Association between estrus and onset of seizures in dogs with idiopathic epilepsy.

BACKGROUND: Catamenial epilepsy in humans is defined as changes in seizure frequency over the course of the menstrual cycle. Three hormonally based patterns of seizure exacerbation have been determined. OBJECTIVES: The aim of this study was to evaluate whether there is an association between onset of seizures and the estrous cycle in intact bitches with presumptive idiopathic epilepsy and whether a pattern to the onset of seizures could be recognized. ANIMALS: Forty-five intact female dogs from a hospital population with a presumptive diagnosis of idiopathic epilepsy. METHODS: In a retrospective study, the database of a small animal hospital in Sweden was searched for medical records of intact female dogs diagnosed with epilepsy or seizures. The stage of the estrous cycle as reported either by the owner or the veterinarian at the time of the first seizure was noted. RESULTS: Of the 45 dogs with idiopathic epilepsy, 17 (38%) had their first seizure when in heat and six dogs (13%) had their first seizure 1-3 months after heat. Nine dogs (20%) had seizures reoccurring in relation to their estrous cycle. CONCLUSIONS AND CLINICAL IMPORTANCE: These findings suggest an association between estrus and onset of seizures in intact bitches with presumptive idiopathic epilepsy. Two hormonally based patterns could be recognized: one during heat and one during a specific time point at the end of diestrus. This could be explained by the proconvulsive effects of estrogen or loss of protective effect against seizures of progesterone, respectively.

Comparison between symptomatic treatment and lomustine supplementation in 71 dogs with intracranial, space-occupying lesions.

Brain neoplasia is diagnosed in an increasing number of dogs. Consequently, there is a higher need for an effective treatment. Chemotherapy is considered in cases where surgery or radiation is not optional. The objective of this retrospective study was to evaluate the difference in median survival time (MST) of dogs with intracranial masses, treated symptomatically with corticosteroids and anti-epileptic drugs, compared with the same symptomatic treatment supplemented with lomustine. The records of 71 dogs with intracranial masses were retrospectively evaluated. Fifteen dogs were treated symptomatically with corticosteroids and anti-epileptics, and 56 dogs received additional therapy with lomustine. There was no statistically significant difference in MST between both groups, being 60 and 93 days, respectively. Age, duration of symptoms, intracranial localization of the mass and intra- or extra-axial localization had no influence on survival time. However, female dogs survived significantly longer than male dogs.

Current insights and controversies in the pathogenesis and diagnosis of disc-associated cervical spondylomyelopathy in dogs.

Disc-associated cervical spondylomyelopathy (DA-CSM) is the most common cause of cervical spondylomyelopathy in dogs. In this condition, progressive caudal cervical spinal cord compression is typically caused by protrusion of one or more intervertebral discs. This disc-associated compression is sometimes seen in combination with mild vertebral abnormalities and dorsal compression resulting from ligamentum flavum hypertrophy. The intervertebral disc space between the sixth (C6) and seventh (C7) cervical vertebrae is most commonly affected. Although several large breed dogs can be affected, the adult to older dobermann is overrepresented. Clinical signs vary from cervical hyperaesthesia to tetraplegia. Dogs can present with a chronic progressive or an acute onset of clinical signs. Many aspects of this multifactorial neurological syndrome are not completely understood and are the subject of controversy and debate. Although several factors have been proposed, the underlying pathology and aetiology remain unknown. Recently, new insights have been gained in the pathogenesis, diagnosis and treatment of this challenging neurological syndrome. This review outlines current controversies and new developments concerning the pathogenesis and diagnosis of DA-CSM.

Muscle potentials evoked by magnetic stimulation of the sciatic nerve in unilateral sciatic nerve dysfunction.

Magnetic stimulation of the sciatic nerve and subsequent recording of the muscle-evoked potential (MEP) was performed in eight dogs and three cats with unilateral sciatic nerve dysfunction. Localisation of the lesion in the sciatic nerve was based on the history, clinical neurological examination and on results of electromyography examination. Aetiology of the sciatic nerve lesion was diverse. A significant difference was found in MEP between the normal and the affected limbs. In addition, absence of conscious pain sensation, absence of voluntary motor function and a poor outcome seemed associated with the inability to evoke an MEP in the affected limb.

Clinical evaluation of 51 dogs treated conservatively for disc-associated wobbler syndrome.

OBJECTIVES: To evaluate the clinical evolution and potential risk factors of 51 dogs treated conservatively for disc-associated wobbler syndrome. METHODS: Medical records of dogs treated conservatively for disc-associated wobbler syndrome were reviewed, and owners were contacted regarding clinical evolution and survival of their animals. Relationships between age, treatment before diagnosis, type of neurological signs, results of medical imaging and outcome were determined. RESULTS: Fifty-one dogs underwent conservative treatment for disc-associated wobbler syndrome. A successful outcome was achieved in 45 per cent (23 of 51) of the patients. Median follow-up period was 18.5 months, and median survival time was 47 months. In 85 per cent of the dogs in which euthanasia was performed because of disc-associated wobbler syndrome, this was carried out in the first year after diagnosis. Outcome score was influenced by type of neurological signs and additional radiographic and/or myelographic abnormalities. Outcome score was not significantly associated with age, number of protruded intervertebral discs, occurrence, type and results of treatment before diagnosis. CLINICAL SIGNIFICANCE: Conservative treatment of disc-associated wobbler syndrome is associated with a guarded prognosis. It can be considered in cases where all four limbs are not affected and no additional radiographic and/or myelographic abnormalities are detected.

Hemifacial spasm associated with an intracranial mass in two dogs.

Two dogs were presented with hemifacial spasm. Computed tomography images of both the dogs revealed an intracranial mass. In the first dog, a lesion at the level of the medulla oblongata was thought to cause primary irritation of the facial nucleus, with consequently permanent contraction of the ipsilateral facial muscles. In the second dog, a mass seemingly arising from the middle cranial fossa presumably isolated the facial motor neurons from upper motor neuron control, which resulted in hemifacial spasm as a result of loss of inhibitory interneuronal activity.

Adenohypophyseal function in bitches treated with medroxyprogesterone acetate.

The aim of this study was to investigate the effects of treatment with medroxyprogesterone acetate (MPA) on canine adenohypophyseal function. Five Beagle bitches were treated with MPA (10mg/kg, every 4 weeks) and their adenohypophyseal function was assessed in a combined adenohypophyseal function test. Four hypophysiotropic hormones (CRH, GHRH, GnRH, and TRH) were administered before and 2, 5, 8, and 11 months after the start of MPA treatment, and blood samples for determination of the plasma concentrations of ACTH, cortisol, GH, IGF-1, LH, FSH, prolactin, alpha-MSH, and TSH were collected at -15, 0, 5, 10, 20, 30, and 45 min after suprapituitary stimulation. MPA successfully prevented the occurrence of estrus, ovulation, and a subsequent luteal phase. MPA treatment did not affect basal and GnRH-induced plasma LH concentrations. The basal plasma FSH concentration was significantly higher at 2 months after the start of MPA treatment than before or at 5, 8, and 11 months after the start of treatment. The maximal FSH increment and the AUC for FSH after suprapituitary stimulation were significantly higher before treatment than at 5, 8, and 11 months of MPA treatment. Differences in mean basal plasma GH concentrations before and during treatment were not significant, but MPA treatment resulted in significantly elevated basal plasma IGF-1 concentrations at 8 and 11 months. MPA treatment did not affect basal and stimulated plasma ACTH concentrations, with the exception of a decreased AUC for ACTH at 11 months. In contrast, the maximal cortisol increment and the AUC for cortisol after suprapituitary stimulation were significantly lower during MPA treatment than prior to treatment. MPA treatment did not affect basal plasma concentrations of prolactin, TSH, and alpha-MSH, with the exception of slightly increased basal plasma TSH concentrations at 8 months of treatment. MPA treatment did not affect TRH-induced plasma concentrations of prolactin and TSH. In conclusion, the effects of chronic MPA treatment on adenohypophyseal function included increased FSH secretion, unaffected LH secretion, activation of the mammary GH-induced IGF-I secretion, slightly activated TSH secretion, suppression of the hypothalamic-pituitary-adrenocortical axis, and unaffected secretion of prolactin and alpha-MSH.

Treatment of growth hormone excess in dogs with the progesterone receptor antagonist aglépristone.

Acromegaly or hypersomatotropism in dogs is almost always due to progestin-induced hypersecretion of GH originating from the mammary gland. The aim of this study was to investigate whether aglépristone, a progesterone receptor antagonist, can be used to treat this form of canine acromegaly. In five Beagle bitches hypersomatotropism was induced by administration of MPA for over 1 year. Subsequently, aglépristone was administered. Blood samples were collected before MPA administration, immediately before, during, and 3.5 and 5.5 weeks after the last administration of aglépristone for determination of the plasma concentrations of GH and IGF-I. In addition, blood samples for the determination of the 6-h plasma profile of GH were collected before MPA administration, before aglépristone administration, and 1 week after the last aglépristone treatment. MPA administration resulted in a significant increase of the mean plasma IGF-I concentration, whereas analysis of the pulsatile plasma profile demonstrated a trend (P=0.06) for a higher mean basal plasma GH concentration and a higher mean AUC(0) for GH. Treatment with aglépristone resulted in a significant decrease of the mean plasma GH and IGF-I concentrations. Analysis of the pulsatile plasma profile showed a trend (P=0.06) for a lower mean basal plasma GH concentration and a lower mean AUC(0) for GH 1 week after the last aglépristone treatment compared with these values before aglépristone administration. Three and a half and 5.5 weeks after the last aglépristone administration the mean plasma IGF-I concentration increased again. In conclusion, aglépristone can be used successfully to treat dogs with progestin-induced hypersomatotropism.

Ghrelin-stimulation test in the diagnosis of canine pituitary dwarfism.

This study investigated whether ghrelin, a potent releaser of growth hormone (GH) secretion, is a valuable tool in the diagnosis of canine pituitary dwarfism. The effect of intravenous administration of ghrelin on the release of GH and other adenohypophyseal hormones was investigated in German shepherd dogs with congenital combined pituitary hormone deficiency and in healthy Beagles. Analysis of the maximal increment (i.e. difference between pre- and maximal post-ghrelin plasma hormone concentration) indicated that the GH response was significantly lower in the dwarf dogs compared with the healthy dogs. In none of the pituitary dwarfs, the ghrelin-induced plasma GH concentration exceeded 5 microg/l at any time. However, this was also true for 3 healthy dogs. In all dogs, ghrelin administration did not affect the plasma concentrations of ACTH, cortisol, TSH, LH and PRL . Thus, while a ghrelin-induced plasma GH concentration above 5 microg/l excludes GH deficiency, false-negative results may occur.