Review for 10.1186/1471-230x-12-52 (2012)

Reviewer's report
Title:Cyclic Vomiting Syndrome (CVS): is there a difference based on onset;
pediatric vs. adult?
Version: 1Date:31 January 2012
Reviewer: David Fleisher
Reviewer's report:
Review of manuscript "Cyclic Vomiting Syndrome (CVS): is there a difference
based on onset; pediatric vs adult? Thangham Venkatesan, Corresponding
Author. Reviewer: David Fleisher, MD
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This is a well-written contribution to the all-too-sparse body of literature on CVS,
and especially adult CVS.
Suggestions to the authors:
1. "Matrilineal inheritance patterns were noted...to be...different...with
pediatric-onset patients having a higher likelihood of...a matrilineal inheritance
pattern..."
Do the authors refer to the inheritance pattern of CVS per se, or to the
inheritance pattern of migraine diathesis and its many presentations, including
migraine headache?
2. "...but some patients developed coalescence of symptoms after several
months/years after they were not treated appropriately."
The hypothesis advanced in the 2005 paper on adult CVS (cit. #7) is that
coalescence results from the patient's despairing sense of being out of control of
an illness that no one understands, is willing to assume clinical responsibility for,
or knows how to manage. Therefore, based on the hypothesis that anxiety and
despair promote nausea, it follows that "appropriate" management involves more
than medications. It should also include an emotionally supportive component
implemented by caring clinicians who are expert in the disorder and have
individualized, rational and effective management protocols for each CVS
patient.
3. "Results of a gastric emptying study..." Please make clear whether the GES
was done while the patient was entirely symptom-free or having inter-episodic
dyspeptic nausea. Also, since a patient's emotional state (e.g., trait and/or state
anxiety) may affect the EGG and Gastric emptying, it would have been a
valuable contribution to have correlated the GES results with the patient's
emotional state at the time the study was done.
4. "The incidence of chronic opiate use was significantly higher amongst
non-responders..." Opiates are used by many adult CVS patients. Why? Are they
employed solely for analgesia in the 67% of patients whose symptoms include
abdominal pain? Were that so, I would expect the use of opiates to be confined
to that 67% and no opiate use by the other 33%. But, my experience has been
that some patients who use opiates do not have abdominal pain. If this is true,
then there must be another reason for the use of opiates. Butorphanol. morphine
and Dilaudid all dramatically ameliorate panic anxiety, an experience more
horrific than isolated abdominal pain itself. The problem of opiate use by CVS
patients is that the majority of adult CVS patients have anxiety complicated by
panic attacks (See cit # 7 and also Olden, Keate & Shapiro, 1999, AJG 94,9
2614). And panic attacks trigger their CVS episodes. This causes some
chronically and severely anxious patients to rely on anxiolytic opiates to the
extent that they become chemically dependent. It often becomes difficult to
distinguish panic-induced CVS episodes from "Cyclic Withdrawal Syndrome."
They have a very similar clinical appearance and, of course, both are relieved by
a dose of Dilaudid. (My approach to sorting this out is to engage an addiction
expert to protect the patient from opiate withdrawal symptoms by use of, say,
methadone, which helps to distinguish CVS episode and panic vs. opiate
withdrawal symptoms.
5. The "significantly longer delay in diagnosis of CVS in the pediatric-onset
group..." should be appreciated in light of the history of CVS. CVS was written
about only rarely between its initial description in 1882 and the early 1990's. Most
pediatricians and pediatric gastroenterologists either didn't know of it or didn't
recognize it and treat it for what it was. That was the reason the report of 71
pediatric cases in JPGN in 1993 was given such prominent placement in that
issue (cit.# 3). A thoroughgoing description of adult CVS wasn't published until
2005 (cit # 7). I still encounter gastroenterologists who fail to recognize the
diagnosis. Therefore, unlike a study of appendicitis, CVS should be viewed in
light of the history of CVS awareness over the past several decades.
6. Regarding the use of marijuana: a) it does alleviate nausea; and b) it does
stimulate appetite during the recovery phase. However, the authors left out
mentioning marijuana's anxiolytic properties which, as in the case of opiates,
does contribute to marijuana's chronic use by some patients. Again, dealing with
CVS management is optimized by sophisticated appreciation of the emotional
components of patients and their illnesses. That's the basis of the
Bio-Psycho-Social model of clinical practice.
This paper is worthy of publication, even in its present form.
David Fleisher, MD