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The gallbladder is an organ on the right side of the upper abdomen. It stores and concentrates bile, which is a dark green liquid produced by the liver. Bile, which travels down tubes out of the liver and into a part of the gut called the duodenum, acts like a detergent in breaking up large fat particles into smaller ones, facilitating the action of digestive enzymes. When fasting, bile is stored and concentrated in the gallbladder. If the balance of substances coming out of the liver in bile is not quite right (and in particular, has too much cholesterol in it, or not enough of some other substances including bile salts), small crystals can be formed in the bile, and over time these can compact together and form gallstones. Because bile spends a lot of time in the gallbladder not doing much, gallstones mostly form here. Now most people with gallstones do not have any symptoms, and surgery is generally not recommended.

The classical symptoms of gallbladder pain due to gallstones (called biliary colic) occurs a few hours after a meal rich in fat (usually the evening meal), and consists of pain across the upper abdomen or lower chest, often felt like a squeezing band, that last 30 minutes to 2 hours. There is usually nausea (feeling sick) and/or vomiting. The pain usually subsides after this, and you are left wondering what the hell happened! This pain is due to the gallbladder squeezing against a stone that becomes temporarily stuck in the outflow of the gallbladder, an area called Hartmann's pouch of the gallbladder, or the cystic duct (the small tube connecting the gallbladder with the common bile duct). The pain is due to an increase in pressure inside the gallbladder which specialised nerves pick up and the brain registers this as pain. Thus when the blockage is relieved, usually by the stone falling back into the gallbladder, or at least not completely blocking the outflow anymore, the pressure inside the gallbladder reduces and the pain settles.

If the stone does not budge and blockage of the outflow of the gallbladder continues, chemicals within the bile in the gallbladder start causing irritation of the lining of the gallbladder. The pain then tends to change, become sharper in nature, and moves to the right hand side of the upper abdomen (where the gallbladder is) as a different set of nerves are now being irritated and the brain can localise where the problem is. There is usually nausea, vomiting and a fever, and the pain may radiate around to the region of the right scapula (shoulder blade). This is called acute cholecystitis.

If a stone is caught in the bile duct, there are generally 3 types of problems that can be caused:

  1. Painful obstructive jaundice

  2. Cholangitis (infection in the bile duct)

  3. Acute pancreatitis

Hiatus Hernia

The normal anatomy of the oesophagus, stomach, and its relationship to the main breathing muscle (the diaphragm) that separates the organs of the chest and the organs of the abdomen are depicted in the first diagram. Usually there is no other organ except the oesophagus going through the diaphragm, and this joins to the stomach 1-2 cm below the diaphragm at what is called the gastro-oesophageal junction (GOJ). In some people the hole in the diaphragm that lets the oesophagus through can be weak and expands in size, allowing contents from the abdomen to migrate into the chest. This is called a hiatus hernia. There are several types of hiatus hernia, which depend on which organ is migrating into the chest and how it is doing so. The commonest is called a sliding hiatus hernia, which is where the GOJ and stomach are 'sliding' up and down through the hiatus (second diagram). The second is called a para-oesophageal hiatus hernia, where a separate part of usually the upper stomach migrates up, but the GOJ stays down in the abdomen.

Symptoms related to hiatal hernia depend on the anatomy, and whether there is associated gastro-oesophageal reflux of acid. Symptoms of a large hiatus hernia itself include pain behind the sternum (breastbone) associated with intake of food/fluid, and nausea, dry retching and/or vomiting. The concern with para-oesophageal hiatus herniae is that incarceration can occur, where the organ (usually a significant part of the stomach) migrates up into the chest and cannot come back down. This presents usually as an emergency, with the above symptoms, and needs semi-urgent treatment. Often the most useful initial manouevre in the emergency department once the diagnosis is established (usually by CT scanning), is placement of a tube through the nose into the upper stomach (called a nasogastric tube or NGT) to decompress the stomach and allow it to deflate. This usually helps in settling the symptoms, and then we can decide on the timing of repair, which is usually by an operation.

Liver Tumours

There are many types of liver tumours, and they are divided into benign (non-cancerous) and malignant (cancerous) tumours. Benign tumours include haemangiomas, focal nodular hyperplasia and liver cell adenoma (also called hepatocellular adenoma). The commonest malignant tumours are colorectal liver metastases, hepatocellular carcinoma (HCC), and cholangiocarcinoma.

Confirming the type of tumour it is is important as depending on whether it is benign or malignant, different treatments may be needed (nothing at all, observation with interval imaging, surgery or chemotherapy).

Liver Cysts

Liver cysts are walled off collections of fluid within the liver, and are quite common occurring in up to 5% of the population. There are different types of cysts, with by far the most common being simple cysts, but there are also cysts caused by infections from parasites (such as Hydatid disease) and also certain types of benign and malignant tumours. Generally ultrasound alone is enough to confirm a simple cyst - further studies such as CT or MRI scan and specialised blood tests may be needed if it is not thought to be a simple cyst on ultrasound examination, and the treatment of these non-simple cysts may include surgery. Simple cysts occasionally can be large enough to cause symptoms, sometimes suddenly, related to bleeding into the cyst, cyst rupture, or pressure on other structures (stomach, bile duct, important blood vessels), and if they are causing symptoms, surgery may be required to deal with them.

Pancreatic Tumours

Pancreatic tumours can be solid or cystic (see section on pancreatic cysts for cystic tumours). There are several different solid tumours of the pancreas, the commonest of which is the malignant tumour called pancreatic adenocarcinoma. This is a cancer originating from the lining cells of the pancreatic duct, the tubing system within the pancreas through which pancreatic digestive juices pass, which is shaped like a fishbone. The commonest tumours are located in the head of the pancreas (75%), with the rest located in the body and tail. Pancreatic adenocarcinoma is a very aggressive tumour with a low cure rate, even with radical surgery. The hope is that after thorough staging, the cancer may appear to be confined to the pancreas, in which case major surgery may be offered in order to prolong survival.

Pancreatic Cysts

Pancreatic cysts are detected increasingly commonly with modern imaging. There are different types of pancreatic cysts, the commonest being pseudocysts (related to a prior attack of pancreatitis), and cystic pancreatic tumours (3 main types, intraductal papillary mucinous neoplasms or IPMN, mucinous cystadenomas or MCA, and serous cystadenoma or SCA)


Acute pancreatitis is inflammation of the pancreas, and the two main reasons for this in our population are gallstones and excessive consumption of alcohol. It usually causes severe pain in the upper middle aspect of the abdomen and going through to the back, with nausea and/or vomiting. As the pancreas produces digestive enzymes in addition to hormones (such as insulin) that are involved in regulating blood sugar, inflammation of this organ can have significant consequences.

Estimating the severity of an episode of pancreatitis is important as it is a guide for whether or not certain types of complications may occur (fluid collections around/within the pancreas called pseudocysts, death of areas of the pancreas which is called pancreatic necrosis).

The treatment of pancreatitis involves adequate pain relief and support for other organs (heart, lung, kidneys) that can be affected by the inflammation of the pancreas.


There are several reasons for jaundice, which can be from liver diseases such as hepatitis, or blockage of the bile ducts leading out of the liver (which is called obstructive jaundice). Symptoms of a blocked bile duct include being off your food and not feeling well, as well as jaundice, which is a yellow tinge to the skin and whites of the eyes, dark urine, and pale bowel actions. This will need confirmation with blood tests, an ultrasound scan and often a CT scan as well, to try and figure out the cause of the jaundice. Common causes of obstructive jaundice include complications related to gallstones, as well as tumours of the bile duct, pancreas and ampulla (the opening of the bile duct in the duodenum).

Abdominal Wall

Abdominal wall herniae (which is the plural of hernia) are defects/holes in the abdominal wall (the muscle and fibrous tissue that keeps everything in the abdomen). These hernias commonly occur at the belly-button (umbilical hernia),  in the groin (either inguinal or femoral herniae), and at sites of previous abdominal surgery (incisional herniae) as these are weak areas in the abdominal wall. Herniae that are causing symptoms should generally be repaired with surgery. 

Obesity (Sleeve

Laparoscopic sleeve gastrectomy is the only operation Dr Mihrshahi performs for obesity, at Macquarie University Hospital and Northern Beaches Hospital.

Basic criteria for bariatric (obesity) surgery in Australia are for patients with a BMI (Body Mass Index) >35 with major health problems attributable to obesity, or a BMI >40 with or without major health problems related to obesity. For a successful result, patients need to make a commitment to significant changes to eating habits and lifestyle.

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