Linear Foreign Body (String Ingestion)

Most swallowed objects either pass or sit harmlessly. A linear foreign body is different, because it does not behave like an object at all — it behaves like a saw.

The mechanism is worth understanding, because it explains everything about how the condition is managed. A strand of thread is swallowed, and one end catches: very commonly it loops around the base of the tongue, where it can be almost invisible, or it snags at the outlet of the stomach. The other end continues down the intestine. The bowel does what bowel always does and tries to move the contents onward, but the anchored end will not budge. Instead of travelling, the intestine gathers itself up along the taut string, concertina-fashion — a pattern vets call plication. With every contraction the string is pulled tighter against the inner curve of the folded bowel, and slowly cuts into it. Given enough time it cuts all the way through, spilling intestinal contents into the abdomen and causing septic peritonitis.

This is why the single most important piece of first aid is a negative one: never pull. An owner who sees thread under the tongue or protruding from the anus and tugs on it may drag the anchored end through the fragile, already-damaged bowel wall. If a strand is visible and at risk of being swallowed further, cut it flush and get to a vet. Otherwise leave it entirely alone.

The clinical picture is often deceptively vague at first — a quiet cat, off its food, vomiting on and off. Owners frequently assume a hairball or a mild upset, and cats rarely offer a useful history. A vet examining a vomiting cat will always look under the tongue for exactly this reason, and imaging may show the characteristic bunched, pleated loops of gut. Diagnosis is much easier once the picture is fully developed, but the outcome is much better when it is caught before that point.

Surgery, done early, is usually successful and cats recover well. Done late, after perforation, it becomes a far bigger undertaking with a guarded prognosis. So the practical advice for owners of cats is preventative and slightly ruthless: sewing thread, dental floss, wool, hair ties, elastic, meat string, ribbon and tinsel all belong behind a closed door. A cat playing with a length of string looks charming, and it is one of the more dangerous games in the house.