A 26 year old female named Anna comes to the clinic one day with complaints of painful and more frequent urination, as well as pain during sexual intercourse, and increased vaginal discharge for the past 5 days. Upon further questioning, Anna tells you that she’s had multiple sexual partners lately. On physical examination, there's purulent vaginal discharge. You obtain a discharge sample with a swab and perform a Gram stain, which reveals the presence of gram-negative diplococci bacteria within neutrophils. You prescribe her a combination of azithromycin and ceftriaxone.
A year later, Anna comes back with similar complaints, but this time she also has a fever; and lower abdominal pain that worsens when she moves. Upon further questioning, Anna reveals that she’s had two more episodes of vaginal infections over the past year, but she didn’t seek medical attention. On physical examination, you notice that Anna has a fever, and when you perform a gynecological exam, movement of the cervix elicits pain.
Now, based on the initial presentation, Anna seems to have vaginitis or cervicitis caused by a sexually transmitted infection, or STI for short. STIs are mainly transmitted from person to person during sexual contact through body fluids, such as vaginal secretions, semen, or blood. The ones most at risk of contracting an STI are sexually active individuals, particularly those who have unprotected sex or multiple sexual partners. But, it’s important to note that sexually transmitted infections can also be transmitted via contact with skin or mucous membranes, including eyes, mouth, throat, and anus. And that’s a high yield fact!
Now, STIs that may cause vaginitis and cervicitis include chlamydia, which is caused by Chlamydia trachomatis; gonorrhea, which is caused by Neisseria gonorrhoeae; and trichomoniasis, caused by Trichomonas vaginalis.
Now, let’s begin with Chlamydia trachomatis, which is a gram-negative obligate intracellular bacterium, meaning that it needs to infect and enter a host cell to be able to replicate. For your exams, it’s important to remember that Chlamydia trachomatis has 15 serotypes.
Serotypes A through C are typically transmitted through contact with secretions from the eyes, nose, or throat of an infected person, and cause chlamydial conjunctivitis, also called trachoma. If untreated, trachoma can ultimately destroy the cornea, resulting in total blindness.
Serotypes D through K of Chlamydia trachomatis are typically transmitted via sexual contact and cause the STI chlamydia. Now, keep in mind that, in both sexes, chlamydia is usually an asymptomatic infection of the genitourinary tract. But what’s important to know for your exams is that symptomatic individuals typically present with mucopurulent discharge, dysuria or pain and burning during urination, and increased urinary frequency.
In males, serotypes D through K can infect the urethral mucosa, causing urethritis. Also, it can cause inflammation of the epididymis, or epididymitis, as well as testicular pain and swelling. Sometimes the infection can spread to the prostate, resulting in prostatitis.
On the other hand, some females may also develop urethritis, but most often, chlamydia affects the lower genital tract, causing vulvovaginitis or inflammation of the vulva and vagina, and cervicitis when the cervix is involved. This may present with changes in vaginal discharge, intermenstrual and post-coital vaginal bleeding, and dyspareunia or pain during sexual intercourse. Now, an important complication in females is pelvic inflammatory disease, which is when the infection spreads to the uterus, fallopian tubes, and ovaries, leading to lower abdominal pain and fever.
If left untreated, chlamydia can cause infertility in both males and females. Now, in some cases, chlamydia can trigger reactive arthritis, which is an autoimmune condition that leads to inflammation of joints, and what’s important to remember is that reactive arthritis develops up to three weeks after the initial infection.
Now, if chlamydia affects a pregnant individual, there is a risk for the infection to be passed down to the baby during vaginal delivery. This can result in neonatal conjunctivitis, which appears 1 to 2 weeks after birth. Alternatively, if the bacteria make their way down the baby’s respiratory tract, it can result in neonatal pneumonia. The most characteristic symptom of neonatal pneumonia is staccato cough, meaning short, repetitive coughing with deep inspiration after each single cough.
Lastly, serotypes L1, L2, and L3 of Chlamydia trachomatis are also transmitted through sexual contact, but they cause a disease called lymphogranuloma venereum, or LVG for short. LVG is characterized by skin lesions over the genital area, such as painless, small papules or granulomas and shallow ulcers, as well as painful inguinal lymphadenopathy, or enlarged lymph nodes, called buboes.
Diagnosis of infection by Chlamydia trachomatis can be confirmed by taking a genital swab or urine sample, and looking for the bacterial DNA with nucleic acid amplification testing or NAAT, or a polymerase chain reaction or PCR. Keep in mind that Chlamydia trachomatis does not Gram-stain well, mainly because it's an obligate intracellular bacterium. So infected cells can be examined on a sample smear with a Giemsa stain or direct fluorescent antibody stain, revealing the presence of intracellular or cytoplasmic inclusions with reticulate bodies, which are the replicating forms of Chlamydia trachomatis within the host cells.
Treatment involves antibiotics that inhibit the synthesis of bacterial proteins, such as macrolides like azithromycin, or tetracyclines like doxycycline. Now, keep in mind that genitourinary infection with Chlamydia is frequently associated with coinfection by Neisseria gonorrhoeae. For that reason, ceftriaxone is usually added to also cover Neisseria gonorrhoeae. And that’s very high yield!
Now, Neisseria gonorrhoeae is a gram-negative diplococcus that causes the STI gonorrhea, which has a clinical presentation that’s very similar to chlamydia. So, individuals typically present with mucopurulent discharge, as well as dysuria, and increased urinary frequency.
And in males, gonorrhea can result in urethritis, epididymitis, or prostatitis; while in females, it may cause vaginitis, cervicitis, and pelvic inflammatory disease.
