Wednesday, August 4, 2010

What's Your Diagnosis?

My bimonthly JAVMA (Journal of the American Veterinary Association) has a regular feature called "What's Your Diagnosis?" (Or, as my sister always called it, "Exhibit Your Symptoms.") Each month, one or more X-ray pictures are printed, and the reader is given a brief synopsis of the case and invited to make a diagnosis. It always makes my day if I can guess it correctly.

Today, I present to you a real life "What's your diagnosis" from a case I saw this afternoon. Here's the history: An elderly woman fell last evening while carrying her 9 week old kitten. Both lady and kitten appeared to be unhurt at the time. Today, however, the kitty had a very swollen neck. Fearing the kitten's neck was broken, the son brought him in to my office at about 1:30pm.

The kitten was obviously distressed, breathing with increased effort, and his gums were cyanotic (bluish in color) indicating a lack of oxygen. He was walking OK, but seemed to tired easily. His neurological reflexes were normal, so I was reassured that his spine was not damaged.

However, his neck was very puffy, and this swelling extended along his back and chest, right down to the kitty equivalent of a waist.

Here's the lateral view X-ray. It's has been a while since we have done this; do you remember how to read an X-ray? Bones are white, air is black, and soft tissues (organs, blood, etc.) are shades of gray. The kitten is lying on his side. His head is on our left, his tail to our right.

[Click on any photo to enlarge.]

Here's a slightly closer view. What do you think?

Go ahead, take your time. I'll wait.




Give up? That's OK, this is a toughie. It may comfort you to know that this is only the second time I have seen this problem, and the first time I have seen it caused by a fall.

Check out this labeled version of the first film. The skin is lifted away from the underlying tissues, and all those black spaces are collections of air under the skin. The technical term is subcutaneous emphysema. I have indicated several of the pockets of air with red *.
The kitten has a tracheal rupture. Every time he breathes in, some air goes into the lung, but some also escapes through the tear in the trachea and ends up under the skin. Because of the one-way valve effect, when he breathes out, the air is trapped there and slowly accumulates.

You can diagnose this on a physical exam, by the crackling, popping feeling you get when you run your finger tips over the skin and press in slightly.

Although this is a bad injury, believe it or not, mild cases of tracheal rupture can be treated with conservative medical management. However, let's look at that X-ray again.
In this closer image, we are focusing our attention on the chest cavity. Anything about this picture bother anybody?




Let's look at the labeled version. The kitten's heart should be in contact with his sternum (breastbone.) Instead, it is elevated, lifted up by an accumulation of air in the chest cavity. One lung is all black, filled with air, while the other is much smaller and gray in color. That lung has collapsed.

Not only does he have a ruptured trachea, he also has a pneumothorax. Now, his prognosis for survival has taken a big step backwards. If we were to attempt treatment, he would need a chest tube to evacuate the air, a tracheoscopy (using a small diameter endoscope to look down his trachea) to attempt to find the rupture, and a surgical specialist to try to find and repair the damage, if possible.

But wait! Kitty's story is not over. When the owner woke to find her kitten in distress, she tried to help him by crushing up a 200mg ibuprofen tablet and mixing an unknown quantity of the powder into some milk. As we all know from Toxicology Tuesday, Non-Steroidal AntiInflammatory Drugs (NSAIDs) like ibuprofen are deadly poisons for cats.

Now, we have a ruptured trachea, pneumothorax, and potential ibuprofen toxicity. Oh, and did I mention that the clients don't have any money? I suppose you can guess the final outcome of this case.

In my job, as in my life, I try to find the good in everything. This case was tragic and very sad, but I was able to turn it into a teaching opportunity for the hospital staff and you, my gentle readers.


Weedpicker Cheryl said...

I thought this was a fascinating post, KatDoc.

You are making the world a better place, and help us learn at the same time. I will cetainly keep the Motrin away from the cats!

KGMom said...

Aww--I went step by step with you, hope rising, and then dashed. Poor kitty.
Jeez--I would NEVER give my cat or dog a HUMAN pill unless the vet said it was OK.

dguzman said...

Oh, KatDoc. I too was hopeful, looking at the bones and not seeing breaks... and missing the sub-cu air and the empty space where that lung should've been.


Julie Zickefoose said...

Oh, I do hope you do more posts like this, Kathi. There is so much to be learned from this. I never dreamt of a ruptured trachea, but I did manage to spot the escaped air under the skin of neck and back, because I've had to care for birds with ruptured air sacs. And I even got the collapsed lung--how awful. To put ibuprofen on top of a mess like that...heartbreaking, and a bad lesson learned, I suppose. Thank you so much for this one. Science Chimp loved it!