martes, 3 de septiembre de 2019

Liver disease diagnosis

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By Dr. Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Editor)

There are multiple causes of liver disease. While some are infective, some are genetic or autoimmune and some metabolic.

This makes diagnosis difficult and often there are a battery of tests that need to be performed in order to correctly diagnose the underlying cause for the disease.

Patients who develop signs of liver disease even nonspecific ones like weakness, fatigue and nausea need to seek medical advice if their symptoms are not otherwise explained.

Fever, jaundice, pain over the right upper part of the liver should prompt medical attention.

History and physical examination

Diagnosis of liver disease is based on initial history and physical examination.

History of previous illness, drug or alcohol intake, family history of liver disease needs to be evaluated in detail.

History of contaminated blood transfusion, unprotected sexual intercourse or sharing contaminated needles can raise suspicion of a chronic infective liver disease with viruses like Hepatitis B or C.

On physical examination all parts of the body including lungs, heart, skin, brain, nervous system and abdomen can provide clues to the cause and extent of liver diseases.

There are certain blood tests that may provide confirmatory findings.

Tests for diagnosis of liver disease (1, 2, 3)

There are three main types of test that are performed in liver disease diagnosis: laboratory tests, radiological studies and biopsies:-

Laboratory examination

Blood – Initial tests for liver disease include complete blood examination. The blood parameters that the tests use are:-
1. Serum enzymes – AST (Aspartate amionotransferase) and ALT (Alanine aminotransferase) are liver enzymes that are raised when there is liver injury or inflammation. Liver enzymes may be raised in both alcoholic and non-alcoholic fatty liver diseases.
2. GGT (Gamma glutamyl transferase) and Alkaline Phophatase are also enzymes that are released from bile ducts and are raised in liver diseases.
3. Blood levels of bilirubin rise in liver disease. Estimation of both conjugated and unconjugated forms of this bile in blood is indicative of different liver diseases.
4. Blood levels of protein and albumin are indicative of healthy functioning of the liver. In liver disease there is derangement of these levels.
Routine blood tests like complete blood count may also be helpful in liver disease estimation.
Total blood counts of White blood cells, red blood cells and platelets may be reduced in advanced liver disease where there is suppression of bone marrow that is the seat of production of these cells.
Routine estimation of blood clotting mechanisms and ability are also indicated.
In chronic liver disease the impaired protein formation leads to decline in levels of clotting factors and raises the risk of bleeding tendencies and easy bruising. In such patients there clotting functions are impaired.
Liver disease may also be accompanied with pancreas inflammation. Pancreatic lipase thus needs to be assessed to rule out such inflammation.
Liver disease may also be associated with disturbed kidney function. This can be assessed by looking at blood urea, creatinine, electrolytes and BUN.
In patients who have developed hepatic encephalopathy there is raised blood levels of ammonia that can be detected on blood examination.
Certain autoantibodies are detected in blood of patients with autoimmune hepatitis.
Blood virological examinations are advised in viral hepatitis. Viral load of blood is often done to detect and monitor treatment of viral hepatitis like hepatitis B and C.
Ascitic fluid – Ascitis is accumulation of fluid in the abdomen. This fluid may sometimes be aspirated and examined under microscope. In liver cancers the examination may reveal cancerous cells.

Radiological studies

Imaging and radiographical studies are used to detect and confirm liver diseases. These include –

Ultrasonogram or USG of the abdomen – This uses sound waves to detect liver pathology. This is useful, inexpensive and a noninvasive method to diagnose several conditions. It is most commonly used to detect gall bladder stones and other pathologies. An USG with Doppler can also look at the blood flow in the portal venous system and diagnose obstructions and portal hypertension.
CT scan – Computed Axial Tomographical image or scan can be used to look at deeper tissues within the liver in detail to diagnose several liver disease conditions.
MRI or magnetic resonance imaging is a clearer imaging study to look at the damaged liver tissues for clues regarding pathology.
ERCP (Endoscopic retrograde cholangiopancreatography) – In this procedure a long thin tube, called an endoscope, that has a camera at its tip is guided into the gastrointestinal tract to look at the bile and pancreatic ducts. Any pathology in these tracts can be detected. ERCP can be used in diagnosis of tumors, gall bladder stones and obstructions, cysts etc. (4)

Liver Biopsy

This procedure involves using a long thin needle to aspirate bits of tissues of the liver under a local anesthetic agent. The needle is guided into the liver with the help of either USG or CT scan.

This is used to confirm the diagnosis. The aspirated material is examined under the microscope.

A liver biospsy specimen may also be obtained when the patient is operated for. This could be for a liver tumor or cancer.

Biopsy may also be obtained during or with a laparoscopic surgery procedure. (5)