Respiratory concepts Flashcards
Why is the pO2 in the left atrium lower than in the pulmonary veins (where the blood just came from)?
b/c deoxygenated blood originating from the bronchial arteries mixes with the oxy blood (“venous admixture”)
secreted from the lamellar bodies of type 2 pneumocytes
Surfactant
the main components of surfactant
phosphatidylcholine (Lethicin) & sphingomyelin (L:S ratio > 2 means lungs are mature)
What kind of transmembrane protein is the CFTR protein (responsible for Cystic Fibrosis)
- an ATP-gated ion transporter - pumps Cl- out against a gradient using ATP for energy
Normal arterial blood gas values
-pH —> 7.35-7.45 -PaO2—> 80-95 -PaCO2 —> 35-45 -HCO3- —> 22-26
How can you tell an absolute erythrocytosis from a relative erythrocytosis?
(Erythrocytosis/ Polycythemia is defined as HEMATOCRIT > 52% in men and >48% in women)
you measure the RBC mass
- if it is increased, they have an absolute erythrocytosis
- if it is normal, they have a relative erythrocytosis (ie: relative to decrs in plasma volume)
DIff bwtween Minute Ventilation & Alveolar Ventilation?
Dead Space
- Minute Ventilation = Tidal Volume (L) x breaths/min
- Alveolar Ventilation = (Tidal volume - dead space) x breaths/min
-Alveolar ventilation only measures the vol of air participating in gas exchange per minute
___________ lung diseases are associated with decreased lung volumes & increased expiratory flow rates (due to decreased lung compliance/ increased recoil and increased radial traction on the airways by the lung)
Restrictive diseases (fibrosis)
Heroin overdose causes what kind of metabolic disturbance?
-Suppresses respiratory centers and causes hypoventiliation, retaining of CO2 –> Respiratory Acidosis
blood flow (Q) is greatest at the _____ of the lung
at the BASE
- Ventilation (V) is also greatest at the base
- but the perfusion (Q) is MUCH GREATER than the Ventilation at the base ((so the V/Q ratio is actually lower at the base ))
Where is the correct place to perform a thoracentesis along the midclavicular line, midaxillary and paravertebral line?
Midclavicular –> btw ribs 5- 7
Midaxillary –> btw ribs 7-9
Paravertebral –> btw ribs 9-11
- The pleural border is usually 2 intercostal spaces below the lung border
- you must go in the space past the lung border but within the pleura.. so you must stay within these rib margins
- remember: Needle goes on TOP of rib
Fetal lung Lethicin (dipalmitoyl phosphatidylcholine) increases production at ___ weeks gestation
increases sharply at 30 weeks
Airway resistance is lowest at the ______________
terminal bronchioles (the smallest )
- Why? – b/c they have the largest total cross sectional area
- most resistance is in the medium and small sized bronchi
At what point on a spirometry reading is the total pulmonary vascular resistance lowest?
at the end of a regular (vital capacity) expiration
- Not at the end of a forced expiration (b/c then the vessles would be compressed and have higher resistance)
In patients with longstanding COPD, what is their main stimulator of respiratory drive??
- CO2?
- O2?
- -Hypoxia (low paO2) sensed at the peripheral chemoreceptors (ie: carotid bodies)* is their only stimulation of resp drive
- their prolonged hypercapnia has caused CO2 to no longer stimulate the medullay resp center
T or F?
Blood flow per minute is always the same in systemic and pulmonary circulations?
TRUE
- the rate of flow through the lungs must equal the flow rate in systemic circulation at all times ( or else the chambers of the heart wouldn’t fill adequately)
Oxygenated blood from the mother flows into the fetus by the Umbilical __________ –> then to the fetal IVC
Umbilical Vein
- 1 vein (oxy)
- 2 arteries (deoxy)
What is the main mechanism for clearing small particles (< 2 microns) from the lungs?
PHAGOCYTOSIS
- largest dust particles are sneezed / coughed out
- particles 10-15 microns are trapped in the UR tract
- particles 2.5 - 10 microns are cleared by mucociliaryelevator
- smallest are phagocytized
What is a normal A-a gradient ?
Normally the Alveolar -arterial gradient is not more than 10-15 mmHg
(the A-a gradient is the difference btw Alveolar and arterial Oxygen)
dV / dP =
**Compliance **
- volume for a given pressure
- reduced in Restrictive lung dz
- increased in Obstructive lung dz
Which lung volume is increased in a person w/ COPD?
Residual Volume
What can decrease lung compliance?
- pulmonary fibrosis
- insufficiant surfactant
- pulmonary edema / congestion (ie: Left sided heart failure)
which nerve mediates the afferent limb of the cough reflex ?
Internal laryngeal nerve
- located in the pharynx in the piriform recess
- fish bones stuck in the piriform recess can damage this nerve and affect the cough reflex
High altitude exposure lasting more than a few days results in hypoxemia and a chronic ________ _____________, that is compensated by increased renal excretion of bicarb
Respiratory alkalosis (hyperventilate , blow off CO2)
Besides Histamine, what is another marker of anaphylaxis, that is released from mast cells?
TRYPTASE
-a pt with a chronic disease, has hypoxia and hypercapnia, blood flow to the brain will be incrs or decrs??
Increased
- hypercapnia causes cerebral vasodilation
- this is common in people with COPD (be careful starting them on Oxygen b/c hypoxia drives their respiratory function– so taking away their hypoxia state could decrease their respiratory drive)**
epithelium type of the TRUE VOCAL CORDS
Stratified Squamous Epithelium
the equilibrium of O2 in a normal person at rest is ________ limited
Perfusion limited
- the air is in the alveoli, exchange depends on the amount of perfusion to the lungs
Mucociliary clearance is so effective that only particles ______ mm or smaller actually reach the alveoli and must be cleared by phagocytes
2 mm
Main effect of vagus nerve on lungs
bronchial smooth muscle constriction & incrs mucous secretion
prolonged untreated sleep apnea can have what effect on the heart and lungs?
- each nocturnal episode of decrs ventiliation leads to transient hypercapnea and hypoxemia
- causes systemic and pulmonary vasoconstriction and sympathetic cardiac stimulation
- can lead to pulmonary HTN and Right Heart Failure!
- inflammation of the nasal mucosa
- mostly caused by Adenovirus
- sneezing, cough, runny nose
**Rhinitis (common cold) **
-etiology can be viral (Adenovirus) or Allergic Rhitnitis
Young child with nasal polyps should be evaluated for _____________
Cystic Fibrosis
benign nasal mucosa tumor in young males, with profuse epistaxis
Angiofibroma
Malignant tumor of epithelium in the nasopharynx, African children or Asian adults, keratin + biopsy, assoc with a virus
Nasopharyngeal Carcinoma
- assoc with EBV
- cervical lymphadenopathy 1st sign
child w/ high fever, sore throat, drooling, dysphagia, stridor
Epiglottitis
- caused by H. flu
- med emergency **
inflammation of the upper airway caused by parainfluenza virus
Laryngotracheobronchitis (Croup)
- hoarse, ‘barking’ cough & stridor
benign papillary tumor on the true vocal cords, due to HPV 6 or 11
Laryngeal Papilloma (warts)
- single in adults
- multiple in babies
Clnical picture of fever, chills, productive cough w/ yellow/green or bloody sputum, tachypnea, pleuritic chest pain, decreased breath sounds, dullness to percussion, elevated WBC count
Pneumonia
- infection of the lung parenchyma
- can be bacterial, viral
- 3 patterns —> Lobar, bronchopneumonia or interstitial
Most common cause of community acquired lobar pneumonia
Strep pneumoniae (95%)
pneumonia w/ ‘currant jelly’ sputum
Klebsiella pneumoniae
- thick sputum b/c the bacteria has a thick, mucoid capsule
Type of pneumocyte that can regenerate both type 1 & 2 pneumocytes
Type 2
type of pneumonia w/ scattered patchy consolidations, centered around the bronchioles
Bronchopneumonia
- bacterial cause
pneumonia w/ mild symptoms, minimal sputum, low fever, associated more w/ virual causes
Interstitial (atypica) pneumonia
- # 1 bac cause –> Mycoplasma pneumonia
- Viral causes –> CMV, RSV, Influenza
2 main causes of lobar pneumonia
1- Strep. pneumo –> normal community acquired
2- Klebsiella –> malnourished, elderly, nursing homes, alcoholics, pts at aspiration risk
cause of secondary bacterial lung infection on top of a viral illness
Staph aureus
cause of bronchopneumonia in patients with Cystic Fibrosis
Pseudomonas aeruginosa
community acquired pneumonia, transmitted from water source
Legionella pneumophilia
cause of atypical pneumonia in the elderly, immunocompromised, and those with preexisting lung dz
Influenza virus
atypical pneumonia w/ high fever (“Q fever”) in farmers/ veterinarians, transmitted by ticks on cattle
Coxiella burnetii
First exposure to TB causes:
- focal, caseating necrosis that undergoes fibrosis –> **GHON COMPLEX **
- asymptomatic but + PPD test
Secondary TB arises with the reactivation of the bacteria (commonly due to AIDS) and symptoms include:
- fever, night sweats, chills, cough, hemoptysis, weight loss
- can spread all over body (lumbar vertabrae is caleled “Pott’s dz”)
Lung dz with decreased FVC, FEV1 and decreased FEV1/ FVC ratio
Obstructive lung diseases
- TLC is increased due to air trapping
cough lasting at least 3 months over a minimum of 2 years , assoc with smoking
Chronic Bronchitis
- hypertrophy of mucous glands
- incresaed thickness of mucous glands compared to overall bronchial wall (“REID INDEX > 50% )
smoking causes _______ emphysema
and A1-antitrypsin deficiency causes __________ emphysema
- centriacinar
- panacinar
PiZZ allele associated w/ __________
panacinar emphysema & cirrhosis
cell mediators in asthma
Th2 cells – secrete IL-4, IL-5 & IL-10
diseases associated with _Bronchiectasis _
1- Cystic Fibrosis
2- Kartageners
3- Tumor or foreign body
4- Necrotizing infection
5- Allergic bronchopulmonary aspergillosis
decreased TLC, FVC, and FEV1….. but *FEV1/FVC ratio is increased *
Restrictive lung diseases
end stage is “honey comb” lung appearance
Idiopathic Pulmonary Fibrosis
- TGF-beta from the injured cells causes the fibrosis
- tx = lung transplant
Interstital lung fibrosis due to occupational exposures to small particles..
Pneumoconioses :
- Coal Worker’s (black lung)
- Silicosis
- Berylliosis (NASA workers/ aerospace work)
- Asbestosis
NON-caseating granulomas
- Sarcoidosis (assoc w/ AA women)
- Berylliosis (assoc with aerospace workers)
young adult female w/ **inactivating mutation of BMPR2 **
Primary Pulmonary HTN
- can lead to cor pulmonale
formation of hyaline membranes thickens the air exchange barrier, “white out” on CXR
Acute Resp Distress Syndrome (ARDS)
- free radical damage of both type 1 & 2 pneumocytes
- hundreds of causes
solitary ‘coin lesion’ on CXR
- Lung Cancer
- benign granuloma
- bronchial hamartoma
type of lung cancer NOT amendable to surgery, assoc with male smokers, central location , has many paraneoplastic syndromes
Small cell carcinoma
most common lung tumor in male smokers, central location , may produce PTHrP (& cause hypercalcemia)
Squamous Cell Carcinoma
Most common lung tumor in non-smokers and female smokers
Adenocarcinoma
- glands / mucin
- peripheral location
Lung cancer with columnar cells growing along bronchioles and alveoli, arise from CLARA CELLS, not related to smoking, peripheral, GREAT PROGNOSIS
Bronchoalveolar Carcinoma
Most common overall lung cancer
METASTASIS form other cancers
rupture of an emphysematous bleb in young adults
Spontaneous Pneumothorax
- trachea deviates TOWARD collapsed lung
penetrating chest wall injury, air enters with each breath but can’t escape, trachea deviates away from collapsed lung
Tension Pneumothorax
definition of a Ghon complex
-a lower lobe fibrotic lung lesion w/ an ipsilateral calcified lymph node — sign of primary exposure to TB
bronchiolitis obliterans is assoc w/ _______ lung transplant rejection
CHRONIC rejection
a cavitary lesion on CXR with an air-fluid level
**Lung abscess **
- ususally a result of aspiration
- fever, weight loss, cough, foul smelling sputum
FNA of a lung lesion in your patient shows Fusobacterium, Peptostreptococcus, or Bacteroides –> what do you think caused it?
ASPIRATION of oropharyngeal contents
- these are anaerobic bacteria
- assoc w/ alcoholism, seizure disorders, dementia, CVA
a worker exposed to Asbestos is at greatest risk for developing ______________
1- Bronchogenic carcinoma
2- Mesothelioma (less common than cancer)
3- Asbestosis
a pt with acute pancreatitis is at risk for what serious lung complication?
ARDS
- hyaline membranes in alveoli
N-acetylcysteine works as a mucolytic by:
cleaving disulfide bonds within mucous –> loosening thick sputum
-used in CF and in Tylenol overdose …
administering ________________ to at risk HIV + patients (CD4+ count < 50) weekly can decrease their chance of Mycobacterium Avium-Intracellulare infections
Azithromycin
a patient is put on inhaled corticosteroids for asthma not well controlled with Albuterol alone… what should you instruct them to do after each puff?
Rinse their mouth out
- these pts are at risk for oral candidiasis
What are the 4 phases of Lobar pneumonia?
1- Congestion (first 24 hours) - lobe is red, heavy, boggy
2- Red Hepatization (2-3 days) - red, firm lobe
3- Gray Hepatization (4-6 days) - gray / pale firm lobe
4- Resolution - enzymatic digestion of the exudate
high circulating levels of _________ increase the ESR (a non specific marker for inflammation)
fibrinogen ( an acute phase protein)
- brought on by IL-6, IL-1 and TNF-alpha
use of oxygen therapy in premature neonates can cause _________
retinopathy
- oxygenation induces VEGF in the retina after return to normal room air
- can lead to blindness
Leukotriene C4, D4 & E4 receptor blockers are useful treatments for ___________
Atopic / allergic asthma
Children who develop asthma have an imbalance of Th1 to Th2 lymphocytes….which one do they have more of?
Th2
antifungals that inhibit the synthesis of the fungal CELL WALL
Caspofungin & Micafungin
Which TB medication requires an acidic environment to kill the bacteria and therfore is most useful against the INTRACELLULAR organisms??
**Pyrazinamide **
- works best in acidic places
- kills TB within the macrophage phagolysosomes
mycobacterium treated with drug X lose their “acid fastness” and stop proliferating, which TB drug is being used?
ISONIAZID
- inhibits the synthesis of mycolic acids (cell wall)
Pneumoconiosis that produces calcified hilar lymph nodes and birefringent particles surrounded by dense collagen fibers
**Silicosis **
- densities form in upper lobes
- increases your risk for TB
drug that blocks endothelin receptors , is used to treat Primary Pulmonary HTN (by decreasing pulmonary arterial pressure and lessening the progression of RVH)
BOSENTAN
most notable side effect of the TB drug, Ethambutol ….
OPTIC NEURITIS
- presents as decrs visual acutiy, scotomas, color blindness
localized pleural thickening with calcification –> pt probably exposed to :
Asbestos
best imaging test for a suspected PE
Helical CT
Why do babies born to mothers with diabetes have decreased surfactant ?
b/c Insulin decreases surfactant production
((the babies have been exposed to high glucose and therfore have been secreting a lot of Insulin))
non-specific Beta-agonist , used in Asthma to relax bronchial smooth muscle , but also has side effect of tachycardia
Isoproterenol
Beta-2 agonists for Asthma treatment
- Albuterol –for acute attacks
- Salmeterol –long acting, for prevention of attacks
Asthma drug that prevents mast cell degranulation, onlt used for prevention, not for acute asthma attacks
Cromolyn sodium
