Respiratory Patient/disease Flashcards
Define the 2 different types of respiratory disease
OBSTRUCTIVE- characterised by increased resisntance of pulmonary airways
RESTRICTIVE- impediment to lung expansion not due to airway resistance
- Diffuse pulmonary fibrosis (lung tissue becomes fibrous) e.g. sarcoidosis
- Immobility of thoracic cage
- Weakness of the respiratory muscle
State some obstructive lung disorders
Bronchial asthma
COPD
Deffinition of asthma
- A chronic inflammatory disorder of the airways … in susceptable individuals, inflammatory symptoms are usually associated with widespread but variable airflow obstruction and an increase in airway response to a variety of stimuli.
- Obstruction is often reversible, either spontaneously or with treatment
What is the prevalence and mortality of asthma
-UK 2012- 8 million have asthma with 6 million taking medication
-Incidences for developing asthma dropping 237/10,000 2012 from 518/10,000 2004
-New cases highest in children
-In UK, 1,246 people die from asthma in 2012, up from 1,205 in 2008
0.2 of all deaths, 1.1% of lung deaths
Most over 65
NHS cost of asthma
- 60,000 emergency hospital admissions per year
- £667 million of prescription items
- Total cost to NHS £1 billion per year
What types of asthma are there
- Chronic and acute
- Chronic = prophylactic Therapy
- Acute = can be life threatening- immediate emergency treatment required
- Adult and children
- Occupational- late onset
- Exercise
- All forms are precipitating factors
Children: risk factors for asthma
- Family history of Atopy (genetic tendency to develop allergic disease)
- Co-existence of atopy
- Male sex
- Wheeze in children (parental smoking, premature birth, viral infection in early life)
- Wheeze not always a predictor of asthma in adult life. Earlier onset better prognosis
Environmental factors for asthma
ALLERGENS- grass, mould spores, animal fur, house dust mites
FOOD- milk, egg, tartrazine, alcohol, nuts
NON-SPECIFIC IRRITANTS- dust, cigarette smoke, atmospheric pollution
MEDICAL CONDITIONS- pregnancy, respiratory infections (viral worst)
Other precipitating factors
-OCCUPATIONAL CAUSES- metal salts, lab animals/microbes,
dyes, plastics
-DRUGS- antimicrobials, penicillins, tetracyclines
Beta blockers, NSAID, sulphasalazine
Diagnosis of asthmas 1/3
- A clinical diagnosis- there is no absolute confirmatory clinical test
- E.g. blood test
- Not always simple
- Symptoms are not unique (share with other disease)
- Hallmark is variability, intermittent nature, provoked triggers, worse at night
Diagnosis of asthma 2/3
-Compare results of test for patient when asymptomatic and symptomatic
-Carry out quality spirometry using the lower limit of normal to demonstrate obstruction
-Obstructive spirometry which is reversed by bronchodilators increase likelyhood of asthma
Normal spirometry in asymptomatic patient doesn’t rule out asthma
Diagnosis of asthma 3/3
-Record the patient as likely to have asthma and start carefully monitored treatment (6 week steroid)
Assess patient status and do an FEV1 clinical test
With good symptomatic and objective response to treatment confirm diagnosis of asthma
If response is poor check inhaler technique and adherence, then consider other prognosis
Investigations- lung function test
Forced expiratory volume (FEV)- patient inhales as deeply as possible- then exhale into spirometer
Forced Vital Capacity- max volume of air exhaled with max effort after max inspiration
FEV1- FEV in the first second of exhalation
FEV1/FEV ratio- measure capability of lungs
Normal range= 70% of total capacity exhaled in 1 sec this is lower in COPD
-In obstruction lung disorders- the ratio is reduced
-FEV1, FVC- there are normal values for comparison but these vary with age, race, gender, height and weight
Lung functional tests (Peak flow)
Peak flow- good for patients to self assess, less reproducible results than spirometer, advantage- portable, patient can do at home
Measure- peak expiratory flow rate- PEF
Max flow rate that can be forced out in expiration
Can be used to assess the improvement or deterioration in the disease as well as effectiveness of treatement
Clinical signs of chronic asthma
Moderate hypoxaemia- PO2 50-70 mmHg (80-90mmHg) but blood pH is normal and no hypercapnia (too much CO2)
Ventilation perfusion ratio- severe impairment
Eosinophilia (>400 mm3)- very characteristic of bronchial asthma, Charcot Leyden crystals in sputum, measure sputum samples