The titular orange squash in “It’s the Great Pumpkin, Charlie Brown” has been replaced with one of my favorite and oft-used (by me) medical phrases – “the Great Undiagnosable.” I coined this phrase and use it every day to describe the occasional futility of trying to shoehorn every abnormality that our patients could possibly have into a neat little box of a diagnosis. There are lots of ways to be alive, even more ways to be sick, and not all of them lend themselves to something as concrete or discrete as a medical diagnosis.

I think we can diagnose many diseases and conditions in pets and people with a great degree of accuracy, given enough time and (sadly) enough money. This last bit – the money – is where veterinary medicine often suffers in comparison to our human MD counterparts. If my son goes to the doctor with nebulous symptoms, they test and test and then test some more and then, just for variety, run some more tests until they arrive at a diagnosis.  I don’t care what it costs – mostly because he is my son and the sun, moon and all the heavens revolve around him, but also because I am only out my $20 co-pay so please figure out why he is ill.

For my dog, cat, rabbit, horse or narwhal (don’t ask), however, the picture is a little different.  The cost of all those tests add up and before too long I’m gonna want some answers to go along with all those mounting bills. One more negative test this week that doesn’t solve the mystery of why my narwhal is off his feed and I am liable to throw my hands up and say “enough – enough of your crazy narwhal tests!”

I see this played out all the time in clinical medicine. People often assume that each test will give a concrete answer to the question of “what ails my varmint?” I wish it were so – I wish all lab tests were like the Magic 8-ball that we played with as kids. But they are not: they give us hints, they give us directions for future testing (oh, great!), they allow us to make educated guesses on what is making the patient sick, but they rarely give us an absolute and steadfast, rock-solid 100% accurate diagnosis.  Sorry; I wish it weren’t so.

They do solve mysteries in lots of cases;  the blood tests come back with diabetes as the answer to why the patient is drinking so much and losing weight, or the biopsy tells us what the strange mass was that we found in the abdomen of that cat. It’s just that in lots of cases they don’t offer concrete, let’s-fix-this-pet-now answers. I am not saying this to imply that there is something amiss with veterinarians, MDs or the laboratories that run the tests. It’s just that this is the way the universe and all living things are put together. Imagine the massive complexity in any living thing – from a bit of mold to a beetle to a person. How can we possibly expect that a little bit of blood or tissue will give up all the secrets of that same living thing when things start to go awry?

Not everything that goes wrong can be neatly defined and quantified. This concept is at once liberating and terrifying. We want to be able to describe the limits and nature of disease, and the degree of damage. To be able to know how much hope there is, or how much we should try. But it’s also liberating in that it allows the doctor to see the shades of gray where before there was only black and white. Definitively saying a patient has ‘disease X’ means we often stop looking for ‘disease Y’ ‘disease Z’ or ‘disease XYZ’ that could also be along for the ride. Making a diagnosis, while often important for treating patients, can make you stop thinking or considering other options.

Once you realize that hard answers can be few and far between, you can begin to appreciate some of the subtleties and uncertainties that exist in the task of getting patients better. This is the nature of the Great Undiagnosable: an elusive answer despite an in-depth and thorough investigation. A murder mystery where the killer is never found, or the wrong individual goes to jail for a crime they did not commit.

As an example of this slippery idea, I was recently chatting on an instant message system with a friend. Her 15-year-old dog was having trouble getting around – legs splaying out, maneuvering stairs, trouble getting up from the floor, etc. While I was pestering her for details, I described her dog’s particularly disjointed way of getting around as ‘loosey goosey’ and she blurted out “THAT’S IT!!!” (… if you can blurt in an instant message, that is). Needless to say, this does not count as a lucid medical diagnosis.

We were talking about the battery of tests that could be run on her dog to try and figure out the cause; blood tests, urinalysis, MRI, etc. All of them could point to concrete causes; weakness can be caused by anemia, which would show up on blood tests; unsteadiness could be caused by a brain or spinal tumor, which could show up on an MRI; but there is a distinct and very real possibility that all of these tests could be normal. That you could run dozens of tests for weeks on end and still not arrive at a diagnosis. Sometimes, things just wear out. The sheer fact of being alive and fighting the cosmos and the forces of entropy can accumulate a lot of infinitesimal wear and tear that doesn’t want our puny tests to know it is there. There are lots of things that want to kill us and make us shuffle off this mortal coil, and not all of them have names.

I don’t write this to make you lose heart and think that we can never figure out what’s wrong or fix things. If that’s the impression, then I have failed in my mission as that is absolutely not the case.  Veterinarians have at their disposal a fairly remarkable array of tests that can pinpoint an ever-growing number of diseases.  Coupled with skills learned in school and in life, every day they can take a complicated mountain of data and interpret it in ways that help pets get over conditions.

Rather, my aim here is to prop open the door on what your veterinarian faces when picking tests and interpreting results and let you see some of the dilemmas that they grapple with as they try and get your pet back to health. I want to replace the absolute and unwavering faith that some have in the power of medicine with a healthy dose of uncertainty and a dollop of tolerance for inconclusive results.

If I have succeeded here, the next time your veterinarian doesn’t have the answer appear in the little window of the Magic 8-Ball, you’ll understand that some more testing and patience may be needed before the universe gives up its mysteries about why your narwhal is feeling poorly.