Thursday, 31 October 2013

Predisposing factors to cervical instability

Factors that can predispose to cervical instability: 

Lax posterior transverse ligament (joining the dens to C1) thought to be a risk factor for atlantoaxial instability (Merrick et al, 2000) 

  • Main movement occurring at this level (atlantoaxial jt) is rotation of 35 degrees in each direction
  • Rotation is limited by the alar ligaments 


Systemic inflammatory diseases (because the inflammation damages connective tissue, ligaments, joints etc) 

  • Lupus
  • RA (most common in cervical spine and MCP joints in the hands)
  • Ankylosing spondylitis (primarily affects c-spine)
  • Down Syndrome (laxity or congenital absence of transverse atlas ligament which can make minor traumas to the neck able to cause subluxation)

  • Degenerative changes of cervical spine (Andrews, 1981) 
  • Hypermobility 
  • Connective tissue disorders (Ehler's-Danlos syndrome, Marfan syndrome) 
  • Congenital bony abnormalities e.g. short dens, odontoid hypoplasia (basically geeky talk for the same thing!) 


Previous or recent RTAs (recurrent whiplash) 
General wear and tear 

DH (medications) 

Long term use of steroids 

Metastatic Disease 

Most prevalent in thoracic spine (1st) lung and breast primary tumors 

Lumbar (2nd) Prostate, colorectal, ovarian cancers 

Cervical (3rd) 

Red Flags of metastatic disease 

Non-mechanical picture (pain not affected by positional changes) 

Unremitting pain (no diurnal or nocturnal variation) 

Night pain and pain worse at night (this is due to more bony lysis occuring aka breaking down or erosion of the bone) 


Merrick J, Ezra E, Josef B, Hendel D, Steinberg DM, Wientroub S. Musculoskeletal problems in Down Syndrome European Paediatric Orthopaedic Society Survey: the Israeli sample. J Pediatr Orthop B. Jun 2000;9(3):185-92.

Andrews LG. Myelopathy due to atlanto-axial dislocation in a patient with Down's syndrome and rheumatoid arthritis. Dev Med Child Neurol. Jun 1981;23(3):356-60.

Friday, 11 October 2013

Morphine OD

I was watching the film "Prisoners" where at the end a little girl is given a lethal dosage of morphine. My flat mate Ed (a med student) told me that the first thing that would kill you from a morphine OD is respiratory failure. As your rate and depth of breathing reduces eventually it's not enough to keep you alive.

The medical fix is naloxone, a drug used to counter the effects of an opiate overdose. BUT the half life of naloxone is much shorter than morphine, it's broken down quicker so patients should be kept in for at least 24 hrs for observation.