Sneezing rats

This is Potato who presented for sneezing. She is a beautiful rat with a big personality. Its very rare to get a definitive diagnosis for airway disease in rats. Exotic DVM Barbara Deeb wrote a paper a few years ago citing a North American serological study which found that 94 per cent of healthy rats were positive for cilia-associated respiratory bacillus, and 93 per cent for Mycoplasma pulmonis. So vets who see rats can safely assume that most actually started out with chronic respiratory disease...and have a high likelihood of developing lung abscesses secondary to bacterial infection.

Quinolones and chloramphenicol can be used to treat mycoplasmas, corynebacteria, straph/strep and gram negative bacteria in rats BUT quinolones are toxic to cartilage in growing animals and chloramphenicol is toxic to bone marrow (it can cause bone marrow suppression).

Deeb comes up with a controversial estimate that every quality day of rat life is worth the equivalent of around a month of human life...I'm not sure how she came to this figure, but I think what she means is that as long as they aren't suffering it is worth treating them.

She gives a "rescue shot" to rats with severe respiratory disease: 0.2mg dexamethasone +5mg aminophylline (bronchodilator) + 4.5mg enrofloxacin + 2-3ml saline via injection SC every 3-4 days.

For Potato and other less severely affected animals my first drug of choice is doxycycline, although dosing is controversial as there are no drugs registered for use in pet rats in Australia that I know of...meaning that every prescription is "off label." I find that these animals are not cured but their symptoms are reduced and they may improve clinically for a period of time.

Medical mistakes

Last day of our holz folks. Sigh. We've become most adept at lounging around the house reading and doing little else and we're going to miss it baaaaaaaaaaadly. Anyway today's read was How Doctors Think by Jerome Groopman MD (am assuming that does not stand for "mouse doctor"). Yes, I know its all about humans, but they're animals too and the book points out some rather interesting things.

The main argument is that most medical mistakes are not obvious stuff ups: "...technical errors account for only a small fraction of our incorrect diagnoses and treatments," he writes. "Most errors are mistakes in thinking. And part of what causes these cognitive errors is our inner feelings, feelings we do not readily admit to and often don't even recogonise" (p40).

For example, a lot of doctors are quite averse to patients who are very ill - possibly because they have feelings of failure when dealing with diseases that resist their efforts to cure the patient. So in some cases - like it or not - they subconsciously avoid these patients, or stop trying. Groopman also points out that doctors (and vets, if you ask me) can become wedded or committed to a particular diagnosis, biasing their interpretation of clinical signs and response to treatment so that they pay attention to those things that confirm their diagnosis and ignore the others. Its too easy to judge a patient eg a dirty old man who is poorly clothed, rough around the edges and admits to sinking a glass of rum a day turns up with a liver problem and people assume he's an alcoholic with cirrhosis because they just want to get the diagnosis made and turf him out the door.

Another common source of error is the tendency to judge the likelihood of a diagnosis "by the ease with which relevent examples come to mind" (p64). For example, you think a patient has subclinical viral pneumonia because you've been treating a lot of those lately...when the symptoms could be explained by something altogether differently. In particular, the last BAD experience you have had with a particular illness always springs to mind. Little wonder that! They're the ones you can't forget because they keep you up at night.

Groopman argues that we should always consider a list of differential diagnoses, even when we think the diagnosis is obvious. I could not agree more. Another helpful strategy is to ask yourself, when you see a patient, "what is the worst thing this could be?"and "what ELSE could this be?" It helps you think broadly, more outside the square, relate the clinical signs to pathophysiology and ultimately not delay diagnosis in grave cases. He also argues that it is helpful to ask what parts of the patient's body occur near the symptom (ie a source of pain).

A pediatrician tells him that they always ask whether the child could have a serious problem - so they don't miss anything. I guess pediatricians are closest to vets in a way - neither can ask their patient where it hurts, the history is gleaned from a carer who may exaggerate or ignore clinical signs and we have to be advocates for them.

There's a great discussion of types of medical uncertaintly: "The first results from incomplete or imperfect mastery of available knowledge. No one can have at his command all skills and all knowledge of the lore of medicine. The second depends on limitations in current medical knowledge. There are innumerable questions to which no physician, however well trained, can provide answers. A third source of uncertainty derives from the first two: this is the difficulty in distinguishing between personal ignorance or ineptitude and the limitations of present medical knowledge"(p152).

Groopman argues that a doctor who is honest about their uncertainly has to be a better doctor - the patient will be more likely to trust them (I would argue that there are, however, some clients who are terrified by the words "I don't know"); it demonstrates a willingness to engage with the patient and change the course of treatment if it isn't working. All in all its a thought-provoking book. There are some very powerful anecdotes about the divergence of medical opinions. If I am ever diagnosed with cancer I'll certainly be seeking a second and third opinion before I commit to any treatment! But as a vet I think its worth a read. Vets and doctors are only human, after all. But some awareness of our fallibility can't hurt.

How attitudes have changed

Continuing our holiday theme, we've been reading a ripping yarn about a final-year veterinary student who finds himself caring for a circus menagerie. Being a massive fan of the circus (ie NOT those that cause animals to suffer! We're talking trapeze artists, costumes and the odd performing dog who is rewarded, not punished, and has a good life) and a massive fan of veterinary history this was the perfect book. But it is based on some very disturbing true events. For example, I had no idea that in 1903 a circus elephant called Topsy killed her trainer after he fed her a lit cigarette. Why anyone would be motivated to do this to an animal is beyond my comprehension and I whilst the consequences were unfortunate they weren't unpredictable. It happened to be the third scalp Topsy had claimed and it was decided that the best course of action was to put her to sleep, as one might an aggressive dog. One does wonder however whether the other deaths were also avoidable. Anyway, being 1903 it was decided (by whom I am not sure) that Topsy's "execution" should be a public spectacle. It was even mooted that she be hung, but the ASPCA stepped in arguing that this was cruel. Instead, Thomas Edison was invited to electrocute her after she was feed cyanide laced carrots. She was made to wear copper-lined wooden boots while a current of over 6000 vaults was sent through her while over 1500 people stood by and watched. There is quite a lot of information about this event on the internet, including newspaper clippings from the time and the video footage taken by Edison although I can't bring myself to watch it. The incident makes our blood boil. If this animal really had to be destroyed (and I am not convinced of this) was there a more humane alternative at the time?

Anyway, the book touches on this and other quite disturbing true events involving animals in the circus but I can say that it is not gratuitous. The author supports a number of animal causes (check her website http://www.saragruen.com/).

The Commercial Advertiser printed the following on January 5 1903:

"BAD ELEPHANT KILLED.
Topsy Meets Quick and Painless Death at Coney Island.
Topsy, the ill-tempered Coney Island elephant, was put to death in Luna Park, Coney Island, yesterday afternoon. The execution was witnessed by 1,500 or more curious persons, who went down to the island to see the end of the huge beast, to whom they had fed peanuts and cakes in summers that are gone. In order to make Topsy's execution quick and sure 460 grams of cyanide of potassium were fed to her in carrots. Then a hawser was put around her neck and one end attached to a donkey engine and the other to a post. Next wooden sandals lined with copper were attached to her feet. These electrodes were connected by copper wire with the Edison electric light plant and a current of 6,600 volts was sent through her body. The big beast died without a trumpet or a groan.
Topsy was brought to this country twenty-eight years ago by the Forepaugh Circus, and has been exhibited throughout the United States. She was ten feet high and 19 feet 11 inches in length. Topsy developed a bad temper two years ago and killed two keepers in Texas. Last spring, when the Forepaugh show was in Brooklyn, J. F. Blount, a keeper, tried to feed a lighted cigarette to her. She picked him up with her trunk and dashed him to the ground, killing him instantly."