A 38 year old woman presents with SOB and palpitations. The SOB has been going for a couple of months, much worse in the last 2 days with associated rapid regular palpitations. For 6 months she has been experiencing lethargy and weight loss of 10kg. 
On examination she is obviously short of breath at rest, talking in short sentences.
Temp 36.7
PR 130 regular, NSR on ECG
BP 110/80
RR 30
Sats 92% on room air
A CXR is performed:

The CXR shows a moderate left sided pneumothorax and associated small pleural effusion. There is a large right sided pleural effusion/opacity that is irregular in contour and tracks up the lateral thorax. There is associated mediastinal shift towards the right.

A left sided chest drain was inserted which resulted in clinical improvement:
HR now 100/min and oxygen saturations up to 96% on room air with a RR of 24.

Repeat CXR showed incomplete re-expansion of the left sided pneumothorax and persistent mediastinal shift to the right.

A CT chest revealed the opacity to be completely fluid with no evidence of mass or malignancy.

A small gauge chest drain was inserted into the right chest. Slightly blood stained fluid was aspirated and sent for microscopy, biochemistry and cytology. However, after approx 20ml, the fluid became very difficult to aspirate with evidence of significant negative intrathoracic pressure. The tubed was clamped and the patient was admitted under cardiothoracics for further management.

The patient underwent thoracotomy and decortication of a pleural rind. She was diagnosed with "trapped lung" likely on the basis of ?endometriosis.The negative pressure on the right side of her chest was sufficient to cause a left sided pnuemothorax.

TRAPPED LUNG
Trapped lung occurs when the visceral pleura becomes encased with a fibrotic rind that renders the lung unexpandable.
Causes of pleural inflammation that eventually lead to trapped lung include pneumonia with parapneumonic effusion (bacterial and mycobacterial), hemothorax, spontaneous pneumothorax, thoracic operations including coronary artery bypass surgery, uremia, and rheumatoid pleuritis.
On chest radiography of trapped lung, the hemithorax with the effusion is reduced in size, indicating that the pleural pressure on the side with the effusion is more negative than that on the contralateral side. Computed tomography (CT) often reveals loculation and pleural thickening, although sometimes pleural thickening is only apparent on an air contrast CT. 
Direct measurement of pleural pressure at the time of thoracentesis usually reveals a negative initial pressure. With fluid removal, a rapid decrease in pleural pressure occurs.
The presence of characteristic pleural pressure changes is strongly suggestive of trapped lung and may be sufficient diagnostically in patients with minimal or absent symptoms. However, confirmation that visceral pleural thickening (a pleural rind) is present requires air contrast computed tomography (CT) or direct visualization via video-assisted thoracoscopy.
Treatment may be conservative or with decortication of the pleural rind on the visceral pleura.

One sunny afternoon in one of our busy and well respected emergency departments an 8 year old girl presents with a "wry neck". She had woken up in that morning with an extremely painful neck, her head tilted over to the right, and unable to move it in any direction.
On further questioning she had had a minor fall in the playground the day beforehand. She had a viral illness about a week ago and had a sore throat.
On examination she appeared alert and well. Her voice was normal, there was no respiratory distress and no stridor. Temp 37.8, PR 100, and normal hydration. Minor tender cervical lymphadenopathy.
Her head was held in a fixed torticollis with head tilted to the right and chin to the left. It was very painful for her to move her neck in any direction including extension.
A lateral neck xray was performed:

The lateral soft tissue neck film shows significant soft tissue swelling anterior to the C2-C5 cervical vertebrae consistent with a retropharyngeal abscess.
Normal soft tissue distances should be 7mm at C2 and 2cm at C7. Any increase in soft tissue thickness may represent infection but is also an important indicator of underlying cervical spine injury in the setting of trauma. Clinical history and examination are, as always, vital.

Causes of torticollis in children:
 While the most common cause of acquired torticollis in children (approx 60%) is injury or inflammation involving the sternocleidomastoid or trapezius muscle, it's really important to consider less common but potentially life threatening conditions during your initial assessment:

Retropharyngeal abscess (confirmed on MRI in this case).
Usually a disease of 2-4 year olds - there is an exception to every rule- early in the disease process, the findings may be indistinguishable from those of uncomplicated pharyngitis.
With disease progression, symptoms related to inflammation and obstruction of the upper aerodigestive tract develop. Children with retropharyngeal abscess generally appear ill with moderate fever. 
Additional symptoms may include:

• Difficulty swallowing (dysphagia), pain with swallowing (odynophagia), and/or drooling with decreased oral intake
  
• Unwillingness to move the neck secondary to pain (torticollis), particularly unwillingness to extend the neck
  
• Change in vocal quality (muffled, or with a "hot potato" quality [dysphonia]), gurgling sound, or stertor
  
• Respiratory distress (stridor, tachypnea, or both); stridor develops as disease progresses
  
• Neck swelling, mass, or lymphadenopathy
  
• Trismus (in approximately 20 percen
•  Chest pain (if there is mediastinal extension)

 
Other life threatening causes of torticollis include: 

• Suppurative jugular thrombophlebitis (Lemierre syndrome) (typically high fevers, rigors and respiratory distress), 
• cervical spine injury (high energy kinetic mechanisms such as MVAs and falls), 
• spinal epidural haematoma (particularly in haemophiliacs) and 
• CNS tumours (consider if headache, vomiting, visual disturbances, papilloedema or CN deficits)