PLEURAL MCQS MEDICINE

8/15/2019 PLEURAL MCQS MEDICINE

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DR. RAJENDRAN’S INSTITUTE OF MEDICAL EDUCATION

+91 93888 52220

PNEUMOTHORAX (12 MCQs)

1) Pressure in the pleural space

a. Negative during inspiration and positive during expiration

b. Negative during expiration and positive during inspiration

c. Negative during both inspiration and expiration

d. Positive during both inspiration and expiration

Ans: (c)

In normal subjects, the pressure in the pleural space is negative with respect to the

alveolar pressure during the entire respiratory cycle. The pressure gradient between the

alveoli and the pleural space—the transpulmonary pressure—is the result of the inherent

elastic recoil of the lung. During spontaneous breathing, the pleural pressure is also

negative with respect to the atmospheric pressure. The functional residual capacity, or

resting end-expiratory volume of the lung, is the volume at which the inherent outward pull

of the chest wall is equal to, but opposite in direction to, the inward pull (recoil) of the

lung.


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2) What is the main physiologic consequence of a pneumothorax?

a. Decrease in the vital capacity

b. Hypercapnia

c. Mediastinal shift

d. Infection

Ans: (a)

The main physiologic consequences of a pneumothorax are a decrease in the vital

capacity and the arterial PO2. In patients without underlying major lung disease, the

decrease in the vital capacity is usually well tolerated. If the lung function of the patient is

abnormal before the development of the pneumothorax, the decrease in vital capacity may

lead to respiratory insufficiency with alveolar hypoventilation and respiratory acidosis.

3) Pneumothorax causes -

a. Chest pain

b. Dyspnea

c. Ventilation-perfusion mismatch

d. Arterial hypoxemia

e. All of the above


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Ans: (e)

A pneumothorax is defined as air in the pleural space, between the parietal and visceral pleura.This condition may be caused by trauma or underlying lung disease, but sometimes happens

spontaneously without obvious cause. When a pneumothorax develops, there is loss of the

negative intrapleural pressure that is needed for lung inflation, and the lung on the affected side

collapses and cannot expand properly. This collapse leads to a ventilation-perfusion mismatch

because there is continued perfusion of a poorly ventilated lung.

Arterial hypoxemia can occur with 50% collapse of the lung. If there is a continued air leak with

increasing positive intrapleural pressure, this can lead to a tension pneumothorax and can lead to

compromise of venous return to the heart, decreasing cardiac output, and causing hemodynamic

collapse.

Patients who develop a pneumothorax usually complain of sudden onset of dyspnea and pleuritic

chest pain. However, the condition may be asymptomatic in 10% of cases. Signs of a tension

pneumothorax (see below) include respiratory distress, tachypnea, distended neck veins, pulsus

paradoxus, displacement of the point of maximal cardiac impulse, and trachea shift.

PNEUMOTHORAX - ESSENTIALS OF DIAGNOSIS

● Pleuritic chest pain

● Acute-onset dyspnea

● Decreased breath sounds on affected side

● Plain x-ray is usually diagnostic. Expiratory films may demonstrate small pneumothoraces

that are not visible on inspiratory films. See x-ray below.

● Chest CT will often be helpful in identifying associated pathology, such as pneumocystis

pneumonia or differentiating pneumothorax from emphysematous blebs in patients with

COPD.


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X-ray – There is complete translucency on the left with absence of vascular markings, diagnostic of a

pneumothorax. The collapsed left lung appears as a left hilar mass.

Hydropneumothorax – Horizontal fluid level on the left


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4) What is the cause of primary spontaneous pneumothorax?

a. Chronic bronchitis

b. Emphysema

c. Subclinical lung disease

d. A and b are true

e. Nonpenetrating chest injuries

Ans: (c)

Spontaneous pneumothorax is one that occurs without trauma to the thorax. Primary

spontaneous pneumothorax occurs in the absence of underlying lung disease. Primary

spontaneous pneumothoraces are usually due to rupture of apical pleural blebs (small cystic

spaces that lie within or immediately under the visceral pleura). Primary spontaneous

pneumothoraces occur almost exclusively in smokers. This suggests that these patients have

subclinical lung disease. Secondary spontaneous pneumothorax occurs when there is underlyinglung disease. In tension pneumothorax, the pressure in the pleural space is positive throughout

the respiratory cycle.

Traumatic pneumothorax results from penetrating or nonpenetrating chest injuries.

TREATMENT OPTIONS

● Observation

● Supplemental oxygen

● Simple aspiration of the pneumothorax

● Simple tube thoracostomy

● Tube thoracostomy with instillation of a pleurodesing agent

● Thoracoscopy with oversewing of the blebs and pleurodesis


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● Open thoracotomy

5) False about primary spontaneous pneumothorax

a. Usually due to rupture of an emphysematous bullae

b. Equally common in men and women

c. Recurrence occur in < 10 %

d. Thoracotomy with pleural abrasion can prevent recurrences in up to 75%

e. All

Ans: (e) All are false.

Pneumothorax due to rupture of an emphysematous bullae is secondary spontaneouspneumothorax. Primary spontaneous pneumothorax is due to rupture of apical pleural blebs.

These are small cystic spaces that lie within, or immediately under, the visceral pleura. It occurs

almost exclusively in smokers. It suggests that these patients have subclinical lung disease. 50%

will have a recurrence.

The initial treatment for primary spontaneous pneumothorax is simple aspiration. If the lung does

not expand with aspiration, or if the patient has a recurrent pneumothorax, thoracoscopy with

stapling of blebs and pleural abrasion is indicated. Thoracoscopy or thoracotomy with pleural

abrasion is almost 100% successful in preventing recurrences.

TREATMENT OF SPONTANEOUS PNEUMOTHORACES


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● Treatment varies depending on the patient's condition, the degree of collapse, the

cause, and the estimate of the chance of recurrence.

● Small (< 20–25%), stable, asymptomatic pneumothoraces in otherwise healthy

patients can be observed. Complete resolution usually occurs within several weeks.

Air is normally reabsorbed at a rate of 1–1.25% per day.

● Larger asymptomatic pneumothoraces taking longer than 2–3 weeks to resolve

place the patient at risk for developing trapped lung as a result of deposition of

fibrin on the visceral pleura. These patients, as well as patients with symptoms or

pneumothoraces associated with pleural effusions, should have them evacuated.

● In highly selected patients, this can be accomplished with simple aspiration . The

immediate and 2-hour delayed chest radiographs should show reexpansion of lung.

Small breaks in the visceral pleural seal once the lung collapses, but they can reopen

with reexpansion. The chance of recurrence is 20–50% with this method. Follow-up

x-ray is therefore mandatory after 24 hours.

● Most patients with significant pneumothoraces (> 30%) require placement of a

closed-chest catheter (8–20F) for reexpansion. This catheter then can be placed

either to underwater suction drainage or to a Heimlich (one-way) valve.

● Chest tubes should be placed in the midaxillary line at the level of the fifth

intercostal space (nipple line).

● Pleurodesis - Patients with air leaks lasting longer than 7 days, patients who do not

fully reexpand their lungs, patients with large bullae or poor pulmonary function,

and patients with bilateral or recurrent pneumothoraces are candidates for

pleurodesis or surgical intervention.


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● Following a single episode, the risk of a recurrent pneumothorax is 40–50%. After

two episodes, the risk increases to 50–75%, and with three previous episodes, the

risk is in excess of 80%. Currently, most first-time patients are treated initially with

simple chest tube drainage; however, with subsequent recurrences, additional

therapy generally is indicated.

6) Treatment of secondary spontaneous pneumothorax

a. Wait till absorbed

b. Simple aspiration

c. Tube thoracostomy

d. Pleural abrasion

Ans: (c)

Most secondary spontaneous pneumothoraces are due to chronic obstructive pulmonary disease.

Secondary pneumothoraces may also be due to pneumonia, cystic fibrosis, asthma, or

tuberculosis. Pneumothoraces have been reported with virtually every lung disease.

Pneumothorax in patients with lung disease is more life-threatening than it is in normal

individuals. This is because of the lack of pulmonary reserve in these patients. Almost all patients

with secondary spontaneous pneumothorax should be treated with tube thoracostomy and the

instillation of a sclerosing agent such as doxycycline or talc. See 2 figures below.

Tube thoracostomy and the instillation of a sclerosing agent such as doxycycline or talc are

needed for almost all patients with secondary spontaneous pneumothorax.


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Indications for thoracoscopy with bleb resection and pleural abrasion are a persistent air leak, an

unexpanded lung after 3 days of tube thoracostomy, or a recurrent pneumothorax.

7) Indications for thoracoscopy in secondary spontaneous pneumothorax

a. Persistent air leak

b. Unexpanded lung after 3 days of tube thoracostomy

c. Recurrent pneumothorax

d. All


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Ans: (d)

8) False about traumatic pneumothorax

a. Nonpenetrating chest trauma does not cause pneumothorax

b. Treated with tube thoracostomy

c. Insertion of central intravenous catheter can cause traumatic pneumothorax

d. All

e. None

Ans: (a)

Pneumothorax can result from both penetrating and nonpenetrating chest trauma.

Traumatic pneumothoraces should be treated with tube thoracostomy unless they are

very small. If a hemopneumothorax is present, one chest tube should be placed in the

superior part of the hemithorax to evacuate the air, and another should be placed in the

inferior part of the hemithorax to remove the blood.

Iatrogenic pneumothorax is a type of traumatic pneumothorax. It is becoming more

common. The leading causes are transthoracic needle aspiration, thoracentesis, and the

insertion of central intravenous catheters. The treatment depends on the degree of

distress - observation, supplemental oxygen, aspiration, or tube thoracostomy.


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9) True about tension pneumothorax

a. Usually occurs during mechanical ventilation

b. Cardiac output is reduced

c. Enlarged hemithorax with no breath sounds

d. Diagnosis is confirmed by needle insertion

e. All

Ans: (e)

Tension pneumothorax usually occurs during mechanical ventilation or during resuscitative

efforts. Difficulty in ventilation during resuscitation or high peak inspiratory pressures during

mechanical ventilation strongly suggests the diagnosis.

In tension pneumothorax, the pressure in the pleural space is positive throughout the respiratory

cycle. See figure below. The positive pleural pressure is life-threatening. Ventilation is severelycompromised. The positive pressure is transmitted to the mediastinum. This results in decreased

venous return to the heart and reduced cardiac output. If the tension in the pleural space is not

relieved, the patient is likely to die from inadequate cardiac output or marked hypoxemia.


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Diagnostic findings are enlarged hemithorax with no breath sounds and shift of the mediastinum

to the contralateral side. Diagnosis is confirmed by needle insertion.

Tension pneumothorax is a medical emergency. If the tension in the pleural space is not relieved,the patient is likely to die from inadequate cardiac output or marked hypoxemia. A large-bore

needle should be inserted into the pleural space through the second anterior intercostal space. If

large amounts of gas escape from the needle after insertion, the diagnosis is confirmed. The

needle should be left in place until a thoracostomy tube can be inserted.

ESSENTIALS OF DIAGNOSIS - TENSION PNEUMOTHORAX

● Shift of cardiac apex to opposite side

● Shift of the trachea to opposite side

● Jugular venous distension


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10) False about tension pneumothorax

a. Most commonly due to COPD

b. USS is better than x-ray to detect small pneumothorax

c. May present as typical SVC obstruction

d. Bronchial breathing is typical

e. All are false

Ans: (e) All are false.

Tension pneumothorax usually occurs during mechanical ventilation or resuscitative

efforts.

The positive pleural pressure is life threatening. Tension pneumothorax presents with

chest pain and dyspnea.

The diagnosis is made by enlarged hemithorax with no breath sounds and shift of the

mediastinum to the contralateral side.

11) Treatment of tension pneumothorax

a. Small bore needle inserted

b. Site of insertion is point of maximum resonance


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pneumothoraces, with sensitivities as low as 36–48% in some studies. Tension pneumothorax can

develop when an injury to the lung parenchyma or bronchus acts as a 1-way valve, allowing air to

enter the pleural cavity but preventing it from escaping. A tension pneumothorax can develop

rapidly and is greatly exacerbated by positive-pressure ventilation, posing a great danger to

intubated patients. Rapid detection of pneumothoraces in trauma patients is critical, and bedsideultrasonography is a fast, reliable means of accomplishing this task.

Findings suggestive of pneumothorax

The presence of a pneumothorax is characterized by the absence of 2 findings: (1) the absence of

pleural (lung) sliding, and (2) the absence of comet-tail artifacts. The lung point is difficult to

identify, but is pathognomonic for a pneumothorax and can be used to measure the size of the

pneumothorax.

Absence of pleural sliding

In normal persons, the pleural line represents both the parietal and visceral layers of the pleura,

and back-and-forth sliding of that line is easily visualized during the respiratory cycle. In the

presence of a pneumothorax, air accumulates between the 2 layers and blocks transmission of

sound waves, so that the sliding is not visualized. This phenomenon can be seen in real time in

the 2-D mode but is more easily visualized by viewing a still image in M-mode.

The appearance of normal lung has been described as the seashore sign. See figure below.

This term refers to the change in appearance between soft tissue and lung, divided by the pleural


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line, a change resembling that between sand and sea waves. In the presence of a pneumothorax,

this demarcation is lost, and the appearance on M-mode imaging is described as the stratosphere

sign . See figure below.

Absence of comet tails

Comet tails are artifacts that are created when ultrasound waves bounce off the interface between

the opposing visceral and parietal layers of the pleura. They appear as hypoechoic vertical

ray-like projections off the pleural line and are parallel to the rib shadows. The presence of air in

the pleural space inhibits the propagation of sound waves, preventing the appearance of comet

tails. The presence of comet tails is 60% specific for the absence of pneumothorax. Combined

with the absence of lung sliding, the absence of comet tails has a negative predictive value of

100% and a specificity of 96.5%.

Lung point

The lung point is pathognomonic for the presence of a pneumothorax. See figure below. The lung

point is the actual point at which the normal lung pattern (ie, lung sliding and comet-tail artifacts)

is replaced by a pattern consistent with a pneumothorax (ie, no lung sliding and no comet-tailartifacts). Although it is the most specific sign of pneumothorax, it is also the hardest to visualize

and may require an experienced operator to locate. Finding both transition zones (from normal

lung to pneumothorax and then back again) allows calculation of pneumothorax size.


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● For video click https://www.youtube.com/watch?v=Xxdedx1HtHo

● Disorders of the Pleura > PNEUMOTHORAX

o Harrison's Principles of Internal Medicine, 19e, Chapter 316.

● Pneumothorax

o Fishman's Pulmonary Diseases and Disorders, 5e, Chapter 78

● Pneumothorax

o Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e, Chapter 68
https://www.youtube.com/watch?v=Xxdedx1HtHo

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