Respiratory pathologies knowledge check

The primary muscle responsible for quiet inspiration is:

• Diaphragm

• Internal intercostals

• Rectus abdominis

• Upper trapezius

Answer explanation

Diaphragm – It is the main muscle for quiet inspiration, creating negative pressure by contracting and flattening to draw air into the lungs.
Internal intercostals – Primarily assist with forced expiration, not quiet inspiration.
Rectus abdominis – An accessory expiratory muscle used primarily for forced exhalation and trunk flexion.
Upper trapezius – During periods of respiratory distress (like a severe asthma attack or COPD exacerbation), the body recruits these large, powerful muscles to assist in lifting the entire rib cage, thereby increasing the volume of the thoracic cavity to draw in more air. It's an ACCESSORY muscle.

Residual volume is best defined as:

• The amount of air remaining in the lungs after a maximal exhalation

• The total amount of air moved in and out in one minute

• The amount of air inhaled during quiet breathing

• The maximum amount of air exhaled after a normal exhalation

Answer explanation

The amount of air remaining in the lungs after maximal exhalation – Residual volume prevents lung collapse and maintains alveolar patency.
Total amount of air moved in one minute – This is minute ventilation, not residual volume.
Air inhaled during quiet breathing – This is tidal volume.
Maximum air exhaled after a normal exhalation – This is expiratory reserve volume (ERV).

Which term describes difficulty breathing while lying flat that is relieved by sitting up?

• Orthopnea

• Tachypnea

• Apnea

• Eupnea

Answer explanation

Difficulty breathing in supine, relieved by sitting or standing; commonly seen in CHF and advanced pulmonary disease.
Tachypnea – Rapid breathing, not position-dependent.
Apnea – Absence of breathing.
Eupnea – Normal, quiet breathing.

Tachypnea is best described as:

• An abnormally rapid respiratory rate

• Complete absence of breathing

• Normal breathing at rest

• An increase in tidal volume with normal rate

Answer explanation

Abnormally rapid respiratory rate – Tachypnea is defined as a fast breathing rate, typically shallow.
Absence of breathing – This is apnea.
Normal breathing at rest – This is eupnea.
Increased tidal volume with normal rate – That describes hyperpnea.

A peak flow meter is used to assess:

• Maximum speed of exhalation

• Residual lung volume

• Oxygen diffusion at the alveoli

• Maximum inspiratory pressure

Answer explanation

Maximum speed of exhalation – Peak flow identifies airflow limitation and is commonly used in asthma. SPIROMETRY measures maximal inspiration volume.
Residual lung volume – Measured via body plethysmography or gas dilution, not peak flow.
Oxygen diffusion at alveoli – Measured by DLCO tests, not peak flow.
Maximum inspiratory pressure – Tested with MIP devices, not peak flow meters.

Incentive spirometry is primarily used to:

• Promote sustained maximal inspiration and prevent atelectasis

• Measure the speed of forced expiration

• Strengthen expiratory muscles

• Determine oxygen saturation levels

Answer explanation

Promote sustained maximal inspiration and prevent atelectasis – It encourages alveolar expansion post-surgery or in restrictive conditions.
Measures forced expiration speed – That is peak flow.
Strengthens expiratory muscles – Not its purpose.
Determines oxygen saturation – That is pulse oximetry.

A common cause of a pneumothorax is:

• Penetrating chest trauma or spontaneous alveolar rupture

• Chronic mucus hypersecretion

• Autoimmune destruction of surfactant

• Bacterial infection of the pleural lining

Answer explanation

Penetrating trauma or spontaneous alveolar rupture – Both introduce air into the pleural space causing lung collapse.
Chronic mucus hypersecretion – Associated with chronic bronchitis.
Autoimmune surfactant destruction – Not a mechanism of pneumothorax.
Bacterial pleural infection – That describes empyema, not pneumothorax.

Aspiration pneumonia most commonly occurs due to:

• Inhalation of food, liquid, or gastric contents into the lungs

• Progressive alveolar wall destruction

• Chronic bronchial inflammation from smoking

• Viral infection of the pleura

Answer explanation

Inhalation of food, liquid, or gastric contents – Common in dysphagia, stroke, or GERD.
Progressive alveolar wall destruction – Describes emphysema.
Chronic bronchial inflammation from smoking – Describes chronic bronchitis.
Viral pleural infection – Not related to aspiration pneumonia.

Which pathology is characterized by permanent enlargement and destruction of alveoli?

• Emphysema

• Pulmonary fibrosis

• Asthma

• Pneumothorax

Answer explanation

Emphysema – Part of COPD, marked by loss of elastic recoil and enlarged air spaces.
Pulmonary fibrosis – Causes scarring and restrictive lung disease, not alveolar enlargement.
Asthma – Reversible bronchoconstriction, not alveolar destruction.
Pneumothorax – Lung collapse, not alveolar remodeling.

COPD typically presents with:

• Chronic airflow limitation that is not fully reversible

• Hyperventilation with increased residual volume

• Sudden collapse of the lung due to trauma

• Reversible airway inflammation triggered by allergens

Answer explanation

Chronic airflow limitation that is not fully reversible – Hallmark of COPD physiology.
Hyperventilation with high RV – RV increases, but hyperventilation is not the hallmark.
Sudden collapse of lung – Pneumothorax.
Reversible inflammation – Asthma, not COPD.