Sensory aspects of respiratory disease Flashcards
What is a symptom?
abnormal or worrying sensation that leads the person to seek medical attention
What is a sign?
observable feature on physical examination
What is cough and what is ist function?
Defense mechanisms to protect lower respiratory tract from foreign material and excess mucous secretion, usually secondary to mucociliary clearance
- High velocity of airflow - Bronchoconstriction and mucous secretion
Where are cough receptors found?
Commonly found at at branchpoints of large airways
Posterior wall of Trachea (most numerous
Upper airways
Larynx
Bronchi
pharynx and the external auditory meatus)
What are the 3 types of sensroy receptors in lung and airway, where they are found and their features
Vagus nerve most important for cough, all sensroy nerves from airway pass through there
- C fibre receptors (chemical)
- Free nerve endings
- Larnx, trachea, bornchi, lungs
- Small unmeliynated
- Irritated by inflammaory mediators
- Release neuropeptide inflammatory mediators (substance P, neurokinin a, calcitonin gene related peptide) - Rapidly adapting stretch receptors
- Main stimulus is inflation
- Naso pharynx, larynx, trachea, bronchi
- Small mylinated
- Mechnical, chemical irritant stimuli, inflammatory mediators - Slowly adpating stretch receptors
- Located inairwaysmooth muscle
- AlsoMYELINATED- so conduct very quickly
- Predominantly in the trachea and main bronchi
What causes stimulation of afferent cough pathways?
- Mechanical: dust, mucous, food/drink
* Chemical: noxious, instrinsic inflammatory agents
What are the afferent neural pathways for cough?
- Stimulation of cough/irritant receptor in lungs and larynx
- superior larnygeal nerve joins with vagus
- links to cough centre
What are the part of the cough centre?
nucleus tractus solitarius- a collection of neurons that are connected to themedullary cough pattern generator
What are the efferent pathways for cough
- Cerebral cortex
- Cough centre in medula
- Sends signals to main muscle groups innervated
- Glottis + Accessory muscles of inspiration
- Diaphragm
- Expiratory muscles
Cerebral cortex also sends direct pathway to glottis
What are the mechanics of cough?
- Inspiratory phase
- trachea bulges out (now round) - Glottic closure
- Increase transpulmonary pressure causes posterior membrane to invagunat and cause crescent –>narrows airway –> airflow increases even more
- Generate pressure behind pressure until glottis opens - Expiratory phase
What brain areas are involved during cough?
Primary somatosensroy cortex
Superior temporary gyrus
cerebellum
What are respiratory causes of cough?
Acute infections (most common, less than 3 weeks) Chronic infections Airways diseases Parenchymal disease Tumours Foreign body Cardiovascular Other Drugs
What are causes of chronic (longer than 3 weeks) cough?
- Asthma and eosinophilic-associated (25%)
- Gastro-oesophageal reflux (25%)
- Rhinosinusitis (postnasal drip) (20%)
- Chronic bronchitis (‘smoker’s cough) (8%)
- Bronchiectasis (5%)
- Drugs e.g. angiotensin converting enzyme (ACE) inhibitors (1%)
- Post-viral (3%)
- ‘Idiopathic’ (10%)
- Other (3%) (naroctic, non naroctic)
What are types of chest pain?
- Chest wall: muscular or rib fracture
- Skin: Herpes zoster
- Pleural pain (pulmonary infarction; pneumonia)
- Deep seated, poorly-localised pain
- Nerve root pain/Intercostal nerve pain
- Referred pain: shoulder-tip pain of diaphragmatic irritation
- Musculoskeletal disorders
- injury to ribs or thoracic muscles
- Cardiovascular disorders
- myocardial ischaemia; dissecting aortic aneurysm
- Gastrointestinal disorders
- Gastro-oesophageal reflux
- Panic
What are the treatments of cough
Central action (opitates) and peripheral not very effective Treat cause (Asthma, reflux disease, post nasal drip (rhinsilitis)
What are the neural afferent pathways for chest pain?
- Spinal nerves
2. Via vagus (may also involve glossopharyngeal (pharynx) and trigeminal (nose)
How is pain relayed?
- A delta and c via dorsal horn
- Crosses over at same anatomical nerve level
- Up spinothalamic tract
- Thalamus
- Primary somatosensory cortex
How is touch relayed?
- Alpha a beta and alpha beta via dorsal horn
- Dorsal columns
- Switch sides at level of caudal medulla
- Primary somatosensory cortex
What are the types of pain?
- Visceral: difficult to localise and diffuse in character and referred to somatic structures
- Less number afferents
- A delta and C
- Somatic: sharp pain
- A alpha and A beta
How is chest pain treated?
- Treat the cause
- Chronic pain is more difficult to manage
- Analgesia may reduce symptoms
- Pain can be severe & refractory
- Such cases best dealt with at specialist ‘pain clinics’
What is referred pain?
- Sensory information comes to spinal cord from one location but interpreted as coming from other location innervated by same spinal cord level
- Afferents converge on neuron at same spinal cord level receiving info from skin so low output pain area interpreted as coming from high output area
- Pain arising from various viscera in the thoracic cavity and from the chest wall is often qualitatively similar and exhibits overlapping patterns of referral, localisation and quality leading to difficulties in diagnosis
What are types of chest pain from the respiratory system
- Pleuropulmonary disorders: pleural inflammation e.g pneumothorax, pulmonary embolism, malignancy
- Get somatic pain
- Very painful attached to pleura - Tracheobronchitis: infections, inhalation of irritants
- Visceral pain - Inflammation or trauma to chest wall: rib fracture, muscle injury, malignancy herpes zoster
What are non repiratory causes of chest pain:
- Cardiovascular
- MI
- Pericarditis
- Aneurysm
- Aortic valve disease
- Gastrointestinal
- Esophageal rupture
- Gastroesophageal reflux
- Pancreatitis
- Psychiatric
What brain areas activated during chest pain?
- Somatosensroy
- Motor processing
- Affective processing (emotional)
- Afferential processing
- Autonomic processing
What is the difference between dyspnea and shortness of breath?
- Occurs at inappropriately low levels of exertion, and limits exercise tolerance
- Unpleasant and frightening experience. Can be associated with feelings of impending suffocation
What pulmonary disorders presnet with dyspnea?
- Airflow obstruction e.g. Asthma, COPD, tracheal stenosis
- Restriction of lung mechanics e.g. idiopathicpulmonary fibrosis
- Extrathoracic pulmonary restriction e.g. Kyphoscoliosis, pleural effusion
- Neuromuscular weakness e.g. Phrenic nerve paralysis
- Gas exchange abnormalities e.g. Right to left shunts
What cardiovascular disorders present with dyspnea?
- Myocardial disease
- Valvular disease
- Pericardial disease
- Pulmonary vascular disease
- Congenital vascular disease
What systemic diseases present with dyspnea?
- Systemic or metabolic disease
- Metabolic acidosis
- Anaemia
- Physiologic processes e.g. deconditioning, hypoxic high altitude, pregnancy, severe exercise
- Idiopathic hyperventilation
What are types of respiratory descriptors?
- Air hunger
- Work/effort
- Tightness
see notes
What are other ways to assess dyspnea?
Subjective ranking (visual anologue, borg) Questionaires (exercise tolerance, quality of life) Exercise test (6min walk, shuttle)
How do you treat dyspnea?
Treat cause
Brocnhodilators (anticholinergic or beta adrenargic agonists)
Drugs affecting brain (morphine, diazepam)
Lung resection (lung volume reduction surgery
Pulmonary rehabilitation (improve general fintess, health, psychologica well being)
