Hello VETAHEADER! Time for our monthly newsletter. This one is all about rabbits! 🐰

First, we have a paper on the use of lidocaine constant rate infusion (CRI) in rabbits with gastrointestinal (GI) obstructions. GI obstruction is a very common condition in rabbits, often with compressed hair pellets in the proximal duodenum. The more proximal obstructions have higher rates of mortality! Because you are a VETAHEADER, you already know that lidocaine has prokinetic effects and can be used in rabbits with GI syndrome. 😉 But how effective it truly is?

In this retrospective study, they aimed to determine the survival to discharge rate of rabbits with GI obstructions treated with lidocaine CRI and other factors associated with survival. They used 64 events of GI obstruction in rabbits, from 2012 to 2021. No rabbits that were taken to surgery were used.

The results showed that 89.7% of rabbits treated with lidocaine CRI (n=39) survived to hospital discharge, while only 56% of rabbits that were not treated with lidocaine CRI (n=25) survived. Rabbits treated with lidocaine were 7.7x more likely to survive!

The take home message is: lidocaine CRI with IV fluids is an effective treatment for GI obstructions in rabbits and results in increased survival compared to medical management without lidocaine.

Second, we have a case report on cannabis toxicity in a pet rabbit. Dogs are most commonly exposed via ingestion of the cannabis plant or prepared edible products, but there were no previous published reports in lagomorphs. Common clinical signs of intoxication in dogs include ataxia, urinary incontinence, mydriasis, depression, or hyperesthesia. Less common ones are hypersalivation, hypermetria, vomiting, tremors, seizures, hypothermia, tachycardia OR bradycardia.

A 3-month-old, male, intact mini rex rabbit was evaluated on an emergency basis for a seizure-like episode. The rabbit presented subdued mentation, bradycardia, sinus arrhythmia, and proprioceptive deficits. Results of a point-of-care blood glucose, complete blood count, and biochemistry panel were all clinically unremarkable. An over-the-counter human urine drug test was performed the following morning when the owners reported potential marijuana ingestion which was positive for tetrahydrocannabinol (THC). 

The rabbit was hospitalized for monitoring and subcutaneous fluids, because further treatment was declined. During 10 hours of hospitalization, the rabbit maintained adequate appetite and stool production, and the neurologic signs and bradycardia resolved without further intervention. 

The clinical signs were very similar to the ones seen in dogs, and CBC/chemistry often are unremarkable in dogs with THC intoxication as well.

The take home message is: suspected case of THC toxicity and recovery in a rabbit, with similar signs to dogs. THC is a metabolite excreted in urine of rabbits and over-the-counter human urine drug test kit can be used.

Lastly, we have a manuscript describing the ultrasonographic features of rabbits’ spleen. Conditions such as splenitis, lymphoid hyperplasia, and lymphoma can occur in rabbits, but data regarding splenic measurements and their variations is scarce in literature. Few previous reports have focused on normal ultrasonographic aspects and size of spleen.

This prospective study aimed to determine the normal ultrasonographic features of the spleen in pet rabbits, determine the normal ultrasonographic features of the spleen in healthy pet rabbits; determine the influence of different variables (i.e., probe frequency, age, sex, weight); and the effects of isoflurane anesthesia on ultrasonographic splenic measurements. Two groups were used:

• 49 healthy pet rabbits of various breeds and ages, without anesthesia;

• 23 rabbits with concurrent disease, evaluated before and after anesthesia.

Here are some highlights of the results:

• All rabbits tolerated handling without any signs of stress during ultrasound without anesthesia, and scanning in dorsal recumbency with ventrolateral probe positioning was adequate. 

• Spleen was visualized in 100% of rabbits. However, in 10 animals only the body and tail could be visualized, as the head was positioned dorsally under the stomach.

• Splenic parenchyma was iso- to hyperechoic to the hepatic parenchyma and iso- to hypoechoic to the renal cortex.

• Splenic parenchyma in adults had a homogeneous echotexture, and either a homogeneous or a mottled echotexture in animals younger than one year. 

• The reference interval for splenic thickness in healthy animals was 2.0-3.9 mm, regardless of the probe frequency (11 or 18 Hz). 

• The spleen was significantly thicker in anesthetized animals (+0.3mm). 

• No significant influence of age, sex, or bodyweight was detected.

The take home message is: the spleen can be routinely evaluated during abdominal ultrasonographic examination in pet rabbits. Ultrasonographic features and thickness of spleen in rabbits was described, and its size was increased under anesthesia. No relationship between thickness and age, sex, or body weight. Echotexture different in immature rabbits, which may be due to greater lymphoid activity.

I hope these are useful! 

As always, I will see you next month.