Respiratory knowledge tutor key points Flashcards
Thoracic duct perforates the diaphragm:
T12
- aorta
- thoracic duct
- coeliac trunk leaves the aorta
T8
- inferior vena cava
What type of blood gas abnormality does altitude most commonly cause?
respiratory alkalosis
Fibrosis predominately affecting the upper zones
CHARTS
Coal worker pneumoconiosus Histocytosis Ankylosing Spondylitis Radiation Tuberculosis Silicosis / sarcoidosis
fibrosis predominantly affecting the lower zone
- asbestosis
- connective tissue disorders, SLE
- idiopathic pulmonary fibrosis
Total lung capacity:
Equals vital capacity + residual volume
In a patient with:
- pneumonia
- dry cough
- atypical chest signs
- autoimmune haemolytic anaemia
- erythema multiforme
is most associated with which organism?
mycoplasma pneumoniae
An 80-year-old man who used to work in ship building presents with progressive shortness-of-breath. A chest x-ray shows multiple pleural plaques and bilateral lower zone interstitial shadowing
asbestosis
- often affects lower zone
Summarise the key pathophysiology in asthma
- chronic inflammation
- many eosinophils release granules (histamine, leukotrienes etc.)
combined with environmental factors:
- —-> 1. smooth muscle spasms
- —-> 2. increased mucus secretion
-TH2 cells —> cytokines —> IL-5, attracts and activates more eosinophils
OR
- neutrophils —> IL8 more severe form
Irreversible changes seen in asthma
- Oedema
- Scarring
- Fibrosis
- —-> thickened basement membrane
- ———-> reduces airway diameter
COPD involves what two conditions
- Chronic bronchitis (productive cough)
2. Emphysema ( enlargement of airspaces)
Summarise type 1 respiratory failure
- Fluid in lungs
- —> water (pulmonary oedema)
- —> pus (pneumonia)
- —> blood (haemorrhage) - Oxygen diffusion impairment
- Hypoxemia as oxygen can’t diffuse
- Occurs with diseases and damage to lung tissues
Summarise type 2 respiratory failure
- Obstruction?
- asthma, COPD
- anything depressing respiratory drive
- neuromuscular conditions such as Guillain Barre or myasthenia gravis.
- CO2 collects leading to hypercapnia
Two classic clinical signs of idiopathic pulmonary fibrosis?
- dry cough
2. SOB
What occurs in the pathophysiology of idiopathic pulmonary fibrosis?
Early inflammatory stage
- repetitive exposure to unknown antigen leads to repetitive cycles of alveolitis
- —-> type 1 pneuomocyte damage - m.phages —cytokine—> IL-8, TNF
- chemotaxis of inflam cells : neutrophils, eosinophils and fibroblasts
LEADS TO
- ——–> 1. Diffuse interstitial pulmonary fibrosis
- ——–> 2. DILATION of prox. small airways
ALVEOLITIS
- type 1 pneumocyte damage
- capillary damage, leakage, leads to interstitial and alveolar oedema —> Hyaline membrane formation
pathophysiology of idiopathic pulmonary fibrosis?
Late inflammatory stage
- increased permeability of capillary and alveoli
- inflammatory cells reach alveoli
- fibrosis
Summarise diagnosis of Idiopathic pulmonary fibrosis?
- Serum Acute phase reactant (lung inflammation)
a) Anti-nuclear antibodies (ANA)
b) rheumatoid factor (RF) - increased m.phage and neutrophils
- restrictive thus lung volumes decreased, low FVC but FEV1/FVC ratio should be normal or slightly high
- Aa gradient increased
- DLCO decreased
ABG of a patient with idiopathic pulmonary fibrosis may show?
Respiratory alkalosis due to dysponea
What might be characteristically seen on CXR of patient with idiopathic pulmonary fibrosis?
Early
- bilateral, diffuse infiltrates
Late
- honeycomb lung, cysts surrounded by fibrosis
Define sarcoidosis?
- chronic immune related
- multisystem granulomatous disease
- non-infectious, non ceasating granulomas
Summarise the pathophysiology of sarcoidosis?
- unknown antigen
- CD4+ T-helper cells —–release—–> cytokines
- non infectious, noncaseating granuloma, epitheloid histocytes (m.phages)
- m.phages in granuloma release 1-a-hydroxylase enzyme
- converts vitamin D to active form
- hypervitaminosis D —–> Hypercalcaemia —-> calcium kidney stones, Very severe pain
- increased Ca2+ absorption from small intestine and reabsorption from DCT via principle cells
which intrinsic muscles of larynx open up the airway by separating the vocal folds?
posterior cricoarytenoid muscles
All intrinsic muscles of the larynx are supplied by which nerve?
who’s the only exception?
recurrent laryngeal nerve of the vagus
only exception are cricothyroid which are supplied by external branch of superior laryngeal nerve.
true vocal folds are lined by what mucosa?
- stratified squamous mucosa , protective as vocal folds exposed to wear and tear.
- not the typical resp epithelium that lines the rest of the tract.
- epiglottis also lined by protective stratified squamous epithelium. largely composed of elastic cartilage.
in embryology the thyroid gland descends from the …
foramen caecum
describe the blood supply of the thyroid gland
- superior thyroid artery which is a branch of the external thyroid artery.
- inferior thyroid artery which is a branch of the thyrocervial trunk of first part of subclavian artery
venous drainage of thyroid
- superior and middle thyroid veins
- to internal jugular veins
- via inferior thyroid veins
- to brachiocephalic vein
what muscle causes tongue to protrude?
- genioglossus muscle
- tongue has squamous epithelium
- thus tumours arising from tongue are typically squamus cell carcinomas
all muscles of tongue are supplied by which nerve?
what is the only exception?
- muscle of the tongue are supplied by hypoglossal nerve
- exception of palatoglossus muscle which is supplied by pharyngeal plexus of nerves
what nerve may be injured during submandibular gland procedures?
hypoglossal nerve
parathyroid gland are all usually supplied by which artery?
inferior thyroid artery
calcitonin secreted from
parafollicular cells of thyroid glands
why are salivary stones more commonly encountered in submandibular gland and less commonly found in parotid gland?
- parotid mainly serous gland
- few scattered mucinous acini
pes anserinus
five terminal branches of facial nerve
four muscles of mastication are…
- Temporalis
- Masseter
- Medial pterygoid
- lateral pterygoid
buccinator muscle innervated by
facial nerve
not a muscle of mastication
muscles of mastication are innervated by the …
mandibular division of the trigeminal nerve
describe the dual blood supply of the lungs?
- via pulmonary artery and the bronchial arteries
- thus obstruction of a small pulmonary arteriole by pulmonary embolus will have no minor effect if patient has intact bronchial circulation
describe the differences in innervation of pleura covering the lungs?
- visceral is poorly innervated, autonomic
- parietal, rich innervation from intercostal nerves and phrenic nerve.
- so in lung disease when disease crosses visceral to parietal pleura, pain becomes an important factor
