Asthma

 Asthma is Chronic inflammatory disorder associated with airway hyper responsiveness leading to recurrent episodes (attacks)

Often reversible airflow limitation

Prevalence increasing in many countries, especially in children

Pathophysiology of asthma

Allergy is the strongest predisposing factor for asthma. 

Chronic exposure to airway irritants or allergens also increases the risk for developing asthma. 

Airway irritants (eg, air pollutants, cold, heat, weather changes, strong odors or perfumes, smoke), 

Exercise, stress or emotional upsets, medications and viral respiratory tract infections. 

Cells that play a key role in the inflammation of asthma are mast cells, neutrophils, eosinophils, and lymphocytes. 

Mast cells, when activated, release several chemicals mediators. These chemicals, which include histamine, bradykinin, prostaglandins, and leukotrienes , perpetuate the inflammatory response, 

causing increased blood flow, vasoconstriction, fluid leak from the vasculature, attraction of white blood cells to the area, and broncho constriction

Clinical Manifestations

• Cough • Chest tightness 
• Wheezing (first on expiration and then possibly during inspiration as well. ) 
• Dyspnea • Expiration prolonged 1-3 or 1-4, due to bronchospasm, edema, and mucus 
• Feeling of suffocation- upright or slightly bent forward using accessory muscles 
• Behaviors of hypoxemia- restlessness, anxiety, ↑HR & BP and cyanosis.

Assessment and Diagnosis

History and patterns of symptoms 

Measurements of Pulmonary function tests 

CXR • ABGs and pulse oximetry 

Allergy testing (skin, IgE) 

sputum and blood tests 

complications of Asthma 

• ftigue or exhaustion
• poor  sleep
• being less productive at work or while studying
• an inability to exercise and be physically active
• reduced lung function
• poor mental health

Medical management 

Medications to Treat Asthma: Inhalers and Spacers

• Inhalers, which are devices that let you breathe in medicine, are the main treatment.
• Spacers can reduce potential for adverse effects from medication.

Quick-Relief Medications

• Rapid-acting inhaled β2 -agonists 
• Short-acting oral β2agonists 
• Systemic corticosteroids 
• Anticholinergics [Atrovent) 
• Theophylline

Long-Acting Control Medications.

• Inhaled corticosteroids 
•  Leukotriene modifiers 
• Long-acting inhaled β2 -agonists in combination with inhaled gluco-corticosteroids 
•  Systemic corticosteroids 
• Theophylline 
•  Cromones 
•  Anti-IgE

Diagnostic Tests

Pulmonary function tests (PFT) 

Pulmonary function tests (PFTs) are routinely used in patients with chronic respiratory disorders. They are performed to assess respiratory function and to determine the extent of dysfunction.

PFTs generally are performed by a technician using a spirometer that has a volume-collecting device attached to a recorder that demonstrates volume and time simultaneously. 

lung volumes, ventilator function, mechanics of breathing and gas exchange. Observe for increased dyspnea or bronchospasm 

ARTERIAL BLOOD GAS STUDIES

Measurements of blood pH and of arterial oxygen and carbon dioxide tensions. 

Arterial blood gas studies aid in assessing the ability of the lungs to provide adequate oxygen and remove carbon dioxide. 

The arterial oxygen tension (PaO2) indicates the degree of oxygenation of the blood, and the arterial carbon dioxide tension (PaCO2) indicates the adequacy of alveolar ventilation.

Pulse oximetry

Pulse oximetry is a noninvasive method to monitor the oxygen saturation of hemoglobin (SaO2). 

A probe or sensor is attached to the fingertip , earlobe, or bridge of the nose. The sensor detects changes in oxygen saturation levels by monitoring light signals generated by the oximeter.

 Normal SaO2 values are 95% to 100%. Values less than 85% indicate that the tissues are not receiving enough oxygen, and the patient needs further evaluation.

SPUTUM STUDIES

Sputum is obtained for analysis to identify pathogenic organisms. 

Periodic sputum examinations may be necessary for patients receiving antibiotics, corticosteroids, and immunosuppressive medications for prolonged periods. 

In general, sputum cultures are used in diagnosis, for drug sensitivity testing, and to guide treatment. 

Bronchoscopy

Visualization (a thin flexible fiberoptic telescope) of the tracheo-bronchila tree via a scope advanced through the mouth or nose

As diagnostic bronchoscopy for :

• examine tissues or collect secretions, 
• determine the location and extent of the pathologic process and to obtain a tissue sample for diagnosis. 
• determine if a tumor can be resected surgically 
• diagnose bleeding sites.

As Therapeutic bronchoscopy to:

• Remove foreign bodies from the tracheobronchial tree,
• Remove secretions obstructing the tracheobronchial tree when the patient cannot clear them, 
• Destroy and excise lesions.

Thoracoscopy

Thoracoscopy is a diagnostic procedure in which the pleural cavity is examined with an endoscope. 

Small incisions are made into the pleural cavity in an intercostal space; the location of the incision depends on the clinic.

Thoracocentesis

A thin layer of pleural fluid normally remains in the pleural space. An accumulation of pleural fluid may occur with some disorders. 

A sample of this fluid can be obtained by thoracentesis (aspiration of pleural fluid for diagnostic or therapeutic purposes).

 Fluid obtained during thoracocentesis may be examined for abnormal cells, bacteria, and other substances to determine the cause of the pleural effusion.

BIOPSY

Biopsy, the excision of a small amount of tissue, may be performed to permit examination of cells from the pharynx, larynx, nasal passages, pleural and lung. 

Local, topical, or general anesthesia may be administered, depending on the site and the procedure.