No Prob-Llama: Abdominal Ultrasound in Camelids
Abdominal ultrasonography is a useful adjunctive technique for camelids.
It is a non-invasive, reproducible and inexpensive tool in the diagnosis of urolithiasis or gastrointestinal disease.
Preparing for the Ultrasound Exam
- Clipping the fibre is not always necessary, but it is recommended for obtaining the best possible images. After clipping, clean the skin, wipe with alcohol and apply ultrasound gel for best possible contact.
- Soaking the fibre with copious amounts of alcohol/methylated spirits and part the fibres where you place the probe will help in unclipped animals.
- Equipment: Ideally a convex probe (approx. frequency range 3.5-5MHz) is used but a rectal probe can be used for basic evaluations.
Ultrasound of the Gastrointestinal Tract
- Evaluate C1 motility & Size
The C1 compartment will usually encompass the entire left side of the abdomen.
The saccules of C1 give its’ wall a unique, hyperechoic appearance.
In cases of distal GI obstruction or ileus (due to enteritis), dilated small intestine (>1.5 cm diameter) may be seen in the caudal ventral left abdomen.
- C2& C3
- Distal small intestine
Note: C1 will normally extend to at least ventral midline, or a little over to the right side.
C3 lies ventrally and to the right of C1
C3 diameter is reported to range from 5-11cm and is slightly larger in adult alpacas than llamas. In juvenile alpacas it is generally 3-5 cm diameter.
Ultrasound of the Urinary Tract
- Evaluate volume, size & shape
- Wall thickness
- Presence of intraluminal abnormalities (calculi, pops, neoplasia)
The kidneys can be imaged on either side in the paralumbar regions.
The left kidney is positioned slightly more caudal in the abdomen than the right kidney.
Visualisation of calculi is possible in the renal calices, pelvis and pyelouteteric/vesicoutereric junctions. For stones >5mm diameter, ultrasound has a sensitivity of 96% and specificity of nearly 100%! For smaller stones this reduces to a sensitivity of 78% and specificity of 31% (Makhdoomi & Gazi, 2013).
In cases of urinary tract rupture, hypoechoic (black) free fluid will be seen in the abdomen (i.e. uroperitoneum). Differential diagnoses for peritoneal effusion in camelids include ascites and Streptococcus zooepidemicus peritonitis (Jones et al, 2009).
- Cebra CK, Watrous BJ, Cebra ML. 2002. Transabdominal ultrasonographic appearance of the gastrointestinal viscera of healthy llamas and alpacas. Vet. Rad. & Ultrasound; 43(4):359–66.
- Jones M, Miesner M, Grondin T. 2009. Outbreak of Streptococcus equi ssp zooepidemicus polyserositis in an alpaca herd. J Vet Intern Med; 23(1):220–223.
- Makhdoomi DM and Gazi MA (2013) Obstructive urolithiasis in ruminants – A review. Vet. World 6(4):233-238