Thursday, 16 September 2010

MRCP revision battle 13.2: SVC obstruction

SVC obstruction can be frightening for the doctor as well as the patient - the first lady I saw with it came in with a lovely slim face and as time went on it became more and more puffy and she became increasingly dyspnoeic.  Once seen it will never be forgotten; I can post this photo:
                                                                     Herbert L. Fred, MD and Hendrik A. van Dijk, Wiki Commons

which demonstrates the type of difference I saw in my patient (normal on right, SVC on left).  My patient however was female and smiled more!

Anyway, lets refocus on points to learn for the MRCP exam:

Features of SVC obstruction:
  • dyspnoea
  • orthopnoea
  • headache 
  • cyanosis
  • cough
  • swollen face/arm
  • engorged veins

There is a rather nice test called Pemberton's Test which involves asking the patient to lift their arms above their head for >1 min and watch for increasing plethora/cyanosis, raised JVP and listen for stridor (that sound every doctor wants to induce in their patient...)  If these things occur it is a positive Pembertons test and suggestive of SVC obstruction.

Causes of SVC obstruction include:
  • lung cancer
  • lymphoma
  • thymus malignancy
  • thrombus around central line

Treatment is surgical, with dexamethasone whilst awaiting this.

Lets return to the small-squared world of the ECG to consider causes of a long PR...