Visiting Veterinarian : Differentiating between a tumor, an egg, and a hernia
A few years back, a client with a backyard flock of chickens noticed one hen, Sweetie Pie, having trouble sitting upright. As I have said before, I only passed Poultry Medicine in vet school because the professor liked me, but this client knows my limitations and thus has reasonable expectations. We learn together.
"No wonder she can't sit up," I said after my exam. "She's swollen up like a water balloon."
The hen's abdomen was full of fluid, a condition called ascites. Recognizing the economic realities of backyard chickens (even those named Sweetie Pie), we opted to skip X-rays and blood tests, to drain the fluid, do empirical treatment, and hope for the best. With a needle, tubing, three-way stopcock, and a large syringe, I removed 700 milliliters of clear, champagne-colored fluid. That's almost three cups.
"Now that the fluid is gone, I can feel a mass inside," I sighed, palpating her deflated tummy. "Odds are it's a tumor."
Since Sweetie was still eating and alert, her owner took her home with a hospice approach. Fluid would gradually build up again, and every month or two, I would drain it. She lived the better part of a year before finally succumbing, with a presumptive diagnosis of cancer.
Four years later. "I've got another hen with a swollen belly," the owner reports. "Can you drain the fluid?" After reiterating my stock disclaimer, "I only passed Poultry Medicine because . . . ," I agree to see the chicken, Whoopie Pie. She does, indeed, have a bulging abdomen, but it is distinctly different from Sweetie's. Not fluctuant and fluid- filled, but a meatier, squishy texture, and I could immediately feel a firm egg-sized mass inside.
"Maybe she's egg-bound," I proposed. Egg binding is defined as any time a bird can't lay an egg with a normal amount of effort in a normal amount of time. There are many causes. Malformed or disproportionately large eggs. Calcium deficiency leading to muscular weakness and inability to contract properly. Vitamin E and selenium deficiencies. Trauma. Genetic predisposition. Environmental stresses.
Symptoms vary depending on exact cause, size of bird, and complications. Usually considered an emergency, affected birds are often in shock, exhibiting abdominal straining, depression, weakness, trouble breathing, difficulty standing or perching, and tail-pumping.
Whoopie did not seem that sick, though her owner reported trouble roosting. "She perches between two other hens and rests her wings on them to balance."
This time, we needed that radiograph. Now if your bird has a big ol' obvious broken femur, I'm your radiology gal. But avian abdominal anatomy? Not my bailiwick.
"There's something egg-shaped in the caudal abdomen," I mused. "It does have the density of calcium-containing material..., but it's very mottled." I paused uncertainly. " It could be grit in her gut, but it sure is egg-shaped."
I offered to post the films on line and consult with some real chicken doctors, but in the meantime we discussed egg binding. Severe egg-binding is life-threatening and requires aggressive intervention, even surgery, but milder cases can be treated medically with calcium injections and providing a very warm, humid environment. Sometimes that is all a hen needs to facilitate passing the egg. I gave Whoopie calcium and sent her home while I got back online.
The chicken doctors were kind and did not make fun of me. The egg-shaped mottled area was not an egg, but oyster shell grit in Whoopie's ventriculus, commonly known as the gizzard. "Isn't that too far back for the ventriculus?" I asked sheepishly. Maybe, but they wanted additional films with better positioning. Her leg bones were obscuring too much abdominal detail in these. Two days later we complied.
"I think the swelling is smaller," her owner said, as I palpated the bulge again. If this was a dog or cat, I'd say it was a hernia, I thought to myself while waiting for the films to be developed.
A hernia is defined as the protrusion of an organ, or other bodily part, through a wall that normally contains it. Hernias in pets come in many sizes and locations. The most common and least serious is the congenital umbilical hernia. Inside the womb, a puppy or kitten is attached to the placentas via the umbilical cord which enters the tummy through an opening in the belly wall - the umbilicus.
Normally at birth, the cord is broken and the umbilical opening closes. But occasionally the inner portion remains open, allowing a little fat or abdominal contents to poke out and sit between the skin and the tummy muscles. This results in a bulging "outy" belly button.
Umbilical hernias rarely cause problems. If a loop of intestines gets trapped and "strangulates," this does create a serious, surgical emergency, but such an occurrence is extremely uncommon. Thought to be an inherited condition, umbilical hernias are more common in puppies than in kittens and can usually be left untreated, or repaired when the pet is neutered.
Many other kinds of hernias occur, each defined by their location. Diaphragmatic, hiatal, perineal, inguinal, scrotal, pericardial, to name a few. Symptoms, treatment, and prognosis vary with the site, cause, and severity.
The fowl films arrived. Hmmmm. Are those loops of bowel in the wrong place? Is that an abdominal hernia there? I wondered silently.
Before venturing an opinion aloud, I posted the new radiographs for the chicken docs. "Yup. Looks like a hernia" they soon responded. "The ventriculus is starting to fall into it."
Well, at least I was correct that her gizzard was unusually far back. I informed the owner of the diagnosis. Probably the result of some kind of trauma. Because the hen seemed to be feeling fine, and because she was, after all, a chicken (even one with a name like Whoopie Pie), her owner declined surgery and decided to see how she fares without treatment.
I don't know how egg-laying will affect the hernia, and vica versa, but I have seen cats and dogs with traumatic hernias like this do okay. Only time will tell.