In exercise-induced or nocturnal asthma, wheezing may be present after exercise or during the night, respectively.

Coughing: Cough may be the only symptom of asthma, especially in cases of exercise-induced or nocturnal asthma. Usually, the cough is nonproductive and nonparoxysmal. Also, coughing may be present with wheezing. Children with nocturnal asthma tend to cough after midnight, during the early hours of morning.

Chest tightness: A history of tightness or pain in the chest may be present with or without other symptoms of asthma, especially in exercise-induced or nocturnal asthma.

Other nonspecific symptoms: Infants or young children may have history of recurrent bronchitis, bronchiolitis, or pneumonia; a persistent cough with colds; and/or recurrent croup or chest rattling. Most children with chronic or recurrent bronchitis have asthma. Asthma is the most common underlying diagnosis in children with recurrent pneumonia. Older children may have a history of chest tightness and/or recurrent chest congestion.

                 During an acute episode, symptoms vary according to the severity.

Symptoms during a mild episode: Patients may be breathless after physical activity such as walking. They can talk in sentences and lie down, and they may be agitated.

Symptoms during a moderate severe episode: Patients are breathless while talking. Infants have feeding difficulties and a softer, shorter cry.

Symptoms during a severe episode: Patients are breathless during rest, are not interested in feeding, sit upright, talk in words (not sentences), and are usually agitated.

Symptoms with imminent respiratory arrest (in addition to the aforementioned symptoms): The child is drowsy and confused. However, adolescents may not have these symptoms until they are in frank respiratory failure.

Additional data. Despite the fact that lung function tests are not decisive in the diagnosis, they help assess the severity of airway obstruction and subsequent response to therapy in chronic and acute situations. VC, FVC,, FEV, the maximum air velocity in the middle of expiration, the maximum expiratory flow rate (test Tiffno), FEV / VC decrease, residual volume (RV) and total lung capacity (TLC) increase  during episodes of obstruction. Reduced FVC <25% of the proper or <0,75 after the appointment of bronchodilator indicates the severity of the disease.

 Pulmonary function test (PFT) results are not reliable in patients younger than 5 years. In young children (3-6 y) and older children who can't perform the conventional spirometry maneuver, newer techniques, such as measurement of airway resistance using impulse oscillometry system, are being tried. Measurement of airway resistance before and after a dose of inhaled bronchodilator may help to diagnose bronchodilator responsive airway obstruction.

Spirometry: In a typical case, an obstructive defect is present in the form of normal forced vital capacity (FVC), reduced FEV1, and reduced forced expiratory flow over 25-75% of the FVC (FEF 25-75). The flow-volume loop can be concave. Documentation of reversibility of airway obstruction after bronchodilator therapy is central to the definition of asthma. FEF 25-75 is a sensitive indicator of obstruction and may be the only abnormality in a child with mild disease. In an outpatient or office setting, measurement of the peak flow rate by using a peak flow meter can provide useful information about obstruction in the large airways. Take care to ensure maximum patient effort. However, a normal peak flow rate does not necessarily mean a lack of airway obstruction.

      Spirograp

Plethysmography: Patients with chronic persistent asthma may have hyperinflation, as evidenced by an increased total lung capacity (TLC) at plethysmography. Increased residual volume (RV) and functional residual capacity (FRC) with normal TLC suggests air trapping. Airway resistance is increased when significant obstruction is present.

 

 Air Displacement Plethysmography (ADP)

Bronchial provocation tests: Bronchial provocation tests may be performed to diagnose BHR. These tests are performed in specialized laboratories by specially trained personnel to document airway hyperresponsiveness to substances (eg, methacholine, histamine). Increasing doses of provocation agents are given, and FEV1 is measured. The endpoint is a 20% decrease in FEV1 (PD20).

Exercise challenge: In a patient with a history of exercise-induced symptoms (eg, cough, wheeze, chest tightness or pain), the diagnosis of asthma can be confirmed with the exercise challenge. In a patient of appropriate age (usually >6 y), the procedure involves baseline spirometry followed by exercise on a treadmill or bicycle to a heart rate greater than 60% of the predicted maximum, with monitoring of the electrocardiogram and oxyhemoglobin saturation. The patient should be breathing cold, dry air during the exercise to increase the yield of the study. Spirographic findings and the PEF rate (PEFR) are determined immediately after the exercise period and at 3, 5, 10, 15, and 20 minutes after the first measurement. The maximal decrease in lung function is calculated by using the lowest postexercise and highest preexercise values. The reversibility of airway obstruction can be assessed by administering aerosolized bronchodilators.

Blood testing: Eosinophil counts and IgE levels may help when allergic factors are suspected.

Recent evidence suggests the usefulness of measuring the fraction of exhaled nitric oxide (FeNO) as a noninvasive marker of airway inflammation, in order to adjust the dose of inhaled corticosteroids treatment. Currently FeNO measurement, due to high cost of equipment, is used primarily as a research tool.

Histologic Findings.

Asthma is an inflammatory disease characterized by the recruitment of inflammatory cells, vascular congestion, increased vascular permeability, increased tissue volume, and the presence of an exudate. Eosinophilic infiltration, a universal finding, is considered a major marker of the inflammatory activity of the disease. Histologic evaluations of the airways in a typical patient reveal infiltration with inflammatory cells, narrowing of airway lumina, bronchial and bronchiolar epithelial denudation, and mucus plugs. Additionally, a patient with severe asthma may have a markedly thickened basement membrane and airway remodeling in the form of subepithelial fibrosis and smooth muscle hypertrophy or hyperplasia.

            Peakflowmetria allows, though tentatively, to control state of the respiratory system and helps to some extent monitor of the effectiveness of treatment.

             Peakflowmeter

Portable spirometer MicroLoop (Micro Medical Ltd., UK) with color sensor screen.