肝門靜脈分流(LIVER SHUNTS)


轉載自~http://younghappy64.spaces.live.com/blog/cns!DB6001A594624E96!550.en

 



Angel的肝門靜脈分流(LIVER SHUNTS)病程分享

肝門靜脈分流(LIVER SHUNTS),一個Angel被診斷出可能的遺傳性疾病,常發生在純種狗狗身上,尤其是雪納瑞、約克夏,肝臟門靜脈負責將消化後富含營養與毒素的血送入肝臟,而門脈分流就是因各種原因造成血管異常分支分流,無法將全部的營養或毒素送至肝臟吸收或排毒所致。在Angel的超音波及X光檢查中,看到她的肝異常的小,據屏東科大江老師所言,「小肝」有二種情形,一是肝硬化造成的肝臟變小(肝臟表面粗糙,通常發生在老狗),二是肝臟的門靜脈分流造成營養沒送至肝臟致肝臟沒有長大到正常大小。 

從小就長不胖的Angel背毛和一般雪納瑞不同,十分柔軟,愛咬纖維質(草、紙、竹筷子)卻又無法消化,就嘔吐出來,腸胃十分敏感。不到一歲就發現一直有泌尿系統的問題,尿裡有肉眼可見的結晶,常舔陰部到後來血尿,開始了吃處方飼料(c/d)的生活,直到第一次發病,3歲一個月時(2005/07),改變食物造成下瀉血便至醫院點滴治療時,雖有照超音波(沒看肝臟的情形)但仍查不出病因,2005年10月那次嚴重的發病,不斷流口水、昏迷(無法自已站立,沒有意識)在台大急救,醫生研判是「急性肝中毒」(血中鈉離子170),給予葡萄糖點滴加解毒強肝藥劑,病情每天都有顯著進步,卻仍未發現真正病因前二次的發病都是嘗試更換主食後所引發的情形,自此次治療後Angel改吃k/d,對肝及腎的負擔都可減少。第三次發病,就十分突然了,在沒有任何原因的情形下,突然沒有力氣、流口水不止,也是點滴治療後病情有所改善。第4次,為了治療細菌性膀胱炎,高雄診所的醫生建議將飼料由k/d改為皇家腎臟處方飼料,卻不幸開始了一連串的不適應,吃了飼料過3-4小時就吐,演變成不吃飼料到後來的厭食,灌食液態營養品,一週的時間都指向著腸胃系統的問題,直到8/25她沒力氣站立,接著伴隨著「流口水」的症狀,我們趕緊帶她上醫院打點滴,一整個晚上醫院的醫生不斷查詢著她可能的病因,雖然止住了口水的分泌,卻無法幫助Angel病情的進步,到一早轉診到屏科大時,她的狀況真的很不好,我們也有了Angel隨時會離開的心理準備,屏科大江老師親自問診後,隨即抽血檢驗,另外加做一項「血氨」,沒想到這個指數高達>800(標準值72) ,這下不妙了,令人害怕的肝性腦病可能被引發了,最後,用盡了各種內科方式,仍為法捥回她的生命。在超音波的檢查裡,看到Angel的肝,很小很小,X光片上寫著「小肝」,並且江老師在膀胱後面找到疑似異常的血管,這也許就是她與生俱來特別的身體與個性的起因「肝外性門靜脈分流」。 

Angel的病兆裡,的確表現的十分微小,毛髮特別細軟、吃不胖、消化系統不良、尿液偏鹼、吃米飯容易發病...,唯有發病時才有明顯流口水、昏迷等症狀,但這些小小的病兆卻指向一個連醫生都難以查覺的問題,如果您的狗狗或貓咪有以下徵兆,別忘了請您的獸醫以超音波檢查牠的肝臟是否發育到正常大小。  

以下譯自Jay Bianco 在1998、1999針對「肝臟的門靜脈分流」所寫的文章,僅以我拙劣的翻譯,獻給Angel寶貝,希望更多狗狗能獲得更好的治療,也祝福所有狗狗能更健康更快樂! 

Angel 媽 翠凰 95.9.8 

11月一次偶與台大獸醫系同學談論此病,95年初第一隻手術成功的黃金由於醫療費用驚人,飼主索性不要狗狗,所以台大給他機會重生,並成功完成手術。通常發病時狗狗的狀況通常很危急,所以大部份診斷出病灶時,狗狗已呈肝腦症(昏迷、僵直、抽慉...)。通常對於米飯、麵包等澱粉類食物,非常容易突顯發病,例如吃完米飯就會抽慉。 

p.s.歡迎轉載~~附上原文,如有需修改之處,請mail至younghappy64@gmail.com 謝謝您!!  






LIVER SHUNTS IN DOGS 

可能取決於肝臟血液轉向的多寡,臨床上症狀與跡象都有許多的變化,在小狗或年青狗中某些「門脈分流」的症狀可能可以做為判斷參考:  


小狗增長不完全(寵物長不大、毛皮仍為胎毛或 肝臟過小,在日本又有「小肝症」的稱呼)
體重不夠
沮喪,沒精神,缺乏感情。
(中樞神經失調的症狀,但此症狀不昜察覺)
虛弱
唾液分泌,流口水
(發病時出現的症狀,起因是肝無法代謝的毒素累積至影響到神經系統)
嘔吐
(中樞神經失調的症狀)
胃口不佳
平衡問題 (也是交感神經失調的症狀)
膀胱結石
目盲 眼睛不佳




如何診斷 

門脈分流問題在吃東西後會使症狀顯著增加,約25%可由吃飯前後膽汁酸分泌的情形來判斷,約75%會有顯現消化系統症狀包括胃口不好(沒食慾)、嘔吐、流口水、腹瀉,或者偶爾胃口混亂(吃紙,等等)。泌尿系統症狀可能包括多渴多尿,在多數門脈分流情況裡,將有水晶或者石頭在泌尿道裡形成。 這些水晶將是尿酸或者銨結晶,大多數狗狗在年齡一歲內被診斷出門脈系統分流,老的大約幾年已經被診斷出狀態。  

有許多可能異常可以判斷門脈分流︰ 

  • 一般實驗工作
    執行常規血液生化檢查對門脈分流器的診斷有所幫助,例如總蛋白質(primarily albumin)量少、血中葡萄糖量少,膽固醇含量少,血尿素氮(BUN)值偏低、尿酸值高等。

膽汁酸在診斷症狀的潛在的門脈分流篩選過程中極其重要。餓肚子,一兩個小時做血液中膽汁酸數值。在門脈分流個案裡膽汁酸水準將有一次重要的升高。膽汁酸適合臨床肝的檢查,目前不建議用在門脈分流情形。 

肝功能用Bromosulfaphthalein(BSP)測試,如果被正確地執行,測試氨容忍度和敏感度是可靠的。這些試驗測量肝的排泄/給認識的代理人解毒的能力,因此可準確測量肝功能。 

  • X光攝影
    X光攝影是門脈分流診斷最重要的方法之一, 並且目前在缺少較大的手術下是唯一普遍接受的確認方法。顯影劑將顯示在X光上的分流愮形,並且為外科的手術做準確的定位。 但是這是相當具侵略性測試如果只為了"篩選" 目的。染料在X光上表現出肝的血流,能漂亮清楚的展現問題。在一般檢查中,有許多可能的異常情形可以被發現,包括低BUN(血尿素氮)、,低的清蛋白、些許的貧血,在較高ALT值或者ALKP值。如果這些跡象存在,測試吃飯血清膽汁酸水準將是一種好想法,在吃之後,如果這次試驗也發現肝功能不良,那麼考慮超音波檢查比X光檢查是比較好的。

 

 

  • 放射性同位素
    這個方式需要昂貴的設備,診斷在比較放射性元素在肝裡與肺或者心臟裡的分佈狀態。 用適合肝的放射性同位素透過黏膜吸收,是一種非侵入式的診斷。如果做這個診斷也無法為外科手術正確指出門脈分流的精確的位置。

 

 

  • 超音波
    目前有研究使用顏色多普勒超音波,不久可能成為更好的篩選和診斷的工具。 過去,超音波對於系統門脈分流的非外科的診斷相當不可靠。(此文作者於1998年撰)



如何治療?
 

目前手術看起來唯一治療門脈分流的方式。

  

門脈分流有遺傳的傾向嗎?

目前根據專家所言,是的,非常明顯的肝臟門靜脈分流是遺傳疾病。 


Portosystemic shunts (門脈分流)
門脈分流是指血液由胃腸道進入肝臟,在肝入口靜脈出現異常的血管的連接,這樣的異常引起血液被轉向到胃腸道沒有通過肝臟的排毒。肝臟在化合物的新陳代謝和解毒裡有非常重要的功能,並且讓身體防禦系統得到抗體。
 

門脈分流可能有先天與後天另一個的疾病而造成血管異常的情形,門脈分流大部份是先天性的(75%),通常又分為肝內性與肝外性的門脈分流。



先天門脈分流
先天門脈分流通常發生在純種狗身上尤其以
雪納瑞、約克夏和愛爾蘭獵狼犬(Irish Wolfhounds)。在某些品種門脈分流有遺傳的傾向性。

肝外的門脈分流非常普通,佔先天的門脈分流61%到94%,並且在小型種的狗常看見,例如雪納瑞、約克夏。肝內的門脈分流佔先天的6% 和40%,常見的有愛爾蘭獵狼犬和黃金獵犬。多數肝內的門脈分流是由於胚胎連接臍帶血管和其靜脈異常打開;在大多數狗裡這個連接在誕生之後3天關閉,但是由於未知原因某些狗並未關閉此開口。
肝微血管發育不良是一個不平常的形式沒有大血管的異常容昜鑑定,這種稀有的狀態與不明顯的臨床症狀有關,要避免血管異常的狀況發生,建議建立遺傳基礎資料。 




後天門脈分流
後天的門脈分流多發生在肝臟疾病所引發,由於肝臟病變,血液無法順利進入肝臟而在門靜脈產生大壓力,造成沒有作用的新生血管。一般多是老狗並且是肝硬化、肝炎或者肝腫瘤患者。




門脈分流的徵兆?
這臨床徵兆反映出狗狗的肝無法消除各種各樣有毒事情,藥和細菌從胃腸道吸收,在吃之後,問題戲劇性增加。絕大百分比可能不能容忍麻醉劑或者寧神劑(tranquillisers),並且繼他們的使用之後可能顯示增加的恢復時間。 其他臨床徵兆:由於肝入口血液流動減少,影響肝必要的正常發展,結果肝臟未充分發展(沒長到正常大小),貯存和分泌的功能被更進一步削弱。 




描述和歷史 .
有先天的門脈分流的狗通常是純種狗,不到一歲。經常在身體較小或虛弱的狗身上發現,飼主可能抱怨那動物無法成長,牠的皮毛狀態是不健康的。




胃腸的跡象 .
大約3 分之2 的病例有嘔吐與腹瀉情形。大約一半的患狗有泌尿道疾病的存在,個案通常產生尿酸鹽結晶,因為在尿裡的氨和尿酸的過度的排泄。有一些狗狗,特別是有昜渴或多尿的症狀,也可能有門脈分流的情形。
 


管理 .
手術有時候是可能的,但是能帶一個非常高的危險,以及高價的費用。食物的控制主要作用是限制神經毒素(neurotoxin)的產生,神經毒素主要在大腸裡生成。主要的毒素全部從含氮物質得到(蛋白質和尿素)並且被在大腸內發現的細菌合成。這些毒素的生產透過限制蛋白質的數量而被降低,餵食易消化蛋白質食物。這些為了降低達到大腸的蛋白質的數量;少量多餐也可以使小腸的消化的能力最大化,更進一步的減少毒素產生。處方飼料提供平衡蛋白質卡路里攝入量並包括膳食纖維,在限制毒素生產過程中有幫助。乳果糖(Lactulose),可溶性纖維,經常被作為補充使用並且能容易被購買。有鋅鹽的增補也改進氨水的解毒以及控制肝性腦病(encephalopathy)。抗生素被在最裡使用,在負責降低大腸內細菌對於神經毒素的產生。在長期及短期的分脈分流藥物控制,口服新霉素通常與乳果糖聯合在一起使用。 





 

[This material used with kind permission of Jay Bianco,
Author & Creator of the "Maltese only" web site. Copyright 1999]

http://www.malteseonly.com/shunt.html

LIVER SHUNTS IN DOGS

Firstly there can be a lot of variation of clinical signs depending on the severity of the condition, which could depend on how much blood flow is diverted past the Liver. Some of the clinical signs of portosystemic shunts that might be recognised in a puppy or young adult that have been reported could include:
· Failure for a puppy to grow
· Poor weight gain
· Depression, Listlessness, apathy.
· Weakness
· Seizures
· Salivation, drooling
· Vomiting
· Poor appetite
· Balance problems
· Bladder stones
· Blindness

Maltese Dogs Liver Shunts
Frequently Asked Questions

by Jay Bianco

1998© All Rights Reserved

What are the signs?

There can be a lot of variation of clinical signs depending of the severity of the condition, which could depend on how much blood flow is diverted past the liver. Some of the clinical signs of portosystemic shunts that might be recognized in a puppy or young adult Maltese that have been reported could include:

  • Failure for a puppy to grow
  • Poor weight gain
  • Depression, listlessness, apathy
  • Weakness
  • Seizures
  • Salvitation, drooling
  • Vomiting
  • Poor appetite
  • Balance problems
  • Bladder stones
  • Blindness

Problems increasing dramatically after eating has also been strongly supported as an indication of a portosystemic shunt. Not all Maltese with the shunt will show this meal associated behavioral change, but in 25% of those affected that do, the diagnosis could become clearer. A high percent of affected Maltese show an intolerance to anesthetics or tranquilizers, & will show increased recovery times following their use. Approximately 75% of those affected will show digestive system symptoms including poor appetite, ascites, vomiting, drooling, diarrhea, or occasionally deranged appetite (eating paper, etc.). Urinary system symptoms may include increased thirst and urination, & in a majority of porto-systemic shunt cases, there will be crystals or stones formed in the urinary tract. These crystals will be either uric acid or ammonium urate (ammonium biurate or thorn-apple crystals.). Most Maltese will be diagnosed with port-systemic shunts under one year of age, but some several years older have been diagnosed with the condition.

How is Liver Shunt diagnosed?

There are a number of possible abnormalities that might point towards a portosystemic shunt on:

  • Routine Labwork
    Routine performed serum chemistries are fairly nonspecific toward confirming the diagnosis of porto-systemic shunts, but there may be a decreased total protein (primarily albumin), decreased blood glucose, decreased cholesterol, & decreased blood urea nitrogen (BUN). The uric acid levels may be elevated in a significant number of those Maltese affected.

Acid levels are extremely important in the diagnostic screening of symptomatic potential shunts. Fasting and a two hour post meal blood samples are evaluated for bile acid levels. In virtually all porto-systemic shunts there will be a significant rise in the bile acid levels over normal. The use of bile acids in screening clinically normal for liver shunts is not currently being advised due to the variation of normal bile acid levels in Maltese, and other breeds as well. Reports of recent vaccination with modified-live vaccines causing high serum bile acid levels in normal animals have not been confirmed as of this time.

Liver function testing with Bromosulfaphthalein (BSP) or ammonia tolerance testing are sensitive and reliable if performed correctly. These tests measure the liver's ability to excrete/detoxify known agents, and thus measure liver function accurately.

  • Radiography
    Radiography is one of the most important methods of establishing a diagnosis of porto-systemic shunt, and is currently the only universally accepted method of confirming a shunt, short of major surgery. Injection of a radiopaque dye into the spleen (Splenoportograpy) will show the shunt on radiographs and allow accurate assessment for surgical correction. But this is a pretty invasive test making it a poor choice for "screening" purposes. Special dyes injected into the liver circulation that show up on X-rays can outline the problem pretty clearly. Most of the time. But this is a pretty invasive test making it a poor choice for "screening" purposes. There are a number of possible abnormalities that might point towards a portosystemic shunt on routine labwork, including low BUN (blood urea nitrogen), low albumin, mild anemia, increases in ALT (serum alanine aminotransferase) or ALKP (serum alkaline phosphatase). If these hints are present, it would be a good idea to test the serum bile acid levels prior to eating and after eating. If this test is supportive of poor liver function then it may be a good idea to consider ultrasonagraphy and dye contrast X-rays.
  • Radioisotope
    This procedure requires expensive equipment and the diagnosis is based on the distribution of the radionuclide in the lung or heart compared to that in the liver. The placement of a radioisotope specific for the liver into the colon for absorption through the mucosa has been gaining favor because of its noninvasive diagnostic value. This procedure also does not identify the exact location of the shunt for surgical correction if required.
  • Ultrasound
    Currently there is research using Color Doppler Ultrasound which could soon be the preferred screening and diagnostic tool. In the past, ultrasound was fairly unreliable for nonsurgical diagnosis of porto-systemic shunts.

How is it treated?

Surgery appears to be the only cure for portosystemic shunts at this time.

Is there a genetic predisposition toward Porto-Systemic shunts?

At the present time, according to the experts, yes, most definitely Hepatic Porto-Systemic shunts are a genetic disorder.

For more information on recognition and management of portosystemic shunts


Portosystemic Shunts
Portosystemic shunts are abnormal vascular connections between the hepatic portal vein [the blood vessel that connects the gastrointestinal tract with the liver] and systemic circulation. Such anomalies cause blood in the gastrointestinal tract to be diverted past the liver, there by limiting the liver's vital functions in metabolism and detoxification of compounds and the body's defences against intestinally derived pathogens. This effectively exposes the body to toxic by products of digestion [toxins and bacteria] and mimics the effects of liver failure.

Portosystemic shunts can be present at birth [i.e. congenital] or acquired as the result of another disease process later on. Congenital shunts are more common, representing approx. 75% of all canine cases, and generally result from anatomic abnormalities of the portal vasculature or fetal vessels. One or occasionally two vessels are involved, and the shunts are classified according to their location as either outside of [extrahepatic] or within [intrahepatic] the liver.

Congenital Shunts
Congenital shunts occur more commonly in pure-bred dogs than in mixed breeds; miniature Schnauzers, Yorkshire Terriers, and Irish Wolfhounds appear to be at increased risk. The prevalence of portosystemic shunts in certain breeds suggests an inherited predisposition. This has only been proven in Irish Wolfhounds, where a number of previously unknown genes appear to be involved.

Extrahepatic shunts are most common, accounting for 61% to 94% of congenital shunts, and are typically seen in small breeds of dogs, such as the Miniature Schnauzer and Yorkshire Terrier. Intrahepatic shunts represent between 6% and 40% of congenital shunts and are more common in large and giant breeds such as Irish Wolfhounds and Golden Retrievers. The majority of intrahepatic shunts are as a result of the embryonic connection between the umbilical vein and the caudal vena cava remaining open; in most dogs this connection closes 3 days after birth but, for unknown reasons, remains open in dogs with intrahepatic congenital shunts.

Hepatic microvascular dysplasia is an unusual form of intrahepatic portosystemic shunting in which no gross vascular abnormality can be identified. This rare condition is associated with somewhat milder clinical signs and appears to be the consequence of a developmental abnormality; it has a higher prevalence in Cairn Terriers, suggesting a hereditary basis.

ACQUIRED SHUNTS
Acquired shunts arise secondary to diffuse liver disease where excessive and sustained pressure at some point within the portal vein causes embryonic, non-functional vascular communications to open. These are generally seen in older dogs with cirrhosis, hepatitis or neoplasia of the liver. In contrast to congenital portosystemic shunts, a number of vessels are usually affected.

What are the signs of Portosystemic shunts?
The clinical signs exhibited by the dogs reflects the failure of the liver to eliminate various toxic matter, drugs and bacteria absorbed from the gastrointestinal tract. Problems increase dramatically after eating. A large percentage may show an intolerance to anaesthetics or tranquillisers, and may show increased recovery times following their use. Other clinical signs arise from the liver being deprived of portal blood flow, which is essential for the normal development of the liver; as a result the liver is underdeveloped and its metabolic, storage and excretory functions are further impaired…

Signalment & History.
Dogs with congenital portosystemic shunts are typically pure bred dogs of less than one year old. Generally the lower the fraction of shunting, the milder and later in onset the clinical signs. Nevertheless the affected are often in poor body condition and of small body stature, especially when compared to their litter mates. Owners may complain that the animal fails to grow and that skin and coat condition are poor.

Gastrointestinal Signs
.
Vomiting and Diarrhoea are present in about two thirds of cases. Evidence of lower urinary tract disease is present in approximately one-half of cases and is usually due to ammonium urate crystals, which are formed because of excessive excretion of ammonia and uric acid in urine. Some dogs, particularly those that develop signs later in life, have polydipsia and polyuria ascites, although the latter is generally seen only in dogs with acquired shunts.
Management.
Surgery is possible in some cases but can carry a very high risk factor, and a high cost. Dietery manipulations for its control are designed to limit neurotoxin production, which occurs principally in the large intestine. The major toxins are all derived from nitrogenous materials [protein and urea] and are synthesised by bacteria found within the large intestine. The production of these toxins is reduced by limiting the amount of protein fed and ensuring that the dietary protein is high quality and highly digestible. These steps reduce the amount of protein that reaches the large intestine; further reductions can be attained by feeding smaller meals more frquently to maximise the digestive capacity of the small intestine. Specific diets are commercially produced tp provide a balanced protein-calorie intake including dietary fibre which assists in limiting toxin production. Lactulose, a soluble fibre, is often used as a supplement and can readily be purchased. Supplementation with zinc salts also improves the detoxification of ammonia and the control of hepatic encephalopathy. Antibiotics are used in most cases to reduce the bacteria within the large intestine that are responsible for the production of neurotoxins. Oral administered neomycin is commonly used for this purpose and is often used in combination with lactulose in both short and long term medical management of portosystemic shunts……..

 

sTaCy 發表在 痞客邦 留言(1) 人氣()