The Case: The GI Obstruction that Wasn't

History 

A 9-year-old intact female miniature poodle presented for anorexia (2 days) and lethargy (1 day). The owners also reported that the patient had breathing difficulty and dark-colored urine; they suspected a gastrointestinal foreign body as the dog had a habit of getting into the trash. Questioning the owners revealed that the dog’s last heat cycle had been 1 year ago, although medical records from a previous veterinary clinic indicated that the dog had been spayed. Acquired as a puppy, the dog had no other pertinent medical history; she is the only dog in the home and is kept indoors. Core vaccinations are up to date.

Physical Examination

The patient was depressed but alert and responsive as well as fully ambulatory. The hair coat was full, clean, and without evidence of ectoparasites. The eyes and ears were clear, with no discharge or debris OU/AU. Eyes demonstrated both direct and indirect pupillary light reflexes.

• Weight:  9.44 lb (4.29 kg)

• Body condition score: 5/9

• Temperature: 102.2<sup⁰sup>F

• Pulse: 160 bpm

• Respiration: 50 bpm (tachypnea), shallow breathing; lung sounds were clear (no wheezes or crackles)

• Mucous membranes: pink/dry

• Capillary refill time: 1 sec

• Hydration: 5%-7% dehydrated

• Peripheral lymph nodes: palpated within normal limits 

• Cardiovascular: tachycardia, no murmurs or arrhythmias auscultated, femoral pulses fair and synchronous 

• Abdomen: moderately distended, tense, +/- pain, difficult to palpate

• Urogenital: female, large swollen vulva, no discharge

Diagnostics 

• Abdominal radiographs: large fluid-filled intestines vs mass effect; large tubular structure in area of uterus

• Blood work: leukopenia, neutropenia, eosinopenia, monocytopenia

  • Packed cell volume/total solids: 38% (range, 33.6-58.7)/8.8 g/dL (range, 5.0-7.4)

  • Blood urea nitrogen: 28 mg/dL (range, 6-31)

  • Globulin: 4.9 g/dL (range, 1.6-3.6)

  • Alkaline phosphatase: 541 IU/L (range, 5-131)

  • Total bilirubin: 1.0 mg/dL (range, 0.1-0.3)

  • Cholesterol: 384 mg/dL (range, 92-324)

• Urinalysis: urine specific gravity––1.017 (range, 1.015-1.050), proteinuria

• Abbreviated ultrasound: large bifurcating tubular structure, with hyperechoic heterogeneous swirl, craniodorsal to urinary bladder

Treatment: An emergency ovariohysterectomy was performed using a routine ventral midline abdominal approach. Brief abdominal exploration was conducted and the abdominal cavity was copiously lavaged with saline and routinely closed.

Anesthesia: 

• Premedication: acepromazine (0.02 mg/kg IV), morphine (0.3 mg/kg IV)

• Induction/maintenance: diazepam (0.25 mg/kg IV), ketamine (5 mg/kg IV) + isoflurane inhalant

Intraoperative treatment: Plasmalyte-A* 10 mL/kg/hr

Postoperative treatment: Supportive care was provided for 2 days:

• Plasmalyte-A + 15 mEq/L potassium chloride: 90-120 mL/kg/day IV 

• Metoclopramide: 0.08 mg/kg/hr CRI

• Ampicillin/sulbactam: 130 mg (30 mg/kg) IV every 8 hrs

• Enrofloxacin: 22 mg (5 mg/kg) IV every 12 hrs

• Fentanyl patch: 25 mcg (<10 kg body weight)

• Maropitant: 4.3 mg (1 mg/kg) IV every 24 hrs

• Morphine: 1.7 mg (0.4 mg/kg) IV every 4 hrs for 24 hours 

• Amoxicillin/clavulanic acid: 62.5 mg (13.75 mg/kg) PO every 12 hrs; initiated but discontinued due to anorexia

• Sucralfate: 250 mg PO every 12 hrs

• Famotidine: 2 mg (0.5 mg/kg) IV every 24 hrs

• Heat support as needed

Significant Diagnostic Findings (1 day postoperatively) 

• Sodium: 143.1 mEq/L (range, 146.0-156.0)

• Creatinine: 0.5 mg/dL (range, 0.6-1.4)

• Packed cell volume/total solids: 32% (range, 33.6-58.7)/6.2 g/dL (range, 5.0-7.4)

Outcome: 

• The patient became anorectic (initially thought to be secondary to opioids), nauseated, and regurgitated several times within the first 24 hours postoperatively.  

• Discharged on day 3 at owners’ insistence with only a transdermal fentanyl patch (25 mcg). Recommended a return visit for a complete blood count and recheck in 48 hours. Patient was lost to follow-up when owner failed to return or respond to telephone calls. 

*A multi-electrolyte solution

The Specialist’s Opinion

Karl Maritato, DVM

A good example of astute history taking and proper physical examination is characterized by this case. While the owners presented with the suspicion that their dog had an intestinal foreign body, further, proper questioning helped guide the clinician’s thought process about possible differentials. The ability to associate the “red flags” presented by the historical notes “intact female” and “last heat cycle” with vague clinical signs such as anorexia and lethargy was an important skill when forming this diagnostic plan.  

Physical examination findings in this case aided in defining both the diagnostics that should be performed and the first-step treatments that should be instituted. In regard to diagnostics, the tense, painful, distended abdomen along with the large, swollen vulva strongly suggests an acute abdominal problem, particularly possible pyometra. Therefore, abdominal radiographs or, if available, abdominal ultrasound, are the best  tests to perform to achieve a diagnosis.

While it is obviously part of any proper physical exam, checking for mammary masses is especially important with suspected pyometra. Mammary masses are commonly encountered in older, intact female dogs and can also be removed during the pyometra surgery. Certain subtypes of mammary tumors have improved prognosis with ovariohysterectomy.¹

One could question the necessity of vaginal cytology even though vulvar discharge was not present in this case. With no discharge (closed pyometra), the cytology likely will indicate only the stage of the estrous cycle and not confirm the presence of an infection. When a discharge is present, it is informative to also perform vaginal cytology. Typically vaginal cytology from a dog with pyometra demonstrates excessive numbers of degenerate neutrophils with intracellular and extracellular bacteria.² 

The blood work results in this case are non-specific, as is common for dogs with pyometra.²

The Final Diagnosis  

Both abdominal radiographs and ultrasound findings were consistent with pyometra. Given there was no vulvar discharge, closed pyometra is the final diagnosis. Prior to surgery, it would have been prudent to perform thoracic radiographs, both as part of geriatric screening and also because of the physical examination findings of tachypnea and shallow breathing. Such radiographs allow proper evaluation of the intrathoracic structures, including heart size and shape as well as any pulmonary abnormalities. Searching for evidence of any occult neoplastic lesions is important in helping owners make proper decisions. Given that approximately 50% of mammary masses are malignant and approximately 50% of those malignancies have pulmonary metastasis at the time of diagnosis, thoracic radiographs are particularly important.³

Surgical Considerations

Emergency surgery is and was the correct treatment in this scenario. The patient was premedicated with acepromazine and morphine. The morphine is acceptable when given IV, as long as it is given slowly, as rapid administration can result in histamine release, which could exacerbate hypotension, to which this patient is predisposed due to the degree of infection present.⁴ Acepromazine is not a good choice for premedication in this patient, given the presence of dehydration, likely hypovolemia, and also the potential for sepsis.⁵ Additionally, patients with pyometra are prone to renal injury.^6,7 Acepromazine is long acting, non-reversible, and causes vasodilation, which are counterproductive in a patient such as this.⁵

Minimal details about the surgical procedure are provided; however “brief” abdominal exploration was described. In my opinion, a complete abdominal exploration should be performed in all animals, but in particular older animals, as occult neoplasia could be present and therefore addressed during the surgery.

Postoperative management was appropriate here. I prefer a fentanyl CRI to morphine as used in this patient. Morphine has a higher incidence of nausea and anorexia, both of which were observed, compared to fentanyl. It is important to maintain proper hydration and blood pressure in patients with pyometra, as they can be dehydrated and hypotensive, as well as to ensure adequate renal blood flow given the potential for renal failure.^6,7

Overall, diagnosis and treatment of this patient were appropriate. Minor adjustments could have perhaps led to a more complete diagnostic picture and a smoother recovery.

The Generalist’s Opinion

Barak Benaryeh, DVM, DABVP

Pyometra is a medical condition that every practitioner will encounter. According to at least one large scale study, nearly 25% of intact female dogs will develop a pyometra by 10 years of age.¹ This condition should always be considered an emergency, with surgery (ovariohysterectomy) being the treatment of choice. The saying “Never let the sun set on a pyometra” stems from the concern that pyometras can lead to endotoxemia and systemic sepsis if not treated immediately and appropriately.

Making the Diagnosis

This dog’s condition was recognized quickly despite the muddled records, which gave no clear indication as to whether or not the dog was spayed. The timing of the last heat cycle did not fit well with the diagnosis as pyometras generally occur under the influence of progesterone and therefore predominantly during diestrus.² According to the owners, the dog’s last heat cycle had occurred 1 year prior. The radiographs clearly indicated a structure that was very likely an infected uterus. The clinicians did a good job of recognizing the condition and instituting the appropriate treatment. This case is a good demonstration that while paying attention to the history is important, one should not let it blind us to the clinical signs and diagnostic information in front of us.

Surgery vs Medicine

An ovariohysterectomy is the most appropriate treatment and considered the standard of care for pyometra. There are several different techniques and protocols available for medical treatment, which involves drugs that lyse the ovarian follicle, open the cervix to allow drainage, and provide antibiotic coverage to deal with the infection. Even if successful, however, such treatments pose a risk for recurrence and for sepsis by choosing not to remove an infected organ. If owners request that you treat medically, be sure to obtain informed consent and counsel the owners that surgery is the treatment of choice.

Pain Control Protocols

Preoperative and postoperative morphine was given intravenously as a method of pain control.  Morphine has an elimination half-life of approximately 1 hour,³ which means that by 3 hours only 25% of the drug remains in effect. If given by rapid intravenous injection, morphine can cause significant hypotension. In addition, it will often cause patients to become nauseated, as was noted in this case. For these reasons, it is an uncommon choice for postoperative pain control and is generally not considered a great option. Other opioids are available that are equally or more effective and do not carry the negative risks and side effects of morphine. In general, a balanced approach for pain control is ideal, which could include an oral opioid as well as a non-steroidal anti-inflammatory drug.  

In addition to morphine, a fentanyl patch was used. While opinions vary, studies do point to fentanyl patches being an effective method of analgesia in dogs.⁴ However, the question of safety must be considered if the patch is ingested (by anyone) or if it is not disposed of properly. Transdermal fentanyl (Recuvyra) is a different dosing formulation with fewer safety concerns, but though still available, is no longer being produced.

Appropriate Follow-up 

It is not known what became of this patient. Recheck exams after surgery are an important aspect of patient care as well as a great client retention tool. Encouraging rechecks, even if they are free of charge, helps to both minimize postoperative complications as well as bond with your clients. At the very least, a follow-up phone call should be made the day after any surgical patient is discharged. This patient failed to return for the exam and the clients did not respond to phone calls, which might indicate that they were dissatisfied. It’s good practice in such scenarios to do a review as to what could have been done better in terms of medical care and/or client relations. It’s possible that nothing else could have been done, but a case assessment always makes us better practitioners and our practices better places for clients to visit.