Diagnosis of Bronchial Asthma | symptoms,signs,investigations and complications

Here is a guide on how to reach a diagnosis in a case of bronchial asthma .
We are going to discuss the history ( symptoms )  and Examination of a patient with B.A .

What does a patient with bronchial asthma complain of ?

Symptoms ;
• Episodic bouts of cough, dyspnea, chest tightness and expiratory wheezing usually provoked by exosure to allergens, emotional stress, viral infection and non specific precipitating events .
• Patients with episodic asthma are usually asymptomatic between exacerbations, this pattern of asthma is common in children or young adults who are atopic.
Diagnosis of Bronchial Asthma In other patients the clinical pattern is of persistent asthma with chronic wheeze and breathlessness, this pattern is more common in older patients with adult onset asthma who are non-atopic and typifies intrinsic asthma .
• Acute severe asthma and its signs (see later).

• Harsh vesicular breathing + rhonchi + signs of hyperinflated chest.
• Rhonchi (generalized, mainly sibilant, mainly expiratory and persistent after cough), this is during the attack.

Cough variant asthma i.e recurrent attacks of bronchospasm presented with paroxysmal cough only with no dyspnea or wheezing.
Nocturnal cough may be the presenting symptom.

Complications of bronchial asthma

• Acute severe asthma
• Respiratory failure .
• Spontaneous pneumothorax
• Side effects of medications e.g arrhythmias.

What are the investigations needed to diagnose bronchial asthma and its significance ?


1- X-ray --->  there is no diagnostic features of asthma on the chest X ray but it may be helpful in excluding pneumothorax or pneumomediastinum as a complication.
2- Blood gases (during attacks) :
         - Mild cases      : wash of Co2 due to hyperventilation ---> hypocapnea
         - Severe cases   : hypoventilation so Co2 either normal or elevated.
3- Skin hypersensitivity test for different antigens.

4- Blood 
+++  Ig E with extrinsic asthma
+++  Ig A with intrinsic asthma !?
Eosinophilia, leucocytosis.
Positive aspergillus Ab.

5- Sputum smears may reveal:
* Churschmann's spirals = mucous that form a cast in the small airways.
* Charcot leyden crystals = breakdown products of eosinophils

6- Metacholine, histamine tests indicate the presence of non specific bronchial hyper-reactivity i.e bronchospasm at a lower dose in asthmatics.

7- Cold air challenge (i.e. inhalation of cold air ~ bronchospasm)
8- Challenge with specific agents in occupational asthma.
9- Respiratory function tests, FEV1 is reduced but may improve after inhalation of bronchodilators.
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Tamer Mobarak

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