Technician Update

A Colic With a Poor Prognosis

By Morgan Passow

On Oct. 12, 2020 at 2 AM, a 7-month-old Mustang filly was admitted to Comstock Equine Hospital. The filly, who weighed 250 lbs, presented for management of multiple episodes of colic. The caretakers of the filly reported that she had been down and thrashing with diffuse muscle fasciculations. It was also stated that the patient had received oral flunixin meglumine.

Upon arrival at the clinic, a physical examination was performed by an associate veterinarian. The physical examination revealed that the filly was bright and alert. Although the patient was comfortable upon arrival, the patient was tachycardic with a heart rate of 60 beats per minute (bpm). Respiratory rate was slightly increased at 20 breaths per minute and lungs auscultated within normal limits.

Mucous membranes were pink with a capillary refill time of 1 second but were also tacky to the touch. Skin turgor was within normal limits at 2 seconds. The filly was not febrile with a temperature of 100.1° F. Borborygmi was auscultated as increased in the 4 quadrants. Digital pulses were within normal limits in all 4 legs. The only indications of discomfort were that the patient did paw once during the exam, and her perineum and tail were caked in dried diarrhea. She did not present with any clinical signs of endotoxemia or overt colic signs upon exam.

This patient had been admitted to the clinic 5 times and had multiple recheck examinations both in the field and at the hospital. During those previous hospitalizations, the patient had been on IV fluid therapy multiple times, received a gastroscope, IV antibiotics, IV pain management, fecal polymerase reaction diarrhea tests, fecal parasite tests, gastroprotectants, multiple different deworming protocols, nasogastric lavage and oral fluids, abdominal radiographs and multiple ultrasounds without a definitive diagnosis for why the patient continued to show colic signs. Coming into this hospitalization, it was noted that the patient had lost 50 lbs from the first hospitalization to this presentation.

Bloodwork indicated a high white blood cell (WBC) count at 11.18 K/microL (reference range: 4.9-11.1 K/microL) characterized by lymphocytosis at 5.83 K/microL (reference range: 1.5-5.1 K/microL) and monocytosis at 0.62K/microL (reference range: 0.2-0.6 K/microL).

It also showed a hypoglycemia at 94 mg/dL (reference range: 109.0-268.0 mg/dL), hypercalcemia at 12 mg/dL (reference range: 9.4-11.8 mg/dL), high aspartate aminotransferase at 308 U/L (reference: high at 208 U/L), low alkaline phosphatase at 290 U/L (reference range: 505.0-4,667.0 U/L), and hyperkalemia at 5.1 mmol/L (reference range: 2.4-4.7 mmol/L).

The high WBV count and diarrhea indicated that the patient needed to be admitted into the isolation facility of the hospital. Upon entering the isolation stall, a 14-gauge needle IV catheter was placed in the filly’s right jugular vein and was secured with 0 prolene on a curved, reverse cutting needle. The patient was started on 500 mL/hr of lactated ringers solution. The patient continued the medication that was previously prescribed by the associate doctor that rechecked the patient that morning which was 500 mcg of misoprostol. Added to that medication was 1 scoop of Platinum Performance Equine Balance every 12 hours, 60 mLs of di-tri-octahedral (DTO) smectite orally every 24 hours, 500 mg of minocycline orally every 12 hours, and 125 mg of flunixin meglumine IV every 24 hours.

Throughout the night, the patient continued to have a high heart rate, increased borborygmi and semi-formed to liquid diarrhea. The filly’s appetite was depressed, and she did not have much interest in grain or fresh grass. The next morning, a fecal sample for a polymerase reaction diarrhea test and a blood antibody test for Lawsonia intracellularis were taken and sent out to a referral laboratory. We also tested for equine coronavirus, Clostridioidis difficile toxins A and B, Neorickettsia risticii and Salmonella spp. The lab results came back later as negative for all tests run. A packed cell volume (PCV), total protein, systemic lactate, and a complete cell count were also taken to check for dehydration and tissue perfusion. The patient’s PCV was 32%, total protein was 6.4 g/dL, and systemic lactate was 1.6 mmol/L. The blood cell count showed the WBC had decreased to 9.45 K/microL, but the monocytes had increased to 0.64 K/microL. These levels were all within normal limits.

The patient started to act painful when more blood was taken; rolling and kicking at her abdomen. She was sedated with butorphanol and xylazine IV, and an ultrasound examination was performed. The doctors noted that thickened intestinal loops were found and the filly had a moderate amount of free fluid ventrally, indicating inflammation within the bowels. After coming out of sedation, the patient remained bright, but her appetite was not consistent. Throughout the day, the patient’s temperature fluctuated between 101.6° F and 99° F.

The following day, the patient became painful in the early morning hours. The filly started thrashing, laying in lateral and groaning with a heart rate of 80. The patient did pass 2 piles of manure in stall that smelled rather foul. Due to the high level of discomfort, the patient was sedated with xylazine IV and butorphanol IV and IM. This amount of discomfort continued throughout the day with the patient becoming intermittently very painful, with the patient rolling, stretching out and vocalizing her discomfort. At 11 AM, the patient’s capillary refill time increased to 3 seconds and mucous membranes had turned red.

Due to the drastic change in comfort, the patient received an abdominal paracentesis as well as another ultrasound. A total protein, lactate and cell count were performed on the abdominal fluid. Total protein and lactate were within normal limits at 0.6 g/dL and 1.2 mmol/L respectively. The cell count on the abdominal fluid was also within normal limits with the total nucleated cell count at 1.20 K/microL with the granulocyte count at 0.89 K/microL and the agranulocyte count at 0.31 K/microL. The fluid was also normal in color and clarity, with the fluid being clear and straw colored. This was compared with the systemic total protein and lactate, which were 6.0 g/dL and 0.9 mmol/L.

Another full panel of blood work was acquired to show any differences that had accorded in the last 24 hours. The new blood work showed that the patient’s WBCs, especially the neutrophils, had vastly decreased to 4.61 K/microL, and the neutrophils had decreased to 2.27 K/microL. This was a potential indicator of a viral infection, but it was not yet known which one due to the fecal results not being finished. A fecal culture for aerobic identification and susceptibility was also sent out to a reference lab.

Unfortunately, the next day, the patient’s pain level increased and, unlike the day before, it could not be controlled by both sedation and non-steroidal anti-inflammatories. The patient was seen looking at abdomen and flehmen response after taking a few bites of feed in the morning at 7 AM. An hour later, the patient was thrashing. She was given xylazine and butorphanol IV as well as flunixin meglumine IV. This only lasted a few hours, and then the patient was found at 12 PM down and thrashing again. The patient was sedated again, this time with xylazine IV and xylazine IM. This again did not last, and the patient had to be given butylscopolammonium chloride IV an hour later.

At this point, the owners were told that the patient’s pain was becoming uncontrollable with sedation. They were given the option of exploratory surgery or humane euthanasia. The owner decided on exploratory surgery.

The patient was then taken to emergency abdominal exploratory surgery. She was given pre-surgical antibiotics amikacin sulfate and ampicillin IV.

She was also given an additional flunixin meglumine and butorphanol, and was then given ketamine and diazepam for anesthesia. The patient was then placed on dorsal recumbency. A 12-mm endotracheal tube was placed, and the patient was given sevoflurane inhalant. The patient received fluids during the surgery at the same rate that was being given before being on the table, 500 mLs/hr. The patient did breathe on her own, ranging from 8 to 11 bpm. A 20-gauge IV catheter was placed in the patient’s submandibular artery for direct arterial blood pressure, which started at a mean of 55 mmHg, so the patient was supplemented with a slow drip of dobutamine, at 1 drop per 3 seconds, to help bring up the mean blood pressure to 75 mmHg.

The patient’s abdomen was clipped and sterilely prepped with chlorhexidine scrub and alcohol. A drape was placed over the patient and an approximately 10-inch incision was made along the midline and the intestine was exteriorized. During the process to exteriorize the intestine, grossly enlarged veins were found throughout the small intestine and a mesenteric rent was found at the base of the mesentery. The surgeon attempted to correct the segment of intestines that had passed through the defect but the placement of tear in the mesentery and the enlargement of the intestine made it impossible to correct the defect, and the surgeon went to inform the owner.

During the few minutes that the surgeon was out speaking about the patient’s poor prognosis, her blood pressure dropped to 40 mmHg and her heart rate dropped from 70 to 50 bpm during the surgery. The patient was quickly turned off all sevoflurane and the surgeon was informed. Since the owner’s decided to humanely euthanize, no further life-saving drugs or procedures were done.

After the patient was euthanized on the surgery table, the surgeon went back into the abdomen to further look at the problem. The surgeon found that one of the engorged veins within the intestines that had passed through the tear in the mesentery had burst, and the patient had blood clots within her abdomen, which was the cause of the patient starting to crash under anesthesia. MeV

Teaching Points
This case was a very interesting case that used a lot of my skills, from the initial hospitalization cases that all culminated in the final step in a colic case. This case exhausted all the resources that were at our disposal until our last option was surgery. This case moved from a mild colic episode to multiple hospitalizations, to an isolation case, and then finally an exploratory anesthetic case.

I was very involved in this case and was able to use a lot of my skills to advance this case. I was intimately involved with the monitoring and treatments in this case throughout the many times the patient was hospitalized. The skills I used within this case were placing an over-the-wire IV jugular catheter, passing a scope for a gastroscopy, IV fluid therapy, IV pain management, oral medications, induction and maintenance of anesthesia including placement of an endotracheal tube, usage of rebreathing bag, placement of arterial IV catheter and monitoring of direct arterial blood pressure, and performing an electrocardiogram.

This case shows the vast progression of medical treatments that can be used to treat colic within the spectrum of veterinary medicine. Monitoring from both the owner’s home between hospitalizations and the staff’s careful observations indicated when the patient needed more treatment. This case also shows that sometimes medical treatment cannot fix all problems during a colic case, and we must move on to the next step in treatment, surgical intervention.