Chlamydia is a common sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis, which affects the genital tract if acquired through vaginal sex and the mouth or anus if acquired from oral or anal sex. It is spread through unprotected sex with an infected person; it can also be spread from an infected mother to her baby at birth.
Most of the time, chlamydia is a "silent" infection and has few symptoms. However, if left untreated it can cause permanent damage to the woman's reproductive tract. In men, chronic infection can lead to sterility.
For women, pelvic inflammatory disease (PID) is inflammation of the upper genital tract from ascending bacteria from the vagina or cervix. Signs and symptoms include lower abdominal pain, vaginal discharge, abnormal vaginal bleeding, abdominal guarding and rebound, and other signs of peritonitis, adnexal tenderness, cervical motion tenderness, and fever.
Fitz-Hugh-Curtis is a complication of PID causing inflammation of the liver capsule.
Consider inpatient hospitalization if a tubo-ovarian abscess is suspected, there is no response to oral antibiotics, the patient is unable to follow an oral regimen, the patient appears very ill, or other abdominal pathology cannot be ruled out.
For men, chlamydial infection can also cause epididymitis or orchitis, which may manifest as pain or swelling of one or both testicles or discomfort with urination. It may trigger reactive arthritis (Reiter syndrome), a disorder classically characterized by arthritis, conjunctivitis, and urethritis, a few weeks after the primary infection in those individuals who may be predisposed (HLA-B27 positive).
In all cases where a child is being evaluated for sexual abuse, specific screening tests for all STIs should be pursued, even in the absence of specific symptoms.
ICD10CM: A56.2 – Chlamydial infection of genitourinary tract, unspecified
SNOMEDCT: 105629000 – Chlamydial infection
Differential Diagnosis & Pitfalls
For girls: If there are concerns about sexual activity, STIs should be at the top of the list because presentation can range from asymptomatic to vaginal to abdominal pain.
In late infection, the differential diagnosis of abdominal pain is as follows:
For boys: If there are concerns about sexual activity, STIs should be at the top of the list. Presentation can range from asymptomatic to penile discharge to systemic symptoms. Other causes of penile discharge and pharyngitis, including gonorrhea, should be considered. In cases of testicular pain, always make sure to rule out testicular torsion, which is a surgical emergency. In testicular torsion, the pain is generally more sudden and severe, with no preservation of the cremasteric reflex. Elevating the testis in torsion leads to continued pain, whereas in epididymitis, elevating the testis may relieve the pain. In cases of epididymitis and appendiceal torsion, the pain gradually develops over a few days, and the patient appears less uncomfortable. In cases of arthritis, other causes of joint pain should be ruled out.