David E Anderson, D.V.M., MS, Diplomate ACVS
College of Veterinary Medicine
The Ohio State University, Columbus, Ohio
South American Camelids (llamas, alpacas)
May represent a significant financial investment for the owner, but they are viewed most commonly as pets, companions, or valued friends. Veterinarians should be aware of potential life-threatening lesions associated with the acute abdomen (colic). Camelids demonstrate clinical signs of abdominal pain similar to those seen in true-ruminants (depression, recumbency, abnormal posture) and horses (kicking at the abdomen, rolling). Clinicians working with camelids must become familiar with the normal activity, anatomy, physiology, and diseases common to these interesting patients.
The esophagus enters the first forestomach compartment (C1) where digesta is fermented, eructated, re-swallowed, passed through the second compartment (C2), third compartment (C3), and pylorus into the duodenum. C1 and C2 function as fermentation chambers and absorb water and various nutrients. C1 motility waves travel from caudal to cranial (2 to 4 per minute). The proximal 80% of C3 absorbs water and nutrients; the distal 20% of C3 is acid secretory and performs gastric digestion. The pH changes from 6.5 to 7.0 in C1, C2, and proximal C3 to 2.0 to 3.0 in the distal C3. The duodenum continues as the jejunum and, then, ileum. The ileum enters the large intestine at the cecocolic junction. The cecum is small and the proximal loop of the spiral colon (ascending colon) is long and larger in diameter than the spiral colon. The spiral colon exits into the transverse colon, descending colon, rectum, and anus.
Although young camelids (< 6-mo-old) demonstrate clinical signs of acute abdominal pain (kicking at the abdomen, rolling, thrashing), these signs are less commonly observed in mature animals. Mature camelids demonstrate abdominal pain as restlessness, lying down and getting up frequently, vocalizing, grinding teeth, straining to urinate or defecate, flagging the tail, lying their head and neck flat against the ground or down across their back, and lying in an abnormal cush position. Changes in diet, defecation, urination, and recent activity (transportation, showing, weaning) are critical pieces of information.
The physical examination should be complete and thorough. Patience is the key. The clinician must differentiate abdominal diseases from those of neurologic or musculoskeletal origin. Physical examination variables in normal adult camelids include: Temp - 37.5 to 38.8 C, heart rate - 60 to 80 beats per minute, respiratory rate - 10 to 30 breaths per minute, and rumination waves - 2 to 4 per minute. Abdominal distention may be evaluated by palpation, simultaneous auscultation/percussion/succussion, and orogastric intubation. The animal's body condition should be evaluated for evidence of chronicity. Digital rectal should be done to determine if feces are present in the rectum. Rectal examination must be performed carefully. Rectal tears have been induced in camelids. The decision to perform rectal palpation may be based on the animal's size and temperament, the palpator's experience, and the expected benefit. I instill 40 ml lubricant and 20 ml 2% lidocaine into the lumen of the rectum and liberally lubricate the rectal sleeve. An epidural may be used to aid the examination of anxious patients.
Selection of laboratory tests is based on history and the results of physical examination. Our "colic work-up" includes a CBC with differential, fibrinogen, serum electrolytes, glucose, creatinine, BUN, SDH, GGT, and CPK. Unlike cattle, camelids do not usually suffer hypochloremic metabolic alkalosis with intestinal obstruction. This is probably because all three forestomachs are absorptive. However, hypokalemia is commonly found.
Ancillary Diagnostic Tests
Ancillary diagnostic tests are chosen based on history, physical examination findings, and initial laboratory data. The common tests performed include C1 fluid analysis, abdominal ultrasound and radiographs, peritoneal fluid analysis, urinalysis, and fecal examination / flotation / occult blood analysis. Other available procedures include laparoscopy, endoscopy, and positive contrast urethrography. The urinary bladder in males can not be routinely catheterized because of the presence of the urethral recess at the level of the ischial arch.
Indications for Surgery and Differential Diagnoses (see table)
Continuous and intractable pain is an indication for exploratory surgery. However, in my experience, C3 ulcers in crias may be exceptionally painful for up to 48 hours after initiating treatment. Persistent, low-grade discomfort despite supportive therapy is an indication for abdominal exploratory. Temp, heart rate, or respiratory rate have not been reliable indicators of surgical lesions. Abnormal rectal palpation findings are an indication for exploratory surgery. Failure to pass feces for > 24 hours is suggestive of intestinal obstruction. Failure to urinate for > 6 to 8 hours is suggestive of urinary tract obstruction. Ultrasound identification of intestinal or urinary bladder distention is suggestive of intestinal or urethral obstruction, respectively. Exploratory surgery should not be used as a "last resort" to establish a diagnosis. Exploratory celiotomy can be done safely and efficiently when performed early in the progression of the disease. Laparotomy performed as an emergency or in a deteriorating patient is more likely to result in complications or death.
Unlike cattle, ventral midline celiotomy with the patient under general anesthesia is the approach of choice for exploratory laparotomy. Paralumbar fossa laparotomy may be useful for nephrectomy, ureteral manipulation, C1 or C3 enterotomy, unilateral ovariectomy. Exploratory celiotomy may be performed after sedation and regional anesthesia, but this procedure is highly discouraged because of the potential for contamination of the abdomen and discomfort to the patient caused by visceral manipulation.
Surgical Diagnosis and Treatment
The most common reason for abdominal surgery in our practice is to perform Cesarian section either because of uterine torsion with poor cervical dilation or severe fetal malposition. Intestinal obstruction is a common cause of surgical gastrointestinal lesions. We have treated digesta impaction of the proximal loop of the spiral colon, enterolith obstruction of the spiral colon, extramural obstruction of the descending colon caused by an umbilical abscess, and post-operative obstructive adhesions with small intestinal strangulation. Impaction of the proximal loop of the spiral colon may be treated by instillation of saline into the mass, message of the impaction, and administration of IV fluids for 48 hours. Enteroliths may be removed via enterotomy. Compromised bowel (strangulation, intussusception) may be treated by resection and end-to-end anastomosis. Umbilical (and rarely inguinal) hernias are occasionally diagnosed in young camelids, but intestinal incarceration or strangulation is uncommon. We perform open herniorrhaphy with appositional closure of the abdominal wall in all patients to ensure that infected umbilical remnants do not remain in the abdomen. Urethral obstruction is an uncommon lesion in our practice, but has been seen more commonly in other geographic regions. Closure of the linea alba should be done using an appositional pattern. I prefer a cruciate suture pattern with No. 1 or No. 2 PDS, Vicryl, or Maxon. Simple continuous suture patterns are acceptable, but the incision should be divided into three segments with each segment closed with a separate simple continuous closure. The skin of the ventral midline in camelids is thin and pliable. Therefore, I routinely place a subcuticular suture pattern (No. 2-0 Vicryl or Monocryl) and do not use skin sutures. An abdominal bandage maintained for 3 days after surgery (changed daily) may markedly reduce post-operative incisional swelling.
Camelids appear to be fairly tolerant of intestinal surgery when performed early in the progression of the disease. Ileus has not been a limiting factor in the outcome of our cases. However, ileus is a prominent feature with transmural enteritis.
Complications of Disease or Treatment
Incisional infection or hernia appear to be uncommon complications of celiotomy. I routinely place crias on sucralfate (1 to 3 g, po, Q8h) as a prophylaxis for C3 ulcers. H2 blockers are ineffective in camelids; therefore, omiprazole (0.4 mg/kg, IV, Q6 to 8h) may be administered to decrease acid secretion in C3.
The decision to perform exploratory celiotomy can be frustrating. In general, medical diseases affecting the abdomen are far more common than surgical lesions. However, diagnosis of a "medical" lesion by exploratory celiotomy may be an acceptable procedure when a definitive diagnosis can not be made based on historical, physical examination findings, laboratory data, and clinical observation. Diagnosis of a "surgical" lesion by the pathologist is undesirable!