2017.11.15.

1

Liver circulatory disorder

Ascites

Dr. Sterczer Ágnes Department of Internal Medicine, University of Veterinary Medicine

Liver blood supply

Afferent dual

Hepatic portal vein 70-80% of blood, and 50% of oxygen

Collect blood from the intestine

Separates into two main branches, entering at hilus Right:supplies the right side of liver

Left: supplies the left + central portion

Hepatic artery 20-30% of afferent blood, but 50% of oxygen

Branches accompany the portal vein

Efferent single

Hepatic veinvena cavaheart

2017.11.15.

2

Liver structure with blood supply

•Terminal branches end into the

periportal sinusoids

•Connect with sinusoidal system

•Sinusoidal blood enters

central vein=terminal hepatic vein

in the liver lobule

•Central veins drain into branches

of hepatic vein

•Caudal vena cava heart

TYPES OF LIVER CIRCULATORY DISORDERS

Alterations in prehepatic supply (v. portae, a. hepatica)

changes in portal (v. portae) blood supply

: following food ingestion, enteritis

active hyperaemia of the liver

: decrease of portal blood flow: CPSS;

portal vein hypoplasia, thrombosis

changes in arterial (a. hepatica) blood supply

: when portal blood flow is insufficient; compensatory!

: hepatic venous congestion

impaired function of the left-side heart, (or rarely

thrombosis, tumors of the hepatic arteries)

2017.11.15.

3

TYPES OF LIVER CIRCULATORY DISORDERS

Alterations in intrahepatic circulation

"Portal hypertonia" often develops alone or with ascites but NOT with general edema

Causes:

congenital anomalies

persistent arterio-venosus fistula

intrahepatic portosystemic shunts (CIPSS)

intrahepatic vascular resistance (diffuse hepatic)

chronic hepatitis, cirrhosis, neoplasms, swelling of hepatocytes

Compensation: acquired portosystemic shunting CNS signs

TYPES OF LIVER CIRCULATORY DISORDERS

Alterations in posthepatic circulation

v. hepatica, v. cava caudalis, right-side heart

Increased outflow: theoretical situation

Decreased outflow

Cause: passive hyperaemia (congestion) of the

liver induration, fibrosis („nutmeg liver”)

Obstruction of v.hepatica or v.cava /right side

heart failure /pericardial disease

Portal hypertonia is common with edema & hydrops in

body cavities)

2017.11.15.

4

Pathophysiology

Development of portal hypertension Common in chronic hepatitis in dogs

(rare in cats)

↑resistance to blood flow

←fibrosis, contraction of Stellate

(hepatocyte swelling, infiltration) Consequences

Ascites APSS GI wall congestion and oedema

2017.11.15.

5

Ascites

Ascites is a pathological accumulation of free fluid within a the peritoneal cavity Strictly, ascitic fluid is serous in nature and is classified, depending on its protein and cellular content composition into following categories:

Transudate, modified transudate, exudate

Ascites

Courtesy of Dr.K.Voros

2017.11.15.

6

Ascites

2017.11.15.

7

ASCITES Abdominal effusion /fluid of low protein and low cell count

Transudate:

Pure: cell:< 2500/ l protein:<2,5 g/dl <1016 clear

Chronic hepatic failure+alb / intrahepatic portal vein hypoplasia / portal vein thrombosis

Modified: cell:< 7000/ l protein:2,5 g/dl 1016-1031 Chronic hepatic failure / heart failure / pericardial disease / caval

syndrome

Exudate: septic / nonseptic

high cellularity, high protein

Endothelial cell-lined sinusoids are highly permeable:

Hepatic lymph: high protein, hypo-moderate cellular

Intestinal lymph: low protein, hypocellular

Ascites in patients with hepatic disease: portal hypertension (CH, cirrhosis, portal vein hypoplasia, LDH) + alb +renal retention of salt and H2O

ASCITES Prehepatic

Intestinal lymph: low protein /hypocellular (pr; cell)

portal flow + high intrahepatic vascular resistance

AV fistula / v. portae hypoplasia / v. portae obstruction

Intrahepatic Presinusoidal

Intestinal lymph (pr; cell)

Periportal fibrosis / portal venule hypoplasia Sinusoidal

Hepatic +(intestinal) lymph (pr/; cell)

Cellular (inflamm, neoplastic), collagen infiltrates Postsinusoidal

Hepatic +(intestinal) lymph (pr/; cell)

Hepatic venular fibrosis

Posthepatic

Hepatic lymph (pr ; cell)

Passive congestion Obstruction of v.hepatica or v.cava /right side heart failure

/pericardial disease

2017.11.15.

8

ascites, caused by hypoproteinemia due to insufficient protein supply True transudate

Modified transudate, due to

right heart failure

858c.tif

860a.tif

Courtesy of Dr.K.Voros

2017.11.15.

9

CAUSES AND PATHOGENESIS OF ASCITES

Causes:

1.

2.

3.

4.

Portal hypertonia

Hepatic lymph production increasesmechanical factors

Hypoalbuminaemia

Hypovolaemia, hyperosmosisfunctional factors

increased aldosterone and ADH release

Pathogenesis:decreased albuminsynthesis

intrahepatic obstruction ofcapillaries

decreasedoncotic pressure

impaired venousoutflow

portal hyper-tension

increased lymphproduction

ASCITES

hypovolaemia

aldosterone production increased inactivation ofaldosterone decreases

Na+ and water retention in thetubuli increases

inactivation of ADHdecreases

CAUSES AND PATHOGENESIS OF ASCITES

Causes:

1.

2.

3.

4.

Portal hypertonia

Hepatic lymph production increasesmechanical factors

Hypoalbuminaemia

Hypovolaemia, hyperosmosisfunctional factors

increased aldosterone and ADH release

Pathogenesis:decreased albuminsynthesis

intrahepatic obstruction ofcapillaries

decreasedoncotic pressure

impaired venousoutflow

portal hyper-tension

increased lymphproduction

ASCITES

hypovolaemia

aldosterone production increased inactivation ofaldosterone decreases

Na+ and water retention in thetubuli increases

inactivation of ADHdecreases

2017.11.15.

10

Liver cirrhosis

Courtesy of Cs. Jakab

Courtesy of Cs. Jakab

Courtesy of Cs. Jakab

2017.11.15.

11

Vascular liver diseases PSS

CPSS

APSS

Portal vein hypoplasia

Primary hypoplasia of portal vein PHPV

Hepatic microvascular dysplasia HMD (mild)

Idiopathic noncirrhotic PH

Hepatoportal fibrosis

Secondary hypoplasia of portal vein

Occlusion of portal vein

Hepatic arterio-venous fistula Hepatic venous outflow obstruction

Budd-Chiari LIKE syndrome

PH

Portosystemic shunts (PSS)

2017.11.15.

12

Healthy state

Heart

Caudal vena cava

Portal vein

Forms of extra- and intrahepatic PSS

Intrahepatic shunt Extrahepatic shunts

2017.11.15.

13

PORTOSYSTEMIC SHUNT PSS is an abnormal vascular communication

between the portal and systemic venous

systems allow portal blood to reach the systemic circulation

without first passing through the liver increased level of enterically derived toxins in the

systemic circulation

(NH3, mercaptan, SCFA, AAA, GABA)

hepatic atrophy decreased hepatic blood flow

lack of hepatotropic factors

Congenital or acquired

PORTOSYSTEMIC SHUNT

CONGENITAL

Intrahepatic

Extrahepatic

AQUIRED

2017.11.15.

14

Congenital PSS anomalous embryonal vessels

short, wide

soliter / single

75% of PSS

usually in < 1 year old animal

portal hypotension

intra or extrahepatic

Intrahepatic PSS always soliter persistent ductus venosus • d. venosus fetal connection v. umbilicalis v. c. c.

• d. venosus is closed functionally in 3 days, anatomically 15-18 days after the born

left, central, right divisional Left division: morphology is consistent with failure

of fetal ductus venosus to close

large-breed dogs Irish wolfhounds, Golden Retriever, Irish Setters, Labrador Retriever, old english sheepdog, German Shepherd

2017.11.15.

15

Extrahepatic PSS always soliter

anatomically abnormal communication between the portal (v. portae, v. gastrolienalis, v. gastroduodenalis, v. mesenterica) and the v. cava caudalis or v. azygos

small-breed and toy dogs, cats (Eu: Yorkshire terrier, Cairn terrier, Shih Tzu, Maltese Terrier, Pug, Mini Schnauzer USA: Yorkshire terrier, Poodle, Mini Schnauzer)

2017.11.15.

16

Aquired PSS multiplex, collateral vessels narrow, twisting, tortuous protective compensatory response to PH

reopening of the existing, but not functioning extrahepatic portocaval or portoazygos anastomosis

portal hypertension (chronic, severe diffuse: cirrhosis, CH, neoplasm, LDH; AVF, PVH)

usually in older animals

not every portal hypertension cause PSS, a different between the blood pressure is necessary Posthepatic PH no APSS (portal and systemic

pressure)

2017.11.15.

17

Hepatic encephalopathy

Hepatocerebral syndrome

2017.11.15.

18

metabolic dysfunction of the brain secondary to liver dysfunction

Acute HE 10% rare -acute, fulminant encephalopathy, caused by sudden, almost complete necrosis of liver

Chronic HE 90% common

PSS collateral circulation + impaired liver function

Portosystemic encephalopathy (PSE) PSE chronic HE PSVA congenital

aquired

HEPATIC ENCEPHALOPATHY HE

HEPATIC ENCEPHALOPATHY dog: PSS + liver function • huge reserve capacityprevents the development of HE even in

severe parenchymal liver disease not accompanied by PSS

very rarely congenital urea cycle enzyme deficiency

cat: PSS+ liver function

Hepatic lipidosis: arginin (anorexia) less reserve,+ can not synthesize arginin in the liver

(intermediate in the urea cycle), inadequate NH3 detoxification

Portosystemic vascular anomalia is required

PORTOSYSTEMIC ENCEPHALOPATHY PSE

2017.11.15.

19

Pathogenesis of PSE

Glutamate neurotransmission and NH3

GABA/benzodiazepin receptor complex

Deranged catecholaminerg neurotransmitter system

Liver

AAA

Neuron

Tyr

Dopa

Dopamin

Noradrenalin

Tyr

Tyramin

Oktopamin

Phe

B-phe

AAA

Trp

Phe

Tyr

HE: BCAAAAA

„FALS NEUROTRANSMITTER”„FALS NEUROTRANSMITTER”

2017.11.15.

20

Hepatic encephalopathy

CNS signs

CPSS 80-90%

episodic (few bad days alternating normal period) and the intensity, severity of the signs is wavy

precipitated by a protein rich meal

lack of correlation between blood NH3 level and severity of encephalopathic signs

HE grade (1-4)

2017.11.15.

21

Vascular liver diseases PSS

CPSS

APSS

Portal vein hypoplasia

Primary hypoplasia of portal vein PHPV

Hepatic microvascular dysplasia HMD (mild)

Idiopathic noncirrhotic PH

Hepatoportal fibrosis

Secondary hypoplasia of portal vein

Occlusion of portal vein

Hepatic arterio-venous fistula Hepatic venous outflow obstruction

Budd-Chiari LIKE syndrome

PH

2017.11.15.

22

Arterioportal fistulae (APF) a. hepatica—portal vein Congenital (hemangioma)

Vascular connection, allow blood to bypass the hepatic inusoidal network, flow retrograde into portal system

Clin: -young dogs (<1,5 y)

APF PH, ascites, APSS, splanchnic vascular congestion Macroscopic: large, thin-walled, tortuous, pulsating vascular channel

distorts the involved liver lobes, elevates the hepatic capsule

Continuous murmur (fremitus) turbulent blood flow over affected liver lobe

US: hepatic AV fistula

extremely dilated, tortuous, anechoic portal branch in a liver lobe=pathognomic finding

High arterial pressure dilatation of affected portal branch and hepatofugal flow

Thanks for your attention!