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Asthma a Chronic Inflammatory Disorder and Its Pathophysiology:Nursing Case Study

Saturday, 8 March 2014

Asthma is a chronic inflammatory disorder of the airways involving episodic, reversible airway obstruction resulting from bronchospasms, increased mucus secretions, and mucosal edema. An asthma attack may begin dramatically, with simultaneous onset of severe, multiple symptoms, or insidiously, with gradually increasing respiratory distress. It is classified into types: allergic, nonallergic/intrinsic, exercise-induced, nocturnal, occupational, and steroid-resistant.

Pathophysiology
With asthma, tracheal and bronchial linings overreact to various stimuli, causing episodic smooth-muscle spasms that severely constrict the airway. Mucosal edema and thickened secretions further block the airways. Immunoglobulin (Ig) E antibodies, attached to histamine-containing mast cells and receptors on cell membranes, initiate intrinsic asthma attacks. When exposed to an antigen such as pollen, the IgE antibody combines with the antigen. On subsequent exposure to the antigen, mast cells degranulate and release mediators, which cause the bronchoconstriction and edema of an asthma attack.

Complications
■ Status asthmaticus
■ Respiratory failure

Assessment
Health perception and management

■ Increasing shortness of breath
■ Chest tightness
■ Feeling of panic or suffocation
■ Increased coughing, usually dry and nonproductive, leading to shortness of breath
■ Inability to move sputum out of the lungs
■ Attack in progress for some time before admission to acute-care setting
■ Increasing fatigue and inability to handle the attack with usual measures
■ Noncompliance with prescribed outpatient treatments
■ Continual inhaler use (either prescription or nonprescription type) without benefit
■ Identification of certain events or environmental factors as major contributors to the attack's development

Nutrition and metabolism
■ Dehydration
■ Lack of eating since the attack's onset because of preoccupation and shortness of breath; possible complaint of nausea, which may be related to medication use or abuse
■ Weight gain (long‑term corticosteroid users)

Activity and exercise
■ Ongoing exercise limitations

Cognition and perception
■ Ability to describe complex strategies for self‑management during an acute attack, but reported inability to put them into effect during an actual attack, when panic may overwhelm problem‑solving skills and hypoxemia may impair thinking

Sleep and rest
■ Coughing that disturbs sleep

Self‑perception and self‑concept
■ Changes in body image related to medication's cushingoid effects (if maintenance corticosteroid therapy is used)
■ Discouragement with appearance and inability to prevent or alter physiologic changes

Roles and relationships
■ Avoidance of public events and activities because of potential attack

Coping and stress management
■ Fluctuations in emotions related to disease

Physical Examination
General appearance and nutrition

■ Anxious
■ Maintenance of upright position
■ Fever (if infection is present)

Integumentary
■ Color initially good; may be flushed; cyanosis a late, unreliable sign
■ Diaphoresis
■ Dry mucous membranes

Respiratory
■ Respiratory rate less than 30 breaths/minute, increasing as attack worsens but possibly lessening with fatigue
■ Prolonged exhalations
■ Wheezing (no wheezing with critical airflow limitation)
■ Cough, possibly decreased sputum production (increased production a positive sign; can be yellow, thick, or crusted)
■ Monosyllabic speech with worsening airflow limitation

Cardiovascular
■ Sinus tachycardia
■ Mild to moderate hypertension
■ Paradoxical pulse becoming more pronounced (greater than 15 mm Hg) as air trapping increases
■ Potential arrhythmias

Neurologic
■ Initially, hyperalert, awake, and oriented; may become progressively less alert, although awake and oriented, as fatigue progresses
■ Restlessness
■ Lethargy

Diagnostic studies
■ Arterial blood gas (ABG) measurements may be obtained only in severe or prolonged attack; hypoxemia is always present; carbon dioxide level is used to stage the attack's progress:
– Stage 1: decreased partial pressure of oxygen (Pao2) and partial pressure of carbon dioxide (Paco2) levels (hyperventilation)
– Stage 2: decreased Pao2 level, normal Paco2 level (increased fatigue).
– Stage 3: decreased Pao2 level (less than 50 mm Hg), increased Paco2 level (critical hypoventilation and fatigue).
■ Sputum specimens—Gram stain detects treatable organisms; eosinophil smear is done if allergens are suspected as the primary cause.
■ Complete blood count and differential shows white blood cell count is increased with infection; eosinophil count is increased with allergy.
■ Serum electrolyte levels show potassium level is invariably decreased.
■ Theophylline level—an elevated level may indicate medication misuse; a decreased level may indicate noncompliance.
■ Chest X‑ray shows hyperinflation; air trapping decreases as airflow obstruction improves; between attacks, hyperinflation resolves; infiltrates are present if infection is a major cause.
■ Pulmonary function testing (PFT) isn't usually performed during an acute attack; measures of airflow rate, peak expiratory flow rate, and forced expiratory flow rate in 1 second are less than 25% of predicted value in severe obstruction; full PFT demonstrates dramatic response to bronchodilators; methacholine or histamine challenge provokes increased airway resistance.
■ Allergen skin test is negative; positive skin test doesn't necessarily indicate that exposure will trigger a respiratory response.

Teaching: Disease process; Teaching: Prescribed medication; Teaching: Procedure/treatment
Teaching checklist

■ Disease process and implications
■ Trigger identification and avoidance
■ Signs and symptoms of an impending attack
■ Relaxation and breathing strategies
■ Purpose, dosage, administration, and adverse effects of all medications
■ Avoidance of over-the-counter medications and herbal remedies unless approved by the practitioner
■ Pulmonary hygiene measures, including indications, schedule, and use
■ Proper use and care of respiratory therapy equipment
■ How to treat an attack and when to seek medical attention
■ Hydration requirements
■ Activity plan
■ Need for flu and pneumococcus vaccine
■ Follow-up care
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