Drug treatment of asthma

1. This case is intended to be done at home in your own time. Answers will be on the web 1 6 3 2 4 7 5 8 The University of Western Australia Integrated Paraclinical Sciences Drug treatment of asthma • Emergency visit • Fred’s wife phones you at 5.30 pm a week later in great distress. On returning from work, she has found him severely breathless and finding it difficult to speak even single words. His hired hand had bought him in from the paddock after they had been breaking in a horse. Initially he tried the inhaler you gave him last week but the effect only lasted a few minutes and further use was not working at all now. • You arrive at his home 10 min later: Which of the following symptoms would indicate the severity of the attack”? • The attack occurred during the day • The beta2 agonist spray was not effective • He was finding it difficult to speak • Examination: • On examinaton at home Fred has a tachycardia of135 beats/min and a tachypnoea. His PEF was difficult to measure but you get a reading of about 150 litres/min • If Fred had been cyanotic or had a bradycardia, what would this indicate? • What is your diagnosis now? • If you had you fancy new portable pulse oxymeter with you, would it be helfpul in Fred’s assessment? Case History Initial consultation: Personal details: Fred Smith – Male, Age: 24 Occupation: Farmer Smoking history: life long non-smoker Family history: mother and brother both suffer from hay fever Past medical history: Wheezy bronchitis as child Presenting symptoms: Fred says that he is often short of breath and particularly when working with chickens • Examination and test results • Fred has shortness of breath and a wheeze when you examine him. He also has a typical wheal on his left hand where a rooster scratched him this morning. The CXR shows nothing of interest and RAST testing reveals allergies to chickens, cats, horses, wheat, dairy products and various pollens. His PEF in the surgery is 400 litres/min. • Diagnosis: • Choose from the following possibilities: • Mild allergic asthma • Severe asthma precipitated by animal dander • What signs, symptoms form the basis for your diagnosis? Question Question Background of the initial examination & testing that might be used Wheeze: Caused by high-velocity airflow through a narrowed airway. Heard during inspiration and expiration in both asthma and bronchitis. Most often heard in the early am or following provocation. Cough: A frequent manifestation of childhood asthma and less common as an isolated sign in adults. Urticaria: A skin condition characterised by transient wheals of varying sizes & shapes with reddish margins and pale centres. Caused by capillary dilatation in the dermis with release of inflammatory mediators. Often caused by animal allergens, pollen etc. Eczema: An eczematous rash is associated with the inheritance of an autosomally dominant predisposition to asthma and hay fever. Most likely tests: Chest X-ray: should be normal in mild asthma. Indicated in severe asthma to look for the changes of allergic bronchopulmonary aspergillosis (collapse and bronchiectasis). Allergy testing: RAST test for specific IgE’s directed against the allergen of interest. Peak expiratory flow: This is the key to objective diagnosis of asthma; may vary diurnally, with allergen exposure, exercise etc. Reversibility testing: Helpful to see whether administration of a B2 agonist by inhalation reverses the diminished PEF or FEV1. A negative test does not necessarily exclude a diagnosis of asthma. • Treatment • The options available to you are: • Beta2 agonist bronchodilators such as salbutamol or terbutaline • Inhaled corticosteroids such as fluticasone or beclomethasone • Oral corticosteroids such as prednisone or prednisolone • Sodium cromoglycate by inhalation • Oral montelukast sodium • Oral theophylline • Avoidance of allergens • Classify each of the drug options according to their pharmacological mode of action, as to whether they are preventers or relievers. • What initial treatment will you recommend to Fred? Explain your decision briefly. Questions Questions • Treatment • The options available to you are: • High dose intravenous steroids • Intravenous aminophylline • High concentration oxygen via a face mask • High dose inhaled beta2 agonists • Which of these would be most appropriate in this case, and in what order? Explain your decision briefly, indicating reasons for rejecting or accepting the various treatments. Question Emergency visit Fred’s wife phones you at 5.30 pm a week later in great distress. On returning from work, she has found him severely breathless and finding it difficult to speak even short sentences. His hired hand had bought him in from the paddock after they had been training a horse for the Bunbury Cup. Initially he tried the inhaler you gave him last week but the effect only lasted a few minutes and further use was not working at all now. Question Asthma Action Plan Once Fred has been stabilised at the local hospital, develop an Asthma Action Plan with him so that future attacks will be managed optimally. KF Ilett 16 Aug 2001