Phasic contractions are driven by slow waves generated by pacemaker ICC – depolarizations enable Ca2+ Entry – action potential – electromechanical Coupling Motility of GI tract is results from coordinated contractions of smooth muscle, which in turn derive from two basic patterns of electrical activity across the membranes of smooth muscle cells — slow waves and action potentials. Slow waves are initiated by pacemakers — the interstitial cells of Cajal (ICC). Slow wave frequency varies in the different organs of the GI tract and is characteristic for that organ. They set the maximum frequency at which the muscle can contract: stomach — about 3 waves in a minute – during fasting, these do not result in contractions. For 2-3 hours after meals, spikes are superimposed on slow waves – result in contractions that propogate distally. Bradygastria – assocaited with GP Tachygastria Disorganised – dysrthythmia duodenum — about 12 waves in a minute, ileum — about 8 waves in a minute, rectum — about 17 waves in a minute. jejunum — about 11 waves in a minute.
The diabetic patient with nausea and vomitingas predominant symptoms is the best candidate for GES.
Abeezar I. Sarela Consultant in Upper GI & Bariatric Surgery Hinduja Hospital, Mumbai St James’s University Hospital, Leeds, UK Gastric Motility Disorders
Why is Scintigraphy the Investigation of Choice?
Very small radio-active dose
Severity of Gastroparesis N Eng J Med 2007;356:820-829 Yes No No Non-pharmacologic treatment Jejunal tube By mouth Rare Nutritional supplements Routine Sometime Rare Homogenised food >35% 16-35% 10-15% Retention at 4 hours Severe Moderate Mild