Chlamydia is the number one sexually-transmitted infection in the United States by far. One of the reasons for that is a large number of asymptomatic carriers. It is caused by the atypical bacterium Chlamydia trachomatis. This bacteria is atypical because it actually lacks a peptidoglycan layer, so it doesn’t Gram-stain well at all.
It is typically transmitted through sexual contact without a barrier method, but it can be transmitted to a neonate during vaginal birth. Therefore, every pregnant woman is screened at their first prenatal visit, to hopefully prevent to spread to the baby.
Once transmitted, it will cause a malodorous, clear-to-gray, thin endocervical discharge, dysuria, and pelvic pain in women. In men, it most often causes dysuria, clear or thin urethral discharge, and scrotal pain. If this is passed to neonates, it can cause neonatal conjunctivitis which can lead to blindness, and an atypical pneumonia that causes staccato coughs. Staccato is a musical term that means a series of short, emphasized sounds. These symptoms are most associated with the serovars D-K.
These serovars are also capable of causing complications. In women it can cause pelvic inflammatory disease. In men it can cause epididymitis and prostatitis, and reactive arthritis.
The serovars A-C, which are more prevalent in Africa most often cause trachoma, which is an infection of the eye that causes the eye to buckle and the eye lashes to scratch the eye causing scaring and eventually blindness.
The serovars called Types L1-L3 are most associated with lymphogranuloma venereum which causes the formation of inguinal lymphadenopathy to the point where they might ulcerate.
This organism is really hard to detect, it can’t be Gram-stained and is really hard to culture, so the gold standard method of diagnosis is through Nucleic Acid Amplification Tests or NAATs.
Once diagnosed, azithromycin as a single dose is very effective. You need to also counsel the patient to avoid all sexual contact for 7 days. You need to retest the patients in a month to make sure the infection is cleared. You also should immediately treat all sexual partners.
Leptospirosis is caused by the spirochete, Leptospira interrogans. This organism is found worldwide and is most associated with the tropics. It is transmitted through the consumption of water contaminated with animal urine. The organism likes to take up residence in animal kidneys and will therefore be consistently secreted with the urine. Therefore, people who work with animals like vets and farm workers are at a higher risk of acquiring this.
Patients will present with a huge range of symptoms from asymptomatic to fulminate organ failure. Phase 1 of leptospirosis presents with fever, headache, myalgias, conjunctivitis without exudate.
Phase 2 is also called Weil’s Disease which presents as jaundice, renal failure, and pulmonary hemorrhage. This is a life-threatening condition.
Diagnosis relies on serology, and treatment is doxycycline for mild disease, but stronger antibiotics might be required for more severe disease.
A 22-year-old female presents with dysuria for the last three days. Vital signs are normal. She reports not feeling any urgency or any increased frequency in urinating, and not feeling any back pain. She says that she has had two new male sexual partners in the last three months and engaged in vaginal intercourse without the use of barrier methods. Pelvic examination reveals a thin, grey, cervical discharge, and no cervical motion tenderness or adnexal tenderness. Urinanalysis reveals a few white blood cells, but no bacteria, casts, blood, or other abnormalities. Smear of the cervical discharge reveals no organisms. Culture on Thayer-Martin media did not produce growth. What is the most likely diagnosis?
A. Gonorrhea
B. Trichomoniasis
C. Chlamydia
D. Bacterial vaginosis
You’re going to focus on eliminating diagnosis in this question. This patient is presenting with dysuria, thin grey cervical discharge, a history of unprotected sexual contact.
The lack of urinary urgency or frequency, and the lack of bacteria in the urinanalysis points away from a urinary tract infection. Not completely, but it does point away.
The lack of back pain and casts in the urine points away from pyelonephritis.
The lack of cervical motion tenderness and adnexal tenderness points away from pelvic inflammatory disease.
A. Gonorrhea is caused by Neisseria gonorrhea. This can present exactly as this patient presents, however this would most likely produce growth on Thayer-Martin media.
B. Trichomoniasis is caused by Trichomonas vaginalis which is a protozoan that would be seen on microscopy of the cervical discharge. Since no organisms were seen, you can rule this diagnosis out.
C. Chlamydia is caused by Chlamydia trachomatis causes thin cervical discharge. It is really hard to visualize, and doesn’t culture well. The only way to definitely diagnose Chlamydia is to utilize NAAT testing.
D. Bacterial vaginosis is caused by many different bacterial organisms, but most often caused by Gardnerella vaginalis. This would most likely present as a vaginal discharge, not a cervical discharge. This would also most likely have many bacteria present in the urinanalysis. Examination of the urine would also show the presence of clue cells which are epithelial cells that are covered in bacteria.
Therefore,
A 23-year-old male presents to the emergency department with a two-day history of high fever, chills, headache, neck stiffness, productive cough, diarrhea, photophobia, nausea, vomiting, hemoptysis, diffuse myalgias, and dark-colored urine. Vital signs reveal a temperature of 101F, a pulse of 119 beats/min, a blood pressure of 149/81 mmHg, a respiratory rate of 24 breaths/min, and oxygen saturation of 94% on room air. Physical examination reveals yellowing of the eyes and face, and negative Brudzinki and Kernig signs, and severe abdominal tenderness. Laboratory studies reveal a negative PPD test, elevated serum transaminase levels, hyperbilirubinemia. Serological analysis revealed the presence of anti-Leptospira spp. IgM molecules. What is the most likely route of transmission for this causative agent?
A. Inhalation of contaminated animal urine
B. Ingestion of aerosolized animal feces
C. Ingestion of contaminated animal urine
D. Through the bite of a mosquito
This question has a complicated clinical picture, but the actual question is relatively easy. It’s telling you that there’s an infection with Leptospira spp. and asking for the transmission route. Leptospira can be transmitted a multitude of ways but the most likely is ingestion of water contaminated with animal urine.
Therefore,
References:
https://microbewiki.kenyon.edu/index.php/Chlamydia_trachomatis
https://www.acha.org/documents/Programs_Services/webhandouts_2010/FR208-Roberts.pdf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5056631/
The Bradley Lab 