Vasovagal reactions during colonoscopy
It is well known that some patients who undergo a colonoscopy or even a CT colonography may develop a vasovagal reaction, sometimes severe [i]. This is related to the distention of the bowel by air or the pressure exerted by the colonoscope. During colonoscopy this happens between 0.1 % to 1 % of the cases. This illustrates the point that perhaps abdominal pain by itself could also create a stimulus intense enough to lead to a cardioinhibitory vasovagal syncope (loss of consciousness mediated by an overstimulation of the vagus nerve). However, this must be rare, and caution is advised: Something else may be going on. For example, the patient may have an underlying cardiac, especially conduction, abnormality and may be prone to bradyarrhytmias (abnormally slow heart beats).
Rarely, it only takes a bowel movement (not pain) to lose consciousness: This is called defecation syncope. Most of the patients with this problem have serious underlying disease [ii].
Abdominal Migraine and Abdominal Epilepsy
Especially in adults two syndromes go often unrecognized, one is called abdominal migraine, which consists of episodic abdominal pain attacks (but not loss of consciousness), and the other one is called abdominal epilepsy. Both conditions are more common in children but can occur in adults. Abdominal epilepsy consists of paroxysmal and brief episodes of abdominal pain or other gastrointestinal symptoms often associated with neurological symptoms such as mental status changes up to syncope (loss of consciousness). This is a rare disorder with approximately one case report per year. Before considering either diagnosis it is important to perform a thorough workup to rule out possible alternative explanations. Differentiating between abdominal migraine and abdominal epilepsy is important because they are treated differently. The following table compares the two conditions:
|Abdominal migraine||Abdominal epilepsy|
|A: At least 5 attacks of abdominal pain fulfilling B-D||A: Paroxysmal (suddenly recurrent) and brief episodes of abdominal pain or other gastrointestinal symptoms.|
|B: Pain has at least two of the following three characteristics:
– 1) Midline location, periumbilical, or poorly localized
– 2) Dull or “just sore” quality
– 3) Moderate or severe intensity
|B: Abdominal pain, most commonly sharp or colicky, in (86%), nausea and/or vomiting in (28%), diarrhea in (5%), and bloating in (3%).|
|C: During attacks, at least two of the following are present: anorexia, nausea, vomiting or pallor||C: Possible presence of associated neurological symptoms, including convulsions, impaired consciousness, and other sensory phenomena|
|D: Attacks last 2–72 h when untreated or unsuccessfully treated||D: Duration of episodes, where reported, was typically no more than a few minutes, symptoms lasting for an hour or more are rare.|
|E: Complete freedom from symptoms between attacks||E: Many of the patients with recurrent abdominal pain have associated disturbances of consciousness, but not necessarily with every episode.|
|F: Not attributed to another disorder||F: Not attributed to another disorder. Presence of interictal epileptiform discharges (IEDs) consist of paroxysmal spikes and/or sharp waves on EEG.|
|Headache Classification Committee of the International Headache Society (IHS). The International Classification of Headache Disorders, 3rd edition (beta version). Cephalagia. 2013;33(9):629–808||Adapted from: Zinkin NT, Peppercorn MA. Abdominal epilepsy. Best Practice & Research Clinical Gastroenterology. 2005 Apr 1;19(2):263-74.|
As previously stated, common explanations for the coexistence of abdominal pain and mental status changes need to be considered first.
If you have questions o concerns about abdominal pain contact your doctor or make an appointment with Dr. Klaus Gottlieb in Templeton or San Luis Obispo.
[i] Neri E, Caramella D, Vannozzi F, Turini F, Cerri F, Bartolozzi C. Vasovagal reactions in CT colonography. Abdominal imaging. 2007 Sep 1;32(5):552-5.
[ii] Kapoor WN, Peterson J, Karpf M. Defecation syncope: a symptom with multiple etiologies. Archives of internal medicine. 1986 Dec 1;146(12):2377-9.