Ultrasonographic assessment of abdominal lymph nodes in puppies.

The jejunal and medial iliac lymph nodes of 53 clinically normal dogs between the age of 4 and 6 weeks were examined ultrasonographically. At least two jejunal and both left and right medial iliac lymph nodes were seen in all dogs. One hundred forty-five jejunal, 53 right medial iliac and 53 left medial iliac lymph nodes in six litters of dogs, for a total of 251 lymph nodes, were measured for cross sectional maximum diameters. Mean jejunal lymph node length was 16.4 mm (range 6.4-34.9 mm) and mean width was 6.0 mm (range 2.3-15.7 mm). The mean medial iliac lymph node length was 13.6 mm (range 7.2-27.8 mm) and mean width was 4.4 mm (range 1.9-8.2 mm). Significant differences of lymph node size, noted between and within breeds, may not be of clinical significance. The mean size of the combined left and right medial iliac nodes was within previously published ranges for normal adult dogs. Lymph nodes were described in four litters of dogs (162 lymph nodes). Lymph nodes were either uniformly hypoechoic (108/163, 66%) or centrally hyperechoic with a hypoechoic rim (55/163, 34%). Although most (60%) lymph nodes were oval, a variety of shapes were seen, including vermiform and complex branching shapes. We concluded that in 4- to 6-week-old dogs, medial iliac lymph nodes are similar in size to adult dogs and jejunal lymph nodes are multiple, routinely seen, are larger than in adults and often have unconventional shapes.