Ulcerative colitis OSCE station

Dermatology
by Medical Educator Dermatology

Ulcerative colitis is a type of inflammatory bowel disease (IBD) that affects the large intestine, or colon. It is an ongoing condition that can be unpredictable and cause periods of relapse and remission. Ulcerative colitis produces inflammation in the lining of the rectum and colon, resulting in painful ulcers, abdominal cramps, diarrhea, and more.

The exact cause of ulcerative colitis is unknown but it’s believed to be caused by a combination of environmental factors and genetics. It may also be triggered by an autoimmune reaction where your body mistakenly attacks its own cells in the digestive system. People with close relatives such as parents or siblings who have IBD are at higher risk for developing this condition themselves.

Now place yourself into this OSCE station as you help this patient ulcerative colitis. Test your knowledge below.

Table of Contents

Question 1

A 25 year old male with ulcerative colitis develops a rash on the front of his shin. His GP gives him a course of flucloxacillin as a treatment for cellulitis.
He is allergic to macrolide antibiotics.

Is this a reasonable choice as a treatment for cellulitis?

  • Yes
  • No

Yes

Macrolide antibiotics are the antibiotics that end in “mycin” e.g. clarithromycin. They have reasonable gram positive coverage. Flucloxacillin is the current recommended first line antibiotic for the treatment of cellulitis.

Question 2

The patient has now Grown MRSA.

With regards the following statement:


The reason that the MRSA is not treated by the flucloxacillin is that the organism is gram negative unlike normal staphylococci which are gram positive

  • true
  • false

False

MRSA is still a gram positive staph aureus which is simply resistant to penicillin (tested using methicillin).

Question 3

Despite receiving inpatient treatment for 11 weeks the area previously thought to be cellulitis has ulcerated and remained ulcerated for the previous 9 weeks. Given these findings it raises concerns about the possibility of …

  • Fungal infection
  • Protazoal infection
  • Pyoderma Gangrenosum
  • Livedo reticularis
  • Bullous Pemphigoid

Pyoderma Gangrenosum

Another exam classic, associated with the following elusive conditions including

RA
Inflammatory bowel disease
Wegener’s

About half are idiopathic.

Unresolving cellulitis in a young person should lead you to consider other (e.g. pyoderma) / additional (e.g. HIV, diabetes mellitus etc) diagnoses.

Pyoderma should be suspected in exam questions particularly when ulcers have an overhanding border with a violacious (violet) edge and fairly deep ulceration.

Pyoderma classically occurs on the legs.

All cases I have seen in rheumatology patients have occured here. It can occur in other areas (including the face and around stoma sites). This is important in IBD: remember peristomal cellulitis may in fact be pyoderma!

Bullous pemphigoind is a blistering skin rash and the presence of large bullae are needed to make the diagnosis (a bulla is a fliud filled sac which is between the epidermis and dermis).

Question 4

The swab of the ulcer comes back with the following result.

“The swab has grown staphylococcus aureus. This is a methicillin resistant strain.”

What is the most appropriate course of action to take?

  • Vancomycin
  • Cefuroxime
  • Co-Amoxiclav
  • Continue on flucloxacillin orally
  • Switch to flucloxacillin IV

Vancomycin

Methicillin resistant staphlococcus aureus = MRSA

MRSA organisms which cause cellulitis are not treated by penicillin based antibiotics and a specific therapy for the treatment of MRSA is needed i.e. Vancomycin in this case from the list.

Other choics include teicoplanin and linezolid which is available in oral form.

Question 5

The chance of any person of being colonised with MRSA in the community is:

  • 1 in 30 000
  • 1 in 3 000
  • 1 in 300
  • 1 in 30
  • 1 in 3

1 in 3

The carriage of MRSA is in about 1 in 3 of the population. This is a smaller proportion than those who will “screen positive” from the standard screen for MRSA which currenly includes

Nasal swab
Axilla swab
Groin swab