Respiratory Flashcards
What does it mean if am entire bronchopulmonary segment or lobe becomes ‘consolidated’?
The tissue is filled with inflammatory cells and oedema
What are the components of the CURB-65 score and what is it used for?
- The CURB-65 score aids in deciding the severity of pneumonia and further management based on this
Components (1 point for each if present):
- Confusion +/-
- Urea >7
- Respiratory Rate >30
- Blood pressure: systolic < 90 or diastolic <60
- More than 65 years old
How is a CURB-65 score of 0/1 managed?
- Home-based care
- Oral amoxicillin for 5 days (macrolide e.g. clarithromycin, doxycycline or tetracycline if penicillin allergic)
How is a CURB-65 score of 2 managed?
- Hospital-based care
- 7-10 day course of dual antibiotic therapy with amoxicillin (IV or oral) and a macrolide
How is a CURB-65 score of 3 managed?
- Hospital / ITU-based care
- 7-10 day course of dual antibiotic therapy with IV co-amoxiclav / ceftriaxone / tazocin and a macrolide
What is the definition of hospital acquired pneumonia (HAP)?
Lower respiratory tract infection that develops more than 48 hours after admission to hospital
What is the definition of pneumonia?
- Lower Respiratory Tract Infection / Pneumonia is caused by infection and subsequent inflammation of the alveoli and terminal bronchioles.
- This leads to an entire bronchopulmonary segment or lobe becoming consolidated, which means that tissue is filled with inflammatory cells and oedema.
In obstructive lung disease, FEV1 would be less than what percentage?
Less than 80%
What kind of molecule is surfactant?
Phospholipid
What are the effects of surfactant?
- Minimises alveolar surface tension
- Improves compliance
Lung compliance is _____ during inspiration as the rate of expansion of alveolar surface area is _____ than the rate of secretion of surfactant during inspiration, hence the alveolar surface tension remains _____ and the compliance _____.
smaller, higher, high, low
During expiration, the _____ volume of surfactant relative to the shrinking of alveoli _____ the surface tension and _____ compliance.
higher, reduces, improves
What is the effect of tension pneumothorax on lung compliance and why?
Lung compliance decreases as the intrapleural pressure becomes greater than the atmospheric pressure
What is the effect of parasympathetic innervation on muscarinic receptors on the airways?
Bronchoconstriction
The lungs mainly contain what kind of beta adrenoceptor to dilate the bronchioles?
Beta 2 adrenoceptors
Cough in ACE inhibitors occurs by what mechanism?
Bradykinin accumulation
What is Poiseuille’s law?
Poiseuille’s law states that as the radius of an airway decreases, the resistance of the airway increases exponentially by its power of 4.
What feature of respiratory bronchioles and alveolar ducts allows for dispersion of total airway resistance?
Parallel arrangement
In chronic hypercapnia, chemoreceptors in the _____ bodies detect _____ oxygen in the blood and send signals via _____ nerves to the _____ respiratory group. Motor output is sent via the _____ nerve to stimulate contraction of the _____ and _____ respiratory rate.
carotid, low, cranial, dorsal, phrenic, diaphragm, increase
What is the cardiac synctium?
The cardiac syncytium is defined as individual cardiomyocytes that are connected by intercalated discs (groups of cell junctions) to work together as a single functional organ. This allows for synchronised cardiac tissue contraction as the electrical signal is propagated.
What is the equation for alveolar ventilation?
This is calculated as VA = (Vt –Vd) x RR where:
VA = Alveolar ventilation (L/min)
Vt = Tidal volume (L)
Vd = Dead space (L)
RR = Respiratory rate (/min)
What is bird fanciers’ lung caused by?
Avian proteins
What are side effects of b2 adrenoceptor agonists?
- Lactic acidosis - b2-adrenoceptor agonists such as salbutamol cause glycogen to break down into lactic acid in muscle, causing lactic acidosis
- Tremor
Oropharyngeal candidiasis can occur as an unwanted effect of what drug class?
Inhaled glucocorticoids due to immunosuppressive actions of this group of agents - A proportion of the inhaled dose of glucocorticoids often can inadvertently come into contact with the oral mucosa, leading to inhibition of the action of T lymphocytes which are important in protection against fungal infections such as candidiasis.
What is the mechanism of action of montelukast?
Leukotriene receptor antagonist (LTRA) - Montelukast blocks the action of leukotriene D4 in the lungs causing a decrease in inflammation and relaxation of airway smooth muscle
Omalizumab is a humanised monoclonal antibody directed towards another antibody involved in the pathophysiology of asthma. Which antibody is it directed toward?
IgE
What is the mechanism of action of theophylline?
Inhibits phosphodiesterase and blocks adenosine receptors which ultimately leads to smooth muscle relaxation
What is an example of a b2-adrenoceptor agonist?
Salbutamol
What type of drug is ipratropium bromide?
Short-acting muscarinic antagonist (SAMA) - blocks parasympathetic activity in the lungs, resulting in bronchodilation
What are side effects of ipratropium bromide?
Brain: drowsiness, dizziness, confusion, hallucinations
Eyes: blurred vision, dry eyes
Mouth: dry mouth
Heart: tachycardia
Bowel: constipation
Bladder: urinary retention
Skin: inability to sweat, overheating
What can be given to treat theophylline toxicity?
Activated charcoal
Surfactant production begins around which week of development?
Week 22
Lung cancer can present with ipsilateral elevation of the hemidiaphragm due to compression of what nerve?
Phrenic nerve
What anatomical defect is associated with male infertility in cystic fibrosis?
Absent vas deferens (sperm duct)
How is cystic fibrosis diagnosed?
Chloride sweat test
Where are peripheral chemoreceptors located and what is their function?
- Located in the bifurcation of carotid arteries and arch of the aorta
- They respond to changes in reduced pO2, increased H+ and increased pCO2 in arterial blood
Where are central chemoreceptors located and what is their function?
- Located in the medulla
- Respond to increased H+ in brain interstitial fluid to increase ventilation
- NB the central receptors are NOT influenced by O2 levels
What are some features of sarcoidosis?
- Erythematous lesions
- Bilateral hilar lymphadenopathy on chest x-ray
- Raised serum ACE
What is a normal tidal volume for males and females?
- Males - 500ml
- Females - 350ml
Which area of the brain stem coordinates the basic rhythm of breathing?
Medulla oblongata
What are features of lung collapse?
- Trachea deviates to the affected side
- Dull percussion
- Reduced breath sounds
What is the definition of expiratory reserve volume?
The maximum volume of air that can be expired at the end of a normal tidal expiration
Foetal haemoglobin’s oxygen dissociation curve lies to the _____ of adult haemoglobin, haemoglobin A. This allows maternal haemoglobin to preferentially offload oxygen to the foetus across the placenta, as foetal haemoglobin has a _____ _____.
left, higher affinity
What are features of a pneumothorax?
- Diminished breath sounds
- Hyper-resonant chest, ipsilateral to the pain
