1. M.A.Zohal pulmonologist
asthma

2. Definition
• Chronic inflammatory disease of airways, characterized by increased responsiveness of the tracheobronchial tree to stimuli • Manifested physiologically by a widespread narrowing of the air passages and clinically by paroxysms of dyspnea, cough, and wheezing • Episodic disease, with acute exacerbations interspersed with symptom-free periods • Most attacks are short-lived, lasting minutes to hours.

3. Epidemiology • Prevalence Increasing in many parts of the world
Approximately 10–12% of adults and 15% of children affected by the disease
Asthma is among the most common reasons to seek medical treatment.
currently affects approximately 300 million people worldwide
• Age
Asthma can present at any age, with a peak age of 3 years. ~50% of cases develop before 10 years of age.
Another one-third of cases occur before 40 years of age.
• Sex
2:1 male-to-female ratio in childhood
Sex ratio equalizes by 30 years of age.

7. Epithelial damage may contribute to AHR in a number of ways, including
loss of its barrier function to allow penetration of allergens;
loss of enzymes (such as neutral endopeptidase) that normally degrade inflammatory mediators;
loss of a relaxant factor
exposure of sensory nerves, which may lead to reflex neural effects on the airway

8. Airway Remodeling
The characteristic structural changes are increased airway smooth muscle, fibrosis, angiogenesis, and mucus secreting cell hyperplasia

10. allergens
Dust mites (often found in pillows, mattresses, carpets and drapes)
Cockroaches
Animal dander, especially cats
Seasonal pollens

11. Physiology
a reduction in FEV1, FEV1/forced vital capacity (FVC) ratio, and peak expiratory flow (PEF), as well as an increase in airway resistance
Lung hyperinflation (air trapping) and increased residual volume
mismatching of ventilation and perfusion
arterial PCO2 tends to be low due to increased ventilation

12. Classification • Allergic (extrinsic) asthma
Associated with a personal and/or family history of allergic diseases, such as rhinitis, urticaria, and eczema Immunoglobulin E mediated Increase Eosinophil in peripheral blood smear

13. Exposure to antigen typically produces an immediate response.
Airway obstruction develops in minutes and then resolves.
30–50% of patients have a second wave of bronchoconstriction, a "late reaction," 6-10 hours later.
In a minority, only a late reaction occurs.

14. Classification Idiosyncratic (intrinsic) asthma
No defined immunologic mechanism
Adult onset asthma
No family history
Most related to occupation

15. Symptoms & Signs • Classic symptom triad • Typical acute attack
Wheezing
Dyspnea
Cough
• Typical acute attack
Often occurs at night
Patients experience a sense of constriction in the chest, often with a
nonproductive cough.
Respiration becomes audibly harsh.
Wheezing first during expiration and then in both phases of respiration
Expiration becomes prolonged.

16. Symptoms & signs Respiratory rate Heart rate
Relative bradycardia with impending respiratory failure
Use of accessory respiratory muscle
Paradoxical thoracoabdominal movement with impending respiratory failure
Pulsus paradoxus (normally < 10 mmHg)
10-25 mmHg in moderate episode
>25 mmHg in severe episode
Ear, nose, and throat examination
Nasal polyps in patients with allergic asthma, cystic fibrosis,
aspirin sensitivity

17. Occupational asthma If occupational exposure is suspected : Ask about
workplace and work history in detail.
Specific contaminants?
Availability and use of protective devices?
Ventilation (dose of environmental agent influenced by intensity and physiology—ventilation rate and depth)
Do coworkers have similar complaints?
Ask about every job; short-term exposures may be significant.

18. DIAGNOSIS Lung Function Tests : reduced FEV1, FEV1/FVC ratio, and PEF
Reversibility is demonstrated by a >12% and 200-mL increase in FEV1 15 min after an inhaled short-acting β2-agonist
Measurements of PEF twice daily may confirm the diurnal variations in airflow obstruction
Increased total lung capacity and residual volume.
Diffusing capacity of the lung for carbon dioxide (DLCO) is usually normal or slightly increased.

19. DiaGn0sis Airway Responsiveness
The increased AHR is normally measured by methacholine or histamine challenge with calculation of the provocative concentration that reduces FEV1 by 20% (PC20).
exercise testing

20. Laboratory Tests • Complete blood count may show eosinophilia.
• Serum immunoglobulin E level
o Elevated in allergic asthma
o Normal in idiosyncratic asthma
o Marked elevations may suggest allergic bronchopulmonary
aspergillosis.
• Sputum examination
o Eosinophilia
o Curschmann’s spirals (casts of small airways)
o Charcot–Leyden crystals
o Presence of large numbers of neutrophils suggests bronchial infection.

21. Laboratory Tests Arterial blood gas Shows hypoxemia during attacks
Usually, hypocarbia and respiratory alkalosis are present.
Normal or elevated arterial partial pressure of carbon dioxide suggests severe respiratory muscle fatigue or airways obstruction and impending respiratory failure.

22. differential Diagnosis
Upper airway obstruction by a tumor or laryngeal edema
endobronchial obstruction with a foreign body.
left ventricular failure
Vocal chord dysfunction
Eosinophilic pneumonias and systemic vasculitis, including ChurgStrauss syndrome and polyarteritis nodosa
COPD

24. Control asthma

26. Prognosis
Mortality
Only 0.09–0.25% of admissions to hospital are at risk of an untoward event.
Particularly good prognosis for those whose disease is mild and develops in childhood
The proportion of children who still have asthma 7–10 years after the initial diagnosis varies from 26–78% (average, 46%).
Only 6–19% continue to have severe disease.
Even when untreated, persons with asthma do not continuously move from mild to severe disease with time.
Clinical course is characterized by exacerbations and remissions.
Some studies suggest:
Spontaneous remissions occur in approximately 20% of those who develop the disease as adults.
~40% can be expected to experience improvement, with less frequent and severe attacks, as they grow older.