Pulmonary System and Asthma Quiz

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Questions and Answers

Which part of the central nervous system primarily controls spontaneous rhythmic breathing?

Cortex

Cerebellum

Hypothalamus

Medulla (correct)

What is the predominant type of autonomic innervation that influences bronchial smooth muscle?

Somatic

Sympathetic

Enteric

Parasympathetic (correct)

Which of the following receptors, when activated, leads to bronchoconstriction and mucus secretion?

M3 receptors (correct)

Alpha-1 receptors

Nicotinic receptors

β2-adrenoceptors

What is the function of β2-adrenoceptors in the airways?

Relax bronchial smooth muscle Signup and view all the answers

Non-myelinated sensory fibers in the lungs release tachykinins which cause which of the following effects?

Smooth muscle contraction and inflammation Signup and view all the answers

Which of the following is a common symptom of pulmonary disease?

Wheezing Signup and view all the answers

What is the primary defining characteristic of asthma?

Recurrent reversible airway obstruction Signup and view all the answers

Which of the following symptoms is typically associated with an asthma attack?

Wheezing and difficulty breathing out Signup and view all the answers

What is the primary characteristic of the 'late asthmatic response' following allergen inhalation?

Inflammatory cell infiltration into the bronchial mucosa. Signup and view all the answers

Which cells are the main source of inflammatory mediators in the airways during an asthma response?

Bronchial mast cells, T lymphocytes, and epithelial cells. Signup and view all the answers

What role do eosinophils play in the pathophysiology of asthma?

They secrete substances that cause airway injury like epithelial damage. Signup and view all the answers

Which of these is not a typical structural change associated with airway remodeling in asthma?

Decreased mucus production. Signup and view all the answers

What is the purpose of spirometry?

To evaluate the performance of the lungs, thorax, and respiratory muscles when moving air. Signup and view all the answers

What does the forced expiratory volume (FEV) measure?

The amount of air a person can exhale during a maximal breath. Signup and view all the answers

What does FEV1/FVC ratio typically represent?

The percentage of total volume of air exhaled in the first second of forced expiration. Signup and view all the answers

Which symptom is least related to the diagnosis of asthma?

Excessive thirst. Signup and view all the answers

Which cellular component is NOT typically associated with the pathogenesis of asthma?

Basophils Signup and view all the answers

What is a typical symptom of asthma that is often more pronounced at night or early in the morning?

Coughing Signup and view all the answers

A patient with adult-onset asthma is LEAST likely to exhibit which of the following?

Positive family history of asthma Signup and view all the answers

What is the primary immunoglobulin associated with the classic immunologic model of asthma?

IgE Signup and view all the answers

Which of the following is a key event during the immediate 'early asthmatic response' following allergen exposure?

Bronchoconstriction Signup and view all the answers

What is the main characteristic of the early-phase response in asthma after inhaling an allergen?

Immediate bronchoconstriction followed by improvement within an hour Signup and view all the answers

A patient experiences asthma symptoms only during specific times of the year when pollen counts are high. This most likely points to which type of asthma?

Environmental asthma Signup and view all the answers

Which of the following statements regarding asthma is most accurate?

The underlying pathology of asthma can progress to a chronic state in some patients Signup and view all the answers

What is the primary function of Omalizumab in asthma treatment?

To inhibit the binding of IgE to mast cells Signup and view all the answers

What treatment is administered every 2-4 weeks for asthma management?

Omalizumab Signup and view all the answers

What type of monitoring is essential during acute asthma treatment?

PEFR or FEV1 and arterial blood gases Signup and view all the answers

In the case of mild asthma attacks, which of the following treatment options is as effective as subcutaneous epinephrine?

Inhalation of a β 2 - receptor agonist Signup and view all the answers

Why is self-administration of Omalizumab generally not recommended?

There's a risk of anaphylactic shock Signup and view all the answers

What is the most effective timing for administering corticosteroids to prevent nocturnal asthma episodes?

Evening Signup and view all the answers

Which of the following corticosteroids is a prodrug activated in bronchial epithelial cells?

Ciclesonide Signup and view all the answers

What is a potential side effect of long-term use of inhaled corticosteroids in children?

Slowed growth rate Signup and view all the answers

What is the equivalent oral prednisone dosage for an average daily dose of beclomethasone at 400 mcg/d?

10–15 mg/d Signup and view all the answers

Which condition is associated with regular high doses of inhaled corticosteroids?

Osteoporosis Signup and view all the answers

What approach can be taken to reduce the risk of long-term use of inhaled corticosteroids?

Use them only during flare-ups Signup and view all the answers

What are cromolyn sodium and nedocromil sodium primarily used for?

Inhibiting asthma attacks Signup and view all the answers

Which of the following is a common indication of oropharyngeal candidiasis as a side effect of corticosteroids?

Sore throat Signup and view all the answers

What is the usual dose of theophylline for oral therapy with the prompt-release formulation?

3-4 mg/kg every 6 hours Signup and view all the answers

What is the mechanism of action of antimuscarinic agents?

They competitively inhibit the action of acetylcholine at muscarinic receptors. Signup and view all the answers

Which of the following is NOT a side effect of theophylline at high concentrations?

Hypotension Signup and view all the answers

How does cigarette smoking affect theophylline clearance?

It increases theophylline clearance. Signup and view all the answers

Which of the following is a clinical use of ipratropium bromide?

All of the above. Signup and view all the answers

Which of the following statements is TRUE about theophylline?

Its use requires occasional measurement of plasma levels. Signup and view all the answers

How long does it take for a new steady-state concentration of theophylline to be achieved after a dosage change?

1-2 days Signup and view all the answers

Why is atropine not commonly used for asthma treatment?

It has significant systemic side effects. Signup and view all the answers

Study Notes

Respiratory System

Respiration is controlled by spontaneous rhythmic discharges from the respiratory center in the medulla.
This is modulated by input from higher central nervous system (CNS) centers and vagal afferents from the lungs.
Input considers the partial pressure of carbon dioxide in arterial blood (PACO2) and oxygen (PAO2).
Voluntary control can be superimposed on automatic breathing regulation.
This implies connections between the cortex and motor neurons that innervate the muscles of respiration.
Irritant receptors and C fibers respond to chemical irritants and cold air, and to inflammatory mediators.

Autonomic Innervation of Airways

Parasympathetic innervation predominates in the bronchial smooth muscle.
Pharmacologically, M3 receptors are the most important.
These receptors are located on bronchial smooth muscles and glands.
They mediate bronchoconstriction and mucus secretion.
A distinct population of NANC nerves also regulates the airways.
Bronchodilators released by these nerves include vasoactive intestinal polypeptide and nitric oxide.

Sympathetic Innervation of Airways

β2-adrenoceptors are abundantly expressed on human airway smooth muscle, mast cells, epithelium, glands, and alveoli.
β agonists relax bronchial smooth muscle, inhibit mediator release from mast cells, and increase mucociliary clearance.

Sensory Fibres in Lungs

Non-myelinated sensory fibers linked to irritant receptors in the lungs release tachykinins such as substance P, neurokinin A, and B.
These act on smooth muscle, secretory, and inflammatory cells to produce inflammation.

Pulmonary Diseases

Common symptoms include shortness of breath, wheezing, chest pain, cough, and sometimes sputum production or hemoptysis (blood in sputum).
Treatment focuses on the underlying disease, but symptomatic treatments like cough relief may be necessary.

Asthma

Definition

Asthma is characterized by recurrent, reversible airway obstruction in response to irritant stimuli too weak to affect non-asthmatics.
Patients experience intermittent attacks of wheezing, shortness of breath (especially when exhaling), and sometimes coughing.
Acute attacks are reversible, but the underlying condition can progress to a chronic state in some.

Cellular Elements in Asthma

Many cells and cellular elements play a role in asthma, particularly many mast cells, eosinophils, neutrophils, T lymphocytes, macrophages, and epithelial cells.

Asthma Symptoms

Symptoms include coughing (especially at night or early morning), wheezing, breathlessness, chest tightness.
There's a wide range of severity, from occasional mild bouts to daily wheezing despite medication.

Etiology of Asthma

Childhood-onset (atopic): Includes positive family history of asthma and allergies (e.g., tree and grass pollen, house dust mites, pets, molds) and IgE-mediated response to environmental allergens.
Adult-onset: Usually lacks a positive family history; sometimes occurs due to workplace exposures to irritants (e.g., wood dust, chemicals).

Other Asthma Types

Environmental asthma, exercise-induced asthma, occupational asthma, aspirin-induced asthma

Pathogenesis of Asthma

The classic immunologic model describes asthma as a disease mediated by IgE.
After exposure to an asthma precipitating factor (like an allergen), IgE is produced and binds to mast cells in the airway mucosa.

Asthma Airway Changes

Injury to the airways (with an accumulation of inflammatory cells, edema, and swelling) leads to bronchospasm.

Asthma Inflammatory Mediators

Inflammatory mediators are released from bronchial mast cells, T lymphocytes, and epithelial cells.
These mediators direct the migration and activation of other inflammatory cells, particularly eosinophils, to the airways.
Eosinophils release biochemicals like major basic protein (ECP) and eosinophil cationic protein (ECP). These cause airway injury, including epithelial damage, mucus hypersecretion, and increased smooth muscle reactivity.

Early and Late Asthmatic Response

Early-phase: bronchoconstriction develops immediately after allergen exposure and improves after an hour.
Late-phase (3-6 hours later): more sustained bronchoconstriction, associated with inflammatory cell influx into the bronchial mucosa, and increased bronchial reactivity lasting weeks.

Pulmonary Function Tests

Spirometry is used to evaluate lung, thorax, and respiratory muscle function, particularly during forced exhalation, to measure how much air a person can exhale during a forced breath..
The FEV1 (forced expiratory volume in one second) and FEV1/FVC (ratio of FEV1 to forced vital capacity) are key measures.
Healthy individuals typically exhale 75-80% of their vital capacity within 1 second.
Peak expiratory flow (PEF) measures the maximal flow rate during forced exhalation.

Treatment Goals

Reduce impairment (symptoms and effects)
Reduce risk of future problems.

Asthma Treatment: Drugs

Sympathomimetic agents: Relax airway smooth muscle, help inhibit the release of bronchoconstricting mediators, and inhibit microvascular leakage (e.g., epinephrine, ephedrine, isoproterenol, salbutamol, terbutaline, metaproterenol, salmeterol, formoterol).
Methylxanthines: Inhibit phosphodiesterase (PDE) enzymes, thereby increasing cAMP and cGMP levels, leading to smooth muscle relaxation. Actions of methylxanthines include inhibition of inflammatory activity and stimulation of cardiac function (e.g., theophylline).
Antimuscarinic agents: Block the effects of acetylcholine by acting on muscarinic receptors, preventing bronchoconstriction; also help to reduce mucus secretion. Examples include atropine and ipratropium bromide.
Corticosteroids: Broad anti-inflammatory effects, mediated partly by inhibiting the production of inflammatory cytokines. Reduce bronchial reactivity. Examples include budesonide, ciclesonide, beclomethasone, flunisolide, fluticasone, mometasone, and triamcinolone.
Cromolyn and nedocromil: Inhibit mast cell activation.
Leukotriene pathway inhibitors (e.g., zileuton, zafirlukast, montelukast): Reduce the effects of leukotrienes to help with bronchoconstriction, increased bronchial reactivity, mucosal edema, and mucus hypersecretion.
Anti-IgE monoclonal antibodies (e.g., omalizumab): Decrease IgE binding to mast cells, lowering asthma exacerbations and reducing steroid needs.

Methods of Administration and Dosage Forms

Drugs can be inhaled or oral as inhalers, oral tablets, or injections.
Dosage forms and delivery methods have different side-effect profiles.

Acute Asthma Management

Hospitalized patients need continuous monitoring and treatment.
Oxygen, inhalers, IV hydrocortisone/methylprednisolone are common treatments.
General anesthesia and mechanical ventilation may be necessary in severe cases.

Other Issues (Asthma)

Asthma can be intermittent or persistent.
Severity of asthma can vary considerably.
Asthma treatment must be tailored to the patient's needs.

Mechanism of Action (Drugs)

Individual mechanisms of action vary for each drug class.
Common mechanisms include smooth muscle relaxation, inhibiting inflammatory mediators, controlling inflammation, or other pathways specific to the type of medication.

Side Effects (Drugs)

Different side effects are possible with different types of drugs.

Diagnosis and Monitoring

History: Symptoms (wheezing, chest tightness, shortness of breath, coughing, mucus production), Pattern (perennial, seasonal), Onset (how it begins), Duration and Frequency, Diurnal Variations (nocturnal/early morning), and precipitating factors.
Pulmonary function tests (PFTs):
- Spirometry measures lung function, particularly forced exhalation measures (FEV1, FVC, FEV1/FVC ratio), and peak expiratory flow (PEF).
Other tests: Blood tests for allergens.

Other considerations

Inhaled corticosteroids are controllers but are only effective when administered..
Oral corticosteroids and some other therapies are for use in acute or long-term cases, as directed by clinicians.

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Description

Test your knowledge on the central nervous system's role in breathing, autonomic innervation of bronchial smooth muscle, and the pathophysiology of asthma. This quiz covers key concepts including receptors involved in bronchoconstriction and the characteristics of asthma attacks.