Behavioral and electroencephalographic studies of beagles with an Eck's fistula: suitability as a model of hepatic encephalopathy

Hyperammonemia and systemic inflammatory response syndrome predicts presence of hepatic encephalopathy in dogs with congenital portosystemic shunts

Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with liver disease. The pathogenesis of he is incompletely understood although ammonia and inflammatory cytokines have been implicated as key mediators. To facilitate further mechanistic understanding of the pathogenesis of HE, a large number of animal models have been developed which often involve the surgical creation of an anastomosis between the hepatic portal vein and the caudal vena cava. One of the most common congenital abnormalities in dogs is a congenital portosystemic shunt (cpss), which closely mimics these surgical experimental models of HE. Dogs with a cPSS often have clinical signs which mimic clinical signs observed in humans with HE. Our hypothesis is that the pathogenesis of HE in dogs with a cPSS is similar to humans with HE. The aim of the study was to measure a range of clinical, haematological and biochemical parameters, which have been linked to the development of HE in humans, in dogs with a cPSS and a known HE grade. One hundred and twenty dogs with a cPSS were included in the study and multiple regression analysis of clinical, haematological and biochemical variables revealed that plasma ammonia concentrations and systemic inflammatory response syndrome scores predicted the presence of HE. Our findings further support the notion that the pathogenesis of canine and human HE share many similarities and indicate that dogs with cPSS may be an informative spontaneous model of human HE. Further investigations on dogs with cPSS may allow studies on HE to be undertaken without creating surgical models of HE thereby allowing the number of large animals used in animal experimentation to be reduced.

PANDAS with catatonia: a case report. Therapeutic response to lorazepam and plasmapheresis

This is a report of an 11-year-old, prepubertal boy with acute-onset urinary urgency and frequency, obsessions and compulsions related to urination, severe mood lability, inattention, impulsivity, hyperactivity, and intermittent periods of immobilization. Fever, cough, otitis, and sinusitis preceded neuropsychiatric symptoms. Antistreptolysin O and DNAse B antibody titers were elevated, and magnetic resonance imaging revealed bilateral diffuse caudate nuclei swelling. Plasmapheresis resulted in significant and rapid clinical improvement of obsessive-compulsive disorder symptoms and a simultaneous decrease in basal ganglia swelling, consistent with an immune-mediated pathophysiological process involving group A beta-hemolytic streptococci. Hyperactivity, impulsivity, and inattention improved with lorazepam, suggesting that the attention-deficit/hyperactivity disorder symptoms could be manifestations of catatonia.

Recovery from parkinson syndrome and prolonged visually evoked potentials in hepatic encephalopathy

The combination of Parkinson syndrome (PS) and prolonged visually evoked potentials (VEPs) in a single patient with hepatic encephalopathy (HE) has not been reported. A 52-year-old male with chronic HE developed PS in early 2001. Treatment with L-DOPA was only of minimal effect. In August 2001 he was admitted because of worsening PS and HE. There was anemia, hyperlipidaemia, markedly elevated liver-function-parameters, hyperammonemia, elevated resting-lactate, steatosis hepatis and hepatomegalia. VEPs showed markedly prolonged P100-latencies. Under L-DOPA, pramipexol, L-ornithin-L-aspartate, paromomycin-sulfate, and lactulose liver-function-parameters normalized and PS markedly improved. In February 2003, VEPs were normal. L-DOPA was discontinued by the patient in April 2003 and pramipexol in December 2003. Since then PS did not recur. This case shows that HE may go along with reversible PS and prolonged VEPs. Under adequate therapy liver-function-parameters and VEPs normalize and PS disappears.

Toxic and metabolic causes of seizures

Seizures are a relatively nonspecific response of the cerebral cortex to insult and can be caused by a variety of toxic or metabolic diseases. Seizure in response to extracranial disease are called reactive seizures. Toxins cause seizures by altering the balance of excitation and inhibition in the nervous system or interfering with energy metabolism. Many therapeutic or illicit drugs will cause seizures through similar mechanisms. Metabolic diseases can cause seizures by interfering with energy metabolism, changing osmolality, or producing endogenous toxins. In addition, metabolic disease may alter the pharmacokinetics of antiepileptic drugs or drugs that have the potential to cause seizures. While seizures represent a serious sign for many of these conditions, reactive epilepsy always carries the possibility that the seizures may be eliminated if the underlying cause is detected and corrected.