Respiratory

Question 1

Symptoms and signs of DVT.

Answer 1

Unilateral:
Leg pain/cramping and tenderness
- May be worse with foot dorsiflexion (Homan's sign)
Leg swelling
Erythema
Distended superficial veins

Question 2

Explain your approach to diagnosis of suspected DVT.

Answer 2

Estimate pre-test probability of DVT. Use Well’s scoring criteria.

If LOW RISK –> D-dimer.
If D-dimer negative, can rule out DVT (not specific, but high negative predictive value).
OR if D-dimer positive –> Venous US.
+ US –> diagnosis of DVT confirmed

3. If pre-test probability moderate or high –> venous US.
   If + US –> diagnosis of DVT confirmed.
   If negative/inconclusive US –> consider: D-dimer, alternative imaging (CT or MRI venography)

Question 3

Give 4 DDX for DVT.

Answer 3

Baker's cyst
Cellulitis
Superficial thrombophlebitis
Lymphoedema
Peripheral oedema
Muscle injury - e.g. ruptured gastrocnemius

Question 4

What are the signs of pneumothorax on:

• Examination?
• CXR?

Answer 4

EXAM:
VITALS 
- Tachypnoea
- Tachycardia, pulsus paradoxus
- Hypotension
RESPIRATORY
- GENERAL INSPECTION: respiratory distress, anxious, restless, cyanotic
- CHEST EXPANSION: reduced on ipsilateral side
- PERCUSSION: hyper-resonant
- AUSCULTATION: reduced breath sounds
- OTHER:
Signs of trauma - chest wall wound
Subcutaneous emphysema

CXR:

• Pleural line with absence of lung markings peripheral to this line
• Ipsilateral flattening of the diaphragm
• Ipsilateral ‘deep sulcus sign’ (deep costophrenic angle)
• Tension –> tracheal deviation away; possibly mediastinal shift away

Question 5

Outline the management of pneumothorax.

Answer 5

DRSABCD
VITALS, LOC, Stable vs Unstable

Respiratory support –> O2 to maintain vitals
Consider imaging -
If tension pneumothorax suspected clinically –> treat immediately w/o imaging.
Otherwise –> US/ CXR/ chest CT. Usually use CXR. On CXR, a pneumothorax is considered small if the rim peripheral to the pleural line is < 2cm.

Usually, decompression of the pneumothorax.

Options for decompression:

• Needle aspiration (IV cannula into 2nd intercostal space mid-clavicular line).
• Chest tube placement
• Intercostal catheter placement

SMALL PRIMARY SPONTANEOUS w/o SX –> observation and repeat CXR in 6-12 hrs

PRIMARY SPONTANEOUS with SX or
SMALL SECONDARY SPONTANEOUS w/o SX –> needle aspiration.

TENSION or
TRAUMATIC pneumothorax or
FAILURE of simple aspiration or 
SECONDARY SPONTANEOUS with SX -->
chest tube or intercostal catheter. 

(with a tension pneumothorax, immediate treatment is required with needle aspiration, which is left in situ and then a chest tube placed)

Question 6

What are the different types of pneumothorax?

Answer 6

SPONTANEOUS:
Primary - no underlying lung disease; usually tall, thin young man
Secondary - underlying disease e.g. COPD
TRAUMATIC
TENSION, which could occur with any of the above