Library: Article

Title: Foxtail Migration – Wally Lund
Date: 7/1/11

Detail:
Every summer in Northern California (and around the world), foxtail barley (Hordeum jubatum) matures and becomes the bane of adventurous outdoor pets and their owners. This summer was no exception, and with a combination of clinical suspicion, advanced imaging, and a little good luck, we were able to help a number of dogs with foxtail related morbidities.

Foxtail spikelets are adapted for animal dispersal. That is, they disarticulate easily. The barbs cause the foxtail to cling to fur, and the movement of the animal causes the foxtail to burrow into the fur, permitted to move only one direction (inward) by the barbs. Therefore, the foxtails can become irreversibly lodged.

Muscular movements (or air flow, in the case of nostrils) can cause the foxtails to continue to burrow through soft tissues, causing infection and physical damage to associated tissues.

Foxtails that have progressed no further than the hair or skin, are readily removed. Once a foxtail has passed beneath the skin however, the inciting cause (foxtail) can be difficult to diagnose, and clinical cases are managed for chronic abscesses. The regional disease and inflammation is often extensive during acute or recurrent episodes, but is readily consolidated with a course of broad-spectrum antibiotics. This “resolution” can lure pet owners into a false sense of security, and many dogs will have dramatic relapses unless the offending foxtail is retrieved. Unfortunately, because radiography and ultrasound rarely identify plant material as small as a foxtail, pre-operative identification and surgical planning are difficult. Advanced imaging (CT, CT fistulogram, MRI) have revolutionized this planning, and have therefore greatly decreased the associated operative morbidity.

Wally exemplifies this clinical dilemma, and evolution in diagnostic imaging.

Wally, a 4-year-old male neutered Plott hound, was presented to VSCD for evaluation of a persistent and recurrent 10cm fluctuant swelling in the right paralumbar fossa of six weeks duration. Five months earlier Wally had previously been evaluated by his family veterinarian for a nonproductive cough and fever. Diagnostic workup at that time was consistent with mild-moderate bronchopneumonia and equivocal pancreatitis. The cough and fever responded to a four-week course of enrofloxacin. However, Wally presented again in late summer for a right paralumbar fossa abscess. Culture of the exudate yielded a polymorphic growth of E.coli and corynebacterium species, raising suspicion for a migrating foxtail or plant material.

A two-week course of ampicillin and enrofloxacin was prescribed based on susceptibility testing, to consolidate the paralumbar disease in preparation for imaging and surgery. CT and CT fistulogram were performed and revealed a right abdominal subcutaneous abscess and cellulitis, with sublumbar myositis suspected to be originating from a small linear foreign body within the sublumbar musculature subjacent to L3-L4.

Based on the 3D spatial localization provided by contrast CT, we explored the right paralumbar fossa and extended this dissection to the retroperitoneal sublumbar musculature – identifying and retrieving a single foxtail spikelet.

Wally was discharged 48 hours after surgery and has not had a recurrence of his paralumbar swelling or pain in the three months post-operatively.

Wally’s case is a great and humbling example the merits of advanced imaging in reducing operative and perioperative morbidity for suspected and confirmed foxtail disease.

	Figure 1. “Wally”
	Figure 2. CT Assisted Fistulogram
	Figure 3. A graduated Bard-Parker number 3 handle highlighting the depth of the surgical dissection beneath the longissimus muscles
	Figure 4. Closure of the surgical incision with closed suction drains in place
	Figure 5. The offending foxtail spikelet - a little smaller than a penny