Diagnostic imaging for linear foreign bodies in cats - Veterinary Medicine
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Diagnostic imaging for linear foreign bodies in cats
These clinicians focus on their diagnostic evaluation of a cat with vomiting and abdominal pain due to a linear foreign body. Find out which imaging techniques will best help you identify these common gastrointestinal foreign bodies in your patients.


VETERINARY MEDICINE


Linear foreign bodies are a well-recognized problem in small-animal practice. In cats, the most common linear foreign bodies are string, carpet, and plastic.1 Clinical signs of a foreign body include vomiting, regurgitation, ptyalism, inappetence, anorexia, depression, diarrhea, abdominal pain, and dehydration. Early diagnosis helps prevent complications such as peritonitis due to gastric or intestinal perforation.2

Since the clinical signs are nonspecific, imaging is almost always necessary to diagnose linear foreign bodies. In our teaching hospital, we use several imaging techniques including survey abdominal radiography, upper gastrointestinal (GI) series with barium or iodinated contrast material, survey or contrast abdominal compression radiography, and abdominal ultrasonography. The advantages and disadvantages of these techniques are discussed below, including a case report in which three of these imaging studies were used to definitively diagnose a linear foreign body in a cat.

CASE REPORT

A 1-year-old spayed female domestic longhaired cat was presented to the Veterinary Teaching Hospital at Kansas State University with a 24-hour history of coughing, vomiting, polydipsia, anorexia, lethargy, and abdominal pain.

Examinations and diagnostic tests

On physical examination, the cat appeared depressed and had dry, tacky mucous membranes. The cat's abdomen was tense on palpation. Oral examination findings were unremarkable. Based on the history and physical examination results, the differential diagnoses included a GI foreign body, pancreatitis, and gastroenteritis of unknown cause.

A complete blood count revealed polycythemia (packed cell volume = 60%; reference range = 30% to 45%), increased plasma protein (9.1 g/dl; reference range = 6 to 8 g/dl), leukopenia (total white blood cell count = 3,600/μl; reference range = 5,500 to 19,500/μl) with slight neutropenia (2,400/μl; reference range = 2,500 to 12,500/μl), and marked lymphopenia (800/μl; reference range = 2,000 to 7,000/μl). These results were consistent with dehydration and inflammation. Intravenous fluid therapy with a crystalloid solution was given to correct dehydration.

Survey radiography


1A &1B. Right lateral and ventrodorsal abdominal radiographs of the cat in this report showing plication of the small intestines and fluid opacity within the pylorus.
Abnormal findings on ventrodorsal and right lateral survey abdominal radiographs were a plicated small intestine, fluid opacity within the pylorus, and a heterogeneous mix of gas and soft tissue opacity in the fundic region of the stomach (Figures 1A & 1B). A left lateral view was also obtained to complete the evaluation of the stomach and pylorus. All views revealed normal serosal detail.

Survey compression radiography


2. A right lateral abdominal compression radiograph of the cat in this report showing the plicated small intestine.
Because this case allowed an additional opportunity for instructing students, abdominal compression radiography with a compression paddle applied gently and uniformly to the left ventrolateral abdomen was performed to isolate the small intestine and enhance the visibility of its shape and contour. This view demonstrated bunching of the small intestine and plication without gas segmentation of the intestine (Figure 2).


3A & 3B. Right lateral and ventrodorsal barium contrast abdominal radiographs showing a linear foreign body outline throughout the intestine in a cat from a different case.
Because plication was identified on the survey and abdominal compression radiographs, a positive contrast GI study was not necessary. We have included right lateral and ventrodorsal views from a different case as an example of a contrast study in a cat with a linear foreign body (Figures 3A & 3B).

Ultrasonography


4A. An ultrasonogram of the cat in this report demonstrating the characteristic appearance of plication in the small intestine.
For teaching purposes, an ultrasonographic evaluation was also performed. Ultrasonography helps to evaluate the length and location of the linear foreign body (as evidenced by intestinal plication), degree of peristalsis, and stomach and intestinal wall integrity and thickness. It also helps to rule out free peritoneal fluid, which is an early indicator of bowel perforation and peritonitis. Linear echogenic material and plication were noted within the duodenum extending into the proximal jejunum (Figures 4A & 4B). The stomach and intestinal walls were a normal thickness. Fluid and peristalsis were present in the stomach and duodenum, which are normal findings. An ultrasonogram of normal small intestine is shown for comparison (Figure 5). Because the linear foreign body extended to the jejunum, endoscopic removal was not an option.


4B. Small intestinal plication produced by a linear foreign body (arrows) in the cat in this report.

Treatment


5. An ultrasonogram of a normal small intestine in a cat. Note the smooth and normal shape of the small intestine. The intestinal walls are easily identified.
The cat was anesthetized and prepared for surgery, and an exploratory laparotomy was performed. A linear foreign body was palpated in the stomach and extended from the duodenum to the colon (Figure 6). A gastrotomy and two enterotomies were needed to access and remove a cotton string. No complications occurred during surgery or recovery. The cat continued to receive fluid therapy, antibiotics, and analgesics for three days and was discharged with instructions for the owner to feed a bland diet.

DISCUSSION


6. An intraoperative picture of the cat in this report showing the plicated small intestine.
Practitioners must know the indications for and advantages and disadvantages of different imaging techniques as well as be able to identify the typical abnormalities consistent with linear foreign bodies that are seen with these techniques.

Survey abdominal radiography

Survey abdominal radiography is always recommended in vomiting patients. In our hospital, ventrodorsal and right lateral views are standard. The advantages of abdominal radiography are that it is noninvasive, provides immediate results, and is relatively inexpensive and readily available. The disadvantages include radiation exposure and summation or superimposition of soft tissues over the stomach and intestines.3


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Source: VETERINARY MEDICINE,
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