Asthma

It's a biggie but a goodie! Asthma is a disease which is common in both children and adults. You need to know about it, how to manage it, how to diagnose it and how to explain Einstein's Special Theory Of Relativity. OK, you don't need to the last of these but it might help...I'll get on with it shall I.

Definition

Asthma in a 3 year old girl
Presenting Complaint: Episode of shortness of breath
History of Presenting Complaint: Made worse by exercise, has similar episodes every few weeks, uses a salbutamol inhaler a couple of times a week. No pain associated with the breathlessness, but the is an accompanying expiratory wheeze
Past Medical History: Diagnosed with asthma two years ago. No other previous visits to hospital or GP. Chronic, episodic inflammation of the airways caused by hypersensitive reaction to an allergen.
Perinatal History: No problems during pregnancy, normal birth, no hospitalisation following birth.
Developmental History: Developing normally, on the 10th centile for weight and height, and has been so since birth. Social interactions, speech and language, gross motor and fine motor all fine.
Family History: Mother has asthma, as does grandmother on father's side.
Social History: Lives with mother, father and older sister (6). Both parents teachers. No smokers in the house, nor any carers who smoke. 2 dogs, a cat and 6 budgies in the house.
Drug History: Takes budenoside once daily, through a spacer. Uses salbutamol when needed. No other medications.
Immunisations: Up to date with immunisations.
On Examination: {{{11}}}

Chronic, episodic inflammation of the airways caused by hypersensitive reaction to an allergen.

Epidemiology

According to Asthma UK, 5.2 million people, including 1.1 million children in the UK suffer from Asthma. Hence, it is a very important disease.

Pathophysiology

Books have been devoted to describing the pathophysiology of asthma. Put very simply, it's an immune response causing your airways to constrict and inflame. Foreign bodies (stimuli/allergens/crap are all valid terms) such as dust, pollen, smoke... enter the airways. In most people, this causes no problems. Asthmatics however, are hypersensitive and so their bodies mount an immune response. This causes the release of IgE antibodies.

This is important in understanding the bronchoconstriction (the "constrict" bit from above). Smooth muscle (which surrounds airways) have Beta-2 receptors which, when blocked, result in the smooth muscle to constrict. "So they get blocked but what does the blocking, Mr Chowdhury?", I hear you say. Well, this is where IgE comes into it. It blocks it.

The bronchial inflammation (the "inflame" bit from above) is also an immune response. Inflammation is a non-specific defence mechanism of the body and it's no different in the lungs. Except for the whole, blocking the airway and potentially killing you thing. But the biochemistry is pretty much the same (not that I remember it).

Risk Factors

Basically, it comes down to: atopy which are conditions like eczema or hayfever based on that old chestnut, hypersensitivity; family history of asthma or any atopic conditions; being a boy; external factors like smoking, pets, house dust mites etc.

Clinical Features

There are basically four:

• Shortness of breath
• Wheeze
• Chest tightness
• Cough, usually worse at night.

Pretty easy, huh. The shortness of breath comes in episodes accompanied by the chest tightness. However, the history also needs to cover what effect the asthma is having on the kid's life. You need to ask about frequency of the symptoms; the effect on the kid's life (what is he not able to do); time away from school in the last 6 months; playing sport; sleep; and the longest symptom-free period.

Classification

Infrequent episodic asthma is what 75% of children have and it consists of fewer than four episodes a year. They are symptom free between attacks.

Frequent episodic asthma sufferers make up a further 20% of asthmatics. These children have symptoms every 2-4 weeks.

Persistent asthma makes up <5% of children with asthma. As the name suggests, these are children with persistent symptoms.

Exercise-induced asthma is asthma which only comes on after exercise.

Investigations

This a peak flow meter. You use it to measure peak flow. Good

Generally, investigations in asthma are unnecessary. Skin tests can used for specific allergens but not for diagnosis of the condition. Chest X-ray can show hyperinflation and can be used in infants to rule out a congenital abnormality. The only investigation that is really necessary is peak flow.

This is only done in over 5s because it is very hard to do peak flow on a two-week old. You should check the value against that of PEFR chart (peak expiratory flow rate).

Management

Managing asthma is based on symptom relief and requires a stepwise approach, adding in treatments depending on how good symptom control is. Names of asthma medication is pretty long list so it's on a seperate page.

Step 1: Beta-2 bronchodilator Step 2: Add inhaled steroids Step 3: Add high-dose inhaled steroid OR low-dose inhaled steroid and long-acting bronchodilator and/or leukotriene Step 4: Add high-dose inhaled steroid (if you haven't already) and/or long-acting bronchodilator and/or theophylline OR Ipratropium and/or leukotriene and/or alternate-day prednisolone

Management of acute asthma

The first thing you need to do is recognise it and recognise if it's severe or even life-threatening.

Severe asthma means:

• Too breathless to talk or feed
• Respiratory rate of >50 breaths/min
• Pulse >140bpm
• Peak flow <50% predicted or best.

Life-threatening means:

• Peak flow <33% predicted or best
• Fatigue, agitation, drowsiness
• Cyanosis
• Silent chest
• Poor respiratory effort

Once you've recognised severe or, indeed, life-threatening asthma you probably ought to do something about it. Relatives are often annoyed by doctors who ignore severe or life-threatening acute asthma because the patients often die. This is undesirable.

What to actually do

Immediate treatment consists of oxygen via a face mask; Beta-2 bronchodilator (5mg salbutamol/terbutaline, 2.5mg <5 years) via an oxygen-driven nebuliser three times, back-to-back; nebulised ipratropium 250 micrograms; and 1-2mg/kg oral prednisolone (maximum of 40mg).