J.Jpn. Surg. Soc.. 63(3): 237-271, 1962
Original article
EXPERIMENTAL AND CLINICAL INVESTIGATIONS ON HEPATIC COMA
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the Department of Surgery Faculty of Medicine, University of Tokyo, Tokyo (Director: Prof. Seiji Kimoto) Motokazu HORI, M.D. |
I. EXPERIMENTAL HEPATIC COMA WITH PORTACAVAL ANASTOMOSIS AND OTHER PROCEDURES
The purpose of the author's experiments is to clarify the causal role of nitrogenous substances in the intestine, the portal-systemic shunt and the liver itself. Experiments consist of the following groups:
1 : Dogs with portacaval anastomosis (Eck fistula) or with additional oral or intravenous administration of nitrogenous substances and other additional surgical aggressions, such as severing the hepatic artery or partial hepatectomy.
2: Administration of ammonium salts in dogs with constriction of the hepatic veins and vena cava in the thorax (ascitic dogs).
3 : Administration of ammonium salts in dogs with portacaval transposition.
4: Intragastric administration of phosphorus in normal and Eck fistula dogs.
5 : Totally hepatectomized dogs or those combined with administration of nitrogenous substances or antibiotics and other viscerectomies.
6 : Administration of ammonium salts into the carotid artery of normal and Eck fistula dogs.
From these experiments the author could not obtain the simple conclusion that hepatic coma is the sequela of direct action of the increased systemic blood ammonia of intestinal origin to the central nervous system.
Provided these intestinal toxic substances including ammonia and amines have any causal role, the author presumes that secondary liver injury which can be caused by these substances, could rather induce true hepatic coma.
Along with the intestines, the kidney as a source of blood ammonia formation can not be neglected in various conditions.
The brain and muscles are important as the compensatory tissues of ammonia metabolism, and reductive amination in these tissues is presumed as its metabolic mechanism.
Reaction of the central nervous system to ammonia is not always the same, and duration of the action and cerebral tolerance to hyperammoniemic state complicate the clinical pictures and the course of hepatic coma.
Portal-systemic shunt has some causality not merely to form liver bypass of enterogenic nitrogenous toxic substances but to produce liver injury in a sense.
Thoracic ductal-systemic shunt is also significant as a liver bypass of intestinal content in ascitic dogs. Significance of the liver itself in the causative factors of hepatic coma is the most important, but what is essential is unknown.
II. HEPATIC COMA IN THE SURGERY FOR PORTAL HYPERTENSION WITH SPECIAL REFERENCE TO ECK FISTULA SYNDROME
The author had 178 cases of surgically treated patients with portal hypertension which consist of 115 cases of Banti's syndrome, 30 cases of liver cirrhosis, 13 cases of Japanese schistosomiasis, and 20 cases of congenital malformation of portal vein. Among them there were 25 cases of hepatic coma including Eck fistula syndrome.
Long term follow-up analyses on the cause of death after operation revealed that death due to recurrent esophageal hemorrhage occurred in a few cases, but Eck fistula syndrome including fatal coma occurred in 5 out of 12 cases with portacaval end-to-side anastomosis only, in 3 out of 9 portacaval anastomosis combined with portal arterialization, in 3 out of 15 portacaval anastomosis combined with intrahepatic arterial implantation, and in 4 out of 18 portacaval side-to-side anastomosis.
However, significant fact is that the occurrence of hepatic coma including Eck fistula syndrome depends rather on original diseases which produced portal hypertension than on the kind of operative procedures. At present any method of surgical procedures can not prevent the occurrence of Eck fistula syndrome, if the liver has been severely damaged and has progressing changes. This gives the proof of the above mentioned consideration on the pathogenetic role of portal-systemic shunt and liver itself.
The author presented some cases of Eck fistula syndrome including a patient with Banti's syndrome who survived for over 11 years after portacaval anastomosis and splenectomy.
The initial neurological symptoms of protracted and recurrent Eck fistula syndrome begin with tremor or athetotic movement of fingers, eye lids and lips and ataxia. Then, they are followed by mental confusion, apathy, curious or stereotyped behavior, disturbances of orientation, memory and impressibility, paraphasia, acalculia, visual agnosia or loss of sensation.
Some cases manifest the symptoms of periodic somnolence with polyphagia. At night patient has a broken sleep by fragmentary dream or falls into delirium. Sedativas have no effect against this state. Abnormalities of autonomic nervous system, such as perspiration, salivation, conjunctival hyperemia or hypertension are not rarely observed.
Niveau-sinking of psychic activities develops gradually into manifested deterioration of feeling and intelligence or fixation of abnormalities of character. Sooner or later, coma to death is ensued in many cases.
Beyond expectation many of precipitating causes of Eck fistula syndrome are rather psychosomatic stress or moist and cloudy weather than taking meat or obstipation. Before shunt operation these patients already have shown the increased concentration of arterial blood ammonia, and the increase was more prominent postoperatively.
However, as the time elapses postoperatively, the central nervous system tolerates the hyperammoniemic state. By acquired brain tolerance, arteriovenous difference of blood ammonia in the brain and muscles/ arterial concentration ratio increases. Decrease of its ratio and arterial ammonia/urea ratio suggests following worse result.
Alimentary problem of these patients is confusing. The author indicates by the followup studies that they require high protein intake, and are permitted to choose some protein such as egg, milk or fishes, which protein score is great and composing amino acids are with small glycine/ glutamic acid and arginine ratio. Arginine glutamate therapy is not always so effective to be recommended.
And the author suggested that the patients with liver cirrhosis have many functional and organic arteriovenous shunts, in liver, lung, muscles, brain and many other organs and tissues. Intrahepatic shunt produces anoxia and following degeneration of parenchyma cells, shunt in extremities forms clubbing of the fingers, and intracerebral shunt disturbes oxidative process of the cerebral metabolism. Intrapulmonary shunt accelerates anoxemia and general tissue anoxia. These are important in hepatic coma.
Biological artificial liver with non-biological hepatic reactors, which the author has devised, remains many interesting problems to be solved in future.
Surgical treatment for the relief of portal hypertension has to be reconsidered because of the postoperative recurrent hemorrhage from the esophageal varices and hepatic coma including Eck fistula syndrome.
In order to relieve the portal hypertension and to prevent hemorrhage, the portacaval end-to-side anastomosis is recommended to be the preferable shunt operation, but surgeons must prepare to the hazard of postoperative Eck fistula syndrome. At operation they are forced to do the adequate surgical procedure in their fair judgement.
In recent cases combined with intrahepatic arterial implantation and portacaval end-to-side anastomosis and cases of side-to-side anastomosis, postoperative decrease of hepatic blood flow is more slight and increase of blood ammonia concentration is less than those seen in end-to-side anastomosis.
The conclusion on which surgical procedure is superior should be made when long-term follow-up studies clarify the problems.
(author's abstract)
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