A mixed-breed dog with an uncommon pure breed gastrointestinal disease
Case Files is a new column where we examine weird, inscrutable and illuminating cases our doctors have encountered. Today, we take a look at Meira, a 4-year-old FS retriever mix suffering from an unusual gastrointestinal disease.
I met Meira in my previous practice, when she was adopted from a rescue as an approximately 6-month-old puppy. She had no history of illness or surgery other than her spay when she presented to me at one of our partner practices on 6/13/2020 for a yearly wellness exam and vaccines.
At that time, her exam was normal except for grade 2/4 dental disease and weight gain (she weighed 53 lbs. from too many treats during the first few months of COVID-19). At that visit, a COHAT was recommended. Meira’s pre-operative bloodwork was within normal limits, and her COHAT was performed on 7/2/2020 without complication. On the day of the dental procedure, Meira weighed 49.1 lbs. She required no extractions.
At her follow-up visit on 7/15/2020, her family felt that she was doing well, her recheck exam was non-remarkable, and her weight was recorded as 47.3 lbs.
5 months later: Presented for diarrhea
On 12/21/2020, Meira presented to another IndeVet for diarrhea.
Patient started having frequent diarrhea after eating sweet potato vine 2 days ago. Asking to go out overnight. Fresh blood and mucus seen in stool today.
Patient vomited 1-2x (bile only) early this morning.
No coughing or sneezing. Normal appetite, attitude, activity and water consumption.
UTD on F/T/HW prevention.
Pet Poison Hotline was called, and the sweet potato vine was reported to be non-toxic.
BAR, euhydrated, mm pink/moist, CRT 1-2 sec.
Weight: 45.8 lbs.
- T: 103
- P: 100
- R: 30
- Oral Cavity: Full adult dentition, clean. No obvious oral masses/lesions on cursory exam
- Eyes: OU – pupils equal in size and reactive to light, no ocular discharge, orbit and globe are symmetrical
- Ears: AU – no aural inflammation or ceruminous debris, otoscopic exam not performed
- Integument: Healthy haircoat, no cutaneous or subcutaneous lesions addressed today; no appreciable ectoparasites
- Lymph Nodes: Mandibular, prescapular and popliteal lymph nodes all soft, small and symmetrical
- Cardiovascular: No murmur, regular rate and rhythm, strong synchronous femoral pulses
- Respiratory: Eupneic, normal bronchovesicular sounds diffusely, no nasal discharge
- Abdomen: Soft/non-painful, no overt organomegaly or masses
- Urogenital: Normal external anatomy, no discharge
- Musculoskeletal: Ambulatory x 4; no ataxia/joint effusion; no asymmetry/atrophy noted; complete orthopedic exam not performed
- Nervous System: Mentally appropriate. No overt neurologic deficits. Complete neuro exam not performed today.
- Rectal: VERY full anal sacs, pt vocalizes on expression, but normal secretions expressed easily.
- Giardia SNAP: negative
- Fecal float: no ova seen
- Large bowel diarrhea, 2 day hx (Ddx: colitis secondary to dietary indiscretion vs. dysbiosis vs. other)
- Bilious vomiting
- Full anal sacs
- Discussed suspected colitis secondary to dietary indiscretion. Recommend symptomatic care. If patient fails to improve over next 2-3 days, recommend bloodwork.
- Dispense: Metronidazole 250 mg, #14, 1 tab po bid x 7 days
- Dispense: Fortiflora x 1 box
- Dispense: i/d LF loaf x 2 cans and i/d LF stew x 2 cans
- Advised O to feed bland diet until stools begin to form and then slowly transition back to regular diet. Can add boiled chicken and rice to i/d.
A little over a month later… Soft stool and coprophagy
On 1/27/2021, Meira presented to a second doctor for recurrence of soft stool with the addition of coprophagy.
O has recently noticed softer, yellowish stool, and that P has started eating her stool starting around the same time. P also occasionally eats rabbit and deer droppings. On Nutro dry and canned, although O recently started giving dry only, which may have improved stool quality slightly. No vomiting. Normal attitude and activity level.
BAR, mm pink/moist, CRT <2 sec, pulses s/s
Weight: 45.2 lbs.
- T: 102.3
- P: 112
- R: pant
- Exam findings consistent with previous exam except:
- Rectal: soft formed stool, no blood or mucus observed, grass noted in stool and also in sample provided by O
- Fecal float: no ova seen
- Giardia SNAP: negative
- Soft stool (r/o nutritional, dietary indiscretion, intestinal parasites, pancreatitis, other infectious or inflammatory, underlying metabolic/endocrine, etc.)
- Discussed coprophagy: recommend supervise when outdoors, pick up feces immediately.
- Limit grass consumption.
- Discussed further diagnostics including bloodwork and imaging. O elects to begin symptomatic tx and monitor in light of some improvement in stools and otherwise normal behavior.
- Rx: Metronidazole 250 mg, #14, 1 tab po bid
- Fortiflora canine – sprinkle 1 packet over food once daily for 7-10 days
- Dispense: i/d canine, dry and i/d LF x 4 cans
- Dispense: Bravecto (44-88 lbs) #2, and Interceptor Plus (26-50 lbs.), box of 6 doses, per O request
12 days later… Continued diarrhea and coprophagy
On 2/8/2021, Meira presented to me for persistent yellow diarrhea and coprophagy.
Presented because she is still having yellow diarrhea. Metronidazole and i/d didn’t help this time. Still getting Fortiflora. O reports no vomiting, normal activity, and maybe slight polydipsia.
BAR/anxious, mm pink/moist, CRT <2 sec, pulses s/s
Weight: 43 lbs.
- T: 103.1
- P: 72
- R: 28
- Exam findings consistent with previous exams except:
- Rectal: watery, grainy stool; smooth rectal walls, anal sacs empty, no masses
- Integument: no evidence of ectoparasites, no dermal or SQ masses, no skin lesions, but coat looks a little dull and thin with some matting present
- Musculoskeletal: progressive weight loss, mild loss of muscle mass
- Chronic intermittent diarrhea (r/o intestinal parasites, SIBO, dietary indiscretion, dietary hypersensitivity/allergy, metabolic i.e. liver disease, pancreatitis, hypoadrenocorticism)
- Progressive weight loss (likely secondary to above primary problem)
- Poor hair coat (likely secondary to malabsorption of nutrients)
- Saw P late in a busy day with more patients still to see. Since she was stable in terms of vital signs, sent her home and notified O I would call with results of diagnostics before the end of the evening and we could make further plans from there.
- Because metronidazole had helped with the first bout of diarrhea, we decided to continue for a total of 2 weeks this time in case Meira was slower to respond (I know – I was grasping at straws!), and we started Royal Canin HP diet in case Meira had developed a sensitivity to chicken.
- Fecal float: no ova seen
- Giardia SNAP: negative
- CBC: mild anemia (Hct = 36.8. Compared to 7/2/2020: Hct = 44.3), no reticulocytosis
- Thrombocytopenia (platelets = 32K. Compared to 7/2/2020: platelets = 115K)
- CBC parameters otherwise wnl
- Chem: Lipase = 166 (normal range 200-1800) – could not compare to previous because was not included in pre-op panel from 7/2/2020
- Amylase was low normal at 516 (normal range: 500-1500)
- BUN was low normal at 7 (normal range: 7-27) – compared to 7/2/2020: BUN = 13
Client call log regarding results of diagnostics
Discussed bloodwork with O.
- Questioning validity of CBC, which shows thrombocytopenia and mild anemia, neither of which match Meira’s clinical appearance today. Discussed thrombocytopenia. Discussed where to look for bruising in a dog as well as signs of internal bleeding.
- Discussed that if the thrombocytopenia is real, there could be an autoimmune disease causing both the gastrointestinal signs and CBC changes. But did stress with O that Meira’s clinical appearance was not consistent with this CBC, and that repeating the test was the first step in determining where to go next.
- Also discussed that low lipase usually doesn’t mean anything, but considering P’s presenting complaint, with a low lipase, borderline low amylase, and low normal BUN, EPI should be considered even though it is rare in mixed breed dogs.
- Recommend GI panel (TLI or PLI, B-12 and folate) and baseline cortisol if diarrhea has not improved in 1 week with HP diet. Also consider fecal PCR for enteric pathogens.
Repeat CBC sent to reference lab: Hct = 41.1. Could not obtain machine platelet count, but estimate was moderately decreased (50-100K) with large platelets present. Pathology review was requested. No blood parasites were seen, and no additional information was obtained. Discussed running full tick/vector borne PCR panel.
Meira’s diarrhea was continuing to worsen, and O reported that loose yellow stool would sometimes leak from her anus. After discussing costs and reasons for baseline cortisol, TLI/B-12/folate, Tick/Vector PCR to look for causes of low-grade thrombocytopenia with large platelets, and fecal PCR for enteric pathogens, O elected to run the baseline cortisol and TLI/B-12/folate.
I also recommended an injection of B-12 after the blood draw, because 1) clinically I was suspicious of EPI, 2) the owners were getting absolutely desperate to help Meira, and 3) it can do no harm.
Baseline cortisol = 4.5 (normal range 2.0-6.0)
Hypoadrenocorticism was ruled out. Meira was doing worse, and was leaking more yellow diarrhea. The GI panel results were not yet available and the owner was very worried, as well as exhausted from constantly cleaning up diarrhea. Recommended adding fecal PCR for enteric pathogens, scheduling abdominal ultrasound in case GI panel didn’t give us a diagnosis and to rule in/out any complicating factors. Started to discuss that, even though Meira is young, cancer could not be ruled out.
O elected to run the fecal PCR and to schedule ultrasound.
We discontinued metronidazole and started Tylan powder pending results of fecal PCR and GI panel already submitted.
Finally: A diagnosis! (Exocrine Pancreatic Insufficiency)
On 2/17/2021, we received the following lab results: Meira has exocrine pancreatic insufficiency!
- TLI = 0.9 (normal range 5.0-35.0)
- Cobalamin = 216 (normal range 284-836)
- Folate = 18.1 (normal range 4.8-19)
While the owner had done a lot of reading about EPI by this point, and was very nervous about it, it was a much better diagnosis than some of the things we had been discussing, and we were able to start treatment.
Meira’s treatment protocol
- Started Viokase at 2 tsp per meal, mixing it in ahead of time and allowing it to stand for 15-30 minutes before feeding. This is something I have always recommended with the EPI dogs, not because it digests the food better, but because the pancreatic enzymes can cause oral ulceration, and they are less likely to be irritating to the oral mucosa if the enzymes are pre-mixed. Discussed with O that hopefully we would be able to decrease the amount of Viokase per meal depending on Meira’s response.
- Recommend B-12 injections every week for 6 weeks, then every other week for 6 weeks, and then monthly for life.
- Recommend low-fat, low-fiber diet. O preferred a commercial food to a prescription food if it would be possible to maintain Meira on a commercial diet. We elected to try starting the Nutro she was used to after the i/d and HP that the owner had already purchased were gone. The fat and fiber content were within acceptable ranges. The owner was told that if Meira didn’t respond well on her old diet, she might need to be on i/d LF permanently.
Meira’s fecal PCR testing came back negative for all pathogens, and her abdominal ultrasound was consistent with EPI (a very thin, wispy pancreas was seen), and no evidence of other gastrointestinal pathology was found.
Client Education Visit
Presented for O to learn to give B-12 injections. P is feeling much better on Tylan and Viokase. Diarrhea is essentially resolved after only 4 days on Viokase. O is getting ready to try starting Nutro Chicken and Brown Rice again.
BAR, mm pink/moist, CRT <2 sec, pulses s/s.
Weight: 43.6 lbs.
A full exam was not performed.
- Exocrine pancreatic insufficiency with secondary cobalamin deficiency, symptoms resolving with pancreatic enzyme and cobalamin supplementation
- Taught O how to give injections. P is to get 0.5 ml B12 SQ once a week x 6 weeks (4 more weeks after today), then 0.5 ml every other week for 6 weeks, then 0.5 ml monthly long-term, or as needed for gastrointestinal health. O understands that B-12 levels can be measured, but with EPI, P will need B-12 supplementation for life.
- Also discussed EPI management in general. Recommend no treats, or extremely minimal amount depending on clinical response, and any treats given should be fat, low fiber, and very small (i.e. training treats only). We may be able to decrease the amount of Viokase Meira gets per meal over time depending on response, and Meira probably will not need Tylan long-term, but since EPI and SIBO can often occur simultaneously, it is possible that Meira will need Tylan again at some point, even if she initially does well when she is finished the 6-week course we dispensed.
- Recommend recheck in 2 months for follow-up physical exam.
Exocrine Pancreatic Insufficiency
For whatever reason, I have always seen a lot German Shepherds, which means I have seen a fair amount of EPI, although it seems to be less common in the breed than it was when I graduated from veterinary school. In any case, it is a disease that is very much on my radar.
What made Meira an interesting case for me is the fact that she is a mixed breed dog. At 4 years of age, she presented at average age for EPI, which is most commonly caused by pancreatic acinar atrophy in the dog.
Histological studies have suggested that PAA is an autoimmune disease that targets the pancreatic acinar cells. Chronic pancreatitis is the second most common cause of EPI, and is the most common cause in older dogs. Those dogs can have concurrent diabetes mellitus. EPI can also be caused by pancreatic neoplasia or pancreatic duct obstruction caused by extrapancreatic neoplasia.
EPI was high on the differential list by the time I was involved with the case. Retrospectively, the progressive weight loss was a huge clue. Even though I had told the owners that Meira had gained weight in June of 2020, most of the time purposeful weight loss is slower than Meira’s weight loss was.
Meira’s case of EPI
In humans, greater that 90% of exocrine pancreatic functional reserve has to be lost before clinical signs occur, and it is suspected to be the same in dogs. Between 6/13/20 and 7/15/20, Meira’s weight went from 53 lbs. to 47.3 lbs. This makes me wonder if Meira had subclinical EPI before she ever presented for diarrhea.
I also wonder if eating the sweet potato vine could have caused just enough gastrointestinal irritation to induce an immune response that caused destruction of the rest of Meira’s pancreatic acinar cells.
By the time she presented the second time for diarrhea, the stool color had changed and she was eating her stool. Lighter stool is typical with EPI, although she did not have the greasy stool that I have seen with other EPI patients.
Also, it has been my experience that when an adult dog becomes coprophagic for the first time, it is more than a bad habit: it is a symptom of malabsorption/maldigestion or a nutritional deficiency.
I am so grateful for the commitment and persistence of Meira’s owners. They understood and authorized all necessary diagnostics, both to get a primary diagnosis, and also to rule out any complicating factors.
While I have not seen Meira for follow-up yet, I have heard from her owners, and they have decreased her Viokase to 1.5 tsp with each meal. She is happy and feeling well!
Amy Lloyd, VMD, is an area medical director for IndeVets.