Approximately 10% of fatty liver disease progress to hepatocellular carcinoma (cancer of the liver). However, this figure is often lower in non-alcoholic fatty liver disease.
When the hepatocytes become non-functional after displacement and loss of its contents to triglycerides, inflammatory processes may take place leading to injury to the cells. Any attempt at healing may result in fibrosis and scaring of the liver. Furthermore, blood and nerve supplies to these affected cells may be limited or totally severed leading to death and necrosis of the part of the liver affected. This stage is known as steatohepatic phase (Cirrhosis). Cirrhosis is one of the major causes of liver cancer.
Liver cancer is the fifth most common but fatal cancer in the world. Its prevalence is higher in Asia and Alaska than in any other part of the world. The prognosis of this condition is often very poor except when it is detected early enough and with prompt intervention. Occurrence of primary liver cancer (originating from the liver cells) is lower than secondary carcinoma (metastatic liver cancer).
Liver cancers are often advanced before detention due to its asymptomatic nature. Therefore, most patients barely survive beyond five years after treatment which often involves:
- Surgical removal of affected parts if the cancer is localized in a particular region. The liver cells have the ability to reproduce and replace lost portion but this is not often achieved in most situation due to rapid metastases to other parts.
- Liver Transplantation: a larger portion of the liver may be removed and the residual portion grafted with harvested part from a suitable donor.
- Destruction of affected cells either with radiation therapy, cryotherapy or chemotherapy to halt its spread to unaffected parts.
- Embolization: method of limiting blood supply to affected cells to inhibit metastases to healthy cells. However, this may be challenging because of the huge blood supply to the liver.
Many more treatment options are being invented to improve and prolong the lives of liver cancer victims.
The pre-morbid statuses of people with fatty liver disease are often used to determine the causative factor of their condition irrespective of the presenting type. The major causes of fatty liver diseases have been researched and found to be either one or more of the following which directly or indirectly lead to deposition and accumulation of fatty acids in the liver:
- Alcoholism: it is alarming to know that over 80% of alcohol consumers develop fatty liver disease, however, only a fewer percentage may actually develop complications which is largely dependent on heredity and metabolic capacity of each alcoholic. Alcohol causes rapid accumulation of fatty acids in the liver.
- Diabetes: insulin resistance in diabetics has been strongly linked to the development of fatty liver due to accumulation of fatty acids in the liver released from adipose tissues.
- Obesity: excessive consumption of calories in diets and reduced physical activities results in fat storage due to imbalance in energy consumption and expenditure. The liver cells are one of the targets for fat deposition. Fatty liver is present in almost all obese people but like the alcoholics, only a few may manifest symptoms and develop complications.
- Impaired fat metabolism: any defect in the process of fat metabolism may lead to excessive storage of fat in the liver.
- Rapid weight loss: either due to extreme fad dieting, malnutrition or severe illness may stimulate fat deposition; however, studies are underway to backup this claim.
- Drugs: certain drugs such as antiviral, tetracycline, tamoxifen, corticosteroids, methrotrexate have been implicated in the development of non-alcoholic fatty liver disease in some patients.
In addition to these, some factors can predispose an individual to develop fatty liver disease irrespective of the cause:
Fatty liver disease progresses asymptomatically in almost all sufferers until it is accidentally discovered during routine medical check-up or investigation for a different ailment. Secondly, most of the signs and symptoms are often mild, non-specific, and vary depending on the stage of the disease. The patients usually overlook these indicators until they begin to interfere with activities of daily living. Most common signs and symptoms of fatty liver disease are:
- Pain: this is one of the earliest symptoms of this condition. It is said to occur as a result of stretching of hypertrophic cells which irritate the pain receptor nerves in the liver.
- Anorexia (loss of appetite
- Nausea: This may be mild or severe and can be non specific.
- Vomiting: expulsion of ingested food mixed with bile.
- Abdominal discomfort: Patients refer to this as ‘queasiness’ which may be generalized or specific.
- Jaundice: this is an alarming sign that often indicate presence of liver malfunction.
- 7. Malaise
- Fever: Fever may be due to inflammation which occurs at a later stage of the disease.
- Ascites: Abdominal distention due to excessive fluid accumulation in the abdominal cavity mostly seen in hepatic disorders. This is noticed at the later stage of the disease.
- Spider angiomas: tortuous veins appearing like web-like structures present on the surface of the distended abdomen of people with Ascites.
- Hepatomegaly: An enlargement of the liver. In the early stage the liver can be enlarged and felt when palpated during physical examination, but it is often smooth and non tender. However, in the later stage of this condition, it becomes hard and uneven.
- Pruritus: General body itching caused by excessive bilirubin in the body (jaundice).
It is important to know that a definitive diagnosis cannot be made with a single complaint of any of the above listed signs and symptoms. A diagnosis of fatty liver disease can only be trusted when a histology report of a liver biopsy specimen is positive and laboratory investigations reveal elevated liver enzymes in addition to triglyceride level above 10%.
People are often filled with fear and anxiety when they are diagnosed with conditions of the liver probably due to the important functions the liver plays in the human body and unfavorable prognosis of most liver conditions. The liver is the second largest organ in the body after the skin. Almost all bodily functions are directly or indirectly dependant on the liver.
Fatty liver disease is a medical condition which occurs when there is an abnormal accumulation of fatty acids and glycerol (triglycerides) in the liver cells (hepatocytes). Although the liver cells contain an acceptable amount of fatty deposit considered ‘normal’, an excessive deposit of these fatty substances leads to this condition often referred to as ‘steatosis’.
Unlike most liver diseases, fatty liver is reversible with appropriate treatment and lifestyle modification; sufferers can achieve total cure and resume normal life. However, when left untreated or when there is an underlying debilitating illness, the condition may become complicated and prove fatal.
Prevalence of fatty liver disease
Many researches and studies have been conducted to determine the epidemiology of this condition and their results could be summarized as follows:
- It affects between 2%-30% of the world population irrespective of age, gender and ethnicity.
- More common among obese people
- Over 80% of alcoholics suffer from this condition
- It affects more men than women.
- It affects one third of the American population.
- It is higher in older adults and postmenopausal women.
- The prevalence is higher in Hispanic and Asian but lowest in Black.
- It affects 2%-12% of children most of which are obese.
- The risk increases in patients undergoing bariatric surgery.
Pathophysiology of Fatty Liver Disease
The disease follows a similar pattern irrespective of the causative factor. With accumulation of triglycerides in the hepatocytes there is a displacement of the cellular contents especially the nucleus and an increase in the cell size (macrovesicular hypertrophy) which causes the cells to undergo several changes and becomes non-functional. This stage is often reversible with the elimination of causative factors.