Obstructive sleep apnoea + Pulmonary Hypertension + Chest Wall Deformities + Obesity hypoventilation syndrome

Question 1

What is obstructive sleep apnoea?

Answer 1

Obstructive sleep apnoea is caused by collapse of the pharyngeal airway during sleep. It is characterised by apnoea episodes during sleep where the person will stop breathing periodically for up to a few minutes.

Question 2

Risk factors for obstructive sleep apnoea

Answer 2

• Middle age
• Male
• Obesity
• Alcohol
• Smoking

Question 3

Features of sleep apnoea

Answer 3

• Apnoea episodes during sleep (reported by partner)
• Snoring
• Morning headache
• Waking up unrefreshed from sleep
• Daytime sleepiness
• Concentration problems
• Reduced oxygen saturation during sleep

Question 4

Which scale is used to measure sleepiness?

Answer 4

Epworth sleepiness scale

Question 5

Investigations for obsturctive sleep apnoea

Answer 5

Sleep studies - This involves the patient sleeping in a laboratory whilst staff monitor their oxygen saturations, heart rate, respiratory rate and breathing to establish any apnoea episodes and the extent of their snoring.

Question 6

Management of sleep apnoea

Answer 6

1. The first step in management is to correct reversible risk factors by advising them to stop drinking alcohol, stop smoking and lose weight.
2. The next step is to use a continuous positive airway pressure (CPAP) machine that provides continuous pressure to maintain the patency of the airway.
3. Surgery is another option. This involves quite significant surgical restructuring of the soft palate and jaw. The most common procedure is called uvulopalatopharyngoplasty

Question 7

What is pulmonary hypertension?

Answer 7

Pulmonary hypertension is defined as an increase in mean pulmonary arterial pressure ≥25mmHg at rest or ≥35mmHg with exercise.

Question 8

Classification of pulmonary hypertension

Answer 8

• Group 1 – Idiopathic pulmonary hypertension or connective tissue disease such as systemic lupus erythematous (SLE)
• Group 2 – Secondary to left heart disease (most common variant), systolic, diastolic or valvular heart disease
• Group 3 – Secondary to chronic lung disease and hypoxia, eg COPD, ILD, high altitudes
• Group 4 –Chronic thromboembolic pulmonary hypertension
• Group 5 – Miscellaneous causes such as sarcoidosis, glycogen storage disease and haematological disorders

Question 9

Signs and symptoms of pulmonary hypertension

Answer 9

Shortness of breath is the main presenting symptom.

Other signs and symptoms are:

• Syncope
• Tachycardia
• Raised JVP
• Hepatomegaly
• Peripheral oedema

Question 10

Pulmonary hypertension investigations

Answer 10

• ECG
• Chest X-ray
• NT-proBNP blood test - if this is raised it indicates right ventricular failure
• Echo - to estimate pulmonary artery pressure

Question 11

ECG changes seen in pulmonary hypertension

Answer 11

The right sided heart strain causes ECG changes such as:

• Right ventricular hypertrophy seen as larger R waves on the right sided chest leads (V1-3) and S waves on the left sided chest leads (V4-6)
• Right axis deviation
• Right bundle branch block

Question 12

Chest xray changes seen in pulmonary hypertension

Answer 12

• Dilated pulmonary arteries
• Right ventricular hypertrophy

Question 13

Pulmonary hypertension prognosis

Answer 13

The prognosis is quite poor with a 30-40% 5-year survival from diagnosis.

Question 14

What is the medical name for pigeon chest and what causes it?

Answer 14

Pectus carinatum

From lung hyperinflation while while the bony thorax is still developing eg in chronic childhood asthma

Question 15

Medical name for sunken chest and associations

Answer 15

Pectus excavatum

Associated with scoliosis; Marfan’s; Ehlers-Danlos syndrome

Question 16

Consequences of pectus excavatum

Answer 16

It is often asymptomatic but may cause displacement of the heart to the left and restricted ventilatory capacity .

Question 17

Define obesity hypoventilation syndrome

Answer 17

A combination on obesity, daytime hypercapnia and sleep disordered breathing, after ruling out disorders that may cause alveolar hypoventilation.

Question 18

When is obesity hypoventilation syndrome typically diagnosed?

Answer 18

Typically diagnosed during an episode of acute on chronic type 2 respiratory failure

Question 19

Obesity hypoventilation syndrome diagnostic investigations

Answer 19

Arterial blood gas and sleep study

Question 20

Obesity hypoventilation syndrome treatment

Answer 20

CPAP (if severe obstructive sleep apnoea) or NIV (if no or milder obstructive sleep apnoea) during sleep

Acute on chronic hypercapnic respiratory failure treated with NIV