Thursday, August 17, 2017

Weeks 6-9 at Littleton Equine Medical Center

Hello again from Littleton!

I hope everyone is having as great of a summer as I am!  I have been learning so much here as always and have been getting to spend some time with family in Boulder doing fun outdoor activities.  There have been a lot of neat cases here lately, and I’m excited to share some of what I’ve been learning here with you.

Things have been going pretty much as usual around here lately with a lot of colic and lameness work.  There have been a few horses that have come in with septic joints or that have been suspected to have them, so I have been able to watch and help with several regional limb perfusions.  Regional limb perfusions are great because they utilize a tourniquet proximally and infusion of a concentration-dependent antibiotic such as amikacin distal to the tourniquet to achieve a high concentration of antibiotic in the area of concern.  This is also favorable because you can avoid some potential complications that could result from systemic use of antibiotics.

One interesting case that came in was a 4-month old foal that was referred in because it had had seizures over the few days prior.  The owner started noticing the seizures occurring after it ran into a fence and was treated for head lacerations.  Luckily for me, I was working in the ICU the day that the foal was admitted so I was able to follow its case and observe it very closely for a few days.  Initially, the foal was somewhat obtunded mentally and was suspected to be blind, but upon ophthalmic exam was seen to have pupillary light reflexes and a dazzle response.  Its menace responses were absent, but those are a learned behavior so they may not have been developed yet in this foal.  Radiographs of the head were unremarkable, and the owner declined to have an MRI performed.

The foal also had some concerning lacerations over two of its fetlock joints, so it was sedated and Dr. Hill distended the joints with sterile saline to see if the lacerations communicated with the joints.  One had a small communication and was flushed and infused with amikacin, but the other joint was intact.  The foal did not have any seizures over the next few days, but over the weekend started having them daily.  Dr. Mullen made a great point by suggesting that either the foal could have had seizures because of the head trauma from running into the fence, or could have run into the fence because it was having a seizure.  She was more inclined to believe that due to the fact that two weeks after the traumatic event that the foal was still having seizures, that it was more likely to have idiopathic juvenile epilepsy rather than being simply trauma-induced.  Initially, the foal was treated with an IV fluid cocktail that included DMSO to help with any potential edema in the brain and later was medicated with phenobarbital and gabapentin to control the seizures.  Once the dose was adjusted, the owner elected to take the foal home.

Speaking of neurologic cases, there was a horse that came in that the owners said appeared to have acutely developed neurologic signs when ambulating.  We had a slow afternoon in the ICU, so I was able to observe Dr. Hill and Dr. Kurkowski work up its case.  When the mare arrived, she was hypermetric in all of her limbs and really hesitated to set down her feet when moving forward.  When she was moved in circles, she didn’t appear to be particularly neurologic—she wasn’t circumducting her hind limbs (swinging them outward when moving) too much and didn’t seem to have any proprioceptive deficits (she appeared to know where her feet were).  On physical exam, the vets noted that she had increased digital pulses in all four limbs, and increased digital pulses indicate pain in those distal limbs that have the stronger pulses.  She also had a positive response to hoof testers in all four limbs, particularly over the toe region.  Due to the quick onset of her signs and the clear indications of foot pain, she was most likely laminitic.  To further assess whether her odd movement was due to pain instead of being neurologic in origin, the vets then did an abaxial sesamoid nerve block with carbocaine in both front feet to block any pain that might be originating from the foot, as would be expected with laminitis.  The difference in her movement was very dramatic, and she moved almost normally after the nerve blocks.  Radiographs were then taken and did show early indications of some rotation, so the mare was treated for laminitis with ice boots and anti-inflammatories.  She did well, and was sent home a few days ago.

As always with veterinary medicine, not all cases have a happy ending.  Fortunately, the vast majority of the colic cases (and all cases in general) that I have seen here have been successfully treated, but some horses that require surgery to correct their colic unfortunately do not have that option due to owner constraints.  Other times, horses are not able to arrive until it is too late and some part of their GI tract has ruptured, which is beyond repair.  Last night, two emergency colic cases arrived late in the evening.  One was a horse in its early 30’s that had been seen in the field and was suspected to have a strangulating lipoma but needed further evaluation to be sure.  This horse did not have a surgical option.  Ultrasonography revealed some even distention of the small intestine but good motility and passage of digesta rather than it “settling out”, or rather seeing the digesta sitting in the bottom on the intestine and not filling it and moving through.  An abdominocentesis was performed (in other words, a belly tap) and lactate was evaluated, which was not significantly elevated.  These were good findings for the horse, because a high lactate (should normally be below 2) indicates poor perfusion (lack of blood supply), and a very high lactate suggests that there is likely dead bowel somewhere in the abdomen.  So, what was expected to be a bad case ended up going pretty well, and the mare was instead treated with IV fluids and monitored closely because she did have a number of signs of dehydration.

Sadly, the other colic that came in was not expected to be as severe as it turned out to be, and the lactate on that horse’s abdominocentesis was 17.  Combined with the other findings on her workup, the owner elected to euthanize her.  I observed and helped take part in the necropsy, which helps the vets and the owner to know definitively what went wrong.  This is helpful, as sometimes a horse’s cause of death is preventable, otherwise can help assure an owner that they made the correct decision, and is a good learning tool for the veterinarians involved as well.  This horse did in fact have a strangulating lipoma (a growth of fat that can tighten down over a loop of intestine, block food from passing through it, and cut off its blood supply) and as a result had several feet of very dead ileum.  The owner definitely made the correct decision for the circumstances involved in this case.  Other cases have been highly rewarding, such as a horse that survived colic surgery that had a 720 degree torsion at the base of her cecum, and two year old that did not have a surgical option and survived medical management for a suspected right dorsal displacement.  Although such cases are highly rewarding and others are very sad, I am so appreciative that as veterinarians we are able to alleviate suffering in either situation.

I wish I could share all of the other neat things I’ve been seeing here lately but seriously, I’d be writing a novel.  I saw an OCD the size of a golf ball removed from a hock, a horse that was referred in to have a vaginal cyst removed but here was found on pre-surgical exam to be an intact hymen, a “sidewinder” horse (a neurologic horse that moves sideways everywhere it goes), and a mare that fractured her coffin bone while playing in the pasture.  This weekend they’re having an open house here, and I’m very excited for my family to see where I’ve been working.  Also, they’re having pony rides and face painting so my 2 and 5-year old nieces will be happy campers. J  Although I love vet school, I am truly not excited for my time to be dwindling down to my final two weeks here.  I’ll save the sappy goodbyes for next week, and I’ll give you all one more post after my final week.


-Calli

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