Inflammatory bowel disease

Today we discussed inflammatory bowel disease. Some important points:

Extraintestinal manifestations of IBD:
Eyes- uveitis
Skin- pyoderma gangrenosum, erythema nodosum
GI- PSC (esp UC)
Renal (stones- affects oxalate metabolism by unabsorbed bile salts binding Ca, allowing oxalate absorption)
Arthritis- Sero-ve, large joint asymmetric. Either peripheral, which parallels IBD or independent (axial)

Extent of UC (treatment):
pancolitis (oral meds), L sided (enemas), sigmoiditis/proctitis (suppositories)

Complications:
UC- bleeding, colon ca, toxic megacolon
Crohn's- aphthous ulcers, malabsorption, fistulae, abscess, strictures
Both: At higher risk for C. Diff, relatively hypercoagulable

Toxic megacolon: Non-obstructing dilation of the colon.
NB- TM can be from infectious causes as well.
Clinical: tachy, hypotension, fever, volume depletion, altered sensorium.
AXR: over 6cm at transverse, thumbprinting (big haustra), pneumatosis coli. Shown in above picture.

Flare treatment:
NPO (bowel rest)
NG
fluid resuscitation (esp attention to phos, K, Mg, albumin)
Possible antibiotics (esp. Crohn's) -cipro, flagyl, possibly vanco
IV steroids (e.g. Solumedrol 30mg IV bid)
DVT prophylaxis
Possible c-scope, although mucosa is very friable; may be deferred until inflammation settles.

Links:

Click here for a recent BMJ review of Crohn's disease

Click here for a Lancet review of new therapies for IBD

Colitis

Today we discussed the approach to bloody diarrhea. Some things that came up:

Bloody diarrhea implies colitis (of some etiology)
Triad of fever, bloody diarrhea, lower abdo pain defines "dyssentry".

Differential diagnosis:
Infectious colitis: campylobacter, yersinia, samonella, shigella, E. Coli (enterohemorrhagic), C.diff. In immunocompromise: CMV.
Ischemic colitis: seen in patients with severe vascular disease, hypercoagulable states, A-fib
Inflammatory colitis: UC (bloody diarrhea and mucous are hallmark symptoms), Crohn's
Post-radiation colitis

Important history:
travel, food, others with same symptoms, medications, hospitalization, sexual contact, symptoms suggesting IBD (inc. extra-intestinal), fhx, constitutional symptoms, immunosuppression risk factors


Antibiotics in infectious diarrhea:

Most causes do not require (and sometimes are worsened by) antibiotics.

Exceptions where Abx are indicated:
C. Difficile
Shigella (to prevent transmission)
Enterotoxogenic E. coli (ETEC) = "traveller's diarrhea", not 0157 (that is enterohemorrhagic)
Entamoeba histolytica
Giardia
Only in severe cases of yersinia, campylobacter, salmonella

Abx are harmful in
Enterohemorrhagic E. coli (as in Walkerton)

Abx not usually needed for
salmonella, campylobacter (most common causes of infectious colitis). Note that campylobacter is not covered by ciprofloxacin (if need to treat, use macrolide)


Extraintestinal manifestations of IBD

Eyes- uveitis
Skin- eryhtema nodosum, pyoderma gangrenosum
GI- PSC (esp UC), stones
Renal (stones- IBD affects oxalate metabolism by unabsorbed bile salts binding calcium, allowing increased oxalate absorption)
Arthritis- Seronegative, large joint symmetric. Either peripheral, which parallels IBD activity, or axial, which is usually independent of IBD activity


Toxic megacolon

Non-obstructing dilation of the colon.
May occur from infectious etiology as well as IBD.
Clinical: tachycardia, hypotension, fever, volume depletion, altered sensorium.
AXR: greater than 6cm at transverse, thumbprinting (big haustra), pneumatosis coli.


Reference:

Click here for a NEJM review of infectious diarrhea