The icteric cat: a case study (Proceedings)

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The icteric cat: a case study (Proceedings)

Orogastric tube feeding permits the instillation of substantial amounts of high quality food into the cat’s stomach in a few seconds.
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Oct 01, 2011

Acute cholangiohepatitis

  • Bacteria (usually anaerobes) live in the duodenum.
  • They ascend the bile duct for reasons unknown.
  • They go through the gall bladder and hepatic ducts to the liver.
  • This results in an infection in the liver and gall bladder.
  • The liver enzymes elevate – after few days of the infection
  • If you check them too soon they will be normal.
  • This is an infectious disease but not a contagious disease.
  • Clinical signs include
  • Lethargy, anorexia, and fever
  • Possibly icterus – depending on severity and duration.
  • It usually occurs in young, adult cats.
  • Treatment
  • Antibiotics especially effective against anaerobes
  • Amoxicillin: my drug of choice (+ Zeniquin)
  • Metronidazole: narrower spectrum, hard to dose, CNS side effects
  • JVIM, May 2007, p. 417. 
  • Biliary cultures positive 23% of the time
  • Liver cultures positive 6% of the time
  • More positive liver cultures if the sample is collected by laparotomy or laparoscopy than by percutaneous needle biopsy.
  • Therefore
  • Do laparotomies for sample collection
  • Consider bile cultures
  • If collected by needle aspiration, empty the gall bladder to minimize the chances for bile peritonitis
  • Do not limit your antibiotic selection to drugs that only get anaerobes
  • Good combo: penicillin + fluoroquinolone
  • Amoxicillin (Clavamox?) + Zeniquin
  • Prognosis: Good if treated long enough with the correct antibiotic.  (2-6 weeks)
  • Usually diagnosed with the clinical picture of
  • Fever, anorexia, lethargy.
  • Response to amoxicillin or Clavamox.
  • In a non-fighting cat.

Hemobartonellosis (hemoplasmosis)

  • New name; no longer considered to be a Rickettsial organism; now a Mycoplasma organism
  • Mycoplasma hemofelis (large form): the primary pathogen
  • Mycoplasma hemominutum (small form): pathogenic when with FeLV or FIV.
  • Mycoplasma turicensis: recently discovered; significance unknown at this time.
  • Diagnostic Essentials
  • Presence of the organism on the RBCs
  • Anemia
  • Evidence of bone marrow response (regenerative anemia)
  • PCR for hemoplasmosis: Several commercial veterinary & university veterinary labs
  • Treatment
  • Doxycycline: 50 mg q24h
  • Baytril: 5 mg/kg q24h; no fever; blindness typically associated with higher doses

Hepatic lipidosis

  • Clinical Signs: anorexia, weight loss, icterus
  • Lab tests: normal Hct, elevated AP, normal GGT
  • Treatment
  • Vitamin K: clotting problems due to liver disease; give 2 doses before liver biopsy       
  • 5 mg/kg SC q12h
  • Fluids: IV (if dehydrated) or SC
  • Food
  • The cat’s gastric capacity may be 10% of normal so small feedings are needed to avoid vomiting.
  • Initially via orogastric tube at 20 mg TID.
  • Eventually by esophagostomy or gastrostomy tube
  • Vitamin B12
  • Stimulates appetite; stimulates methylation reactions; stimulates endogenous SAMe production; helps restore normal liver function; 250-500 mcg q24h
  • B-complex Vitamins
  • 2 ml to each liter of fluids; protect from light
  • Denosyl: a very active form of s-adenosylmethionine (SAMe); Nutramax – (800) 925-5187)
  • Up to 10# cat: 90 mg q24h
  • 10-25# cat: 2 X 90 mg q24h
  • Double the dose if fasting is not feasible
  • Marin: the active ingredient in milk thistle; promotes liver regeneration; Nutramax
  • Denamarin available – combo of Denosyl and Marin
  • Antiemetics PRN: Zofran (ondansetron)  0.2-1.0 mg/kg BID-QID + metoclopramide
  • Cerenia: Use same dose in the cat as in the dog.  Excellent efficacy.  Adverse events: injection-site pain and constipation.

Fine needle biopsy of the liver

  • Ultrasound guidance needed
  • Pros: Minimally invasive; much better sample than a fine needle aspirate
  • Cons: Not as good a sample as a wedge biopsy
  • Equipment: 12 cc syringe; IV extension set; 22 ga. disposable needle
  • Penetrate the liver capsule at one location and do the “woodpecker” technique

Morals of the story

  • “Cost is of concern” is often an excuse.
  • Do not diagnose hemoplasmosis without establishing the presence of a regenerative anemia.
  • Do not assume that icterus is due to hemolysis; this is much less common than liver diseases.
  • Assume icterus is due to liver or biliary disease until proven otherwise.
  • Do not use doxycycline (or tetracycline) when liver disease is present without a compelling cause.
  • Do not give up on cats with “end stage liver disease” or hepatic lipidosis.
  • Remember that “Cats have 9 lives.

Orogastric tube feeding

Orogastric tube feeding permits the instillation of substantial amounts of high quality food into the cat’s stomach in a few seconds. The tube is passed but not left indwelling. It may be performed several times per day, if needed. This is a technique that trained veterinary technicians should be able to perform easily. However, it is not a procedure that owners should be taught except under very unusual circumstances.

The equipment includes an 18 Fr. feline orogastric tube, a feline mouth speculum, and two 60 cc catheter tipped syringes. (The tube and speculum are available from DVM Solutions, 1-866-373-9627.)  The author’s preferred feeding product is Maximum-Calorie (Iams). A 10 pound cat needs about 160 ml per 24 hours. One can is put in a microwavable container with 15 ml of water. After heating to about body temperature, the mixture is stirred well. Then, it is ready for feeding. What is not fed is placed in a refrigerator for storage up to 5 days. The next feeding is preceded by heating the food in a microwave to about body temperature. Failure to heat the food will result in very poor syringability and vomiting by the cat.

Feeding should occur on a gradually increasing schedule. A 10 pound cat should receive about 25-30 ml per feeding the first day. Depending upon what time of day feeding begins, it should get either one or two feedings that day. If there is no vomiting, it should get two feedings of about 50 ml twice the second day then about 80 ml twice per day thereafter.

Loading syringes

The food is removed from the refrigerator and warmed in a microwave oven. The syringes are filled with the calculated amounts. The tip of the orogastric tube is dipped into the food for lubrication. Both syringes are loaded and placed on the feeding table.

Routine feeding

The cat’s front and rear legs are held by one technician. The index finger is placed between the carpi, and the hand is closed resulting in wrapping the thumb around one leg and the other 3 fingers around the other. The same approach is taken for the rear legs at the level of the hock. The cat is held in an upright position so gravity facilitates the food staying in the stomach. The mouth speculum is placed in the cat’s mouth so its canine teeth are in the rectangular holes. The tube is advanced through the oropharynx. The tube is passed so only about 2-4 inches are visible. This assures that it is in the stomach. The first syringe is attached to the tube and emptied. To empty this large syringe, the base of the plunger is placed against one’s sternum, and the plunger is pushed into the barrel by leaning forward. Be sure to hold the flange of the tube and the barrel of the syringe as the food is injected. Be sure not to pull the tube out of the stomach as the food is injected, as the esophagus will not hold 60 cc of food. The first syringe is removed, but the tube is not. The second syringe is attached and emptied in the same manner. The tube is removed with the syringe attached. This prevents food from dribbling into the pharynx during tube removal.

About 10% of the time a third person is needed for restraint. This occurs because the cat is resistant to feeding and is strong enough to pull its head out of one's hand or the cat is especially large. Note that the third person uses both hands to hold the cat's neck so it cannot continue to pull away. This permits easy and efficient feeding.

Problems and special situations

There are some situations that require caution. Cats that are fractious should not be fed with an orogastric tube because there is increased risk of passing the tube into the trachea and infusing food into the lungs. If the medical situation permits, the fractious cat can be given a low dose of acepromazine, diazepam, or other sedative then fed. However, do not sedate the cat so the swallowing reflex is diminished. Cats with intrathoracic disease (heart failure, pulmonary edema, pleural effusion, etc.) that compromises respiration should not be fed with an orogastric tube as the stress of this procedure could decompensate them. Cats with nasal congestion (upper respiratory infections) should be fed with caution. Cats are nasal breathers and become anxious when forced to breathe through their mouths. If the nasal passages are blocked and an orogastric tube is passed, they can panic and die of respiratory failure.

If the cat is very small, proper tube depth can be determined by placing the tip of the tube at the level of the last rib and marking the tube at the level of the cat’s nose. The 18 Fr. orogastric tube is too large for kittens less than 6 months of age. For those cats use an 12 Fr. rubber tube (Sovereign Feeding Tube and Urethral Catheter). However, the food (Maximum Calorie) needs to be poured through a kitchen strainer to remove particles that will obstruct this smaller tube. It may also be necessary to add more water than described above. However, the more water is added the more the quantity of food is needed.

Esophagostomy tube placement

Indications

The purpose of the esophagostomy tube is to permit feeding for long periods of time in anorectic cats. It is placed in the esophagus, not in the stomach. If it is in the stomach the lower esophageal sphincter will be open permitting reflux of gastric acids that will cause esophagitis.

Surgical procedure

Esophagostomy tubes are available from DVM Solutions, 1-866-373-9627.

Anesthesia should be induced with either propofol or an anesthetic gas (sevoflurane, isoflurane, or halothane). The cat should be intubated and maintained on a gas anesthetic.

Prep the left side of the cat’s neck because the esophagus is on the left at this level. If the tube has a closed tip, cut the tip off so food flows out its end. A stylet is inserted into the tube so the tip of the stylet is at the tip of the e-tube. It should not protrude from the end. A curved 5-7” forceps is inserted through the mouth into the esophagus. The tip of the hemostat is seen pointing laterally. Go nearly to the point of the shoulder if your hemostat is long enough.

Position the tip of the hemostat so it is about 2 cm dorsal to the jugular vein. Cut over the tip of the hemostat until it is exposed. A final cut of transparent esophageal lining is needed. Grab the stylet-containing tube and pull it about 2-3 cm into the esophagus. Release the forceps and remove them from the mouth as you redirect the tube in a caudal direction. Traction on the cat’s head in a cranial direction aids in this step. Advance the tube and stylet about 2 cm, and then withdraw the stylet as the tube is further advanced into the esophagus. Advance it so about 8 cm of tube is visible.

Using soft, 3-0 or 4-0, non-dissolvable suture material, create a purse string suture around the tube. Tie the suture in the center so about 20 cm ends are remaining. Using these ends make a Chinese finger trap to secure the tube. To do so, pass the ends of the suture around the tube in opposite directions then tie them off, being careful not to crimp the tube with the knots. Repeat this two more times, moving up the tube 2-3 mm with each knot.

Spray the hairless area with 3M No Sting barrier spray. (This product is available through veterinary distributors that carry products made by 3M Animal Health.) Hold the cat’s head over the edge of the table to facilitate the taping procedure. Make a gentle curve with the tube so the plastic fitting is at the dorsal midline and directed caudally. Wrap 1” adhesive tape around the plastic fitting then encircle the cat’s neck several times to completely cover the exposed parts of the tube.

Feeding procedure

Feeding should occur in such a way as to prevent too much food being delivered into the esophagus at one time. Dispensing 12 cc syringes is safer than 35 or 60 cc syringes. Elevating the cat’s front end during food injection is also helpful. Tell owners to inject the food at the rate of 1-2 cc every second.

When the food had been injected, flush the tube by injecting 2-3 cc of tap water. This prevents food drying in the tube and causing an obstruction. The final step is to replace the cap.

Changing the bandage

The tape holding the esophagostomy tube in place should be changed about every 2 weeks. To do so, the old tape is cut and removed completely from the tube. When the tape has been removed, it is important not to let the cat shake it head or it might cause the tube to come out, requiring surgical replacement. The area is cleaned with hydrogen peroxide. The skin is sprayed with No Sting Barrier Spray. A 2 by 2 gauze square is cut to it will fit around the esophagostomy tube. Triple antibiotic ointment is applied to it. The gauze is placed around the tube so the ointment is on the ostomy site. Tape is reapplied to the esophagostomy tube and around the neck as done at the time of e-tube placement. It is important that the bandage stick to the skin and hair so the cat cannot dislodge it. It is also important that the bandage is not placed so tightly that the cat is uncomfortable.

Tube removal

Tube removal should occur after the cat has been eating for 3-4 days. The bandage and suture are cut, and the tube is removed. The ostomy should not be sutured; it will close in 2-3 days.

What to feed

Norsworthy’s preferred feline diet is Iams Maximum-Calorie (canned).

Put 3 cans in a microwavable container and add 45 ml of tap water. Heat in a microwave until it is about body temperature. Shake or stir to achieve even consistency and heating.

A 10# cat should be fed about 120-140 ml of this mixture per 24 hours. This amount should be divided into 2 to 4 feedings per day.