Thank you for your query.
1. The narrowest part of the gut is the cricopharynx (upper opening of the esophagus
). If the coin passes through this, it is usually expelled after a couple of days. What is his age?
2. There are normally four constrictions of the food pipe (esophagus) where the coin may get stuck (impacted). Ideally, it should be removed, however many a times it may slip or be pushed down into the stomach safely as it is usually expelled. The next narrow junction is the ileo-cecal junction near the origin of the appendix
If it passes this, it is easily expelled.
3. I usually recommend a follow up chest, abdomen and pelvis X-ray after a couple of days as a coin is easily visible and cannot be missed. If it is not seen, it has been expelled. You may also keep inspecting his feces regularly for a few days to try to identify the coin.
4. There is no side effect of the metals in the coin. There is usually no cause for worry unless you find that the coin is still visible on the X-rays.