Prevalence of nonconvulsive seizures and nonconvulsive status epilepticus in dogs and cats with a history of cluster seizures: A retrospective study.

BACKGROUND: Nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE) are frequently observed in human patients. Diagnosis of NCS and NCSE only can be achieved by the use of electroencephalography (EEG). Electroencephalographic monitoring is rare in veterinary medicine and consequently there is limited data on frequency of NCS and NCSE. OBJECTIVES: Determine the prevalence of NCS and NCSE in dogs and cats with a history of cluster seizures. ANIMALS: Twenty-six dogs and 12 cats. METHODS: Retrospective study. Medical records of dogs and cats with cluster seizures were reviewed. Electroencephalography was performed in order to identify electrographic seizure activity after the apparent cessation of convulsive seizure activity. RESULTS: Nonconvulsive seizures were detected in 9 dogs and 2 cats out of the 38 patients (29%). Nonconvulsive status epilepticus was detected in 4 dogs and 2 cats (16%). Five patients had both NCS and NCSE. A decreased level of consciousness was evident in 6/11 patients with NCS, 3/6 also had NCSE. Mortality rate for patients with NCS (73%) and NCSE (67%) was much higher than that for patients with no seizure activity on EEG (27%). CONCLUSION AND CLINICAL IMPORTANCE: Prevalence of NCS and NCSE is high in dogs and cats with a history of cluster seizures. Nonconvulsive seizures and NCSE are difficult to detect clinically and are associated with higher in hospital mortality rates. Results indicate that prompt EEG monitoring should be performed in dogs and cats with cluster seizures.

Coxofemoral luxation as a complication of localised tetanus in a cat.

Case summary: A 9-month-old male neutered domestic shorthair cat presented 2 weeks after castration with a 48 h history of acute-onset lateral recumbency and severe hindlimb rigidity. Physical examination findings included hyperthermia, tachypnoea, hindlimb rigidity and a healed orchidectomy site. Neurological examination of the head and forelimbs was normal; however, there was a spastic, non-ambulatory paraparesis of the hindlimbs, which was more severe on the left. Abnormal findings included mildly elevated serum creatine kinase levels and on electromyography there was bilateral pathological spontaneous activity of the biceps femoris muscles. A tentative diagnosis of tetanus was made based on clinical presentation. Treatment was initiated with tetanus antitoxin, diazepam, metronidazole, buprenorphine and physiotherapy of the hindlimbs. There was an improvement over the following 20 days. Twenty-five days later the cat presented with acute, painful, non-weightbearing lameness of the left hindlimb. Physical examination was suggestive of craniodorsal coxofemoral joint luxation, which was confirmed radiographically. This was treated with analgesia and rest. A marked clinical improvement was observed at the 3-month follow-up. Relevance and novel information: To our knowledge, there have been no previously published reports of spontaneous coxofemoral joint luxation as a complication of hindlimb localised tetanus infection in cats. This report suggests that coxofemoral luxation should be considered as a possible complication in young cats with hindlimb localised tetanus.

EEG spectral changes induced by hemodialysis.

OBJECTIVE: To investigate the EEG spectral changes induced during hemodialysis in patients with chronic kidney disease (CKD), and to identify the risk factors associated with changes in the Central Nervous System (CNS) during hemodialysis. Paradoxical neurological deterioration at the end of hemodialysis sessions, known as dialysis disequilibrium syndrome (DDS) has been described, but previous studies on EEG spectral changes during hemodialysis were controversial. METHODS: We performed quantitative EEG spectral analysis in 56 consecutive patients who underwent hemodialysis. We compared EEG at the start and at the end of the hemodialysis, and we correlated the spectral changes with the biochemical and clinical characteristics of the patients, using multivariate analysis. RESULTS: At the end of hemodialysis sessions, we found a significant increase in total EEG power, relative power in delta frequency band and the ratio of delta-theta/alpha-beta power. EEG spectral changes were associated with younger age, recent start of hemodialysis therapy, level of uremia and lower level of glycaemia. CONCLUSIONS: Quantitative EEG spectral analysis showed that hemodialysis induced slowing of the EEG background activity. These changes were associated with risk factors of DDS. SIGNIFICANCE: EEG spectral changes are potential biomarkers for monitoring CNS function during hemodialysis.

EEG Patterns Orienting to Lafora Disease Diagnosis-A Case Report in Two Beagles.

Lafora Disease (LD) is a rare, fatal, late-onset, progressive form of myoclonic epilepsy, occurring in humans and dogs. Clinical manifestations of LD usually include seizures, spontaneous and reflex myoclonus with contractions of the neck and limb muscles. We studied the electroencephalogram (EEG) patterns of two beagles in whom LD was subsequently confirmed by genetic testing. In both cases, the EEG recordings, accompanied by electromyography (EMG), have shown similar uncommon patterns. The hypovoltaged background rhythm was interrupted by waxing "crescendo" polyspikes-slow wave complexes appearing 80-250 ms after the start of intermittent photic stimulation, followed by myoclonic jerks after 80-150 ms. This study highlights the value of EEG in establishing a presumptive diagnosis of LD in dogs.

Semiology of subtle motor phenomena in critically ill patients.

PURPOSE: to investigate the semiology of subtle motor phenomena in critically ill patients, with- versus without nonconvulsive status epilepticus (NCSE). METHODS: 60 consecutive comatose patients, in whom subtle motor phenomena were observed in the intensive care unit (ICU), were analysed prospectively. The semiology of the subtle phenomena was described from video-recordings, blinded to all other data. For each patient, the type, location and occurrence-pattern/duration were described. EEGs recorded in the ICU were classified using the Salzburg criteria for NCSE. RESULTS: only 23% (14/60) of the patients had NCSE confirmed by EEG. None of the semiological features could distinguish between patients with NCSE and those without. In both groups, the following phenomena were most common: discrete myoclonic muscle twitching and discrete tonic muscle activation. Besides these, automatisms and eye deviation were observed in both groups. CONCLUSION: subtle motor phenomena in critically ill patients can raise the suspicion of NCSE. Nevertheless, EEG is needed to confirm the diagnosis, since none of the semiological features are specific.