Download Infections of the Genitourinary System

Infections of the
Genitourinary System
In general there are no microbes found in the upper part of
the urinary tract and urine is generally sterile (due to low
pH, salt and urea). But the lower part of the urethra does
have normal flora. These organisms include:
Lactobacillus, coagulase-negative Staphylococcus,
diphtheroids, Hemophilus, Streptococcus, and Bacteroides.
In females, the normal flora and susceptibility to infection
varies with the ovarian cycle. When estrogens are
present, the vagina is more acidic (due to the metabolism
of glycogen by Lactobacilli) and thus less susceptible to
infection.
Bladder infections (cystitis) are
more common in women
Causes include enterobacteria (like E. coli causing about 80% of cases),
Staphylococcus saprophyticus, Pseudomonas, and Enterococcus.
Cystitis in women is often accompanied by dysuria (pain or burning during
urination) and may lead to kidney infections (pyelonephritis).
Symptoms of cystitis include: burning sensation during urination,
urgency, frequency, and an odor. Glomerulonephritis AKA Bright’s
Disease causes inflammation of the kidneys that leads to damage in
some cases it even leads to kidney failure. This is a common
nosocomial infection that is an important source of fatalities (especially
when it spreads to the kidneys causing pyelonephritis with fever, chills
vomiting, back pain, blood in urine etc. or glomerulonephritis that is a
condition related to strep infections and the immune system, see figure
20.5). Women are predisposed to UTIs (urinary tract infections) due to
their short urethras, sexual intercourse, and use of diaphragms. Older
men become more susceptible as their prostates enlarge. They also
can get prostatitis although the mechanism of contamination is
unknown. The presence of a catheter also increases susceptibility.
Diagnosisurinalysis, culture
and isolation
Treatmentantibiotics
Prevention- drinking
plenty of fluids
and for women
and girls wiping
front to back.
Leptospirosis
Cause Leptospira interrogans
Leptospirosis is a zoonosis (lots of animals carry it- dogs,
cows, rats, cats etc. and pass the bacterium in their
urine) and is spread to the urinary system from the
bloodstream. The bacterium enters the body through
mucous membranes (of the eye, nose, or mouth) or
through breaks in the skin. Often asymptomatic, but the
mortality rate for more severe cases when untreated can
be as high as 30%. Onset is abrupt and includes
headache, fever, chills, redness of the eyes. Most
recover, but in some, symptoms reoccur and they may
have bleeding from various sites, confusion and organ
damage. In fact, about 5-30% of untreated cases result
in death. Fewer than 100 cases are reported in the U.S.
/year.
DX- culture and isolation on
special media and
extended incubation
times
TX- antibiotics (e.g.,
tetracycline) before the
4th day of infection
Prevention- avoid contact
with non-human animal
urine, and vaccinate pets
Gonorrhea
Cause - Neisseria gonorrhoeae
Humans are the only reservoirs of infection. It is among the most
prevalent of the STIs but the incidence has been decreasing over the
last 15 years (there are about 342,000 cases/year). Infections can
also occur in the throat or anus. Moreover, the organism can survive
for weeks in dried masses of pus (yuck). The ID (infectious dose) is
relatively small. In males, the infection is often symptomatic causing
painful urination and pus formation and can be self-limiting. In
women the disease can be asymptomatic for a long time with
complications: PID (leading to sterility or ectopic pregnancies) and
eye infections in newborns (ophthalmia neonatum); eye infections
can even occur in adults. Untreated infections in males can also
lead to sterility due to orchitis and also lead to UTIs. Systemic
infections (disseminated gonococcal infection, DGI) can occur.
Gonococcal arthritis is the most common cause of joint infection in
16-50 year old people. Antibiotic resistance is increasing in this
organism.
Dx - in males a Gram stain
on material obtained from
the urethra, in females
culture on special media,
or molecular probes
Tx – antibiotics
Prevention – monogamy,
safe sex (consistent and
proper use of condoms),
abstinence, there is no
vaccine
Nongonococcal urethritis (NGU)
mostly chlamydial infections
Cause - Chlamydia trachomatis
Humans are the only reservoirs. Like gonorrhea, there are infections of
the genital tract and eye (acquired during birth or interestingly
enough from non-chlorinated swimming pools). This STI is the most
common with 4 million cases/year. In males, the manifestations are
a nongonococcal urethritis. In females who are symptomatic, a
cervicitis occurs which is characterized by vaginal discharge,
endometritis, in some cases painful urination, abnormal vaginal
bleeding, and abdominal painand also PID. Infants born to women
who are infected can develop pneumonia (usually not until 2-3
months after birth) or eye infections (but the same drops used to
prevent gonococcal eye infection in infants prevent chlamydial
infections).
Dx - tissue culture or
serological testing
Tx – antibiotics
Prevention – monogamy,
safe sex (condoms) and
abstinence
There are other organisms
that cause
nongonococcal urethritis
Syphilis
Cause - Treponema pallidum
Humans are the only natural reservoirs. Syphillis is called
the great imitator due to the similarity between some of
the symptoms and other diseases. The risk of infection
when having intercourse with an infected person is 1230% and transmission usually involves sexual
intercourse, but it can be transmitted (rarely) by kissing.
However, there was a dramatic decrease in new cases in
1990. Less commonly, it can be passed from mom to
fetus in utero causing congenital syphilis and by blood
transfusion. Although the ID is not known, it is thought to
be small.
Syphilis is a systemic infection
with the following clinical
manifestations: (1) primary
syphilis is characterized by a
chancre at the site of infection.
The chancre progresses from
a small, red, hard bump to an
enlarged lesion with a shallow
crater surrounded by firm
margins. Chancres most
commonly occur on the
genitalia (and are painless at
this site) but may also occur on
the lips, nipples, fingers etc.
The chancre heals in about 4-6
weeks
(2) After the primary latent
period, the disease then
progresses to the next
stage. (3) Secondary
syphilis occurs about 3
weeks to 6 months after
the chancre heals. The
disease is now systemic
and this stage is
characterized by fever,
headache, sore throat
and a peculiar red or
brown rash that
disappears in a few
weeks (in general).
(4) After these symptoms
disappear, @ 30% of those
infected will enter a highly
varied secondary latent period
(up to more than 20 years).
(5)The final or tertiary syphilis
is rare due to the use of
antibiotics (to treat other
infections ). Tertiary syphilis is
characterized by a variable
combination of: cv problems,
gummas (soft granulomas) of
the liver, bones, skin, and
neurosyphilis giving rise to
severe headaches,
convulsions, derangement,
blindness, and loss of
coordination
Dx - serology, darkfield microscopy,
fluorescent antibody,
and treponemal
immobilization tests
Tx – antibiotics
Prevention - safe sex,
and abstinence
• Congenital syphilis
Chancroid
Caused by Haemophilus ducreyi.
The manifestation is a single or
multiple genital sore(s) that are
painful (unlike the chancre of
syphilis). It can spread to the
groin area and cause large
buboes (not plague bubos) It is
more common in other countries
than in the U.S. (about 100
cases/yr in U.S.). Dx involves the
identification of the organism from
the lesions or fluid from the
lesions. Although it is often selflimiting, antibiotics are used for
treatment because the lesions
heal more rapidly with treatment.
Genital Herpes
Cause - herpes simplex virus usually type 2
This is among the top four most common STIs and rarely
non-sexual transmission occurs. Symptoms include
itching, burning, and in women sometimes pain. Then
vesicles occur and ulcerate. Like oral herpes infections,
these become latent and then reoccur. A complication is
a congenital infection called neonatal herpes that can be
fatal or cause brain damage and that is acquired from
mom which can be prevented in most cases by a Csection. In addition, the risks of cervical cancer
increases in women with herpes. Herpetic whitlow can
also occur
Dx - tissue culture
Tx - of symptoms with
medication such as
acycclovir that decreases
the severity of the
disease and the
incidence of recurrences.
Prevention – monogamy,
safe sex helps but
condoms do not eliminate
the chance of
transmission, and
abstinence
Genital Warts
Cause – papillomaviruses
Genital warts are one of the most common STIs in the US
(at least ½ of sexually active men and women become
infected at some point during their lifetime) The warts
are unsightly or they mayasymptomatic or silent. The
silent types have been linked to an increased risk of
cancer (cervical and penile). However, the warts do not
always develop but the person is still infected. Infected
mothers occasionally transmit these warts to their babies
that cause infections of the respiratory tract.
Dx – symptoms, a new
screening test that replaces
the original pap smear, DNA
tests can determine if
someone is infected with a
strain linked to cancer.
Tx - wart removal
Prevention - safe sex and
abstinence, although
condoms do not work as
well in preventing the
transmission of these
viruses
Acquired Immunodeficiency
Disease (AIDS)
Cause - Human Immunodeficiency Virus
AIDS is one of the biggest concerns worldwide due
to the high mortality associated with it. It is
among the leading causes of death in young
adults. It cripples the immune system and thus
infections occur that are eventually fatal. It is
estimated that 1 to 2 million Americans are
infected with HIV and perhaps as many as 9
million. World-wide it is estimated that 4.8
became infected in 2003. In that same year, 2.9
million died.
Dx – serology
Tx - new drugs
prolong life but
so far there is no
cure
Prevention - safe
sex and
abstinence,
universal blood
and body fluid
precautions, and
screening blood
and tissue
donors.
Vulvovaginal candidiasis
Candida albicans
Characterized by itching and
sometimes a rash on the external
genitalia of women. However, it is
sometimes asymptomatic.
Antibiotic therapy, pregnancy,
diabetes and the use of oral
contraceptives are predisposing
factors.
Dx - the presence of budding yeast in
a vaginal smear
Tx - Antifungal medications
Prevention – safe sex
Trichomoniasis or Trich
Cause - Trichomonas vaginalis
Not always symptomatic but when it is
symptoms are most likely to occur
in women (burning, itching, and a
yellowish discharge). Humans are
the only reservoirs but the parasite
can survive for short periods of
time in other moist environments
and thus is occasionally
transmitted nonsexually. There are
about 7.4 million cases in the
U.S./year.
Dx - presence of the parasite in
vaginal smear
Tx - antiparasitic drugs (Flagyl) or
douching with vinager.
Prevention - safe sex and abstinence
Prevalence of Trichomoniasis in
Selected Populations
Toxic Shock Syndrome
Cause - Staphylococcus aureus
Symptoms of TSS include fever, diarrhea,
muscle aches, and a rash. It is
caused by the production of toxins and
is exacerbated by the use of highly
absorbent tampons (or tampons that
are left in for long periods of time) that
result in a decrease in the amount of
Magnesium in the vagina. The
contraceptive sponge also caused
some cases of TSS and was taken off
of the market.
Dx - culture and isolation
Tx - antibiotics
Prevention - frequent changing of tampons
Bacterial vaginitis
occurs when the
normal flora of the
vagina are
compromised and is
caused by
opportunists.
Gardnerella vaginalis
Caused by Gardnerella vaginalis
in combination with anaerobic
bacteria e.g, Bacteriodes. It is
characterized by a grayishwhite, slightly bubbly discharge
from the vagina, an odor,
decrease in the pH of vaginal
secretions, and the presence
of clue cells. Flagyl helps by
killing the anaerobes and
allowing the lactobacilli to
recolonize the vagina.
Douching with yogurt can also
be used to treat this vaginalis.
• Multicellular parasites
(e.g.,lice AKA crabs,
scabies, caused by
mites) are also
common.
End of notes for Genitourinary System