The shock news of Constitution Hill’s disappointing workout and subsequent poor scope caused reverberations around the racing world just two weeks ahead of this year’s Cheltenham Festival.

Here, we look at some of the key questions raised by the dramatic development:

What problems arise from mucus in a horse’s trachea (windpipe)?

Mucus is continually being produced by all horses and cleared from the lungs – if it is healthy and clear. However, bacterial or fungal infections lead to excess mucus secretion and any change in colour to yellow, green or even brown makes it thicker and harder to move. This mucopurulent discharge contains a combination of mucus and pus, which can cause difficulty in breathing and reduced exercise performance.

Is this a regular occurrence?

“Horses are like humans, look how many people had the awful cough around Christmas that took ages to get rid of,” commented trainer Nicky Henderson. Constitution Hill himself has been affected by a similar setback already this season, when forced to miss the Unibet Hurdle on Cheltenham’s Trials day. On that occasion, Henderson reported back in mid-January: “A routine scope last week wasn’t entirely satisfactory and a follow up this morning shows the issue hasn’t resolved and therefore there would not be time to get him ready for next week. In the meantime, he will continue with light exercise, be rescoped in a fortnight’s time and then start his preparation for March.”

How long does it take to clear up?

Obviously, much will depend on how severe the infection is, but an immediate course of antibiotics will be administered and aid any recovery. Henderson said: “Both our own vet and the racecourse veterinary surgeon who scoped him feel we definitely have a chance of correcting this in time and we will be doing everything possible to do so. We have a fortnight to work him and it is possible, so we will keep everybody notified accordingly. He is absolutely fine within himself and we have simply got to get on top of this issue as quickly as possible.”

Just how big is Constitution Hill for Cheltenham?

Every sport needs its superstars, and in the shape of Constitution Hill the world of National Hunt racing certainly has one. He is a perfect eight from eight over hurdles and the idea of defeat when he is at his best is more or less unthinkable. Think Frankel, but over jumps.

How has the Champion Hurdle betting been affected?

Constitution Hill was as short as 1-4 to retain his crown, while Coral even made him favourite to record the biggest winning distance at this year’s Festival. However, he was eased out to as big as 6-4 at one point with Champion Hurdle sponsors Unibet, who then trimmed him back into 5-4 after a more encouraging update, with State Man their 4-5 favourite. That firm is one of only a few not now offering odds on a non-runner, no bet basis. With that concession, Constitution Hill is 4-6 at best with Coral, Ladbrokes and William Hill – and still as short as 2-5 in places. William Hill spokesperson Lee Phelps said: “We might be non-runner, money back on the race, but we believe there is significant doubt now about Constitution Hill’s participation and even if he does run there have to be concerns, so we’re prepared to take him on.”

Will any other connections now be tempted to run their horses?

Bookmakers are taking no chances with the odds of Lossiemouth, but Willie Mullins may still prefer to keep his exciting mare separate from stablemate State Man, especially as last year’s Triumph Hurdle star is such a short-priced favourite for the Mares’ Hurdle. Owner Rich Ricci said after Lossiemouth’s latest Cheltenham success on Trials day: “We’ll go for the Mares’ Hurdle I think, and I think we learned last year that these four-year-olds turning five, it is very hard to run in open company.” Gordon Elliott could consider dropping Irish Point back from the Stayers’ Hurdle, with the Cullentra handler and owners Robcour also having Teahupoo at the head of the betting for that Thursday feature.