Sunday, February 20, 2011

IBD markers are not screening tools

Again, I am fascinated by how some physicians order an "IBD panel" in a kid with abdominal pain to r/o Crohn's disease (CD) or Ulcerative colitis (UC). Unless I am confused, an IBD panel's role is to help differentiate the two types of IBD, and not make the diagnosis (substantial false positives and false negatives).

Here is some information I found useful:

Main laboratory markers:

ANCA: anti-neutrophil cytoplasm antibody
ASCA: anti-Saccharomyces cervisiae antibody
Anti-OmpC: anti E coli-related outer membrane porin C
Anti I2
Anti-Cbir1: antibody against flagellin

pANCA present in two thirds of UC patients and one third of CD
pANCA-positive CD patients have a clinical picture similar to UC
ASCA (IgG or IgA) present in half of patients with CD
High titers of ASCA in the absence of pANCA highly predictive of CD
Antibodies to OmpC and I2 are associated with more strictures and internal perforations
Anti-Cibr1 associated with CD, particularly penetrating disease, fibrosing disease, and SB involvement.
pANCA positive CD patients less likely to respond to inflixamab than ASCA positive or totally seronegative

Reference:
Wyllie R, Hyams JS, Kay M (2011). Crohn's Disease. In Wyllie R, Hyams JS, Kay M (Edx.), Pediatric Gastrointestinal and Liver Disease 4th ed (pp 462-489). Elsevier.
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This publication from the Mayo clinic is concise and useful too.

Saturday, February 5, 2011

Neonatal testicular torsion: what are the options?


This read stemmed from a hallway conversation I had with my favorite French-Canadian urologist (and not because he's the only FCU I know). I had been under the impression that, unlike ovarian torsion (where you detorse the ovary and give it a chance regardless of how it looks because of the possibility of viable tissue surviving), an orchiectomy for testicular torsion with ischemia was mandatory. The rationale behind that is the theory that leaving a necrotic testicle behind results in contralateral testicular injury. This injury results from an autoimmune response that occurs because of a breach in the hematotesticular barrier on the ischemic side. Well, that turned out to be erroneous thinking.

Djahangirian et al discussed this subject in a recent outcome study from Quebec and noted that the concern for the breach of the hematotesticular barrier applies to pubertal boys only (I should have figured that one out myself, given that you need sperm to form antisperm antibodies!!). Their main discussion was regarding the different management options for neonatal testicular torsion (NTT), which is defined as torsion detected within 30 days of birth, and constitutes 5% of all cases of testicular torsion. They discussed management rationales for the affected testicle as well as the contralateral one (which is presumed to be at risk of torsion too). Regarding the management of the torsed testicle, they noted that a prenatally torsed testicle (which constituted 50% of their cases) had no chance of survival so emergent surgery in an attempt to salvage the testicle was not recommended, and the options were elective orchiectomy or observation. In cases where the torsion occurs postnatally (the other 50%), and because of a slim chance of salvage (mostly in patients who present with signs of discomfort only), emergent exploration was indicated.

As to the management of the contralateral testicle (which they noted could torse in 5% of cases, either synchronously or metachronously), they suggested that elective orchidopexy, and even observation with strict instructions to the parents regarding the signs of torsion, were viable options.

Between medico-legal concerns and guaranteed sleepless nights, observation of the contralateral testicle does not sound like a reasonable option to me, so I would stick to an exploration with orchiectomy and contralateral pexy.

Timing of surgical management of neonatal testicular torsion. Djahangirian et al. Journal of Pediatric Surgery (2010) 45, 1012-1015