Mumps – symptoms, diagnosis, treatment, pathology


Mumps is a disease caused by the mumps virus,
which is a member of the paramyxoviridae family. This is actually a large family of viruses
which includes measles virus and parainfluenza viruses, and all of these tend to affect children
the most. Mumps only affects humans and and is spread
by tiny respiratory droplets that are small enough to be carried short distances in the
air, so mumps virus is extremely contagious and anyone near a person with mumps is at
risk for getting the disease as well. The mumps virus has a single strand of RNA
and a viral polymerase enzyme surrounded by a phospholipid bilayer envelope studded with
viral proteins hemagglutinin-neuraminidase, or HN protein, and fusion or F protein. The HN protein allows the virus to stick to
a potential host cell, and cut itself loose if necessary, and the F-protein which fuses
the viral and cell membranes together allowing the mumps virus to enter the cell. Once mumps enters a cell, the single stranded
RNA, which is negative sense, gets transcribed by the viral polymerase enzyme, into a complementary
positive sense strand of mRNA, which can then be translated by the host cell ribosomes into
new copies of the envelope proteins and the viral polymerase, which get assembled into
new viruses. What also ends up happening with these, though,
is that those HN and F-proteins on the cell surface now bind other cells, so they actually
end up bind epithelial cells to one another, which forms a clump of connected cells called
a multinucleated giant cell or a syncytium. Mumps enters the body and first infects the
epithelial cells of the nasopharynx, where it starts replicating and causing local damage
to the tissue. From there, it can cause viremia or virus
in the blood, and reach various organs and tissues. The mumps virus has tropism, or preference
for, the parotid salivary glands, and the most classic finding in mumps is swelling
of parotid salivary glands either on one side or on both sides, sometimes with an associated
earache. The swollen parotid gland lifts the earlobe
up and out and obscures the angle of the jaw, and can sometimes cause trismus which is spasm
of the muscles of mastication or chewing. Mumps also has affinity for the central nervous
system, and can cause meningitis, which is an infection of the lining of the brain, as
well as encephalitis, which is an infection of the brain tissue itself. These infections can cause symptoms ranging
from those that feel like the common cold, like headache and neck stiffness, as well
as more severe symptoms like difficulty with balance and hearing loss, but in general,
the infection is self-limited and symptoms go away as the body recovers. In boys, usually in adolescents and young
men, mumps can infect the testicles and epididymis, and cause orchitis and epididymitis, respectively,
most often on just one side. This can cause testicular atrophy in some
men, as well as a decrease in sperm count and sperm motility, but rarely does this cause
infertility. Less commonly, mumps can infect the kidneys,
and cause glomerulonephritis, which eventually leads to hematuria and proteinuria—blood
and urine in the urine. It can also affect the joints, causing arthritis,
usually in the large joints like the hips, knees, ankles, and shoulders. And it can affect the heart causing myocarditis,
as well as the pancreas, causing pancreatitis. As a final note, pregnant women with mumps
are not at an increased risk of having a baby with congenital defects. Alright, like a lot of other viruses, diagnosis
is done by looking at antibody titers, though for treatment there aren’t any effective
antivirals for mumps. For prevention, Individuals with mumps, particularly
young children, are usually kept isolated for 5 days after the onset of symptoms to
prevent it from spreading. Best of all for prevention, though, is the
mumps vaccine which is about 90% effective at preventing the disease in the first place. The vaccine is a live attenuated vaccine,
which means that it’s a weakened mumps virus which is not infectious, but still stimulates
the immune system to generate a strong response to prevent a future infection from the actual
wild-type mumps virus. Mumps vaccine has reduced the occurrence of
mumps dramatically, with outbreaks happening most often in areas where children aren’t
vaccinated. Alright, as a quick review, mumps is very
contagious and spreads through the air by respiratory droplets, and most classically
infects the salivary parotid glands, causing them to become swollen, but can also cause
meningitis, encephalitis, orchitis, and epididymitis. Luckily, there is mumps vaccine that is safe
and effective in preventing nearly 90% of cases. Thanks for watching, you can help support
us by donating on patreon, or subscribing to our channel, or telling your friends about
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