Symptoms: Fatigue, pain in the upper right abdomen, yellow skin, weight loss, loss of appetite, jaundice, swollen abdomen, oedema, weakness, liver damage, confusion
Causes: Metabolic syndromes like insulin resistance, high cholesterol, high blood pressure, high triglycerides, type2 diabetes, obesity, prescription drugs like amiodarone, tamoxifen, and diltiazem or steroids

Risk Factors: Obesity, type 2 diabetes, prediabetes, Hispanic and non-Hispanic ethnicity, high cholesterol and triglyceride level, high blood pressure, drugs like corticosteroids, cancer drugs, age, rapid weight loss, hepatitis C, insulin resistance
Severity: Mild to severe
Which doctor to consult: Hepatologist or Gastroenterologist

Overview 

Fatty liver disease is a relatively common condition that indicates fat accumulation in the liver. It is also called steatohepatitis and is caused primarily by excessive consumption of alcohol, occasionally resulting in liver damage. The liver is the body's most vital component for transferring nutrients and blood filtration. Other than that, it also helps prevent specific infections. So, any damage can sabotage the body's normal functioning, giving rise to numerous other symptoms. 
Maintaining a balance is essential since a small amount of fat is necessary for the proper functioning of a healthy liver. The problem arises when the fat increases by 5% to 10%. 
Fatty liver disease can be of two types – Non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver or alcoholic steatohepatitis. 
NAFLD can further be categorised into two types: 
Simple fatty liver
Nonalcoholic steatohepatitis (NASH) 
Those suffering from simple fatty liver do not experience any inflammation of the liver cells. However, NASH can be severe if not taken care of and cause cirrhosis or liver cancer. 
Alcoholic fatty liver, on the other hand, occurs due to heavy consumption of alcoholic beverages. This is because alcohol is broken down mainly in the liver before getting expelled from the body. But this breaking down of alcoholic substances can produce harmful toxins in the body causing liver cell inflammation and damage. Chronic cases of alcoholic fatty liver are cirrhosis and alcoholic hepatitis. 
The good news is that fatty liver disease, especially alcoholic liver, is generally reversible. However, non-alcoholic steatohepatitis or NASH is an irreversible condition where the fat builds up in the liver, eventually stopping proper liver function completely. The only remedy is preventing other conditions contributing to fatty liver disease. 

When to Consult a Doctor? 

It is highly recommended to seek medical assistance for any of the following situations:
On Symptoms: Fatty liver disease may not always be fatal but it is better to consult a specialist. Sudden weight loss despite following a healthy diet and sufficient physical activity is an immediate indicator of something wrong. Other symptoms to consider are a yellow tint on the skin and the whites of the eyes. Even individuals who do not consume alcohol can be diagnosed with fatty liver. Hence, a medical assessment by a professional is recommended. However, alcoholic fatty liver may go away on its own once the alcohol consumption is stopped. 
During Pregnancy: Obstetric emergencies can become problematic for pregnant women as these can result in a dysfunctional liver and even death. So, supportive maternal care need to be provided to the expecting mother. 

Diagnosis 

A hepatologist and gastroenterologist can diagnose and treat fatty liver. It is advised to consult both doctors for an accurate diagnosis and faster recovery. The hepatologist attempts to preserve the remaining liver condition only after examining the risk factors thoroughly. For this, a proper diagnosis must be made in the following manner. 
Physical Examination: During a routine physical test, a doctor will conduct various exams to identify and better understand the symptoms. Further testing may be recommended if suspected fatty liver or abnormal liver test results are noted. The hepatologist and gastroenterologist will ask about the patient's medical history, lifestyle, and family history. The doctor should also be informed about the patient's medication. 
Blood Tests: Once NAFLD is suspected, a blood test is the best way to determine liver enzyme levels. This includes detecting alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Usually, the blood test for NAFLD is scored as APRI/FIB-4. This combination helps predict the significant possibilities of fibrosis and cirrhosis of liver. Other tests include:
Complete blood count (CBC) test
Liver function test (LFT)
Tests for chronic viral hepatitis A and hepatitis C
Screening of celiac disease
Blood sugar test (Fasting)
Haemoglobin A1C test 
Lipid profile test 
Imaging Tests
During the diagnosis of any liver disease, an imaging test is one of the primary procedures followed. This includes an abdominal ultrasound, computerised tomography (CT) scanning, and magnetic resonance imaging (MR) of the abdomen area. However, the processes cannot differentiate between NAFLD and NASH. 
Abdominal Ultrasound: An ultrasound of the abdomen area is the primary test for diagnosing fatty liver diseases. This test examines various parameters such as the deep beam attenuation, parenchymal brightness, gallbladder wall definition and liver-to-kidney contrast. The qualitative grades can range from mild to moderate or severe (grade zero to three), with zero being the normal range. 
CT Scan or MRI: CT scanning or MRI imaging of the abdomen is also recommended, although they cannot distinguish between NASH and NAFLD. Although inefficient in detecting mild steatosis, the quantitative assessment done by these limited diagnostic measures can identify advanced or severe cases. A CT scan can determine pre-cirrhotic liver fibrosis with parameters like decreased hepatic veins diameter and caudate-to-right-lobe ratio.
Magnetic Resonance Elastography: MRE or MR elastography is one of the best non-invasive measures for detecting the stages of liver fibrosis. The process combines MRI images with sound waves and produces an elastogram or visual map. This helps doctors understand the stiffness of the body tissues. The testing method of MRE is similar to a FibroScan but more accurate. 
Transient Elastography: Transient elastography is another non-invasive imaging procedure for checking liver stiffness (LSM). This is done to examine the possibility of hepatic fibrosis via LSM in the NAFLD patient. Transient elastography also allows the determination of the histologic stage of fibrosis of the liver and aids in treating chronic liver diseases with greater accuracy. 
Liver Biopsy: A liver biopsy or liver tissue test is done when all the above tests return non-inclusive results. A sample tissue is removed from the liver using a thin needle and sent to the laboratory for further testing. This procedure is done to check for signs of scarring and inflammation and determine the level of liver damage. The test can cause discomfort to patients, and subtle risks are involved as a thin needle is inserted into the abdominal wall of the liver. 

Treatment 

Home Care: Certain home remedies may ease the symptoms of fatty liver disease. The simplest way to recover from alcoholic fatty liver disease is to stop consuming alcohol. However, for NAFLD, making changes in the diet may be necessary since not all diets will suit the patient. But it is essential to consult a hepatologist or gastroenterologist before making any changes. Losing excess weight (about seven to ten per cent of body weight) can improve the condition. 
Medication: Currently, there is no medication available for treating fatty liver disease. However, certain drugs like choline, metadoxine, orlistat, pioglitazone, and ursodiol can offer some relief. Among these, choline is the most popular for pregnant women and helps prevent the occurrence of any neural tube defect in the offspring. However, only a licensed medical practitioner can prescribe these medications. 
Surgical Treatment: Since fatty liver disease is primarily associated with obesity, bariatric surgery, gastric bypass, or sleeve gastrectomy return sustained weight loss results. 

Risk and Complications if Left Untreated 

Fibrosis: If left untreated, fatty liver disease can trigger inflammation of the liver cells, causing an excess of liver fat accumulation. This, in turn, can infiltrate the immune cells and increase the secretion of cytokines. This condition is usually observed in patients suffering from non-alcoholic steatohepatitis or NASH and can gradually cause liver fibrosis. Over time, fibrosis can reduce the blood throughout the organ, causing permanent scarring of the tissues. 
Untreated Cirrhosis: Patients with fatty liver disease are also susceptible to developing liver cirrhosis. The signs of the disease are similar to excessive alcohol use and are irreversible. Even if the symptoms are resolved, the damage to the liver is permanent. However, with proper treatment, it is possible to keep the symptoms under control. 
Liver Failure: The stages of advanced liver fibrosis and cirrhosis can eventually cause liver failure. The condition can aggravate other issues, such as diabetes, high blood pressure, and kidney disease. 
Liver Cancer: Both cirrhosis and steatohepatitis are risk factors for hepatocellular carcinoma or liver cancer. The chance of developing liver cancer increases if fatty liver syndrome occurs at a young age. However, the liver can recover from mild cases of fatty liver disease with proper lifestyle changes and medical supervision. 

Additional Information 

Diabetes due to fatty liver: Fatty liver disease (FLD) itself may not always cause any significant symptoms, only at a later stage are they observed. However, when the fat content of the liver goes over 10%, the fatty liver can make patients more prone to type-2 diabetes. This is because the liver is responsible for regulating blood sugar. The fat build-up in the organ disrupts this flow, making the body resistant to insulin. This puts a lot of strain on the beta cells of the pancreas, aggravating type-2 diabetic conditions. 
Impact of smoking on fatty liver: Patients are advised to stop smoking to recover from many liver problems, not just fatty liver disease. Smoking produces various toxic effects in the body, which can directly or indirectly impact the functioning of the liver. These effects can also be immunological and oncogenic. The cytotoxic potential of smoking cannot be ignored when considering the possibility of necroinflammation and fibrosis of the liver.