Saturday, 13 November 2010

MRCP revision battle 48.1: Genital warts

Today's battles have a distinctly dermatological flavour to them...

MRCP revision battle 48.1: Genital warts
MRCP revision battle 48.2: Livedo reticularis and erythema ab igne
MRCP revision battle 48.3: Antiphospholipid syndrome
MRCP revision battle 48.4: Skin conditions associated with malignancy
MRCP revision battle 48.5: Sturge-Weber Syndrome
MRCP revision battle 48.6: Erythema multiforme
MRCP revision battle 48.7:  Toxic Epidermal Necrolysis and Steven-Johnson Syndrome

MRCP revision battle 48.1: Genital warts

Genital warts are not a topic I want to dwell on so lets make this very concise.

Posh medical name for genital warts = condylomata accuminata

HPV, most commonly strains HPV 6 and HPV 11.
Less than 1% of people who become infected with HPV develop warts.

Prevention: gardasil vaccine protects against HPV 6 and 11 (associated with warts) and 16 and 18 (associated with cervical cancer)

  • 1st line: topical podophyllin/cryotherapy
  • 2nd line: imiquimod

Lets move rapidly onwards...

MRCP revision battle 48.2: livedo reticularis and erythema ab igne

livedo reticularis is a mottled, reticulated vascular pattern that appears like 'purple lace' on the skin.

Click here for an image
Click here for another

Causes of livedo reticularis include:
  • idiopathic - commonly occurs in young females
  • secondary
    • rheumatological: RA/SLE/PAN/dermatomyositis/antiphospholipid syndrome
    • pancreatitis
    • infections: TB/lyme disease/syphillis
    • lymphoma

Note how similar it looks to erythema ab igne (AKA livedo recticularis e calore) which is a rash caused by prolonged heat exposure, for example by sitting by a radiator or holding a hot water bottle.  (photo form wiki commons, taken by Dr Heilman)

Now lets move on to look at one of the causes of livedo reticularis, antiphospholipid syndrome

MRCP revision battle 48.3: Antiphospholipid syndrome

Antiphospholipid syndrome is characterised by:
  • recurrent venous/arterial thromboses
  • fetal loss
  • thrombocytopenia

Livedo reticularis may also be a feature.

Antiphospholipid syndrome is associated with:
  • lupus anticoagulant - an inhibitor of the coagulation pathway in vitro; pro-coagulant in vivo
  • anti cardiolipin antibodies - IgG and IgM

Management is with aspirin post thrombus, or if recurrent thromboses despite aspirin warfarin.

In pregnancy expert advice is needed; in general aspirin is taken once pregnant and LMWH started once the fetal heart is seen.  This is continued until 34 weeks.   This regime results in 70% success compared with 10% with nothing.

Now for some pictures...

MRCP revision battle 48.4: Skin conditions associated with malignancy

A brief run-through of a few skin conditions that can be associated with malignancy.

1.  Acanthosis nigricans

Acanthosis nigricans is a brown, velvety pigmentation of the skin, as illustrated below.

Acanthosis nigricans is associated with:
  • insulin resistance 
    • diabetes
    • acromegaly
    • cushings
    • obesity
    • hypothyroidism
  • PCOS
  • adenocarcinoma - particularly of GI tract/stomach

2. Acanthosis palmaris

Acanthosis palmaris, also known as 'tripe palms' is associated with lung or GI cancer.

3. Erythema gyratum repens

Erthema gyratum repens can be just the most beautiful swirly patterned erythema - click here to see a picture.  Unfortunately it is associated with lung cancer.

4. Necrolytic migratory erythema

From a beautiful rash to a truelly ugly one - necrolytic migratory erythema is associated with glucagonomas.  Click here for more information and images.

5. Sweets syndrome

These are tender purple-red plaques associated with haematological malignancy and IBD.  The patient is likely to have a fever.  The picture below is from wiki commons, posted by Cohen:

On to a very brief battle, Sturge-Weber syndrome...

MRCP revision battle 48.5: Sturge-Weber Syndrome

Sturge-Weber syndrome is the association of a port wine stain on the face with ipsilateral vascular  malformations and epilepsy.

Glaucoma and learning difficulties may also be features.

Now for some target lesions...

MRCP revision battle 48.6: Erythema multiforme

Erythema multiforme is characterised by target lesions.

Two pictures of erythema multuforme are below; the second is by Dr Heilmann.

50% of cases of erythema multiforme are idiopathic.

Secondary causes include:
  • drugs
    • penicillin
    • sulphonamides
    • phenytoin
    • carbamazepine
    • ACE-i
    • barbituates
    • NSAIDs
    • thiazides
  • infections
    • mycoplasma
    • herpes
    • orf

Management is to treat the underlying cause and supportive treatment.

For the final battle of the day on to what used to be considered as a severe form of erythema multiforme....

MRCP revision battle 48.7: Toxic Epidermal Necrolysis and Steven-Johnson Syndrome

Steven-Johnson Syndrome and Toxic Epidermal Necrolysis (TEN) are now consider to be varients of the same entity, with TEN being more severe.

They are characterised by irregular purpuric macules with occasional blistering and most patients also have extensive mucosal involvement. 

Although the appearence may initially seem similar to erythema multiforme (ableit more severe) histologically they are different:
  • erythema multiforme - cell-rich infiltrate, lots of T lymphocytes
  • SJS/TEN - cell-poor infiltrate, macrophages and dendrocytes

The difference between SJS and TEN is arbitrarily defined as SJS involves <10% body surface while TEN involves >30%.

The commonest cause of SJS/TEN is medication, with sulphonamides being the most commonly implicated drug.  

Other drug precipitants include:
  • phenytoin
  • carbamazepine
  • barbituates
  • allopurinol
  • penicillin
  • NSAIDs

The commonest time for SJS/TEN to develop is 9 to 14 days after starting a new drug.

Infections can also cause SJS/TEN.

In addition to the rash patients are systemically unwell and have a + Nikolsky's sign.

Management is:
  • stop precipitating drug
  • often ITU
  • IV IG
  • ?immunosupression ?plasmophoresis