DDx: Asthma Flashcards Preview

10 PULMONARY AND CRITICAL CARE MEDICINE > DDx: Asthma > Flashcards

Flashcards in DDx: Asthma Deck (11):
1

Diffrerential Diagnosis of Asthma:

Asthma

COPD 

Vocal cord dysfunction

Heart failure

Medication side effect

Bronchiectasis

Pulmonary infiltrates with eosinophilia (ABPA, eosinophilic granulonatosis with angiitis

(Churg-Strauss),Loeffler syndrome, chronic eosinophilic pneumonia)

Obstructive sleep apnea

Mechanical airway obstruction

Cystic fibrosis

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Asthma

Hx: Episodic cough triggered by cold air and hyperventilation. The symptoms are suggestive of cough-variant asthma. 

Mild persistent asthma: Symptoms more than 2 days per week but not daily, and wakes up once a week but not nightly. 

Dx: Spirometry: Abnormal spirometry results (reversible obstruction) can help to confirm an asthma diagnosis, but normal results do not exclude asthma.  A reduced FEV1 or a reduced FEV1/FVC ratio documents airflow obstruction. An increase in FEV1 of >12% with a minimum increase of 200 mL in FEV1 after bronchodilator use establishes the presence of airflow reversibility and the diagnosis of asthma. 

Peak flow variability: A patient with normal spirometry results but marked diurnal variability (based on a peak-flow diary kept for >2 wk) may have asthma, which may warrant an empiric trial of asthma medications or bronchoprovocation testing.

Bronchoprovocation testingIn a patient with a history highly suggestive of asthma and normal baseline spirometry results, a low PC20 (concentration of inhaled methacholine needed to cause a 20% drop in FEV1) on methacholine challenge testing supports a diagnosis of asthma. A normal bronchoprovocation test essentially excludes asthma.

Chest radiography: Chest radiography may be needed to exclude other diagnoses but is not recommended as a routine test in the initial evaluation of asthma.

Allergy skin testing: There is a strong association between allergen sensitization, exposure, and asthma. Allergy testing is the only reliable way to detect the presence of specific IgE to allergens. Skin testing (or in vitro testing) may be indicated to guide the management of asthma in selected patients, but results are not useful in establishing the diagnosis of asthma.

Tx: Regardless of disease severity, all patients are prescribed a short-acting, inhaled β-agonist medication.  If short-acting bronchodilators are needed for symptom relief more than twice a week for daytime symptoms or twice a month for nighttime awakenings, a long-acting controller medication is indicated. Use of more than one canister of short-acting β-agonist per month may be a clue to poor control of asthma and warrants further investigation.

Mild persistent asthma is treated with a single long-term controller medication.  A low-dose inhaled glucocorticoid is the preferred long-term controller medication; alternatives include a mast cell stabilizer, leukotriene modifier, or sustained-release methylxanthine.

Moderate persistent asthma is treated with one or two long-term controller medications. Use either low doses of inhaled glucocorticoid and a long-acting β-agonist (preferred) or medium doses of a single inhaled glucocorticoid. In patients who remain symptomatic while taking medium doses of inhaled glucocorticoids, the addition of a long-acting bronchodilator (eg, salmeterol) results in improved lung physiology, decreased use of short-acting β-agonists, and reduced symptoms when compared with doubling the dose of inhaled glucocorticoid.

Patients with severe persistent asthma may require at least three daily medications to manage their disease (ie, high doses of an inhaled glucocorticoid plus a long-acting bronchodilator and possibly oral glucocorticoids). 

 

 

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COPD

Less reversibility of airflow obstruction; associated with a history of tobacco use. COPD may coexist with asthma in adults.

4

Vocal cord dysfunction

Abrupt onset of severe symptoms, often with rapid improvement. Monophonic wheeze heard loudest during either inspiration or expiration. The preferred diagnostic test is direct visualization of the vocal cords during symptoms. May closely mimic asthma, particularly in young adults.

5

Heart failure (see Heart Failure)

Spirometry results may or may not be normal; wheezing may be a sentinel manifestation. Consider when there is not prompt improvement with asthma therapy. Heart failure always is a consideration for persons with underlying cardiac disease.

6

Medication side effect

Chronic cough may occur with certain medications (eg, ACE inhibitors).

7

Bronchiectasis

Bronchiectasis is the permanent and abnormal dilatation and destruction of bronchi and bronchiolar walls associated with impaired drainage and recurrent infection that leads to chronic inflammation. Voluminous sputum production, often purulent and sometimes blood tinged. Suspect if physical examination reveals crackles with wheezing or clubbing or if chest radiograph shows peribronchial thickening.

8

Pulmonary infiltrates with eosinophilia (ABPA, eosinophilic granulonatosis with angiitis

(Churg-Strauss),Loeffler syndrome, chronic eosinophilic pneumonia)

Wheezing may be seen in ABPA, chronic eosinophilic pneumonia, and eosinophilic granulonatosis with angiitis (Churg-Strauss). Note that in uncomplicated asthma, chest radiographs are normal. Findings of infiltrates, striking peripheral blood eosinophilia, and constitutional symptoms (eg, fever, weight loss) suggest chronic eosinophilic pneumonia. Asthma with eosinophilia, markedly high serum IgE levels, and intermittent pulmonary infiltrates is characteristic of ABPA. Difficult-to-treat asthma, upper airway and sinus disease, and multisystem organ dysfunction suggest eosinophilic granulonatosis with angiitis (Churg-Strauss).

9

Obstructive sleep apnea (see Obstructive Sleep Apnea)

Excessive snoring and daytime fatigue; the patient's sleep partner may offer a history of noisy, labored, or erratic breathing. Obstructive sleep apnea is more common in obese patients.

10

Mechanical airway obstruction

Respiratory noises may be more pronounced in the inspiratory or expiratory phase of respiration, depending on location of obstruction. Diagnosed via flow-volume loop.

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Cystic fibrosis

Associated with thick, purulent sputum containing bacteria and with GI symptoms due to pancreatic insufficiency. Recurrent respiratory infections may be present without GI or other system involvement.