Cushing's Disease and Weak Back Legs in Dogs: Why It Happens and What Helps

Sudden collapse or dragging of both back legs is a different problem, and it is an emergency.

This guide walks through why it happens, what else could be causing it, what your vet will do, and how to keep your dog on his feet while treatment settles in. For a wider look at the full list of causes, start with our overview of back leg problems in dogs.

Why does Cushing's disease make a dog's back legs weak?

The medical term for it is hyperadrenocorticism, where "hyper" means overactive and "adreno" means adrenal gland.¹

Whatever the underlying type, the signs are essentially the same, and the most common are increased appetite, increased water consumption and increased urination.¹ Lethargy, meaning drowsiness or lack of activity, and a poor hair coat are also common.¹ Many of these dogs develop a bloated or "pot-bellied" look, partly from fat inside the abdomen and partly because the muscles of the abdominal wall become weaker and eventually atrophy, which means shrink in size.¹

The legs still work. They just will not hold up for long.

Cushing syndrome dog back legs pictures: what owners are actually looking at

Owners searching for pictures are usually trying to match a photo to what they see at home: a tucked, narrow hind end over a round belly, a low stance, back legs that shake after a short walk and a dog that sinks back down soon after standing. Other common signs include panting, thin skin, chronic skin infections, dark-coloured spots, poor skin healing and persistent bladder infections.¹

Photos only take you so far. If you want to see how the picture changes over time, our guide to how Cushing's affects the back legs at each stage walks through it.

Could it be something other than Cushing's?

The common ones:

• Arthritis and hip dysplasia. Osteoarthritis is a chronic, progressive joint disease that commonly affects dogs, causing pain, inflammation and difficulty using the affected limb.² Hip dysplasia, cruciate ligament damage, kneecap problems and old fractures all feed into it.² Our guide to arthritis in a dog's back legs covers this in detail.
• Degenerative myelopathy, a disease of the spinal cord that causes slowly progressive hind limb weakness and paralysis.³ Early signs include the hind paws knuckling or turning under so the dog walks on its knuckles, hindquarters that sway when standing still, and hind feet that scrape the ground.³ Most affected dogs do not seem in pain, just very weak.³
• Other spinal and nerve problems. Spinal injuries, spinal tumours, lumbosacral stenosis (narrowing in the lower spine), fibrocartilaginous embolism (a blockage in the spinal cord's blood supply), myasthenia gravis (a fault in the signal between nerve and muscle) and discospondylitis (infection in the spine) can all produce similar signs.³

One rough clue: if the hind paws knuckle under, the hind feet scrape the ground and the dog seems weak rather than painful, that points toward a spinal cause such as degenerative myelopathy, whereas obvious pain suggests another problem such as arthritis is also present.³ Only testing settles it, and more than one can be true at once. If the legs buckle under your dog without warning, read why back legs give out.

Red flags that mean today, not next week

Go in now, same day, if your dog suddenly cannot use both back legs, is dragging them, is knuckling over on the tops of the feet, has lost bladder or bowel control, is crying out, or has back feet that feel cold or painful to touch. Trauma is the most common cause of sudden limb paralysis in dogs.⁴ Our guide on a dog who suddenly can't walk explains what the emergency visit involves.

The three kinds of Cushing's, in plain English

There are three types, each with a different cause.¹

• Pituitary. The most common cause, 85% to 90% of all cases, is a tumour of the pituitary gland at the base of the brain,¹ which drives the adrenal glands to produce cortisol.¹
• Adrenal. Less common, 10% to 15% of cases, is a tumour in the adrenal glands themselves.⁵ In cases of benign adrenal tumours, surgery is usually curative.¹
• Steroid induced. This form occurs when there is excessive use of an oral or injectable steroid,¹ usually given for a legitimate medical reason.¹ Long-term use brings on the same muscle weakening and wasting.¹ Treatment means discontinuing the steroid, and it must be done in a controlled, gradual way so other complications do not occur.¹

What to expect at the vet visit

Expect screening tests first, then confirmation, then a hands-on look at the legs themselves. A thorough examination and history, baseline blood work and urine testing will tell your veterinarian if Cushing's is present.¹ Imaging such as X-rays and abdominal ultrasound can also help.¹ Several blood tests are used to confirm it, the two most common being the ACTH stimulation test and the low-dose dexamethasone suppression test, both hormone blood tests.¹

Ask for a nerve and joint exam at the same visit, so the legs get assessed separately from the hormones. If another problem such as hip dysplasia or chronic arthritis is also present, it can contribute to loss of function of the hindquarters.³ If a joint problem is found, our guide to back leg surgery options explains what may be on the table.

Will the legs come back once the Cushing's is controlled?

Medical treatment cannot cure a dog with Cushing's disease, but control is possible for many years if the tumour is small.¹ Lifelong treatment may be necessary, and most dogs can be successfully treated with few side effects, but your pet must be carefully monitored using blood tests and clinical signs.¹

That gap is the reason to support your dog actively now rather than waiting for the medication to do everything.

Day-to-day support at home

Small changes make a bigger difference than people expect. The management list used for dogs with hind limb weakness is a good template: rugs, carpets or yoga mats on hardwood or tiled surfaces, pet ramps or steps where necessary, a sling or harness to assist with walking and standing, booties to protect scuffed paws, and addressing anything like arthritis that is also contributing.⁶

Practical additions for a Cushing's dog specifically:

• Keep nails short, since long nails ruin footing on smooth floors.
• Use ramps instead of stairs and discourage jumping on and off furniture.
• Check pressure points, hocks and elbows daily on a dog who lies down a lot.
• Keep a short diary of good days and bad days to take to recheck appointments.

Gentle handling of the hind end helps too. See how to massage your dog's back legs for a safe routine, and our page on caring for a dog with weak back legs for the full daily setup.

Rebuilding hind-end muscle without overdoing it

Little and often beats one long walk. The goal is to minimise pain, slow the progression of damage and maintain or develop muscle mass, using low-impact activity such as leash walks or swimming, and rehabilitation including an underwater treadmill and range of motion exercises.² Avoiding obesity matters, so diet and exercise are vital.³ Stop while your dog is still steady, and a rehab vet can set the dose for you.

When a rear support wheelchair helps a Cushing's dog

A cart suits the weak-but-not-paralysed dog who still wants to walk and runs out of back end halfway down the street. Considering a wheelchair to support the hind limbs is one of the listed management steps for dogs with degenerative myelopathy.⁶ A wheelchair does not treat Cushing's or rebuild anything by itself. What it does is carry the weight so your dog can keep walking and keep using his legs while the medical side is being managed.

The OldPal Rear Support Dog Wheelchair was built for exactly this stage. The padded harness carries weight through the hips and chest rather than the spine, which matters for a dog with a heavy abdomen and thin, fragile skin, and every strap adjusts so nothing digs in. The frame is set so the back legs hang free or lightly brush the ground, and dogs can squat and go to the bathroom while in the chair, which is no small thing for a dog who is urinating more often. The aluminium frame is light with all-terrain wheels, and most owners start with 10 to 15 minute outings rather than full-time use.

Sizing is one measurement: rear leg height, from the top of the hip straight down to the toe pad, taken with your dog lying on his side and the leg at its natural bend. Five sizes cover 3 to 27 inches. Use the measuring guide and fit finder, or email a photo and your measurement to help@oldpalpets.com and a person will check it. If the size is wrong, our Fit Guarantee lets you exchange the frame for the one that fits.

Other Cushing's problems that make the legs worse

Chronic skin infections, skin mineralisation, poor skin healing and persistent bladder infections are common in dogs with Cushing's, which also leaves dogs lethargic and run down.¹ In a dog with degenerative myelopathy, who already has difficulty getting up from a lying position, urinary incontinence tends to develop as the disease advances, so accidents become more frequent at the same time that mobility becomes more severely restricted.³ Flag any new straining, odour, redness, sores that will not close or a sudden drop in willingness to walk at your next recheck.

Frequently asked questions

Related guides

• Back leg problems in dogs: the full overview
• How Cushing's affects the back legs at each stage
• Caring for a dog with weak back legs
• Arthritis in a dog's back legs
• When back legs shake
• When a back leg won't bear weight

Sources