Thursday, 9 September 2010

MRCP revision battle 6.1: ankylosing spondylitis

Today's revision threw up a mixed bag of topics... a splash of rheumatology with a dash of respiratory and a hint of ophthalmology.


Battle 6.1: ankylosing spondylitis
Battle 6.2: acute iritis
Battle 6.3: Reiters syndrome
Battle 6.4: pleural effusion
Battle 6.5 yellow nail syndrome

Lets get started!

6.1: Ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the spine and sacroiliac joints.

It affects males more than females, intially around 6:1 but altering to around 2:1 by the age of 30.

 95% of patients are + for HLA B27

Patients often present with low back pain which is worse at night and improves on moving.

Clinically, the things to observe on regarding a patient with AS are:
  • a loss of lumbar lordosis
  • a fixed kyphosis which is compensated by extension of the cervical spine leading to the classical 
  • 'question mark' posture
  • if the patient turns their head to the side, the whole body may turn
  • there may be decreased chest expansion forcing increased diaphragmatic excursion and hence a
  • prominent abdomen
A possible test to undertake is Schobers test - find L5 (roughly level with the sacral dimples) then mark a level 5cm below and 10cm above.  Get the patient to bend over; this 15cm distance should increase to at least 20cm, if it doesn't is suggests AS.

    Associations of AS include:
    • iritis
    • aortic regurgitation
    • fibrosis (rare)
    • cardiac conduction abnormalities (around 10%, mostly long PR)
    • secondary amyloidosis

    Management is keeping mobile, NSAIDs and in severe cases tumour necrosis factor alpha blockers such as infliximab.

    As an aside, if considering a TNF alpha blocker its a good idea to check TB status as it is likely to reactivate latent TB.

    Onwards.... 6.2!

    MRCP revision battle 6.2: acute iritis

    If you're anything like me eyes are a bit a vague part of the body... as an A&E SHO I hated dealing with 'the red eye'.  The good news is that MRCP doesn't have too many ophthalmology questions so there aren't too many topics you have to be familiar with.  One not to miss however is acute iritis.

    As an aside, acute irits and anterior uveitis are often used by doctors almost interchangeably, but technically anterior uveitis encompasses both iritis (inflammation of the iris) and iridocyclitis (inflammation of the iris and ciliary body).  Fortunately management is pretty much the same.

    Acute iritis presents as:
    • red eye ('circumcorneal redness'
    • pain
    • photophobia
    • blurred vision
    • lacrimation
    • small pupil (in reccurent cases the pupil may be irregular due to adhesions)

    You may be able to illicit a positive Talbot's test, which is an increase in the patient's pain when you get their eyes to converge (due to the pupils constricting)

    On slit lamp examination you may spot:
    • cells in the anterior chamber
    • white precipitates on back of cornea
    • sometimes a hypopyon (= sterile anterior chamber pus)

    It is associated with ankylosing spondylitis and also Bechets disease.
    It may relapse.

    Treatment requires ophthalmic input due to the need for steroids - and if steroids are given inappropriately to an infected eye the patient may become blind....

    On that happy note, lets move on to Reiters Syndrome

    MRCP revision battle 6.3: Reiters syndrome/Reactive Arthritis

    Reactive arthritis is one of the spondyloarthropathies (alongside ankylosing spondylitis, psoriatic arthritis and enteropathic arthritis).  It is characterised by a sterile arthritis which usually affects the lower limb days to weeks following an infection.  It is associated with being HLA B27 positive.

    Infections commonly associated with reactive arthritis fall into 2 groups:
    • GI infections 
      • campylobacter
      • salmonella
      • yersinia
      • shigella
    • GU infections
      • chlamydia
      • gonnorhora
      • ureaplasma

    The classical triad associated with reactive arthritis is Reiters Syndrome of uveitis/conjunctivitis, urethritis and arthritis ("can't see, can't pee, can't climb a tree")  Apparently in some parts this is becoming a politically incorrect term as Dr Reiter was a member of the Nazi party with a less than perfect record by the 1940s...

    Reactive arthritis can also be associated with keratoderma blenorrhagica, which is brown raised plaques on the hands and feet.  Rarely it can cause aortic incompetance.

    Treatment is generally resting/splinting the affected joint and NSAIDS.

    Now time for some diversification to the liquid world of the pleural effusion....

    MRCP revision battle 6.4: Pleural effusions

    Pleural effusions for me are one of the most interesting clinical signs.  A dull day can be made just that tad more interesting by the characteristic stoney dull percussion note, reminding you there is a reason you percuss everyone's chest.  A chest xray can then almost instantly confirm your clinical judgment (unlike with a murmur, which you may never know if you were just imagining or not) but then theres the 'oh bugger' moment as you realise you need to work out why this patient has an effusion... and most of the options aren't entirely positive....

    The main thing to establish with an effusion is if it is an exudate or a transudate.

    Traditionally a transudate was defined as containing <3g/dl of protein.  However, some doctors prefer to use Light's criteria for determining which label to apply (a criteria which will misclassify 25% of transudates as exudates...)

    Lights criteria is that for a fluid to be an exudate it must either have:
    • pleural:serum protein > 0.5 or
    • pleural:serum LDH > 0.6 or
    • pleural LDH >2/3 upper limit of serum LDH

    So, obviously to make your diagnosis you need a pleural fluid sample and a blood sample.  You should send your pleural sample off for:
    • cell count
    • cytology
    • glucose
    • protein
    • LDH
    • amylase
    • pH
    • Ziel-nielson staining
    and remember to send bloods for glucose, LDH and amylase at the same time (plus any other bloods, like FBC, you might need)

    Armed with the knowledge of transudate or exudate, you can spin forth a list of diffentials:

    Causes of transudates:
    • heart failure
    • renal failure
    • liver failure
    • peritoneal dialysis
    • hypothyroidism
    • Meigs
    • constrictive pericarditis

    Causes of exudates:
    • infection: TB, pneumonia, subphrenic abscess
    • inflammation: Dresslers, pancreatitis, SLE, RA
    • malignancy: mesothelioma, local cancer, lymphoma
    • other: PE, uraemia, yellow nail syndrome

    As the list of differentials is still quite big, apart from your clinical acumen some of the other pleural fluid results can help narrow it out:

    Glucose <3.3 or pH <7.2 or raised LDH suggests:
    • TB
    • malignancy
    • empyema
    • SLE
    • RA
     Its worth noting that *really* low glucoses are usually due to RA or empyema

    Raised amylase suggests:
    • pancreatitis
    • carcinoma
    • bacterial pneumonia
    • oesophageal rupture

    Cytology results can give more clues:
    • neutrophils: pneumonia, TB
    • lymphocytes: malignancy, TB, RA, SLE, sarcoid
    • mesothial cells ++ : pulmonary infarction
    • multinucleated giant cells: RA
    • lupus cells: SLE

    Hopefully these lists should equip you well for any MRCP pleural effusion questions (or even, shock horror, real life on the wards!)

    On to the final battle of today, yellow nail syndrome

    MRCP revision battle 6.5: yellow nail syndrome

    Yellow Nail Syndrome falls into that subsection of clinical conditions that is rarely relevant in real life but disproportionately prevalent in MRCP questions.  Thankfully its fairly straightforward.

    • thick nails which are
    • excessively curved from side to side and
    • pale yellow. They are
    • slow growing (showing uncovered bulbous fingertips) and have
    • absent lunulae (the little 'moon-shaped' white bits at the base of your nails)
    • onycholysis may be present

    The importance from an MRCP point of view is that they are associated with:

    Thats all for today.  If you fancy a quick little test on yesterday's topics, click here

    MRCP questions: War 5

    As with previous 'wars' after 'battles' these are just a few quick questions to see if your brain cells have retained the information provided in battles 5.1 to 4.5.

    Jot down your answers on a piece of paper then compare to mine here

    Question 1:
    State the cardinal triad of nephrotic syndrome.

    Question 2:
    Try and list 10 potential complications of nephrotic syndrome

    Question 3:
    In a patient with nephrotic syndrome, what complication might be implied if the question states they develop 'loin pain'?

    Question 4: 
    What is the commonest glomerulonephritis in adults?

    Question 5:
    Does frank haematuria imply a good or bad prognosis in Bergers disease?

    Question 6:
    What HLA types is Bergers disease associated with?

    Question 7:
    What is the treatment for acute epiglottitis?

    Question 8:
    What is the commonest cause of nephrotic syndrome?

    Question 9:
    What tends to be raised in Bergers disease - C3 or C4?

    Question 10:
    Which gender is more affected by Bergers disease?

    Answers here