Traumatic asphyxia

This beautiful hand-drawn image is stolen from www.america.pink. Note that the patient appears to be holding a martini glass. This moustachioed gentleman is illustrating the clinical signs of traumatic asphyxia, a 30%-weighted first part of Question 10 from the first paper of 2016.  These signs consist of facial oedema, cyanosis, conjunctival haemorrhage and widespread petechii.

Not content with commonplace bread-and-butter ICU problems like base of skull fracture and fat embolism, the college decided to pull out a rarity which tripped up a whole population of candidates. Certainly, the incidence of this syndrome is such that one may spend four years in a major Australian trauma centre and never see one single case. A South Australian forensic pathology article (Byard et al, 2006)managed to scrape up 77 autopsy cases from a 25-year period (1980 to 2004), of which the majority were motor vehicle trauma and industrial accidents. Oh's Manual doesn't even mention it once. J.Dwek first described the syndrome in 1946, calling it the "ecchymotic mask"- he wrote about it on the basis of only one case,  out of a busy trauma service history of treating roughly 18,500 accident victims in an area with heavy military traffic.

Pathophysiology of traumatic asphyxia

"Traumatic asphyxia" is defined as "a form of suffocation where respiration is prevented by external pressure on the body". It is essentially a crush injury of the thorax, with impaired respiration as the result of greatly decreased chest expansion. Failure of venous return from the upper body results in the characteristic clinical findings, all of which can be attributed to greatly increased venous pressure. Traumatic asphyxia is a common cause of death among people being crushed by a crowd in a panic, or when law enforcement officers decide to restrain an individual by sitting on them.

Clinical features of traumatic asphyxia

This list is composed on the basis of articles by Byard et al (2006) and  Eken et al (2009)

Common features::

• Cyanosis of the upper body, especially the face
• Conjunctival haemorrhage
• Conjunctival oedema
• Petechial haemorrhages and purpura over the face, neck and upper face
• Oedema and congestion of the head
• The "brassiere sign" - petechhii and congestion of asphyxia spare those areas of the thorax which were covered by tight-fitting clothing, as it obstructs cutaneous blood flow and prevents the formation of petechii. This is typically observed in women who were wearing a bra during their crush injury, or a tight-fitting singlet as in the case of the moustachioed gentleman above.

Uncommon features:

• Chemosis
• Exophthalmos
• Retinal haemorrhages and visual loss
• Vitreous haemorrhagic exudates (Purtscher’s retinopathy- Choi et al, 2010 )
• Retrobulbar (posterior orbital) haemorrhages
• Haemotympanum

Other sequelae:

• Loss of consciousness
• Seizures
• Blindness
• Hearing loss
• Cerebral venous infarction