___________________________________________________________ Asthma: Diagnosis and Management
Pediatric Concerns Differential diagnosis for children presenting with wheezing and recurrent lower respiratory infections should include cystic fibrosis, bronchopulmonary dysplasia (prevalent in premature infants), dysmotile cilia syndrome, alpha-1-antitrypsin defi- ciency, and immunodeficiencies [9; 31]. Cystic Fibrosis Cystic fibrosis is the leading cause of chronic debilitating pulmonary disease and pancreatic exocrine deficiency in the first three decades of life. The median age at diagnosis is 6 to 8 months; more than 75% of patients are diagnosed by 2 years of age. It occurs most often in White children, and it is estimated that 1 in every 20 White Americans is a carrier of the cystic fibrosis mutation. Among Black individuals, the incidence is approximately 1 in 16,000, and in Asian Americans, it is 1 in 31,000 [31; 32]. Although cystic fibrosis can be a multisystem disorder, the respiratory system is almost always involved and tends to dominate the clinical picture. Common respiratory complications include air trapping and wheezing, chronic cough and sputum production, retractions, tachypnea, and recurrent or chronic pneumonia. However, the earliest signs of cystic fibrosis can be gastrointestinal and pancreatic, not respi- ratory. Signs of cystic fibrosis include radiograph abnormalities such as bronchiectasis, atelectasis, infiltrates, and hyperinfla- tion. Therefore, a chest x-ray or computed tomography scan may be useful in determining the correct diagnosis, especially in children [9; 31]. GERD Excessive mucosal secretion secondary to GERD or gastroin- testinal malformation may cause wheezing in both children and adults and should be considered during evaluation. It is reported that 34% of patients with GERD experience chronic cough and/or wheezing as part of their symptomatology. Additionally, bronchiole irritation resulting from repeated exposure to gastric acid may trigger asthma symptoms. Gen- erally, asthma-like symptoms that stem from GERD can be controlled with initiation of reflux medications and lifestyle modification [9; 31]. Structural Issues If respiratory difficulties are suspected to be more of a structural issue, a bronchoscopy may be performed. This is especially important if congenital abnormality, such as laryngomalacia or tracheobronchomalacia, or tumors or growths are suspected. It can also rule out foreign body aspiration. Samples of tissue and sputum to be used in additional testing may be taken during the procedure, if necessary [9; 31].
Adult and Geriatric Concerns In adults, CHF and other cardiac conditions, such as mitral valve disease, should be considered in the differential diag- nosis of asthma. Establishing an asthma diagnosis is difficult for patients older than 55 years of age due to the increased incidence of CHF and respiratory difficulties resulting from cardiac problems, or “cardiac asthma.” Conversely, asthma can aggravate heart disease when oxygen supplied by the lungs is inadequate for the reduced blood supply to the heart. Any diseases or conditions that may cause dyspnea should be considered when determining a differential diagnosis of asthma [9; 33]. A particular form of an infection-plus-allergy condition known as allergic bronchopulmonary aspergillosis, often shortened to aspergillosis or ABPA, should also be considered. The condi- tion initiates with the introduction of the fungus Aspergillus fumigatus, a mold that is abundant in damp straw, compost heaps, birdcages, and any decomposing material. A. fumigatus does not usually have an adverse effect on those with normal immune systems. However, in individuals with asthma or immunocompromise, the spores from this mold may begin to grow in the lung tissue. An allergic reaction may then occur in response to the fungus. This is an important consideration for those who work in agricultural occupations and is one example of the usefulness of a thorough history and lifestyle question- naire in the diagnosis and management of asthma [9; 33]. ABPA may present comorbid with asthma or the similar symptoms may result in a false asthma diagnosis. The signs and symptoms of ABPA include rubbery plugs of golden-brown or green sputum; a fever apparent only when the asthma symptoms are severe; worsening symptoms despite treatment; dependence on steroid medications; and very high levels of serum IgE. ABPA is normally treated with steroids to control the allergic reaction and with physiotherapy to clear the mucus from the lungs [9; 33]. There are also certain medications that may induce asthma- like symptoms. Specifically, there are two conditions, aspirin- sensitive triad and nonallergic rhinitis with eosinophilia syndrome (NARES), known for their similar presentation to asthma. The diagnosis of aspirin-sensitive triad is based on three distinct symptoms: perennial rhinitis, nasal polyps, and asthma. Patients with an aspirin-sensitive triad diagnosis tend to collect all three symptoms gradually, in no particular order, over a period of years or decades. Although it is not known how common nonsteroidal anti-inflammatory drug (NSAID) sensitivity is for adult patients with asthma, various reports site frequencies from 3% to approximately 40%. It is far less common in pediatric patients with asthma; women in their third decade are most commonly affected [9; 33].
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