Current Drug Safety, 2009, 4, 17-21
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Reyes’s Syndrome, Encephalopathy, Hyperammonemia and Acetyl Salicylic Acid Ingestion in a City Hospital of Buenos Aires, Argentina Abraham Lemberg1, María A. Fernández1, Carlos Coll1, Diego O. Rosello1, Salvador Romay1, Juan C. Perazzo1 and Ester J. Filinger*,2,3 1
Cátedra de Fisiopatología, 2Cátedra de Farmacia Clínica, Facultad de Farmacia y Bioquímica, U.B.A., Junín 956, 1113, 3CONICET, Buenos Aires, Argentina Abstract: Twelve cases of Reye’s syndrome are presented with different degrees of encephalopathy, hyperammonemia and hypoglycemia; associated to acetyl salicylic acid (ASA) ingestion. The aim of the present retrospective study was to describe our experience in selected patients with Reye’s syndrome associated to the ASA ingestion and to underline the influence of hyperammonemia on Reye’s encephalopathy. All the cases presented moderate hyperbilirubinemia, elevated alanine aminotransferase, aspartate aminotransferase with an average of 302±205 UI/L and 285±149 UI/L respectively. Arterial blood ammonia averaged 172.4±71.3 mol/L and glycaemia averaged 35.2±17.0 mg/dl. A high mortality was found in our series (41.7%). Considering that encephalopathy is the leading syndrome in these cases, the influence of ammonia on brain tissue was described. Glutamate is an excitotoxic neurotransmitter, capable to produce neuron and astrocyte damage and apoptosis. The presence of ASA could cause the onset of the mitochondrial permeability transition and the mitochondrial swelling in the astrocyte, leading to hyperammonemia. In Reye’s syndrome, hyperammonemia and perhaps the increase of glutamate are the leading factors in the mechanism of brain damage and encephalopathy. Aspirin must be carefully administrated and controlled by professionals. Furthermore, parents must be informed about the risks in the use of this drug in children.
Keywords: Reye’s syndrome, encephalopathy, hyperammonemia, acetyl salicylic acid. INTRODUCTION Several decades have passed since Reye et al. [1], reported a childhood disease, characterised by acute encephalopathy and fatty degeneration of the liver. Brain et al. [2] and Johnson et al. [3] added new cases stressing on the severity of the disease and its possible relationship to viral disease. This entity, commonly presents a biphasic evolution, with a digestive or respiratory onset followed by psychoneurological symptoms. Once established, Reye’s syndrome is basically constituted by the presence of microvesicular liver steatosis and encephalopathy of different degrees, possibly as a complication due to hyperammonemia. Besides, this syndrome is associated with elevated levels of serum alanine aminotransferase, aspartate aminotransferase and occasionally hypoglycaemia. Initially, Reye’s syndrome was attributed to influenza or varicella type viruses, and also was associated to acetyl salicylic acid (ASA) ingestion [3]. Since 1980, when the information of the relationship between aspirin and Reye’s syndrome was widely diffused, there was a sharp decline of cases reported [4, 5]. In spite of the important decline, some cases are still appearing in the literature. Nevertheless in several countries, such as Argentina, where drugs can be acquired without professional control, ASA is still used in child, without physician or pharmaceutical advice. *Address correspondence to this author at the Cátedra de Farmacia Clínica, Facultad de Farmacia y Bioquímica, U.B.A., Junín 956, 1113, Buenos Aires, Argentina; E-mail:
[email protected] 1574-8863/09 $55.00+.00
Whatever the aetiology of Reye’s syndrome can be, the major symptom is the life-threatening encephalopathy, associated to liver pathology, predominately microvesicular steatosis. The accumulation of brain ammonia causes a spectrum of effects on cerebral function, exerted by direct and indirect mechanisms [6]. The aim of the present retrospective study was to describe our experience in selected patients with Reye’s syndrome associated to the ASA ingestion and to underline the influence of hyperammonemia on Reye’s encephalopathy. MATERIAL AND METHODS Subjects Twelve children with ages between 24 months and ten years old were included in this study. All of them were admitted into the emergency room in the Pirovano Hospital from Buenos Aires, Argentina and transferred to the Paediatric Intensive Care Unit in accordance with their clinical condition. All the cases were recollected from the Paediatric Intensive Care Unit data file, searching by diagnosis in a period of 15 years (1985-2000). The study was performed according to the principles of the Declaration of Helsinki and was approved by the Ethical Committee of the Pirovano Hospital. The inclusion criteria [7] used in this study were: 1.
Children of all ages.
2.
During or while recovering from viral illness (most commonly varicella infection or influenza).
© 2009 Bentham Science Publishers Ltd.
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3.
Repetitive vomiting, fever and altered behaviour and the presence of lethargy, confusion, irritability, aggressiveness.
4.
In children under one year of age, respiratory disturbances such as hyperventilation or apnoeic episodes may be prominent.
The evaluation of severity of hepatic encephalopathy was based on the West Haven Criteria for semi-quantitative grading of mental status, referring to the level of impairment of autonomy, changes in consciousness, intellectual function, behaviour, and the dependence on therapy [8, 9] and divide in four grades: Grade I -
Trivial lack of awareness; Euphoria or anxiety; Shortened attention span; impaired performance of addition.
Grade II -
Lethargy or apathy; Minimal disorientation for time or place; subtle personality change; inappropriate behaviour; impaired performance of subtraction.
Grade III -
Somnolence to stupor, but responsive to verbal stimuli; Confusion; Gross disorientation.
Grade IV -
Coma (unresponsive to verbal or noxious stimuli).
Abdominal ultrasonography and X-Ray thorax examination was also performed, several times to each patient. Laboratory Investigation Serum bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, gamma glutamyl transpeptidase, pseudocholinesterase, lactate dehydrogenase, ornithine carbamyl transferase activities were determined using standardized and optimised commercial Roche kits (Germany). Plasma ammonia concentration was determined using Bio-Merieux Kits (France) and ornithine carbamyl transferase activity was measured with OCT kits from Sigma (Saint Luis, USA). Serum ASA was determined according to Tinder’s method [10]. Serum studies of EBV, CMV, hepatitis A and B viruses, were realised in order to exclude viral hepatitis.
Lemberg et al.
symptoms and admission corresponded to an average of 7 days (range: 3-21 days). There was no history of paracetamol (acetaminophen) ingestion, or other drugs, except aspirin. One child had varicella infection that involved his two brothers also. At admission the patients had in common the existence of hyperammonemia, encephalopathy and liver involvement with hypoglycaemia and abnormal liver function tests. Physical examination showed jaundice, hepatomegalia and encephalopathy in all the cases. Hepatomegalia was important in two cases and moderate in 10 cases. In addition, splenomegaly was found in 3 patients, one presented influenza B virus infection and the remaining two had varicella infection. Encephalopathy ranged from a somnolent state (Grade III) to coma (Grade VI). One patient who showed renal failure with elevated creatinine levels presented a bad evolution and finally died. An autopsy was performed in this patient. Biochemical alterations were observed in all patients. Serum bilirubin was elevated in all cases (averaged: 3.95±1.45 mg/dL). Serum ALT and AST activities were elevated; glycaemia was markedly decreased in 8 cases (Table 1). Gamma glutamyl transferase was elevated only in one case: 190 IU/L and alkaline phosphatase activity were at normal values in all cases. Serum pseudocholinesterase activity was normal in 9 cases, and lower than normal in 2 cases. Serum ammonia determination showed, in the 12 cases, elevated values with an average of 172.4 mol/L (Table 1). Lactate dehydrogenase activity was elevated in all the cases. Ornithine carbamyl transferase activity was determined in only 5 cases, and was elevated respect to normal values (average: 29 IU/L, range: 25-34 IU/L). Table 1.
Biochemical Blood Parameters NV
Media
SD
SEM
N
Ammonium (mol/L)
6.5-35
172.4
71.3
20.6
12
Glucose (mg/dL)
80-110
35.2
17.0
4.9
12
ALT (IU/L)
40
302
205
59
12
AST (IU/L)
39
285
149
43
12
OCT (IU/L)
1-15
29.4
3.5
2.72
5
Normal values.
Pathology Liver samples were obtained post mortem from five patients. The samples were fixed in 10% formaldehyde, embedded in paraffin and stained with haematoxylin and eosin, Masson’s trichrome, silver impregnation for reticular fibers, Perls blue and PAS. Descriptive Statistics Interval and ratio variables were expressed as mean ± standard deviation and/or range. RESULTS Six patients were males and six females. All cases showed symptoms of a mild viral-like disease, moderate fever and bronchial symptoms, before admission and received ASA. The period of time between the initiation of the
Prothrombine time were measured in 5 cases and presented a decreased percentage against normal value with an average of 43 % (range 32-55%). The 12 cases received ASA as medication; in 3 cases the amount of ASA administrated was higher than the therapeutic doses (therapeutic range: 20-25 mg/100 mL); with symptoms of moderated intoxication (toxic range: > 30 mg/100 mL) [11]. Serum ASA determination in 7 cases showed an average of 29.07±9.29 mg/100 ml (range: 15.40-40.20 mg/100 ml). Five patients died during the first week of admission. In one case, autopsy was partially performed. In the other four, liver punction was made post-mortem. In the partially autopsied case and in the other 4 children it was found a fatty de-
Reye’s Syndrome and Acetyl Salicylic Acid in Argentina
generation, with no inflammatory process in the liver biopsy (Fig. 1). The distribution of the abundant and small droplets of fat was panlobular. In the autopsied case, fat droplets were found in kidney also. In liver, it was documented the absence or very low content of glycogen in most of the samples.
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American countries it is possible to acquire some drugs without prescription and in our country, ASA is considered as a drug out of the counter. Bhutta et al. [16], recently, described a case of Reye’s syndrome associated to aspirin ingestion, in a patient that presented an acute nervous system and liver dysfunction. This report result useful to remind, that beside the decline in the use of aspirin, cases are still appearing. Deschamps et al. [17] administered salicylic acid to mice and documented a reduction of 50 and 65% of the oxidation process of long chain fatty acids associated with a markedly decreased blood glucose concentration and increased plasma ketone bodies. It was demonstrated that in the isolated rat liver, the perfusion of salicylate repeatedly, increased ketogenesis and decreases glucose production [18]. Also the administration of salicylic acid increases markedly hepatic triglycerides and produces microvesicular steatosis in the liver. Deschamps et al., concluded that salicylic acid diminish the mitochondrial activation, and thus -oxidation of long chain fatty acids, presumably sequestering extra mitochondrial coenzyme A and possibly carnitine [17].
Fig. (1). Liver histopathology from a patient liver biopsy showing widespread diffuse steatosis changes. PAS technique, 400 X magnifications.
The rest of the patients ameliorate their clinical and biochemical conditions and abandoned the Hospital in good condition. DISCUSSION Our results showed that in our twelve cases, hyperammonemia was presented, with the addition of the ingestion of aspirin in all the cases. It is known that the presence of an acute liver disease, different degrees of clinical encephalopathy and hyperammonemia characterise Reye’s or Reye-like syndromes [1, 2, 7]. In some cases the presence of liver pathology produced the decrease in blood clotting factors synthesis [4]. It is accorded that the presence of panlobular small droplets of fat characterises liver injury in microscopic observation, this distribution is similar to fatty liver documented in virus C hepatitis and severe jaundice of pregnancy [12]. We found fatty livers in all our patient’s biopsies. Some antipyretic drugs, as acetaminophen and ASA, can find host with a varying degrees of deficits in several enzymatic activities [13, 14]. The activation of systemic hostdefence mechanisms against viruses or drugs can result in a depression of various induced and constitutive isoforms of cytochrome P-450 mixed function oxidase systems, in the liver and brain. These modifications in enzymes that participate in biotransformation of drugs, even after the administration of therapeutic or low doses of drugs, in some genetically predisposed patients, may respond perhaps with clinical alterations, adding another risk factor to acute liver pathology. Moreover, Hurwitz [15], based on epidemiologic studies, suggested the presence of a dose-response relation between risk of Reye’s syndrome and dose of aspirin ingested during the illness, providing supportive evidence for a causal link between this syndrome and aspirin. In most of Latin-
The interaction of salicylate with the respiratory chain of liver mitochondria generates reactive oxygen species, which in turn oxidize thiol groups and glutathione. This oxidative stress, leads to the induction of the mitochondrial permeability transition (MPT) in the presence of Ca2+. This phenomenon induces further increase of oxidative damage resulting in impairment of oxidative phosphorylation and beta-oxidation, cardinal features of Reye's syndrome in the liver [19]. Moreover, salicylate may cause the mitochondrial swelling in the hepatocyte, leading to hyperammonemia. Several neurological disorders are characterised by an increase in ammonia concentration in brain, including congenital urea cycle disorders, hepatic encephalopathy associated with liver failure and Reye’s syndrome [20]. Butterworth [21] suggested that the increase in ammonia concentration in brain, as possible occur in Reye’s syndrome, as well as in liver failure due to viral infection, produces alterations in glutamate neurotransmitter system, in particular in glutamate transport [22]. The decrease or lack of glutamate transport activity in brain, due to acute liver failure and hyperammonemia, is associated with an increase in extracellular brain glutamate concentration, hyperexcitability and cerebral oedema. Astrocytes constitute the principal target of ammonia toxicity, but neurons directly or indirectly participate in this process, as well [23-25]. Our 12 cases presented a hyperammonemic state with an average of 172.4 mol/L ammonia in blood, associated to ASA ingestion. The glutamine accumulation in astrocytes due to ammonia detoxification produces increased osmotic forces inducing cellular swelling. Moreover, glutamine has a key role inducing free radical generation and the MTP, as well [23]. Furthermore, glutamate, the excitotoxic neurotransmitter is converted to glutamine by the cytoplasmic enzyme glutamine synthetase, and this glutamine is further metabolised in mitochondria by phosphate-activated glutaminase, producing glutamate and more ammonia. These steps increase the
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Lemberg et al.
toxic effect of glutamine and ammonia in the pathogenesis of Reye’s syndrome encephalopathy.
country to acquire some drugs without prescription would contribute to the persistence of this high mortality pathology.
Activities of mitochondrial enzymes, AST, ALT, glutamate dehydrogenase, glutaminase and GABA transaminases were suppressed during hyperammonemia. In our cases eight children showed elevated activities of AST and ALT enzymes in circulating blood, probably due to the presence of the hepatocellular damage.
REFERENCES
Pathophysiological concentrations of ammonia cause a significant reduction in membrane cholesterol in rat brain, but without altering the total phospholipids content of membranes. Furthermore, cholesterol depletion is thought to increase the vulnerability of neurons to glutamate excitotoxicity [26]. All these data constitutes signs of brain lipid derangements. Ornithine carbamoyl transferase deficiency is the most common hereditary urea cycle disorder. It is an X-linked recessive disorder that usually presents encephalopathy and hyperammonemia, low blood urea and normal glycaemia. The increase of serum ornithine carbamoyl transferase observed in 5 of our patients showed that at least in these cases, did not exist a defect in this enzyme that could indicate an alteration of mitochondrial function. Reye’s syndrome must be considered as a complex disease that produces important alterations in lipid, carbohydrate and protein metabolism, as had been described in our cases, including severe hypoglycaemia and diminished liver glycogen.
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The children included in this study apparently did not have melena, bloody stools or ingestion of high protein diet, as to explain, the increase amount of ammonia via the portal vein to the liver and then the systemic circulation, as occur in portal vein thrombosis or liver cirrhosis [27].
[12]
Another possible factor that contributes to maintain ammonia levels in brain could be that ASA or some other drug implicated in this syndrome interfere the astrocyte detoxification process, through the cycle glutamate/glutamine modification and the contribution in the pH alterations.
[14]
The above-mentioned information on the hyperammonemia associated to ASA ingestion are leading factors in the mechanism of brain damage; and also strongly suggests its important contribution in Reye syndrome or Reye-like disease, and for the direction of future therapeutic investigation to ameliorate also this syndrome.
[15] [16]
In conclusion, in our retrospective study, the twelve children with Reye’s syndrome presented encephalopathy and liver failure, which were documented as leading syndromes. Liver impairment was demonstrated by the presence of small lipid droplets with panlobular distribution and a severe decrease of glycogen content, associated to an increase in serum ALT and AST. We also suggest that the presence of elevated ammonia concentrations in blood, associated to the ingestion of ASA is important factors to produce the derangement of several metabolic pathways in brain and liver. Moreover, it is important to mention that the uncontrolled ingestion of variable ASA doses and the easiness in our
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Received: April 28, 2008
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Revised: June 20, 2008
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Chou YC, Lin SB, Tsai LH, Tsai HI, Lin CM. Cholesterol deficiency increases the vulnerability of hippocampal glia in primary culture to glutamate-induced excitotoxicity. Neurochem Int 2003; 43(3): 197-209. Scorticati C, Prestifilippo JP, Eizayaga FX, et al. Hyperammonemia, brain edema and blood-brain barrier alterations in prehepatic portal hypertensive rats and paracetamol intoxication. World J Gastroenterol 2004; 10(9): 1321-24.
Accepted: July 3, 2008
