The mysteries of life and death
Cupcake is a ten-year-old little white dog, a cross between a Bichon Frise and a Shih Tzu. Like many little white dogs that tend to have sensitive skin, she's had various rashes, lumps, and bumps over the years, but when her caretaker brought Cupcake to see me in December her problem seemed more serious. A patch on her back, a bit larger than a silver dollar, was matted over with dried goo. As I shaved away the wad of crusty fur, a large, irregular, ulcerated lesion revealed itself. Not your average "hot spot," it was deeper, more erosive looking. Running my fingers over her, I found multiple lumps and smaller but equally nasty-looking sores. I picked up the phone and called her owner.
"I'm really worried," I said frankly. "I'm afraid Cupcake might have a kind of skin cancer called mycosis fungoides. We should do some tests." I didn't want to be alarmist, but I had a bad feeling. Mycosis fungoides (MF) is a type of cutaneous lymphoma that causes characteristic "micro-abscesses" in the skin. It usually occurs in older dogs and is notoriously difficult to treat. Although some variants may not be too aggressive, other forms are highly malignant and may have a poor prognosis.
Cupcake's owner gave us permission to send impression smears to the lab. This non-invasive procedure is done by simply pressing slides against the oozing sores. If the pathologist saw cancerous cells, we would have our diagnosis. Otherwise, we might need to cut a section of skin for a biopsy sample. "Let's hope it's just a horrible bacterial infection," I said gloomily and sent Cupcake home with oral antibiotics and topical ointment.
Two days later the pathology report came back. "Marked inflammation. No overt sepsis noted. Specific cause is not evident. No overt neoplasia seen. The loosely cohesive epithelial cells may suggest underlying immune-mediated disease or possible underlying carcinoma. Biopsy should be considered." I called Cupcake's mother and translated.
"They didn't see any cancer, but it's suspicious." I began. "I hate to be pessimistic, but we should get a biopsy before my office closes for vacation." As I elaborated on my concerns, Cupcake's mother interrupted.
"You can stop now," she chided me gently. Having known me for decades, she is aware of my tendency to expect the worst. "I know how you are. Of course we'll do the biopsy, but Cupcake's skin is really looking much better." Later that day, using a local anesthetic, I punched out a tiny circle of Cupcake's lesion, popped it in a jar of formalin, and sent it to the pathologist. "I'm off to Florida tomorrow," I concluded. "I'll check in with the lab from down there and call you when the biopsy results are in."
Cupcake's mother and I played phone tag from Florida to the Vineyard. The lab was running slower than usual as they, too, took a brief holiday break. Two calls to the lab from poolside yielded no information and her mother continued to report improvement. Maybe my pessimism was unwarranted. When I finally collected the results after New Year's, the diagnosis was "focal subacute necro-ulcerative dermatitis." There was no evidence of cancer. The pathologist's comment was "The cause is not apparent."
Cupcake's mother was greatly relieved... and I felt a pang of guilt. Had I caused her needless worry? Ruined her Christmas? Should I have downplayed my concerns? What is the right approach to take in a case like this? To be reassuringly optimistic until there is a definitive diagnosis? Or is it better to be conservatively pessimistic, hoping you are wrong, but making sure there is no chance you will have to give sudden, unexpected bad news to an owner? Pondering this conundrum, I went on about my business.
A week later Daisy, a one-and-a-half-year-old pug, came in. She hadn't been herself for a few days. Her owner reported than her hind end would sort of "fall out from under her" and that she had brief spells, lasting ten to 30 seconds, of appearing dizzy. "Let's take a look," I said cheerfully. Daisy was certainly alert and happy at the moment. Her temperature was normal and she was bouncing around the room without a hint of wobble. On physical examination I found she had an infection in the external ear canals. Could that be causing dizziness? If the infection extended into the middle or inner ear, it could, but we would expect other signs, such as a consistent head tilt, circling, or ongoing loss of balance. Daisy seemed tender when I palpated her lower back and her mom mentioned she had been hesitant on the stairs recently. Was it back pain making her unsteady, not dizziness? Daisy had also vomited. Certain types of food poisoning can cause dizziness, but again, one expects more continual symptoms. Or did Daisy have primary central nervous system disease?
"It's unlikely to be a brain tumor or stroke in such a young dog," I reassured the owner. "There are no other signs indicating infectious disease. I suppose it could be an unusual form of idiopathic epilepsy. There's no definitive way to diagnose that, other than ruling out everything else and waiting to see if she develops full-blown seizures." We ran blood work, including tests for tick-borne disease. Daisy had antibodies indicating exposure to Anaplasma. "I doubt that's significant," I offered, thinking of the dozens of healthy dogs I'd seen this year that also had these antibodies. We reviewed our differential list. Ears, back, upset tummy, anaplasmosis. "We can send out more definitive tests, treat her symptomatically, and start antibiotics until the results come back."
As I watched Daisy trot around the room, the picture of health, I thought, "This will probably disappear on its own and we'll never know exactly what caused it." Then I thought one more thing. I paused. I had needlessly worried Cupcake's owner. Should I mention the lethal disease that just crossed my mind?
"We should put one more thing on our differential diagnosis." I said hesitantly. "Pug encephalitis . . ."
Pug encephalitis is an inflammatory condition of the brain of unknown cause, although a genetic component is strongly suspected. It is characterized by rapidly progressive neurological symptoms including circling, pacing, depression, seizures, visual deficits, personality changes, and, ultimately, death. Similar syndromes are reported in Maltese, Yorkshire terriers, and Chihuahuas. The main treatment is massive doses of corticosteroids and/or other immunosuppressive drugs, but the prognosis is very poor. I have personally seen very few cases, and they have all died within a week. I gave Daisy's owner a brief rundown about pug encephalitis but opted not to dwell on it. "You would need to go off-Island for an MRI to diagnose it. I'm not too worried. It's probably something else. Let's see how she does for a day or two before going to those lengths." I suggested they make an appointment to see a neurologist soon, in case things didn't improve, and sent them home.
Things didn't improve. In fact, overnight Daisy started seizuring severely. Early the next morning, she was seen by the veterinarian on emergency call, who did a heroic job of getting the convulsions under control. As soon as she stabilized, Daisy's parents headed off to the neurologist, where her MRI confirmed massive brain abnormalities. Almost immediately after completing the tests, Daisy died... less than 48 hours after her mother first brought her in to see me and I reassured her and told her not to worry too much. Cupcake is making a full recovery. Daisy, like a flower, lived a brief, happy life, then suddenly left this world, succumbing to a rapid, baffling disease. What a beautiful and terrible mystery life is.