Anaphylaxis may present with wheezing, but the

patient will often have urticaria and sometimes gastrointestinal symptoms. CHF may present with "cardiac

wheezing;' but the patient will often have "wet" lungs

sounds with rales in the bases, an enlarged heart on CXR,

peripheral edema, and jugular venous distention. CHF

ASTHMA

Figure 21-2. Pea k flow meter.

can have many underlying causes, but often these individuals will have underlying heart disease and other

comorbidities. The presence of wheezing is common in

COPD, but unless the patient has a history of

a1

-antitrypsin deficiency, this type of presentation is

found in patients with smoking history and who are

..A.Figure 21-3. Handheld nebul izer treatment.

CHAPTER 21

Suspected asthma

exacerbation

Alternate diag nosis

(CHF, PE, upper

airway obstruction)

Treatment

• 02

• Albutero l

• Steroids

• +/- Atrovent

• +/- CXR

r Good

response to

treatment

Discharge

Poor

response to

treatment

Admission

Magnesiu m, terbutaline,

epinephrine; consider

intubation and ICU if no

improvement

Figure 21-4. Asthma diag nostic algorithm. CHF, congestive heart fa ilure; CXR, chest x-ray; ICU, intensive care

unit; PE, pulmonary embolism.

typically over the age of 40 years. Patients with pneumo ­

nia may have underlying wheezing, but typically have a

fever and an infiltrate of CXR. Other diagnoses such as

foreign body aspiration, PE, and upper airway obstruction should also be considered. Stridor is an indicator of

upper airway swelling and should be differentiated from

wheezing in the lung fields.

Once the diagnosis of asthma has been made, the treatment decisions are based on the severity of illness (Figure 21-4).

Mild exacerbations can be treated with beta-1 agonists and

other supporting medications, and the patient can be discharged. Moderate disease may require further treatments

with beta-2 agonists, and the disposition will depend on the

response to treatment. Severe presentations will require

aggressive management with serial or continuous beta-agonist

treatments and can require other medications such as magnesium and epinephrine.

TREATMENT

Patients who present with difficulty breathing should have

oxygen applied via nasal cannula or facemask and titrated

to keep the level of oxygenation >94%. Cardiac monitoring

and IV access should be used in moderate to severe asthmatics. In conjunction with these, beta-2 agonist therapy

should be instituted as the first-line therapy. Patients who

are started on beta-2 agonists will still receive oxygen

though the nebulized treatment. There are several other

therapies that should be considered during an exacerbation, depending on the severity. All medications discussed

here are safe to use during pregnancy except epinephrine,

which is associated with congenital malformations and

premature labor.

Beta Agonists. Albuterol is the most commonly used

beta-2 agonist agent and is considered first-line therapy. It

causes bronchodilation by increasing cyclic adenosine

monophosphate and relaxing airway smooth muscles. Its

onset of action is <5 minutes. The nebulized form consists

of albuterol 2.5 mg in 3 mL of saline given every 20 minutes x 3, or as a continuous nebulizer for severe asthmatics

using albuterol 10 mg over a period of 1 hour. A metered

dose inhaler (MDI) delivers albuterol using 2 puffs with a

spacer every 20-30 minutes and requires active participa ­

tion.