Examination of the abdomen
As with all areas of the body, examine the abdomen thoroughly, observing and recording any abnormalities:
Examine the external surfaces of the abdomen for swellings, abnormal external lumps or masses, bite wounds, claw wounds, bullet wounds, puncture wounds, etc. Small puncture wounds on the abdominal wall must be explored carefully to determine whether they penetrate into the abdominal cavity in which case there is a significant risk of peritonitis and damage to abdominal organs. Check for any oedema (fluid collection) in the skin and subcutaneous tissue along the ventral border of the abdomen. Monitor for signs of bloat (gas build up in the stomach) – although rare in tigers it can happen.
Palpate all internal areas of the abdomen carefully attempting to identify the major organs and any abnormal masses. Although this can be done with the tiger on its side, it is often easier when placed on its back. In adult tigers the size of the abdomen makes detailed palpation difficult. This is especially so in individuals that have ample abdominal fat reserves. However, it should be possible to palpate large masses, feel free fluid if an effusion is present and identify any significant build-up of gas in the intestines (bloating). Firm faecal material in the large bowel is not an unusual finding. In infant tigers it is important to examine the umbilicus for signs of swelling or infection.
The following organs should be identified if possible, but this will require knowledge of abdominal anatomy: Stomach, liver, spleen, kidneys, intestines, bladder, and in the case of a female, the uterus. (In a non-pregnant female or one in the early stages of pregnancy this will not be possible. However, it should be possible in an adult female that is in the mid to late stages of pregnancy). With experience it is also possible to identify a grossly infected and swollen uterus (pyometra).
The mammary glands of female tigers should be examined and checked for lactation as well as wounds, masses and asymmetry. Tigers that have just entered a rehabilitation centre and are lactating may have dependent cubs somewhere or be in the late stages of pregnancy.
MORE ADVANCED DIAGNOSTIC TECHNIQUES:
Some advanced diagnostic techniques such as radiography, ultrasonography and endoscopy are undoubtedly valuable in investigating structures in the abdomen. However, these are specialist disciplines requiring expensive equipment and considerably veterinary skill and experience to conduct and interpret. Other advanced techniques require veterinary expertise but can be performed with relatively simple equipment.
Abdominocentesis is the collection of free fluid from the abdomen. A sedated tiger should be placed in right lateral recumbency. An area centred on the umbilicus is clipped and cleaned with surgical scrub. A 2.5 cm x 19 gauge needle is then inserted caudal to, and to the right of, the umilbicus. The needle should initially be inserted without a syringe attached as an open needle is more likely to result in fluid flow. If there is fluid flow a syringe can then be attached to collect a sample. Fluid should be placed in EDTA tubes for cytology and in a sterile plain tube for culture.
Collecting free fluid by abdominocentesis in tigers is unusual and is an abnormal finding. See Sampling & Testing for Health Screening resource for details of the types of fluid and their causes.
Catheterising the bladder is usually performed to collect a clean urine sample, to empty the urinary bladder, or when combined with radiography to instill a contrast agent into the urinary tract.
For male tigers a flexible sterile urinary catheter 60 cm in length and 2–4 mm in diameter (6-12 French gauge) is used. The tiger should be positioned in lateral recumbency and the tail held upwards and out of the way of the prepuce. The prepuce is cleaned with an antiseptic and the catheter removed from its outer wrapper and the tip covered in lubricant such as KY gel. The penis should then be extruded using gently pressure each side of the prepuce. The catheter can then be gently introduced into the urethra, and advanced by holding the penis and prepuce and pulling them gently in a caudal direction to straighten the urethra. Urine will flow down the catheter as soon as it enters the bladder. A syringe attached to the free end of the catheter is used to collect a sample.
For female tigers a flexible sterile urinary catheter 60 cm in length and 3-5 mm in diameter (9-15 French gauge is used. The tiger is be positioned on its back and the hindlimbs held flexed cranially. The vulva should then be cleaned with antiseptic. The catheter is removed from its outer wrapper and the tip covered in lubricant. A speculum with light is then be inserted into the vestibule and the site of the urethral orifice on the ventral floor of the cranial vestibule identified. The catheter can then be gently advanced into the bladder. Urine will flow down the catheter as soon as it enters the bladder. A syringe attached to the free end of the catheter is used to collect a sample.
Cystocentesis is used to collect a sample of urine direct from the bladder. It is very difficult to perform without ultrasound guidance in adult tigers but in cubs and immature individuals it is possible using palpation. In an adult tiger the animal should be placed in lateral or dorsal recumbency (on its back) and the caudal abdomen clipped and prepared for an ultrasound examination. When the bladder has been identified using the ultrasound probe an area over the site should be aseptically prepared. Using ultrasound guidance, a 5 cm x 21 gauge needle is then inserted into the bladder and a sample of urine drawn up into a syringe attached to the needle.
Small tigers should be positioned in dorsal recumbency and the bladder palpated manually in the caudal abdomen. An area of fur is shaved and aseptically prepared in the mid-line just in front of the pelvic brim. A 5 cm x 21 gauge needle is then inserted into the bladder and a sample of urine drawn up into a syringe attached to the needle.
The urine collected should be placed immediately in a sterile plain tube for basic urinalysis, urine protein: creatinine ratio and sediment analysis; and in a boric acid tube for culture. Both tubes should be stored in a fridge before analysis. (See Sampling & Testing for Health Screening resource)
Endoscopy of the gastrointestinal tract is a medical procedure in which an instrument (an endoscope, or ‘scope’) is introduced into the gastrointestinal tract to gain a view of internal structures. It is unlikely to be practical in field circumstances requiring expensive equipment and specialist training. Long endoscopes (> 3 metres) are necessary for tigers even to evaluate the oesophagus and stomach. In mid- sized and adult tigers most endoscopes will not be long enough to reach the duodenum.
Radiography is an advanced imaging technique using X-rays or similar ionizing radiation to view the internal form of an object. Diagnostic radiography does have a role in detecting abnormalities in abdominal organs in tigers, but for adults a powerful machine is required. There are significant health and safety issues to be addressed by operators of xray equipment, and interpretation of the images is a specialist task. Battery operated units suitable for use in the field are available at a price.
Ultrasonography is an extremely useful technique to investigate structures within the abdomen, although the equipment is currently expensive and requires specialist training to use effectively. It is recommended that a clinician with extensive ultrasonography experience performs any scan. For adult tigers a 3.5MHz convex probe is recommended. A detailed description of the equipment and its use will not be given here.