Young adult patients who engage in unprotected sex are at risk of contracting a number of sexually transmitted infections (STIs). The risk of STIs is especially high when people engage in unprotected sexual activities with many partners or partners that are not monogamous (McCance & Huether, 2019). Before a diagnosis of chlamydia is confirmed, the clinician must first rule out other sexually transmitted infections.
Gonorrhea
Figure 1: Cervicitis and vaginal discharge caused by N. gonorrhoeae.
Figure 2: Penile discharge as a result of urethritis from a N. gonorrhoeae infection.
Images taken from https://www.sexandu.ca/stis/gonorrhea/
The patient admits to sexual intercourse without a condom, making gonorrhea a likely infection. Chlamydial and gonorrheal infections cause similar clinical manifestations because each of the bacteria are able to infect and cause inflammation within the same structures of urogenital tract, and the infections may be indistinguishable from each other without proper screening. It is important to note that both diseases can be asymptomatic in both males and females. Gonorrhea is a sexually transmitted bacterial infection caused by Gram-negative Neisseria gonorrhoeae cocci bacteria. The patient complains of painful urination (dysuria), and vaginal discharge. Infection and inflammation of the cervix in female patients leads to mucopurulent discharge and physical examination would reveal a red and swollen cervix, in both Chlamydia and Gonorrhea infections. In addition to the cervix, the bacteria can infect and cause inflammation of the urethra, causing pain or burning with urination, as seen in the patient. Urethritis and cervicitis often lead to patient complaints of discomfort during sexual intercourse. While intermittent bleeding can occur with a Chlamydia infection, gonorrhea is more likely to cause changes to menstrual patterns, patients may complain of increased pain from cramps and heavier menstrual flow. If left untreated, both diseases can lead to the development of pelvic inflammatory disease. Pelvic inflammatory disease (PID) occurs when the bacteria are able to move up the urogenital tract and infect the ovaries, and fallopian tubes. Patients will experience symptoms common of infection including fever, chills, nausea, and vomiting, along with pain of the lower abdomen. In men, bacteria infecting the urethra will also cause inflammation leading to discharge and pain while urinating. Penile discharge can vary slightly between the diseases, with chlamydia causing a clear mucoid discharge, and gonorrhea a pus-filled discharge. Untreated gonorrhea infections have a risk of bacteremia leading to a systemic disseminated gonococcal infection. Although rare, the widespread infection could lead to the development of joint pain, rashes, meningitis, and endocarditis. Diagnostic testing is required to differentiate the two infections. Nucleic acid amplification testing of urine, cervical, urethral, or vaginal samples can inform the clinician of the infecting bacterial organism (McCance & Huether, 2019).
Mycoplasma genitalium Infection
Figure 3: Computer generated image of M. gentialium bacteria.
Image taken from https://www.shfpact.org.au/about-us/30-info-sheets/sti-s/57-mycoplasma-genitalium
Due to the patient’s complaints of dysuria, and vaginal discharge, another possible diagnosis is infection by Mycoplasma genitalium. Mycoplasma genitalium is a type of bacteria that is able to cause infection of the urogenital organs and is transmitted through unprotected sexual intercourse, much like the patient reports. Research continues to uncover information about the structures M. genitalium is able to infect and the resulting symptomatology, but has proven difficult due to lack of growth in bacterial laboratory cultures. Unlike in Chlamydia infections, it has not yet been confirmed that M. genitalium causes inflammation of the urethra in females. However, it has been linked to cervicitis. Inflammation of the cervix is responsible for mild mucopurulent vaginal discharge, and pain with urination, as exhibited in the patient. The cervicitis can also lead to vaginal pruritus, and generalized pelvic pain and discomfort (Martin, 2019). Even when patients present with symptoms, vaginal pruritus and generalized pelvic pain, without the complication of pelvic inflammatory disease, are not often seen in Chlamydia infections (McCance & Huether, 2019). Although studies have not shown a strong link, it is believed that M. genitalium can lead to PID. If PID develops from a M. genitalium infection, patients will present with symptoms similar to those caused by PID from a Chlamydia infection. In men, M. genitalium infection has been linked to urethritis which results in itching, dysuria, and mucopurulent penile discharge. M. genitalium bacterial cells do not have a cell wall, so gram-staining and microscopic evaluation of the specimen does not allow for visualization. To differentiate from gonorrhea and chlamydia, clinicians will use vaginal or cervical swabs for nucleic acid amplification tests to determine the specific organism present in women. In men, urine or urethral swabs will be used for nucleic acid amplification test results (Martin, 2019).
Trichomoniasis
Figure 4: Vaginal discharge caused by a T. vaginalis infection.
Figure 5: Penile discharge caused by a T. vaginalis infection.
Images taken from https://www.sexandu.ca/stis/trichomoniasis/
Trichomoniasis is a genitourinary disease caused by a flagellated protozoan called Trichomonas vaginalis. Worldwide, trichomoniasis is the most prevalent nonviral sexually transmitted disease. While Chlamydia tends to infect the cervix in females, T. vaginalis more often infects the squamous epithelium of the vagina, urethra, and paraurethral glands. Similar to chlamydia, trichomoniasis is often asymptomatic. When symptoms are present, trichomoniasis in women often presents with redness around the vulva and vaginal mucosa, as well as a “green-yellow, frothy, malodorous discharge” in 10-30% of symptomatic women (Sobel, 2019). This mucosal texture/color combination distinguishes trichomoniasis from chlamydia. Other symptoms in women can include “burning, pruritus, dysuria, frequency, lower abdominal pain, or dyspareunia” (Sobel, 2019). Many of these symptoms can also be seen in chlamydia. Unlike chlamydia, trichomoniasis does not progress to pelvic inflammatory disease (PID), and therefore infection with T. vaginalis will not likely show up as PID-typical symptoms such as abdominal or pelvic pain. In men, Trichomonas most commonly affects the urethra. Symptoms of trichomoniasis are the same as would be for any other cause of urethritis (dysuria, urethral discharge) and therefore are not reliable for differential diagnosis in males. Overall, both men and women are often asymptomatic and symptoms can be variable, so the gold standard for differential diagnosis is lab testing. Since chlamydia is caused by a bacteria and trichomoniasis is caused by a mobile, flagellated protozoan, microscopy may be useful in observing the jerky motion of the T. vaginalis. However, the most reliable method for distinguishing the two is Nucleic Acid Amplification Testing (NAAT) in which RNA unique to the microorganism is amplified using polymerase chain reaction (PCR) in order to be detected (Sobel, 2019). With a 98-99% sensitivity, the NAAT is the best available option for diagnosing both chlamydia and trichomoniasis (Hsu, n.d.). While chlamydia is most likely to be detected in females ages 16-20, trichomoniasis is more likely to be detected at ages 47 to 53, so advanced age may be an indicator of trichomoniasis (Sobel, 2019).