Monday, 13 September 2010

MRCP revision battle 10.1: Hereditary Haemorrhagic Telangiectasia

Once again I can see a sunny day... through the window my desk sits in front of.  Although today I've found the sun a catalyst for working rather than a mocking presence as my lovely other half has promised me a picnic later, so the sooner I finish the sooner I get jam sandwiches!

Today's topics are:

MRCP revision battle 10.1: Hereditary haemorrhagic telangiectasia
MRCP revision battle 10.2: Motor Neurone Disease
MRCP revision battle 10.3: Bulbar Palsy
MRCP revision battle 10.4: Pseudobulbar palsy
MRCP revision battle 10.5: Multifocal Motor Neuropathy
MRCP revision battle 10.6: Lesch-Nyhan Syndrome
MRCP revision battle 10.7: Low voltage ECG complexes

I promise that's less than it looks...

MRCP revision battle 10.1: Hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is an autosomal dominant condition associated with abnormal blood vessel formation.

Features of HHT include:
  • telangiectasia on skin
  • telangiectasia on mucosal membranes (leading to nose bleeds/GI bleeds)
  • arterio-venous malformations (AVMs)
    • commonest in lung
    • also in liver
    • brain
    • spine (rarest)

The diagnostic criteria are:
  1. spontaneous and recurrent nosebleeds
  2. telangiectasia
  3. AVMs
  4. positive family history - a first degree relative
The international consensus  states if 3 or 4 of the above features are present HHT is definite.  If 2 are present it is possible.  Less than that is unlikely.

A rare symptom the MRCP exam may throw up is platypnoea, which is difficulty breathing when sitting up/standing which is relieved on lying down.  Platypnoea is therefore the direct opposite of orthopnoea!  To briefly diversify, apart from lung AVM two other possible causes of platynoea are left atrial tumour or left atrial thrombus.

A rare sign associated with lung AVM is a 'humming sound' on auscultation over that area of the chest.

Management of HHT is symptomatic.

After that forray into the world of bleeding bits we're about to dive into the murky world of neurology with motor neurone disease...