.
Inspiration
• 5-6 anterior ribs, the lung apices, both costophrenic angles and lateral rib edges
Projection
• AP vs PA film
• Tip- if there is no label, then assume it’s a PA. Also, if the scapulae are not •
Exposure
• Left hemidiaphragm visible to the spine and vertebrae visible behind heart
Chronic bronchitis (blue bloater)
PRESENTATION
Findings: wheezing, crackles, cyanosis (hypoxemia due to shunting), dyspnea, CO2 retention, 2° polycythemia.
PATHOLOGY Hypertrophy and hyperplasia of mucus-secreting glands
in bronchi >Reid index (thickness of mucosal gland layer to thickness of wall between epithelium and cartilage) > 50%.
OTHER Diagnostic criteria: productive
cough for > 3 months in a
year for > 2 consecutive years.
[Class notes]:
Elimination: Difficulty in clearing secretions because of poor ciliary
function, distal airway occlusion and ineffective cough
secondary to respiratory muscle weakness and reduced peak
expiratory flow
Production: Airflow obstruction: increased mucus hypersecretion causes luminal occlusion,epithelial layer thickening encroaches on the
airway lumen and increased mucus alters airway surface
tension, thereby predisposing it to expiratory collapse
Inflammation:
Inhaled cig smoke and noxious stimuli • Increase neutrophils in airway lumen • Macrophages in airway lumen, wall and parenchyma • CD8 lymphocytes in airway wall and parenchyma (as opposed to CD4 in asthma)
Asthma (FA)
Findings: cough, wheezing, tachypnea, dyspnea, hypoxemia, decreasedinspiratory/ expiratory ratio, pulsus paradoxus, mucus plugging. Triggers: viral URIs, allergens, stress. Diagnosis supported by spirometry and methacholine challenge
Bronchial hyperresponsiveness
> reversible bronchoconstriction. Smooth muscle hypertrophy and hyperplasia, Curschmann spirals (shed epithelium forms whorled mucous plugs), and *Charcot-Leyden crystals (eosinophilic, hexagonal, double-pointed, needle-like crystals formed from breakdown of eosinophils in sputum
Aspirin-induced asthma: COX inhibition >leukotriene overproduction >airway constriction. Associated with nasal polyps
Bronchiectasis (FA)
Bronchiectasis
Findings: purulent sputum, recurrent infections, hemoptysis, digital clubbing.
Chronic necrotizing infection
of bronchi >permanently dilated airways.
Associated with bronchial obstruction, poor ciliary motility (eg, smoking, Kartagener syndrome), cystic fibrosis, allergic bronchopulmonary aspergillosis.
[class notes] • occurs in the context of chronic airway infection and inflammation • mild to moderate airflow obstruction • Small airways in bronchiectasis are obstructed from an inflammatory infiltrate in the wall
Etiology (think infection)
• Congenital or hereditary conditions: cystic fibrosis, intralobar
sequestration of the lung, immunodeficiency states, primary
ciliary dyskinesia and kartagener syndrome
• Bronchial obstruction due to tumor, foreign bodies, and mucus
impaction
• Other conditions such as rheumatoid arthritis, systemic lupus
erythematous, inflammatory bowel disease, and post-
transplantation (chronic lung rejection and chronic graft-
versus-host disease after bone marrow transplantation)
What are the symptomatic classifications of asthma severity (intermittent, mild, moderate, severe)
Intermittent: symptoms <2 days/wk
-exacerbations requiring oral systemic corticosteroids 0-1 times/yr
Step 1 treatment- consider low dose inhaled corticosteroids, As needed short acting beta agonists
Mild: symptoms >2 days/wk but not daily,
-exacerbations requiring oral systemic corticosteroids 2 times/yr
Step 2 treatment - low dose inhaled corticosteroids, leukotriene receptor antagonist, low dose theophylline, As needed short acting beta agonists
Moderate: symptoms daily
-exacerbations requiring oral systemic corticosteroids 2 times/yr
Step 3 treatment: Low dose ICS/LABA (long acting beta2 agonists)
Severe: symptoms throughout the day
-exacerbations requiring oral systemic corticosteroids 2 times/yr
Step 4 or 5 treatment: normal dose of ICS/LABA, add on treatment of tiotropium, anti-IgE, anti IL5, bronchial thermoplasty
*same time frames for usage of short acting beta agonists
Define restrictive work and elastic work
Resistive work: energy needed to move air through the conducting airways to the alveoli.
Elastic work: energy needed to expand the lungs against their own recoil and the recoil of their surroundings (e.g. chest wall, abdomen, etc.)
Primary Ciliary Dyskinesia
• Autosomal recessive syndrome with variable penetrance
• 1 in 15,000 to 40,000 births, poorly functioning cilia
• There is an absence or shortening of the dynein arms
• Kartagener syndrome: bronchiectasis, sinusitus, and situs
inversus or partial lateralizing abnormality.
Therapy
• Airway clearance • Antibiotics • Antinflammatory • Preventing exacerbations
What is samter’s triad
Samter’s triad (Aspirin Exacerbated Respiratory Disease (AERD), also known as Samter’s Triad or Aspirin Sensitive Asthma)
- Asthma,
- Chronic rhinosinusitis with polyposis,
- aspirin/NSAID sensitivity)
Upper airway cough syndrome
Upper Airway Cough Syndrome
• Post nasal drip due to various etiologies
• Secretions in airway stimulate cough receptors in the laryngeal mucosa
• Common reason for chronic cough
• Tx: treat post nasal drip
Paradoxical Vocal Fold Motion/Vocal Cord Dysfunction (VCD)
Paradoxical Vocal Fold Motion/Vocal Cord Dysfunction (VCD)
*important to think for treatment resistant asthma
• Mistimed vocal fold closure creates difficulty breathing
– Vocal folds are held in a paramedian position through inspiration and
expiration
• Misdiagnosed as asthma
• Psychogenic component theorized
• Post nasal drip, inhaled or aspirated irritants, allergies or
GERD may cause laryngeal hyperresponsivenss
• TX- Treat underlying causes, reassurance, breathing
instruction
Vocal fold paralysis
unlateral vs bilateral
Vocal Fold Paralysis
• Unilateral- Usually asymptomatic
• Airway obstruction can be measured during both quiet and
active breathing
• The action of inspiratory airflow producing a Bernoulli effect
on the flaccid vocal fold (because they are now closer together, increases chance of the two collapsing on each other)
• Inappropriate reinnervation of the paralyzed vocal fold with
active signals for adduction during inspiration
• Tx- Surgery or botulinum toxin injection
Bilateral- Very symptomatic on exertion, weak, breathy voice
• Most commonly due to surgery in the anterior compartment of
the neck (Thyroid Surgery)
• Injury to recurrent laryngeal nerves
• Loss of vocal cord abduction during inspiration
• Loss of adduction for phonation
• Tx- Surgery, botulinum injection, tracheotomy
Glottic Stenosis
Glottic Stenosis
Scarring of the larynx • Usually posterior (PGS)
• Most common event associated with onset is prolonged
intubation (foreign body leading to excessive scarring)
• As the endotracheal tube rubs against the mucosa of the
posterior larynx, the mucosa is eroded and inflammation
develops
• Clinically and endoscopically it can be difficult to distinguish
from bilateral vocal fold paralysis
• PGS usually have a normal voice because vocal fold
adduction is maintained
Subglottic and Cervical Tracheal Stenosis
Subglottis is surrounded by a firm cartilaginous structure and
the mucosa lies over the surface with only a normal
submucosa for support of the epithelium
• Prone to injury from pressure or inflammation
• Injury to the mucosa by any one of the prior processes can
lead to exposure of the perichondrium, which then responds
with inflammation and scar tissue formation
• The scar tissue impedes airflow and mucus clearance
Caused by prolonged intubation, surgery, and autoimmune
disease (Granulomatosis with Polyangitis)
• Tx- Surgical
Significant predictors of hypersensitivity pneumonitis
ESPIRL
Exposure to known offending antigen - OR 38!
Symptoms 4-8 hours after exposure OR: 7
Positive precipitating antibodies
Inspiratory Crackles
Recurrent episodes of symptoms
weight Loss
Note: all six variables positive 98% chance of having HP; w/o weight loss 97% chance
croup
Caused by parainluenza viruses (paramyxovirus). Virus membrane contains hemagglutinin
(binds sialic acid and promotes viral entry) and neuraminidase (promotes progeny virion release)
antigens. Results in a “seal-like” barking cough and inspiratory stridor. Narrowing of upper trachea
and subglottis leads to characteristic steeple sign on x-ray
A . Severe croup can result in pulsus
paradoxus 2° to upper airway obstruction.
Respiratory illness characterized by a
hoarse voice, dry ‘barking’ cough,
inspiratory stridor and a variable amount of respiratory distress resulting from upper airway obstruction.
• 64 year old male admitted through the ER to the
ICU for chief complaints of fevers, cough and
shortness of breath. • Fever and rigors for 3 days. • Progressive shortness of breath for the last day • No significant past, family or occupational history • Current smoker (2 packs per day)
• Vital Signs: Temp 102 °F, pulse 130/min, BP 80/20mmHg, RR 28/m, room oxygen saturation by pulse oximetry: 89%. • Skin: Dry with reduced turgor • Cardiac exam: Tachycardia • Lung exam: Bronchial breath sounds, egophony, whispered pecteriloquy in the right lung base
posteriorly
• CBC: Hb: 14g%, Hct: 40, WBC: 20.000/μl, 85%
polymorphonuclear leucocytes, 14% bands, 1
lymphocyte. • Serum Chemistry: S.Na: 140, S.K: 4.0, S.Cl:
104, S.
H2Co3: 18, BUN: 72, S.Cr: 3.6, S.Glucose: 74 mg/dl, S. lactate: 6.0 mg/l
ABG: pH: 7.35, PaCO2 33 PaO2 60
Density in right lower lobe
he has consolidation
renal failure
lactic acidosis with hypoxia and huge A-a gradient.
Consolidation with right lower lobe
Severe Community Pneumonia with hypoxemia, leucocytosis, left shift, gap metabolic acidosis due to lactic acidosis.
• Blood and sputum culture, sensitivity was obtained.
What are the three kinds of ventilator induced lung injury
• Positive pressure ventilation results in
– End-inspiratory alveolar overdistention (volutrauma)
– End-expiratory alveolar derecruitment (atelectrauma)
– Biochemical injury and inflammation (biotrauma)
Volutrauma
• Large tidal volumes lead to increased wall stress (“stretch”)
– Gross physical disruption of lung tissue
– Activation of stretch-responsive inflammatory pathways in lung epithelial cells.
– Increased parenchymal inflammation, atelectasis, hypoxia and cytokine production.
Atelectrauma
• Cyclic closing and reopening of alveoli with each
tidal breath
• Alveolar shear-stress related injury
– Biochemical injury and inflammation (biotrauma) results from this mechanical stress
Lung Protection strategy
– Low tidal volumes (6cc/kg PBV) – Optimal PEEP – Recruitment maneuvers – Prone positioning
Rales vs Rhonchi
Rales = discontinuous sound, crackles, associated with alveoli, the most distal portion of airway
-usually due to fluid accumulation - pneumonia, pulmonary edema, can also be caused by atelectasis from PE
Rhonchi = wheezing, occurs in large airways, bronchus, continuous sound
-inflammatory in nature - asthma, chronic bronchitis, wheezing, constriction - or can be due to secretions
Rales in the tails, rhonchi in the bronchi!
What are vesicular breath sounds
Bronchial breath sounds
Vesicular
- normal sound on most of lung
- soft, low pitch
- inspiration longer than expiration
- no gap between phases
Bronchial
-abnormal in majority of lung that is far from main airways
-loud tubular quality
-high pitched
-inspiratory and expiratory phase equal
-definite gap between phases
HEARD in - Consolidation, lobar Collapse with patent bronchus, lung Cavity
What breath sounds are associated with consolidation?
Consolidation occurs through accumulation of inflammatory cellular exudate in the alveoli and adjoining ducts. Simply, it is defined as alveolar space that contains liquid instead of gas. The liquid can be pulmonary edema, inflammatory exudate, pus, inhaled water, or blood (from bronchial tree or hemorrhage from a pulmonary artery). It must be present to diagnose pneumonia: the signs of lobar pneumonia are characteristic and clinically referred to as consolidation
- increased tactile fremitus
- Bronchophony
- Aegophony (BEE heard as BAY)
- Whispering pectoriloquy
Wheeze breath sound
Continuous and musical quality
Expiratory usually
indicates narrowing of airways EITHER due to bronchospasm OR secretions in small airways
low pitch or high pitch
High pitch polyphonic or monophonic
during inspiration the elasticity of the airways will cause them to dilate which will allow air to flow around the obstruction. As the airways contract during exhalation, airflow will increase causing the high pitched sounds associated with wheezing
Crackles
Interrupted and non musical
inspiratory usually
peripheral airway collapse on expiration due to either interstitial fibrosis or secretions/fluid
During inspiration, rapid air entry abruptly opens these collapsed smaller airways and alveoli producing crackling noise.
Can be
- early inspiratory in small airways disease like broncholitis
- mid inspiratory in pulmonary edema
- Late inspiratory in pulmonary fibrosis, pulmonary edema, COPD, resolving pneumonia, lung abscess, tuberculous lung cavities
- biphasic in bronchiectasis
Fine crackles - broncholitis, pulmonary edema, pulmonary fibrosis
Coarse: COPD, resolving pneumonia, lung absess, tuberculous lung cavities, bronchiectasis
How to differentiate if a rub is pleural lining or pericardium,
you must perform a brief inspiratory hold maneuver, if the rub continues during the maneuver it is most likely a pericardial rub.
Lung cancer (general)
Presentation,
site of metastases from lung and to lung
SPHERE of complications:
Risk factors
Treatment
Leading cause of cancer death. Presentation: cough, hemoptysis, bronchial obstruction, wheezing, pneumonic “coin” lesion (solitary nodule) on CXR or non calcified nodule on CT.
- Sites of metastases from lung cancer: adrenals, brain, bone (pathologic fracture), liver (jaundice, hepatomegaly).
- In the lung, metastases (usually multiple lesions) are more common than 1° neoplasms. Most often from breast, colon, prostate, and bladder cancer.
SPHERE of complications:
Superior vena cava syndrome: obstruction of SVC leads to distended head and neck veins with edema and blue discoloration of arms and face (SVC syndrome)
Pancoast tumor: a tumor of the pulmonary apex. It is a type of lung cancer defined primarily by its location situated at the top end of either the right or left lung. It typically spreads to nearby tissues such as the ribs and vertebrae.
Horner syndrome
Endocrine (paraneoplastic)
Recurrent laryngeal nerve compression
(hoarseness)
Effusions (pleural or pericardial)
Risk factors include smoking, secondhand smoke,
radon, asbestos, family history.
Squamous and Small cell carcinomas are Sentral (central) and often caused by Smoking.
Small cell usually not amenable to surgical resection (chemotherapy and radiation)
Non-small cell: usually amenable to surgical resection, usually doesn’t respond well to chemo)
Small cell carcinoma Characteristic histology Association Location Comment
[Small cell carcinoma] Characteristic histology: 1. poorly differentiated small cells from neuroendocrine cells [chromogranin positive] 2. Neuron-specific enolase positive
Association: male smokers
Location: central
Comment: rapid growth and early metastasis may produce endocrine (ADH or ACTH) or nervous system: (Labert-Eaton myasthenic syndrome: antibodies against presynaptic Ca2+ channels
Paraneoplastic myelitis, encephalitis, subacute cerebellar degeneration
Amplification of myc oncogenes common. Managed with chemotherapy +/- radiation
Adenocarcinoma (non small cell carcinoma) Characteristic histology Association Location Comment
+ bronchoalveolar subtype
[Adenocarcinoma]
Characteristic histology: glands or mucin production (stains positive)
Association: nonsmokers and female smokers (most common lung cancer overall excluding metastasis)
Location: Peripheral
Bronchoalveolar: grows along alveolar septa> apparent “thickening” of alveolar walls. Tall columnar cells containing mucus *may present as pneumonia like consolidation on imaging but excellent prognosis
Comment: activating mutations include KRAS, EGFR, and ALK. Associated with hypertrophic osteoarthropathy - clubbing
Bronchial carcinoid and bronchioalveolar cell have less association with smoking
Squamous cell carcinoma Characteristic histology Association Location Comment
Squamous cell carcinoma
Characteristic histology: *keratin pearls OR intercellular bridges
Association: male smokers
Location: central
Comment:
Hilar mass arising from bronchus: 3C’s cavitation, cigarettes, hypercalcemia from PTHrP
Large cell carcinoma Characteristic histology Association Location Comment
Characteristic histology: pleomorphic giant cells
Association: smoking
Location: central or peripheral
Comment : highly anaplastic undifferentiated tumor, POOR prognosis, less responsive to chemotherapy, removed surgically. Strong association with smoking .
Bronchial carcinoid tumor
Excellent prognosis, metastasis rare
SYmptoms due to mass effect or carcinoid syndrome: flushing, diarrhea, wheezing
Nests of neuroendocrine cells, chromogranin A positive like small cell carcinoma.
Not related to smoking
central or peripheral, classically presents as a polyp-like mass in the bronchus. Its a low grade malignancy!
Common causes of pneumonia
Neonates (<4 wk) Children (4 wk - 18 years) Adults (18-40) Adults (40-65) Elderly
Neonates (<4 wk)
Group B streptococci
E coli
Children (4 wk - 18 years) -Viruses (RSV) -Mycoplasma -C trachomatis (infant s –3 y r) -C pneumoniae (scho ol- a ged children) S pneumoniae Runts May Cough Chunky Sputum
Adults (18-40) Mycoplasma C pneumoniae S pneumoniae Viruses (eg, influenza
Adults (40-65) S pneumoniae *H inluenzae *Anaerobes Viruses Mycoplasma
Elderly (65+) S pneumonia Influenza virus Anaerobes H influenza Gram negative rods
Pathoma:
What are the high yield types of lung benign lesions and their presentation
coin lesion especially in younger patients (<40)
- Granuloma- often due to TB or fungus
* *If Midwest - Histoplasma - bronchial hamartoma - benign tumor composed of lung tissue and cartilage often calcified on lung
If you find a solitary nodule on xray, what is the next step?
Look at old xrays
What is TNM staging system (Stage - spread)
pulm
TNM staging system (Stage = Spread):
T = Tumor size/invasiveness - obstruction of SVC leads to distended head and neck veins with edema and blue discoloration of arms and face (SVC syndrome)
-involvement of recurrent laryngal (hoarseness or phrenic ( diaphragmatic paralysis nerve)
-involvement of the SNS chain (Horners) and brachial plexus (should pain and hand weakness is seen with pancoast tumors!
N = Node involvement
-hilar, mediastinal
M = Metastases Each TNM factor has independent prognostic
value; N and M factors are often most
important.
**adrenal gland is high yield
exudate vs transudate
Light criteria
[exudate] Cellular (cloudy) elevated protein (> 2.9 g/dL) elevated LDH (vs serum) Due to: Lymphatic obstruction (chylous) Inlammation/infection Malignancy
[transudate)
Hypocellular (clear)
low protein (< 2.5 g/dL)
low LDH (vs serum)
Due to:
increased hydrostatic pressure (eg, HF, Na+ retention)
reduced oncotic pressure (eg, cirrhosis, nephrotic syndrome
Light Criteria
Diagnostic analysis comparing serum and pleural fluid protein and LDH levels. Pleural effusion is exudative if ≥ 1 of the following criteria is met:
Pleural effusion protein/serum protein ratio > 0.5
Pleural effusion LDH/serum LDH ratio > 0.6
Pleural effusion LDH > 2⁄3 of the upper limit of normal for serum LDH
Restrictive lung diseases
Restricted lung expansion causes reduced lung volumes (reduced FVC and TLC).
PFTs: FEV1/FVC ratio ≥ 80%.
Patient presents with short, shallow breaths.
Ty p e s :
1. Poor breathing mechanics (extrapulmonary, peripheral hypoventilation, normal A-a gradient):
-Poor muscular effort—polio, myasthenia gravis, Guillain-Barré syndrome
-Poor structural apparatus—scoliosis, morbid obesity
2. Interstitial lung diseases (pulmonary reduced diffusing capacity, increased A-a gradient):
-Pneumoconioses (eg, coal workers’ pneumoconiosis, silicosis, asbestosis)
-Sarcoidosis: bilateral hilar lymphadenopathy, noncaseating granuloma; increased ACE and Ca2+
-Idiopathic pulmonary fibrosis (repeated cycles of lung injury and wound healing with
increasedcollagen deposition, “honeycomb” lung appearance and digital clubbing)
• Repeated cycles of epithelial activation/injury by some unidentified agent followed by abnormal
epithelial repair at the site of injury
• Leads to excessive fibroblastic proliferation resulting in characteristic fibroblastic foci seen on
lung biopsy
• Areas of both early injury/repair and late collagen deposition lead to characteristic “temporal
heterogeneity”
Radiographic feature: basal-predominant reticular abnormality with volume loss.
Granulomatosis with polyangiitis: inflammation of multiple blood vessels or lymph vessels (Wegener)
Pulmonary Langerhans cell histiocytosis (eosinophilic granuloma)
Drug induced pulmonary fibrosis: (bleomycin, busulfan, amiodarone, methotrexate)
Hypersensitivity pneumonitis—mixed type III/IV hypersensitivity reaction to environmental antigen. Causes dyspnea, cough, chest tightness, headache. Often seen in farmers and those exposed to birds. Reversible in early stages if stimulus is avoided.
• Also called extrinsic allergic alveolitis • Results from repeated inhalation of finely dispersed
antigens
• Antigens encompass a wide variety of organic
particles
• Sources include mammalian and avian proteins,
thermophilic bacteria, fungi, certain small MW chemical compounds
• Acute form results from intermittent and intense
exposure • Symptoms occur 4-8 hrs. after exposure and
characterized by fever, chills, malaise, dyspnea and
cough
• Subacute and chronic forms result from continual, low-level exposure, usually in the domestic environment • Onset insidious; main symptoms are dyspnea and
fatigue • Unrecognized and untreated subacute form may
progress to chronic form with irreversible lung changes • Exam usually shows tachypnea and crackles in all forms
• Acute form shows diffuse ground-glass appearance
or air-space consolidation
• In subacute form CXR shows fine nodular or reticulonodular pattern
• Chronic form shows predominantly a reticular
pattern • Distribution involves mainly the upper two-thirds
of the lungs
Inhalation injury and sequelae
Pulmonary complication associated with smoke
and fire.
Caused by heat, particulates ( chemical
tracheobronchitis, edema, pneumonia,
ARDS. Many patients present 2° to burns, COinhalation, cyanide poisoning, or arsenic
poisoning.
Bronchoscopy shows severe edema, congestion of bronchus, and soot deposition ( A , 18 hours
after inhalation injury; B , resolution at 11 days after injury).
Pneumoconiosis
Coal workers’ pneumoconiosis, silicosis, and asbestosis > increased risk of cor pulmonale, cancer, and Caplan syndrome (rheumatoid arthritis
and pneumoconioses with intrapulmonary nodules).
Asbestos is from the roof (was common in insulation), but affects the base (lower lobes). Silica and coal are from the base (earth), but
affect the roof (upper lobes).
Asbestosis
Associated with shipbuilding, rooing,
plumbing. “Ivory white,” calcified, supradiaphragmatic and pleural plaques
are pathognomonic of asbestosis. Risk of bronchogenic carcinoma > risk of
mesothelioma.
Affects lower lobes. Asbestos (ferruginous) bodies are golden-brown
fusiform rods resembling dumbbells,
found in alveolar sputum sample, visualized using Prussian blue stain, often obtained by
bronchoalveolar lavage.
increased risk of pleural effusions (consistent with increased risk of lung cancer)
Berylliosis
Associated with exposure to beryllium in
aerospace and manufacturing industries.
Granulomatous (noncaseating) on histology
and therefore occasionally responsive to steroids.
Affects upper lobes
