The Gallbladder and bile ducts

Gallbladder

• The gallbladder is a pear-shaped reservoir in continuity with the common hepatic and common bile ducts through the cystic duct.
•  It is usually 7.5 to 12cm in length, is 3 to 5 cm in diameter, and has a capacity of 35 to 50 mL.
•  The gallbladder lies on the inferior surface of the liver partially enveloped in a layer of peritoneum.
•  The gallbladder is anatomically divided into the fundus, body, infundibulum, and neck, which empties into the cystic duct.
•  Both the gallbladder neck and the cystic duct contain spirally oriented mucosal folds known as the valves of Heister. 
• The valves prevent the passage of gallstones and excessive distention or collapse of the cystic duct, despite variations in ductal pressure. 

The Hepatic Duct (ductus hepaticus)

• Two main trunks of nearly equal size. Arising from the liver at the porta. one from the right, the other from the left lobe.
• The common hepatic duct is less than 2.5cm long  and is formed by the union of the right  and left hepatic ducts.
• It passes downward and to the right for about 4 cm.
• Joined at an acute angle by the cystic duct to form the common bile duct. Lies between  the layers of the lesser omentum.
• Is accompanied by the hepatic artery and portal vein. 

Cystic duct

The cystic duct varies in length from 1 to 5 cm and in diameter from 1 to 3 mm; it usually joins the common hepatic duct at an acute angle.

The Common Bile Duct 

The common bile duct is formed by the junction of the cystic and hepatic ducts.

• Length: It is about 7.5 cm. long.
• Diameter: That of a  goose-quill.

• Course and extent : It descends along the right free margin  of the lesser omentum along with   portal vein ( which is behind it ) , and to the right of the hepatic artery. 
• Then behind the superior portion of the duodenum,
• After crossing the duodenum, it runs on the posterior surface of the head of the pancreas, and in front of IVC. 
• Occasionally completely imbedded in the pancreatic substance. 
• At its termination it lies for a short distance along the right side of the terminal part of the pancreatic duct and passes with it obliquely between the mucous and muscular coats. 
• The two ducts unite and open by a common orifice upon the summit of the duodenal papilla, situated at the medial side of the descending portion of the duodenum, a little below its middle and about 7 to 10 cm. from the pylorus. The short tube formed by the union of the two ducts is dilated into an ampulla, the ampulla of Vater. 

Blood supply

• Gall bladder is supplied by Cystic artery, a branch of right hepatic artery.
• The blood supply to the common hepatic duct, cystic duct and common bile duct comes from the gastroduodenal, retroduodenal, postero-superior pacreatico duodenal arteries. 

Lymphatics

• The lymphatics of gallbladder (subserosal and submucosal) drain into the cystic L/N of Lund.
• Small veins and lymphatics course between the gallbladder fossa and the gallbladder wall, connecting the lymphatic and venous drainage of the liver and gallbladder. These connections are the cause of the direct inflammatory and carcinomatous spread from the gallbladder into the liver.

Calot’s triangle

Formed by:

• Common hepatic duct to the left
• Cystic duct below and 
• inferior surface of the liver above.

Content:

• the cystic artery, 
• the right hepatic artery, and
• the cystic duct lymph node.

Functions of gall bladder

• Stores bile
• Concentrates bile
• Secretion of mucus

Embryology

• The hepatic diverticulum arises from the ventral wall of the foregut and elongates into a stalk to form the choledochous.
• A lateral bud is given off, which becomes the gall bladder and the cystic duct.

Congenital abnormalities

• Absence of the gall bladder
• The Phrygian cap
• Floating gall bladder
• Double gall bladder
• Absence of the cystic duct
• Low insertion of the cystic duct
• An accessory cholecystohepatic duct

Biliary atresia

It may be due to viral infection or defective embryogenesis resulting in the inflammatory destruction of extra- and intrahepatic biliary tree.
Incidence 1 in 12000 live births
Male and female equally affected.
It may be associated with: cardiac lesions, polysplenia, situs inversus, absent vena cava and a preduodenal portal vein.

Classification

Type I: atresia restricted to the common bile duct
Type II: atresia of the common hepatic duct
Type III: atresia of the right and left hepatic ducts

Clinical features

• Progressive jaundice in a new born.
• Steatorrhea
• Osteomalacia
• Biliary rickets
• Severe pruritus
• Clubbing and skin xanthomas

D/D

• Alpha 1-AT deficiency
• Cholestasis associated with i.v feeding
• Choledochal cyst
• Inspissated bile syndrome
• Neonatal hepatitis

Treatment
In correctable cases:
Roux-en-Y hepaticojejunostomy
In noncorrectable cases:
Hepaticoportojejunostomy (Kasai’s operation)
Radical excision of all bile duct tissue up to the liver capsule is performed.
A roux-en-Y loop of jejunum is anastomosed to the exposed area of liver capsule above the bifurcation of the portal vein creating a portoenterostomy

Liver transplantation: in case of unsuccessful

Caroli’s disease

It is a congenital, multiple, irregular dilatations of the intrahepatic ducts with stenotic segments in between.
Extrahepatic biliary system is normal.

Types :

Simple type
Presents later with episodes of aqbdominal pain and biliary sepsis

Associated with:
Congenital hepatic fibrosis
Polycystic liver
Cholangiocarcinoma
Periportal fibrotic type
Presents in childhood

Periportal fibrotic type is associated with:
Biliary stasis
Stone formation and
Cholangitis

T/T

• Antibiotics for chalangitis and removal of calculi.
• If limited to one lobe of liver- lobectomy

Choledochal cyst

Choledochal cysts are congenital dilations of the intra- and/or extrahepatic biliary system.

Classification (Todani)

Type Ia and b: diffuse cystic
Type II: diverticulum of the common bile duct
Type III: diverticulum within the pancreas
Type IV: extension into the liver
Type V: cystic dilatation only of the intrahepatic ducts

Clinical features

• Can occur in any age.
• Patients may present with jaundice, fever, abdominal pain.
• O/E right upper quadrant mass which is smooth, soft, not moving with respiration, not mobile and resonant.

Ix

Ultrasonography abdomen:
Confirms the presence of  abnormal cyst

MRI/MRCP:  
reveals anatomy. Esp. relationship between the lower end of the bile duct and the pancreatic duct.

CT: 
show the extent of intra- and extrahepatic dilatation.

Treatment
Radical excision of the cyst is the t/t of choice with reconstruction of the biliary tree using a RouX-en-Y loop of jejunum.

Neonatal complications of diabetes during pregnancy

• Premature delivery
• Fetal macrosomia
• Neural tube defects (e.g Caudal regression syndrome)
• Hypoglycemia
• Hypocalcemia
• Polycythemia
• Respiratory distress
• Transient hypertrophic cardiomyopathy.

Sexual appearance of fetus at (second to third month) (third to fourth) and (at time of birth) of pregnancy

Sexual appearance of fetus at (second to third month) (third to fourth) and (at time of birth)of pregnancy.

Patau syndrome & Edwards syndrome Manifestations

Trisomy 13 (Patau syndrome) is the third most common autosomal trisomy identified in liveborn infants, and the most severe. Affected children typically die within the first week of life, with only 5% surviving the first six months. In the majority of trisomy 13 infants cytogenetic studies demonstrate nondisjunction (47XX, +13); this chromosomal abnormality arises during maternal meiosis I and is associated with advanced maternal age.

The prominent phenotypic features of trisomy 13 are associated with an early defect in prechordal mesoderm development. As a result, the midface, eye, and forebrain are most markedly affected. The clinical manifestations of Patau syndrome include the abnormalities categorized by system below.
1. Head and neck: severe cleft lip and/or palate microphthalmia or anophthalmia, coloboma, cyclops, malformed or absent nose, deafness, scalp defects (aplasia cutis)
2. CNS: severe mental retardation microcephaly, holoprosencephaly (failure of brain to divide into hemispheres) absent olfactory nerve or bulb, neural tube defects
3. Extremities: polydactyly, rocker-bottom feet
4. Cardiac: PDA, atrial septal defect, ventricular septal defect
5. Renal: polycystic kidney disease
6. Gastrointestinal: abdominal wall defects associated with omphalocele or umbilical hernia, pyloric stenosis.

Clinical manifestations of trisomy 18 (Edwards syndrome) include
prominent occiput micrognathia,
small mouth low-set and malformed ears, and rocker-bottom feet.
Clenched hands with the index finger overriding the middle finger
and the fifth finger overriding the fourth finger are characteristic for this condition.
Meckel’s diverticulum and malrotation are common gastrointestinal abnormalities.  

Associations of autosomal and sex chromosomal-inherited disorders

A variety of autosomal and sex chromosomal-inherited disorders are associated with developmental cardiac and/or aortic defects or cardiac pathology. The major associations are as follows:


1. Down syndrome: endocardial cushion defects (ostium primum ,ASD, regurgitant AV valves)
2. DiGeorge syndrome: tetralogy of fallot and aortic arch anomalies
3. Friedreich’s ataxia: hypertrophic cardiomyopathy
4. Marfan syndrome: cystic medial necrosis of the aorta
5. Tuberous sclerosis: valvular obstruction due to cardiac rhabdomyomas
6. Turner’s syndrome: coarctation of the aorta. 

Cardiovascular Embryology

The earliest sign of the heart is the appearance of paired endothelial strands-angioblastic cords-in the cardiogenic mesoderm during the third week .An inductive influence from the anterior endoderm stimulates early formation of the heart. These cords canalize to form thin heart tubes.

As lateral embryonic folding occurs, the endocardial tubes approach each other and fuse to form a heart tube.Fusion of the heart tubes begins at the cranial end of the developing heart and extends caudally.

The heart begins to beat at 22 to 23 days Blood flow begins during the fourth week and can be visualized by Doppler ultrasonography 

The fusion begins at the cranial ends of the heart tubes and extends caudally until a single tubular heart is formed. The endothelium of the heart tube forms the endocardium of the heart. As the heart elongates, it forms regional segments and bends upon itself, giving rise to an S-shaped heart 

COMMON TYPES OF PERSISTENT TRUNCUS ARTERIOSUS (PTA)

Diagram of a malformed heart illustrating transposition of the great arteries (TGA). The ventricular and atrial septal defects allow mixing of the arterial and venous blood. TGA is the most common single cause of cyanotic heart disease in newborn infants. As here, it is often associated with other cardiac anomalies (ventricular septal defect [VSD] and atrial septal defect [ASD]).

TETRALOGY OF FALLOT. Observe the four cardiac deformities of this tetralogy: pulmonary valve stenosis, ventricular septal defect (VSD), overriding aorta, and hypertrophy of the right ventricle.

Sagittal sections of the primordial heart during the fourth and fifth weeks illustrating blood flow through the heart and division of the atrioventricular canal. The arrows are passing through the sinuatrial (SA) orifice. D, Coronal section of the heart at the plane shown in C. Note that the interatrial and interventricular septa have started to develop.

Ultrasound scan of a fetal heart at 23.4 weeks' gestation with an atrioventricular septal defect and a large ventricular septal defect (VSD). 

Postductal coarctation of the aorta. B, Diagrammatic representation of the common routes of collateral circulation that develop in association with postductal coarctation of the aorta. C and D, Preductal coarctation.

Closure of the ductus arteriosus (DA). A, The DA of a newborn infant. B, Abnormal patent DA in a 6-month-old infant. C, The ligamentum arteriosum in a 6-month-old infant.

Pharyngeal and pharyngeal arch arteries. A, Left side of an embryo (approximately 26 days). B, Schematic drawing of this embryo showing the left pharyngeal arch arteries arising from the aortic sac, running through the pharyngeal arches, and terminating in the left dorsal aorta. C, An embryo (approximately 37 days) showing the single dorsal aorta and that most of the first two pairs of pharyngeal arch arteries have degenerated

The relation of the recurrent laryngeal nerves to the pharyngeal arch arteries. A, At 6 weeks, showing the recurrent laryngeal nerves hooked around the sixth pair of pharyngeal arch arteries. B, At 8 weeks, showing the right recurrent laryngeal nerve hooked around the right subclavian artery and the left recurrent laryngeal nerve hooked around the ductus arteriosus and the arch of the aorta. C, After birth, showing the left recurrent nerve hooked around the ligamentum arteriosum and the arch of the aorta.

FETAL CIRCULATION

Observe that three shunts permit most of the blood to bypass the liver and lungs: (1) ductus venosus, (2) oval foramen, and (3) ductus arteriosus. 

Neonatal circulation. The adult derivatives of the fetal vessels and structures that become nonfunctional at birth are shown.