Sensory Aspects of Respiration Flashcards
What are the typical symptoms of lung diseases?
Breathlessness (or dyspnoea) is a sensation of difficult or uncomfortable breathing. Cough Sputum production Haemoptysis Chest discomfort Wheeze Stridor Hoarseness Snoring history Daytime sleepiness
What may breathlessness be due to? (x5) IMPORTANT for when we become doctors.
NOT JUST lung disease. Heart disease. Pulmonary vascular disease. Neuromuscular diseases (e.g. diaphragm weakness). Systemic disorders (e.g. anaemia, hyperthyroidism, obesity). Equally, if someone has already been diagnosed with one of these diseases, and have exacerbated breathlessness, consider that they may have another one of the above listed diseases).
What is the epidemiology of lung disease?
Respiratory disease affects 1 in 3 in England. It is the third biggest cause of death, killing 1 in 5. Winter observes highest lung disease incidence.
What are the top three rankings for deaths from respiratory diseases?
Lung cancer. COPD. Pneumonia.
What is the prevalence of cough? (x2 points)
3rd most common GP complaint. 10-38% of respiratory outpatients complain of cough.
What is the prevalence of chest pain?
Most common pain for patients seeking medical help (35%).
What is the prevalence of dyspnoea? (x2 points)
6-27% of the general population and 3% of visits to A&E.
What is the difference between symptoms and signs? Examples in the context of respiratory diseases? (x3 and x3)
SYMPTOMS: abnormal or worrying sensation that leads person to seek medical attention e.g. cough, chest pain, dyspnoea. SIGNS: observable features on physical examination e.g. hyperinflation, dullness on percussion and increased respiratory rate.
What is the purpose of a cough? (x2)
Crucial defence mechanism to protect large respiratory tract from inhaled foreign material and excessive mucous secretion. Secondary to mucociliary clearance.
Where are the respiratory sensory receptors located?
Present in the upper airways, larynx and the trachea. Less numerous in the more distal airways and absent beyond respiratory bronchioles.
What are the three types of sensory receptor in the respiratory system: Where? Stimulus? Structure? Function?
THESE ARE ALL IRRITANT RECEPTORS. C-FIBRE RECEPTORS: stimulated by chemicals. Free nerve endings are found in the larynx, trachea, bronchi and lungs that are unmyelinated and release neuropeptide inflammatory mediators (Neurokinin A, Calcitonin Gene Related Peptide, Substance P) in response to inflammatory mediators and chemical stimuli. RAPIDLY ADAPTING STRETCH/IRRITANT RECEPTORS: stimulated by stretch on inspiration. Found in the nasopharynx, larynx, trachea and bronchi. They are small, myelinated fibres that respond to mechanical, chemical and inflammatory stimuli. These are what INDUCE COUGH and respond to stretch in inspiration. SLOWLY ADAPTING STRETCH RECEPTORS: located in airways smooth muscle, predominantly in the trachea and main bronchi. They are myelinated nerve fibres and mechanoreceptors – respond to lung inflation.
What is the afferent neural pathway (involved in cough)? (x1 +1) What are the receptors associated with the afferent neural pathway and their structure? (x2)
These are the sensory nerves that take signals from the sensory nerves to the CNS. IRRITANT RECEPTORS are stimulated, and their afferent neurone is the VAGUS NERVE which travels to the cough centre in the MEDULLA. The superior laryngeal nerve is a branch of the vagus nerve – look at photo. IRRITANT RECEPTORS – mechanoreceptors (cell bodies located in the nodose ganglion, and sensory receptors activated by mechanically-gated ion channels), and nociceptors (cell bodies located in the jugular ganglion) that detect chemicals such as bradykinin and citric acid.
What do mechanical and nociceptors respond to?
MECHANICAL: dust, mucous, food/drink. NOCICEPTORS: noxious, intrinsic inflammatory agents. Nociceptors responds to damaging or potentially damaging stimuli by sending “possible threat” signals to the spinal cord and the brain. If the brain perceives the threat as credible, it creates the sensation of pain.
What are the efferent neural pathways involved in cough?
Activation of motor pathways to effect changes in breathing to cause expiratory airflow (control glottic muscles and expiratory muscles (diaphragm, intercostals, laryngeal muscles, abdominal muscles – refer to photo)). Cough centre is influenced by the cerebral cortex.
What are the mechanics of cough?
- Inspiratory phase with negative flow during inhalation. 2. Glottic closure produces build-up of pressure and minimum air flow – hence called minimum flow phase. 3. Glottis opening. 4. Expiratory phase: this is the expulsive phase, which generates high velocity airflow, facilitated by bronchoconstriction and mucous secretion.
What does a cough sound waveform look like and why?
2 phases with an initial explosive phase that is the first cough sound, followed by an intermediate phase with decreasing sound. An additional third phase called a voiced or glottal phase which gives rise to a second cough sound. [PHOTO 4].
What happens to the trachea during a cough?
When you initially inspire, trachea is round. THEN COMES THE COUGH – intrathoracic pressure causes the posterior tracheal membrane to invaginate = narrows the airways.
What are the causes of a cough?
[Don’t really need to recite these, these should just be recognisable in an exam as causative.] Acute/chronic infection. Airway disease. Parenchymal disease. Tumours. Aspirated foreign bodies. Cardiovascular disease.
What are the two types of cough and causes of each?
ACUTE COUGH (less than 3 weeks): caused by common cold, linked to post-nasal drip (accumulation of excess mucous in nasal cavity that eventually drips down back of throat), throat clearing, nasal blockage and nasal discharge. CHRONIC COUGH (more than 3 weeks): caused by asthma, GO reflux, postnasal drip, chronic bronchitis, bronchiectasis, ACE inhibitors, post-viral.
What is cough hypersensitivity syndrome?
Irritation in throat or upper chest for idiopathic reasons, causing increased cough reflex; triggered by deep breathing, talking, laughing, smoking… IT IS A TYPE OF CHRONIC COUGH!
What is the cough response test?
Test with capsicum in saline solution. Increase capsicum dilution in the saline and record the amount of coughing with each dose. Normal non-coughers require higher dose to cough.
How is the neural pathway in the cough reflex plastic?
Plasticity refers to ability to change and reorganise itself. Excitability of AFFERENT nerves is increased by CHEMICAL MEDIATORS e.g. prostaglandin E2. Causes an increase in receptor numbers or neurotransmitter increase in brain stem.
What treatments are there for cough? (x2 and x3)
SYMPTOMATIC SUPPRESSANTS: opiates act centrally (codeine…) and moguistine/levodopropizine peripherally. These therapies are not very good. DISEASE-SPECIFIC: corticosteroids (eosinophil associated diseases), proton pump inhibitors (GO reflux disease) and steroids for post-nasal drips (e.g. rhinosinusitis).
What are the treatments for cough called?
Antitussives.
