Today we'll be talking about influenza, a viral infection that causes yearly
epidemics, typically affecting up to 15 to 20% of the world's population.
These annual epidemics lead to approximately half a million deaths
around the world each year.
And pregnant women, like this 28-year-old freelance photographer,
are at especially high risk of developing severe complications.
Mel was 32 weeks pregnant when she was brought to the One night by her worried
husband.
She had been suffering from what she thought was a minor cold,
that began with a cough, headache and sore throat two days ago.
She later also developed a runny nose and itchy, watery eyes.
Her husband thought she may have been slightly febrile over the past two days.
But tonight she became noticeably warm and started to look very pale.
She was lying in bed breathing rapidly when her husband came home from work.
Mel told her husband that she felt short of breath, but she wasn't sure if that was
a normal pregnancy symptom for someone in the third trimester.
This was her first pregnancy, so neither Mel nor
her husband knew exactly what to expect.
But the pregnancy had gone smoothly and
Mel had received regular prenatal care from an obstetrician and a doula.
She had also established a birth plan, which had her giving birth naturally
at home, with minimal medical intervention, including pain medication.
Throughout the pregnancy,
she had been meticulous about trying to minimize potentially harmful exposures.
And had even refused the flu shot, which her obstetrician had recommended,
since Mel would be pregnant during the peak flu season.
At the The physician on duty noted that Mel looked fatigued and unwell.
With a fever of 102 degrees Fahrenheit, an elevated heart rate and breathing rate,
and an O2 saturation that was decrease to 90% on room air.
She was pale and sweating and appeared anxious.
On examination of her lungs, the Physician noted coarse rhonchi and
decreased breath sounds over the bases of her lungs.
Her mucous membranes also appear dry,
suggesting that she was dehydrated from poor fluid intake during her illness.
Because of these concerning findings, the Physician suspected influenza infection.
He decided to admit Mel and started her on IV fluids and supplemental oxygen.
He then performed a nasal swab and sent it for viral PCR to test for influenza virus,
as well as obtaining a sputum sample which he sent for gram stain and culture.
After some consideration, he also ordered a chest X-ray.
Despite the fact that radiation exposure from X-rays is avoided,
if possible, during pregnancy.
He knew that the risk from this small dose of radiation
was outweighed by the need to determine if Mel had developed pneumonia.
A complication for which she was at high risk because of her pregnancy.
The influence virus, which enters the host via respiratory droplets from
infected individuals, owes its virulence to two major glycoproteins
on the virion surface, hemagglutinin and neuraminidase.
Hemagglutinin is the protein responsible for viral binding to
respiratory epithelial cells via sialic acid on the cell surface.
Neuraminidase cleaves the sialic acid,
which releases newly formed virions from the host cell surface.
Neuraminidase also decreases the viscosity of the mucous film coating
the respiratory tract, exposing the cell surface and
facilitating the spread of virus-containing fluid.
Within a short time, many cells in the respiratory tract become infected and
eventually killed directly by the virus.
This damaged respiratory epithelium
is then susceptible to secondary bacterial invaders or superinfection.