Hepatitis C virus

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Hepatitis C virus

USMLE® Step 1 questions

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USMLE® Step 1 style questions USMLE

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A 56-year-old woman patient presents to an outpatient clinic with fatigue and malaise. She reports worsening malaise over the past several weeks and noted that her abdomen seems more protuberant. She regularly uses intravenous drugs but has not used in several weeks. Vitals are within normal limits. Physical examination is notable for scleral icterus and a positive fluid wave. Initial work up is notable for an ALT of 451 U/L and an AST of 321 U/L. The remainder of her laboratory findings are demonstrated below.

Which of the following is the most likely diagnosis?


Hepatitis C virus is a part of the flaviviridae family, and it can be broken down in hepat- which refers to the liver, and -itis, which means inflammation.

So this virus affects the liver, causing hepatitis.

Hepatitis C virus is enveloped, meaning that it is surrounded by a membrane.

It also has a lipoprotein envelope that’s very similar in structure to two lipoproteins that normally transport cholesterol through the blood: low density lipoprotein, or LDL and very-low-density lipoprotein, or VLDL.

Underneath the membrane, there’s an icosahedral capsid, which is a spherical protein shell made up of 20 equilateral triangular faces.

The capsid holds a single strand positive-sense RNA, meaning that it has positive polarity, which is why it can be used directly by the host ribosomes to synthesize viral proteins.

Now, hepatitis C virus can be transmitted through contaminated blood or through sexual contact.

Once inside the body, hepatitis C virus circulates the blood and reaches the liver, where it infects the main liver cells called hepatocytes; and B lymphocytes, which are a type of immune cells that create antibodies.

First, the virus binds to the cells using its envelope, which is very similar to LDL and VLDL, so it can attach to specific LDL receptors.

Then, the virus enters the cell by endocytosis, which is when it’s wrapped by the cell membrane and brought inside the cell in a bubble called an endosome.

Next, the viral membrane fuses with the endosome and releases the capsid which dissolves in the cytoplasm, leaving only viral RNA.

Then, viral RNA binds to the host ribosomes and is used to create structural and non-structural proteins.

Structural proteins will be used to make the viral particle, while the non-structural proteins make the replication complex that contains an enzyme called RNA dependent RNA polymerase.

This enzyme uses the positive-sense viral RNA to create a negative-sense template.


The hepatitis C virus (HCV) is an enveloped, single-stranded RNA virus of the Flaviviridae family. It infects the liver cells and causes chronic hepatitis. HCV is highly infectious and can be transmitted through contact with blood or body fluids from an infected person. HCV is most commonly spread through sharing contaminated needles or other injection equipment among people who inject drugs and from mother to child during birth. Hepatitis C infection can progress to cirrhosis and liver failure after many years, and it also poses a risk of developing hepatocellular carcinoma.


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