Signalment & History
- This patient presents to your clinic for vomiting over the past several days, which had been acutely worse the last several hours.
- On presentation, he was minimally responsive, had an unauscultable heart rate, and a rectal temperature of 101.2 F. His systolic blood pressure was 40mmHg. He had dry, pink mucous membranes with a capillary refill time of >3.
- After stabilizing the patient, you order abdominal radiographs.
Findings
Two populations of small intestines are identified: several of these loops of small intestines are moderately gas distended. The diameter of these intestines (from serosa to serosa), measures up to 3.2 times the height of the mid-body L5 (the narrowest height of L5). There is an ill-defined, heterogeneous, cylindrical soft tissue opaque structure (indicated by the oval) surrounded by multiple gas filled loops of small intestines (arrows) in the caudal abdomen. Additionally, there is an ill-defined, heterogeneous, cylindrical soft tissue opaque structure (indicated by the oval) surrounded by multiple gas filled loops of small intestines (arrows) in the caudal abdomen. The remaining intra-abdominal structures are normal.
Diagnosis
- This patient was diagnosed with a small intestinal mechanical obstruction via a corn cobb based on the presence of two populations of small intestines, measuring greater than 1.6 times the height of the mid-body of L5.
Conclusions
- Small intestinal dilation is a cardinal sign of obstruction but its recognition depends upon the observer’s experience and anecdotally derived parameters for normal small intestinal diameter.
- A ratio of the maximum small intestinal diameter (SI) and the height of the body of the fifth lumbar vertebra at its narrowest point (L5) was used.
- A value of 1.6 for SI/L5 is recommended as the upper limit of normal intestinal diameter for clinical use.
- The model showed that obstruction is very unlikely if the SI/L5 value is less than this. Higher values were significantly associated with obstruction.
References
- Quantitative estimation of intestinal dilation as a predictor of obstruction in the dog. Graham JP, Lord PF, Harrison JM. J Small Anim Pract. 1998 Nov;39(11):521-4.
