Asthma

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Chronic lung condition, inflammation and hypersensitivity of the airways.

Diagnosis is clinical

**Ten facts**

1. Chronic lung condition, inflammation and hypersensitivity of the airways.

## Symptoms

Worse at night

* Wheeze
* Cough
* Chest tightness
* Dyspnoea

3 questions use to determine severity...

1. In the last month/week have you had difficulty sleeping due to your asthma?
2. have you had your usual asthma symptoms during the day
3. has your asthma interfered with your usual daily activities?

## Pathophysiology

* Airflow limitation (usually reversible spontaneously or with treatment)
* Airway hyperresponsiveness (to a wide range of stimuli)
* Inflammation of the bronchi (T lymphocytes, mast cells, eosinophils with associated plasma exudation, oedema, smooth muscle hypertrophy, matrix deposition, mucus plugging and epithelial damage)

In chronic asthma, inflammation may be accompanied by irreversible airflow limitation as a result of airway wall remodelling that may involve large and small airways and mucus impaction

## Factors

* Smoking
* Environmental
* Allergens
* Occupational sensitisers
* non specific- everything else
* Drugs-

**NSAIDs**-prevents certain prostaglandins

**Bblockers**- airways have a direct parasympathetic innervation that cause bronchoconstriction. However there is no direct sympathetic innervation. Parasympathetic action is antagonised by circulating adrenaline which act through beta2receptors on the surface of the smooth muscle cells. Betablockers prevents this effect and causes bronchoconstriction and airflow limitation in asthmatic patients.

## Investigations

### PEF/spirometry

FEV1/FVC <0.7

>400ml improvement in FEV1 after 400mcg inhaled salbutamol

exercise test

trial corticosteroids

### Blood/sputum:

unexplained peripheral blood eosinophils

Skin prick test

## Management

### Ladder

 3
Assess control of asthma:
-Good response to LABA, continue
-if benefit but inadequately controlled, increase steroid strength
-no response to LABA, stop LABA and increase steroid strength
 4
 5

### Inhaled steroids

Consider if patients have any of the following:

* exacerbation in the last 2 years
* using inhaled *β2 agonists* three times a week or more
* Symptomatic 3x a week or more
* waking 1 night a week

###

## Acute severe asthma

Asthma that has failed to resolve in 12 hours of therapy use

### Features:

* RR>25
* Tachycardia>110bpm
* PEF<50% predicted
* Feeble respiratory effort
* Cyanosis
* Exhaustion
* Bradycardia
* Hypotension
* Exhaustion/confusion/coma
2. 100% O2 non rebreathe mask sat upright in bed
3. 5mg salbutamol with 0.5mg ipratropium bromide nebuliser
4. IV hydrocortisone 100mg/ PO prednisolone 5mg (both if very unwell)
5. CXR- exclude pneumothora
2. IV Magnesium sulphate 1.2-2g over 20mins
* prednisolone 40-50mg/24h PO for min 5days
* nebulised salbutamol every 4hrs
* monitor peak flow and O2 sats
* IV hydrocortisone 100mg, or PO prednisolone 30mg
* Salbutamol nebuliser every 15min or 10mg cont. per hour
* Continue ipratropium 0.5mg every 4-6mg

------------ if no improvement
* Senior/ITU
* repeat salbutamol nebuliser every 15min
* IV MgSO4 1.2-2g over 20min (unless given already)
* Consider amniophylline/ IV salbutamol
* ITU

## Brittle asthma

Brittle asthma is catastrophic sudden severe asthma. These patients are usually well controlled between attacks. The attacks can occur in hours/minutes and can cause sudden death.

These patients require optimised standard therapy, emergency supplies and equip including O2/ resus equip/ *β2 agonists* nebulizer/ self injectable adrenaline/ prednisolone tablets at home/work/car, and medic alert bracelet.

If these patients develop wheeze they must attend nearest hospital immedietly.

Asthma Questions

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