Health & Medical

How much water has your unspayed dog been drinking this week? It sounds like small talk. It is actually one of the sharpest diagnostic questions in small animal practice, and for owners of unspayed females it can be the difference between a routine surgery and a dog fighting for her life in intensive care.

Pyometra is an infected uterus, and calling it an infection undersells it badly. What builds up inside is not a teaspoon of pus. It can be a litre or more in a big dog, sealed inside an organ that was never designed to hold it, leaking bacterial toxins into the bloodstream the entire time. It is one of the most common true emergencies in unspayed dogs and cats, and roughly a quarter of unspayed female dogs will develop it by the age of ten.

The mechanism is worth understanding because it explains the timing. After a season, progesterone stays high for around two months whether or not the dog is pregnant. That hormone thickens the uterine lining and quietens the local immune response, and it also relaxes the cervix. Season after season, that lining grows thicker and more cystic. Eventually bacteria that live perfectly harmlessly in the vagina wander up through the open cervix into what has become an ideal incubator. Hence the classic timing: four to eight weeks after a season, in a dog over six, who has had several uneventful seasons before this one.

Two versions, and the dangerous one looks better

An open pyometra means the cervix is still partly open, so pus drains out. Owners notice discharge on bedding or on the dog's back end, often smelly, often blood-tinged or creamy. Unpleasant, obvious, and comparatively fortunate, because the pressure has somewhere to go and the dog usually gets seen sooner.

A closed pyometra means the cervix has sealed. Nothing comes out. There is no discharge to spot, no smell, nothing on the bedding, and so owners often have no idea anything is wrong until the dog is genuinely ill. The uterus swells, toxins accumulate, and the risk of rupture rises. Closed pyometra is the one that kills, and it is precisely the one that gives owners the least to see.

What both versions share is thirst. Bacterial toxins interfere with the kidneys' ability to concentrate urine, so the dog drinks noticeably more and urinates more. Owners describe refilling the bowl twice as often, or a house-trained dog asking to go out overnight. Alongside that: appetite fading, low energy, vomiting, a swollen and tender abdomen, sometimes panting, sometimes a fever, sometimes a temperature that has actually dropped below normal, which is a bad sign. Some dogs simply seem flat and off-colour and the owner cannot put a finger on why.

Cats get pyometra too, though less often, and they hide it even better. A quiet, off-food, unspayed queen a few weeks after a season deserves the same suspicion.

Getting to the diagnosis quickly

Vets tend to move fast on this one because the clinical picture is fairly distinctive. Signalment does most of the work: an unspayed female, recently in season, drinking heavily and feeling unwell. Bloodwork usually shows a dramatically elevated white cell count, though in the sickest dogs it can be low instead, which is more worrying rather than less. Kidney values often come back raised. Ultrasound is the confirming test and it is excellent, showing a fluid-filled uterus clearly and distinguishing it from pregnancy. X-rays can show an enlarged uterus but are less reliable early on.

If your vet suggests admitting the dog straight away rather than trying a course of antibiotics first, they are not upselling. Antibiotics alone do not clear a uterus full of pus.

Surgery, cost, and the honest numbers

The treatment is removal of the uterus and ovaries, essentially an emergency spay, and it is a considerably bigger operation than a routine one. The uterus is fragile, heavy and full, and spilling the contents into the abdomen causes life-threatening peritonitis. Most dogs are stabilised first with intravenous fluids and antibiotics, sometimes for several hours, then taken to theatre. Recovery in hospital typically runs one to three days, longer if the dog was in septic shock on arrival.

Costs vary enormously by region and severity, but expect something in the range of one to three thousand for a straightforward case and considerably more where intensive care is required. Compared against the cost of a routine spay, the maths is bleak and it is the single strongest practical argument for neutering a female who is not part of a planned breeding programme.

Medical management with prostaglandins and aglepristone exists for valuable breeding bitches with an open pyometra who are otherwise stable. It is slower, it fails in a fair proportion of cases, recurrence at the next season is common, and it is not appropriate for a sick dog or a closed pyometra. Most owners are better served by surgery.

Prognosis is genuinely good when treatment happens early. Survival rates for uncomplicated cases sit somewhere around ninety-five percent, and once the uterus is gone the condition cannot come back. Dogs who arrive already in septic shock, or whose uterus has ruptured, face far steeper odds. Time is essentially the whole prognostic variable.

So the red flags, plainly. An unspayed female who is drinking more than usual within two months of a season needs seeing that day, not next week. Any vaginal discharge that is not a normal season, any vomiting, any collapse, a distended painful belly, pale gums, rapid breathing, or a dog who simply will not get up: those are emergency vet calls at whatever hour it happens to be.

Nothing written here can examine your dog, and plenty of other conditions cause thirst and lethargy, from diabetes to kidney disease to Cushing's. That is rather the point. All of them need a vet and a blood sample, and pyometra in dogs is the one on that list where waiting until morning sometimes costs the animal. If she is unspayed, recently in season, and drinking like she has been in the desert, make the call.