- During presentation with acute episodic disease, the diagnosis of asthma
is typically straightforward given the presence of wheezing and dyspnea.
- As part of the assessment, personal & family history indicative of
allergic disease including eczema, urticaria, and rhinitis provides
additional support. Asthma is often characterized by nocturnal awakening
with wheezing and/or dyspnea.
- If nocturnal awakening is not present,
its absence is sufficient to cast doubt concerning the asthma diagnosis.
Nevertheless, other conditions may make the asthma diagnosis
- For example, airway obstruction caused by tumor or laryngeal edema
constitute an alternative to the asthma diagnosis. However, these
patients will present with stridor with harsh respiratory sounds
that appear localized to particular tracheal area. That is, the more
diffuse wheezing throughout the lung fields will be missing.
Bronchoscopy or laryngoscopy may be required to resolve the
- Glottic dysfunction can induce symptoms similar to asthma because
these patients narrow their glottis while breathing causing
occasional severe airway obstruction with periodic carbon dioxide
retention. In these cases, by contrast to asthma, arterial oxygen
tension is maintained. Furthermore with glottic narrowing,
alveolar-arterial oxygen gradient is maintained in contrast to the
alveolar-arterial oxygen gradient widening seen with lower airway
obstruction (asthma). Direct examination of the patient will
symptoms are present is required to establish glottic narrowing
- Alternative presentations may be seen in generalized endobronchial
disease following foreign body aspiration, bronchial stenosis, or
tumor presence. In these cases, persistent wheezing will tend to be
quite localized in presented together with coughing paroxysms.
- Occasionally, acute left ventricular heart failure exhibit some
signs and symptoms consistent with asthma; however, gallop rhythms,
blood-tinged sputum with basilar rales allow discrimination.
- Bronchospasm secondary to carcinoid tumors, chronic bronchitis,
and recurrent pulmonary emboli also present diagnostic
- With chronic bronchitis one would not expect persistent
symptom-free periods; by contrast, in asthma there should be
symptoms-free periods, although with chronic bronchitis acute
wheezing may occur at this is on top of persistent coughing with
- On the other hand,
pulmonary emboli symptoms may be quite close to those exhibited
in asthma. For example, episodic breathlessness observed on
exertion with wheezing may be common. Pulmonary function
diagnostics also may reveal peripheral airway obstruction. Lung
scans may be of normal. Differential diagnosis may be aided by
patient response to bronchodilator medications and anticoagulant
treatment; however, angiographic assessment would be the gold
standard in establishing the definitive diagnosis.
- Diagnosis: Asthma must be
demonstrated through documentation of reversible airway obstruction in
which reversibility may be defined as a 15% or greater increase in FEV1
following two puffs about beta-adrenergic agonist (e.g. terbutaline). If
the initial spirometry tests are normal, increased airway reactivity may
be unmasked through the use of provocative agents such as methacholine,
histamine, or by forcing the patient to hyperventilate cold air.
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