Sinuses explained

“Sinuses are complex, air-filled structures comprising seven compartments on each side of the head,” says Tim Barnett MRCVS. “Five are interlinked to form an air space at the back and top of the head, the other two communicate with each other to form an air space at the front.

“These compartments are linked to the nasal cavities through two narrow drainage slits that come together and empty into the back of the nose. This area can easily become occluded [blocked] — it could be described as a ‘design fault’ of the horse.

“Infectious agents and foreign materials are constantly being inhaled through the nostrils, some of which will find their way into the sinuses and can establish infection. In many cases the horse deals with these infections, as we would with a cold, and a snotty nose for a few days soon clears.

2 discharge

“Occasionally, the inherent architecture of the sinuses and/or the inflammatory response set up by the infection impede natural drainage so that infection cannot get out.

“If anti-inflammatory drugs and antibiotics fail, infection in the sinuses — sinusitis — can remain. Inflammation caused by the disease can further occlude the drainage and a circle of worsening disease ensues, as with Trig Point (read his case below, pictured top).

“Sinusitis usually responds well to medical treatment — especially primary sinusitis, where an infectious agent has colonised the sinus without an underlying cause. Where clinical signs do not fully respond to initial treatment, an underlying cause for the infection may be present, such as dental disease, trauma or sinus cysts. Further investigation by nasal and oral endoscopy, and radiography, may be needed.

“More accurate and detailed 3D images are provided by computed tomography [CT] imaging, which enables us to find causes and plan treatments more precisely.”

Scope into sinus

Scope into sinus

The diary of a four-star horse’s fight for life

Sinus problems are not uncommon in horses and usually respond well to treatment. Complications can occur, however, in these complex cavities.

A rare infection in both sinuses triggered by a straightforward tooth extraction nearly proved fatal for four-star eventer Trig Point. When antibiotics failed to resolve the problem, Nicky Roncoroni’s 13-year-old gelding endured multiple operations and invasive procedures as vets battled to bring the infection under control.

His story starts late last year, when a slab fracture was identified in his upper 11 molar (the highest under the eye) during a routine dental examination.

18 November, 2014

Nicky is “grating carrots and making the softest mash” for Trig Point (known as The Mighty Jerry, or TMJ) after successful extraction of the offending tooth.

“A videoscope showed horrible sores in his cheek, so goodness knows what pain he must have been in,” writes Nicky on her Facebook page. “Humbling that he is so incredibly stoical.”

19 November

A blood-tinged discharge is spotted in TMJ’s left nostril. Although the original tooth site is healing well, it is thought that the trauma of the extraction has caused bleeding in the sinus.

20 December

A stubborn infection persists, so a drain is inserted into TMJ’s left sinus to flush out the cavity. A swab reveals resistance to some types of antibiotic, but it is hoped that a new course of medication will do the trick.

17 January, 2015

TMJ is now off the antibiotics, but Nicky returns from a trip abroad to find he has taken a turn for the worse.

“His face was very swollen,” she says. “It was incredibly distressing — he was dunking his nose in the water trough as if his face was on fire.”

TMJ is admitted to an equine clinic, where vets discover that one of the infectious agents in his sinus is a species of Pseudomonas — bacteria that are particularly difficult to deal with. Drains are inserted into the sides and top of his head to enable daily flushing of both sinuses.

11 February

“Releived and delighted to have this boy home after over three weeks in hospital,” writes Nicky, as TMJ is given a tentative all-clear after further treatment. “It’s rare for both sinuses to be affected, rare to get this particular bacteria and rare for it to get so bad. He’s just been unlucky.”

Endoscopy reveals clear sinus linings and TMJ is no longer on antibiotics. It seems that he has finally beaten the bacteria.

15 February

Within days, infection reappears. Nicky, who calls the vet out on Sunday evening to a very sick TMJ, reports: “During a frank discussion, the vet tells me that there’s a chance that TMJ might lose his life if we can’t get on top of this.”

The gelding is immediately admitted to hospital, this time to Rossdales Equine Hospital in Newmarket.

Surgeon Tim Barnett MRCVS takes up the story: “TMJ had undergone an extensive array of treatment before coming to us, including systemic antibiotics guided and selected through laboratory culture testing. He’d had repeated keyhole surgery of both sinuses to remove infected material and diseased tissues, and to ensure adequate and open drainage from the sinus compartments.

“One of the problems was that the drainage between TMJ’s front and back sinus compartments failed to remain open, trapping infection.”

4 March

Lavaging (washing) the sinuses through a catheter is the main treatment in such cases, but when this is unsuccessful, the Rossdales team decide to perform more invasive surgery.

“Bone flaps were made into the sinuses on each side of his head, providing greater access and allowing much larger drainage to be created into his nose,” says Tim. “This permitted more radical removal of infected and diseased tissue from within his sinuses. This is usually performed using sedation and local anaesthetic — sadly, TMJ had become fed up with surgery and we felt that carrying out the procedure under general anaesthesia would be safer.”

Nicky writes: “The next few weeks will be critical with risks of infection of the surgical sites and also from the bacterial superbug that has plagued him for so long. It is now over to TMJ to fight with all the mightiness he has. Come on, big man.”

7 March

Five times a day TMJ’s sinus compartments are washed with five litres of fluid to remove remains of diseased tissue and infectious agents.

“Flushing with saline and dilute iodine did not seem to work,” says Tim. “After consultation with some small animal clinicians, who deal with these infections more commonly, we decided to lavage with dilute acetic acid (sterile vinegar). This seemed to coincide with the resolution of TMJ’s condition.

“Turnout in the paddock ensured that he kept his head down as much as possible, encouraging natural drainage from the sinuses into his nose.”

9 April

TMJ returns home after seven weeks at Rossdales. “What he’s had to endure to get to this point is extraordinary,” reports Nicky. “It is now hoped that time, the spring sun and Dr Green [plenty of grass] work their magic to put an end to his ordeal.”

6 Back competing

Nicky and TMJ at Barbury

17 April

Nicky is back in the saddle as TMJ’s recovery continues. The aim is that light exercise will stimulate his sinuses and promote the healthy blood circulation necessary for healing.

9 July

After eight months fighting the infection that threatened his life, TMJ returns to competition at Barbury Castle.

“I’m indebted to all those who helped him to recover,” says Nicky. “We’re taking each day as it comes, as reinfection is still a threat, but for today we have so enjoyed having this incredible horse out and back doing what he loves.”

Further reading

www.horseandhound.co.uk/?s=sinus

• See also next week’s vet column on resistance to antibiotics

Ref: Horse & Hound; 17 September 2015