DISEASE SUMMARY PAGE

Epilepsy and Convulsions in Bears, Lagomorphs and Great Apes

Summary Information
Diseases / List of Miscellaneous / Metabolic / Multifactorial Diseases / Disease summary
Alternative Names
Disease Agents
In Bears
In Lagomorphs

Primary idiopathic epilepsy is rare in rabbits but is sometimes seen in blue-eyed white rabbits. (B601.11.w11, B603.4.w4; B606.13.w13, J15.28.w1)

  • Idiopathic epilepsy is more prevalent in blue-eyed, white breeds of rabbits, such as the Beveren white and the Vienna white. (B603.3.w3)
  • A strain of blue-eyed white rabbits (Beverens and hybrids of these) was found to be susceptible to audiogenic seizures. (J462.193.w1)

Other causes of seizures in rabbits include: (B601.11.w11, B602.20.w20, B603.1.w1, B603.3.w3; B606.13.w13, J15.28.w1)

In Bonobos/Great Apes
  • In a wild-born adult female bonobo (Pan paniscus - Bonobo) possibly related to calcified lesions detected in the cerebrum and cerebellum. Seizures were most common in the week before menstruation, correlating with loss of the protective effect on progesterone. (J2.42.w1)
  • In a wild-born adult female at Milwaukee Zoo (born about 1972), associated with ovulation; these may have been due to the proconvulsant effects of oestrogen. (J2.42.w1)
  • In a male western lowland gorilla (Gorilla gorilla - Gorilla), probably associated with hydrocephalus. (J2.42.w1)
Infectious Agent(s) --
Non-infectious Agent(s)
Physical Agent(s) --
General Description
In Lagomorphs
  • Primary idiopathic epilepsy is rare in rabbits, although seizures may occur for a variety of reasons (see above). (B603.4.w4; B606.13.w13)
In Bears
  • Epileptic seizures, increasing in frequency, occurred in one yearling Ursus arctos - Brown bear at Berne Barengraben for six weeks before the bear was euthanased. (B214.3.4.w16)
  • In one Ursus maritimus - Polar bear, seizures occurred about weekly; the bear eventually died of other causes. (B16.9.w9)
  • In an Ursus thibetanus - Asiatic black bear, at Antwerp Zoo, clonic jerks involving all four limbs were seen. Other signs included anorexia, weight loss and dry lips. The bear became more drowsy and died after one week. (J271.19.w1)
  • A male Ursus americanus - American black bear, about eight years old, at Antwerp Zoo, developed severe epileptic attacks involving the left side, and also severe behavioural changes: indifference towards his keeper, refusal to eat and play, and periods of several minutes at a time screaming in fright. On examination, it was lethargic and reluctant to rise, although locomotion appeared normal. When lying down, myoclonic jerks were seen affecting the proximal muscles of the hind legs and the abdominal wall. Three weeks later, after considerable weight loss, it showed severe thirst; by this time it also appeared to have balance problems. It died a week later. (J271.19.w1)
  • A second male Ursus americanus - American black bear, about 4-5 years old, at Antwerp Zoo, lost weight, became drowsy, showed occasional involuntary movements, turning aimlessly to the left then falling, developed a horizontal head tremor and a few days later showed jerking of all four legs, and limitation of neck movement. After about three weeks it developed rigidity, was unable to rise and had several seizures with opisthotonus; a week later it died. (J271.19.w1)
  • One adult female moon bear (Ursus thibetanus - Asiatic black bear) was euthanased due to epileptic fits. (P85.1.w4)
  • "Petit mal" type seizures have been observed in a male Tremarctos ornatus - Spectacled bear, seen particularly just before feeding. (P77.1.w19)
  • A 20-year-old male Tremarctos ornatus - Spectacled bear had convulsive seizures for a period of four years, which occurred particularly during feeding and in the winter. The bear was eventually euthanised because of the repeated fits. (P85.1.w4)
  • A hand-reared Ursus maritimus - Polar bear was observed in convulsions soon after drinking a whole bowl of water, and subsequently in the next few days until the water was strictly rationed and then gradually increased. (J23.12.w2)
  • In two hand-reared Ursus maritimus - Polar bear, convulsions started in a male cub at 55 days of age and recurred to 65 days when the seizures lasted for more than an hour and the cub never regained consciousness. The female sibling first developed a convulsion on day 61, and died on day 71. (J23.11.w3)
Pathology
In Bonobos/Great Apes
  • In a wild-born adult female bonobo (Pan paniscus - Bonobo) at Milwaukee Zoo (born about 1950), seizures were seen periodically starting in 1986 and particularly in the week before the onset of menses; they became exacerbated during perimenopause. (J2.42.w1)
  • In a wild-born adult female  at Milwaukee Zoo (born about 1972), seizures occurred on the day of ovulation (determined by urine ovulation test); examination of records revealed injuries had commonly been recorded on the day of ovulation, in retrospect these were presumably associated with unobserved seizures.  (J2.42.w1)
  • In a male western lowland gorilla (Gorilla gorilla - Gorilla), seizures occurred at one month old, stopped, then recurred five months later. (J2.42.w1)
Further Information
In Lagomorphs
Treatment
  • Diazepam or midazolam, intravenously, intramuscularly or subcutaneously. (B602.20.w20, J29.16.w7)
  • Oral phenobarbitone, 1-2 mg/kg per day may be useful for control of seizures in the absence of a specific diagnosis, but the prognosis is poor. (J15.28.w1)
  • Consider systemic antibiotics. (J15.28.w1)
  • Supportive care. (J29.16.w7)
In Bears

Note: Seizures have been reported not uncommonly associated with bear anaesthesia. 

Treatment
In Bonobos/Great Apes
Diagnosis
Treatment
  • In a female Pan paniscus - Bonobo wild-born in about 1950: (J2.42.w1)
    • Initially phenobarbital (Phenobarbitone) 100 mg orally twice daily; this produced partial control and dosage was adjusted depending on the frequency of seizures.
    • By 2000, 120 mg orally twice daily was failing to control seizures, and higher doses produced somnolence. Also, doses of 150 mg orally twice daily resulted in abdominal bloating. (J2.42.w1)
    • Acetazolamide 250 mg orally twice daily plus phenobarbitone 100 mg orally twice daily controlled seizures fully for about a year. With recurrence of seizures, acetazolamide was increased to 312.5 mf orally twice daily, and phenobarbital was increased just for a few days in the week before the onset of menses (when seizures were most likely to occur). (J2.42.w1)
    • When the bonobo entered perimenopause and cycles became irregular, oral birth control pills (1 mg norethindrone acetate plus 20 g ethinyl estradiol) were given daily for periods of 12 weeks with a two-day hormone-free interval between each set of 12 weeks. Higher doses of phenobarbital were given during the two hormone-free days; breakthrough seizures occurred only infrequently. (J2.42.w1)
  • In a female Pan paniscus - Bonobo wild-born in about 1972:
    • Initially 121.5 mg phenobarbital orally twice daily, but this resulted in lethargy and painful abdominal bloating. (J2.42.w1)
    • Levetiracetam, initially 250 mg orally, twice daily; this resulted in fatigue and aestenia, therefore the dose was lowered to 125 mg orally twice daily; this dosage did not disturbe behaviour but gave a blood level of 3.7 micrograms/mL (blood taken six hours after dosing), which in humans would be considered subtherapeutic. Six months later, after a further seizure, the dose was returned to 250 mg orally twice daily and side effects were not a problem; this dosage gave a blood level of 7.2 micrograms/mL 5.5 hours after dosing. (J2.42.w1)
    • Additionally, the bonobo was given an extended-cycle oral contraceptive regime. (J2.42.w1)
    • Treatment was effective as indicated by a lack of further seizures observed prior to the bonobo's death from cardiovascular disease and stroke. (J2.42.w1)
  • In a male Gorilla gorilla - Gorilla: (J2.42.w1)
    • Initial phenobarbitone (15-30 mg orally once to three times daily) and dilantin (15-30 mg orally once to twice daily) were not effective. Dilantin was discontinued due to excessive drowsiness.(J2.42.w1)
    • Carbamazepine 50 mg orally twice daily was started after 19 days, with dose frequency increased to three times daily at one year; phenobarbital was tapered and discontinued after the first week of carbamazepine. The treatment was successful as indicated by a lack of seizures, and the drug was gradually reduced and discontinued some years later. (J2.42.w1)
Associated Techniques
Host taxa groups /species Further information on Host species has only been incorporated for species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken). Host species with further information available are listed below:

Lagomorphs

List does not contain all other species groups affected by this disease. [N.B. Miscellaneous / Traumatic Diseases tend to be under-reported and the majority are likely to affect all bird and mammal species, given exposure to the related disease agents/factors.]

Disease Author Nikki Fox BVSc MRCVS (V.w103); Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referees John Chitty BVetMed CertZooMed MRCVS (V.w65)

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