Sexually Transmitted Infections — MCQs
Which is NOT a sexually transmitted disease?
Genital warts are caused by:
A 24-year-old woman presents with vaginal discharge, dysuria, and lower abdominal pain. On examination, there is cervical motion tenderness and mucopurulent cervical discharge. What is the diagnostic test of choice?
A man who has a penile chancre appears in a hospital's emergency service. The VDRL test is negative. The most appropriate course of action for the physician in charge would be to
A 27-year-old white man presents to his family doctor complaining of being tired all the time and having a slight fever for the past two weeks, following a recent trip to Las Vegas. His physical examination is unremarkable, except for a macular rash over his trunk and on the palms of his hands, with no lesions or ulcers on the penis. What is the causative organism of this man's illness?
Which of the following STDs causes fetal abnormality?
A 22-year-old woman presents for STI screening. She reports multiple sexual partners and inconsistent condom use. What screening tests would be most appropriate?
A 25 year old lady presented with curdy white discharge from the vagina is likely to be suffering from:-
A patient presents with genital grouped vesicles, as shown in the image. What is the most likely causative organism?
Which one of the following statements best characterizes lympho-granuloma venereum (LGV)?
Sexually Transmitted Infections Indian Medical PG Practice Questions and MCQs
Question 1: Which is NOT a sexually transmitted disease?
- A. Yaws (Correct Answer)
- B. Granuloma Inguinale
- C. LGV
- D. Chancroid
Explanation: ***Yaws*** - Yaws is a **chronic infectious disease** caused by the bacterium *Treponema pallidum pertenue*, a subspecies of *Treponema pallidum*, the same bacterium that causes syphilis. - It's primarily transmitted through **skin-to-skin contact** with infectious lesions, not sexual contact, and is common in warm, humid, tropical regions. *Granuloma Inguinale* - Also known as **Donovanosis**, this is a chronic, progressive **bacterial infection** caused by *Klebsiella granulomatis*. - It is **sexually transmitted** and primarily affects the skin and mucous membranes of the genital, inguinal, and perianal areas. *LGV* - **Lymphogranuloma Venereum (LGV)** is a sexually transmitted infection (STI) caused by specific serovars of *Chlamydia trachomatis*. - It is characterized by **lymphadenopathy** and can cause invasive infections of the lymph nodes and lymphatic tissue, particularly in the genital and anal regions. *Chancroid* - Chancroid is a **bacterial STI** caused by *Haemophilus ducreyi*. - It is characterized by the development of **painful genital ulcers** and often swelling of the lymph nodes in the groin.
Question 2: Genital warts are caused by:
- A. Human Papilloma Virus (Correct Answer)
- B. Chlamydia trachomatis
- C. Epstein Barr virus
- D. HSV
Explanation: ***Human Papilloma Virus*** - **Human Papilloma Virus (HPV)** is the primary cause of genital warts, particularly low-risk types like **HPV-6** and **HPV-11**. - HPV infection is common and is transmitted primarily through **sexual contact**. *Chlamydia trachomatis* - **Chlamydia trachomatis** is a bacterium that causes a common sexually transmitted infection (STI), leading to **urethritis**, **cervicitis**, and pelvic inflammatory disease, but not genital warts. - It can cause symptoms like **dysuria** and **vaginal discharge**, or be asymptomatic, but does not result in wart-like lesions. *Epstein Barr virus* - **Epstein-Barr virus (EBV)** is a herpesvirus primarily known for causing **infectious mononucleosis** (glandular fever). - It is associated with certain cancers like nasopharyngeal carcinoma and lymphomas but not with sexually transmitted genital warts. *HSV* - **Herpes Simplex Virus (HSV)** causes **genital herpes**, characterized by painful **blisters** and **sores** that typically recur. - While HSV is a sexually transmitted infection, the lesions it causes are vesicular and ulcerative, distinctly different from the fleshy, wart-like lesions of HPV.
Question 3: A 24-year-old woman presents with vaginal discharge, dysuria, and lower abdominal pain. On examination, there is cervical motion tenderness and mucopurulent cervical discharge. What is the diagnostic test of choice?
- A. Culture on modified Thayer-Martin medium
- B. Wet mount examination
- C. Gram stain of cervical secretions
- D. Nucleic acid amplification test (NAAT) (Correct Answer)
Explanation: ***Nucleic acid amplification test (NAAT)*** - NAATs are the **most sensitive and specific** tests for detecting *Chlamydia trachomatis* and *Neisseria gonorrhoeae*, common causes of cervicitis, which is suggested by the patient's symptoms (vaginal discharge, dysuria, lower abdominal pain, cervical motion tenderness, mucopurulent discharge). - They can be performed on **non-invasive samples** (e.g., urine, vaginal swabs), making them convenient and preferred for screening and diagnosis. *Culture on modified Thayer-Martin medium* - While **gonococcal culture** on modified Thayer-Martin medium is a specific test, it has **lower sensitivity** compared to NAATs and is more labor-intensive. - It is often reserved for cases where **antibiotic resistance testing** is needed or when NAATs are unavailable. *Wet mount examination* - A **wet mount** can identify motile trichomonads (*Trichomonas vaginalis*), yeast (candidiasis), and clue cells (bacterial vaginosis). - However, it **does not diagnose cervicitis** caused by *Chlamydia* or *Gonorrhea*, which are strongly suspected given the cervical motion tenderness and mucopurulent discharge. *Gram stain of cervical secretions* - A **Gram stain** can identify gram-negative intracellular diplococci suggestive of **gonorrhea**, but its **sensitivity is variable** in women, especially in asymptomatic cases, and it cannot detect chlamydia. - It is **insufficient for definitive diagnosis** of chlamydial infection or as a sole diagnostic tool for gonorrhea due to its lower sensitivity compared to NAATs.
Question 4: A man who has a penile chancre appears in a hospital's emergency service. The VDRL test is negative. The most appropriate course of action for the physician in charge would be to
- A. Repeat the VDRL test in 10 days
- B. Send the patient home untreated
- C. Swab the chancre and culture on Thayer-Martin agar
- D. Perform dark-field microscopy for treponemes (Correct Answer)
Explanation: Perform dark-field microscopy for treponemes - A penile chancre is highly suggestive of primary syphilis, even with a negative VDRL, as the VDRL test can be negative early in the infection due to an insufficient antibody response. - Dark-field microscopy directly visualizes the spirochetes (Treponema pallidum) from the chancre and is the gold standard for diagnosing primary syphilis. Repeat the VDRL test in 10 days - While the VDRL test might become positive later due to seroconversion, waiting 10 days delays diagnosis and treatment, allowing the infection to progress. - Direct visualization methods like dark-field microscopy offer an immediate and definitive diagnosis for primary syphilis. Send the patient home untreated - This is an unacceptable course of action as the patient presents with a chancre, a classic sign of syphilis, which requires prompt diagnosis and treatment to prevent disease progression and transmission. - Untreated syphilis can lead to severe complications, including neurological and cardiovascular damage. Swab the chancre and culture on Thayer-Martin agar - Thayer-Martin agar is used to culture Neisseria gonorrhoeae, the causative agent of gonorrhea. - Treponema pallidum, the bacterium causing syphilis, cannot be cultured on artificial media, making this option inappropriate for diagnosing syphilis.
Question 5: A 27-year-old white man presents to his family doctor complaining of being tired all the time and having a slight fever for the past two weeks, following a recent trip to Las Vegas. His physical examination is unremarkable, except for a macular rash over his trunk and on the palms of his hands, with no lesions or ulcers on the penis. What is the causative organism of this man's illness?
- A. Chlamydia trachomatis
- B. Borrelia burgdorferi
- C. Treponema pallidum (Correct Answer)
- D. Neisseria gonorrhoeae
Explanation: ***Treponema pallidum*** - The patient's symptoms, including **fatigue**, **low-grade fever**, and a **macular rash on the trunk and limbs that may later involve the palms and soles** [1], are classic manifestations of **secondary syphilis**, caused by *Treponema pallidum*. - Although there are no genital lesions currently, the rash and systemic symptoms are highly suggestive of disseminated infection following an untreated primary chancre. *Chlamydia trachomatis* - This bacterium is a common cause of **urethritis**, **cervicitis**, and **lymphogranuloma venereum**, but it does not typically cause a diffuse macular rash on the trunk and palms. - While it can cause systemic symptoms in some cases (e.g., reactive arthritis), the described rash is not characteristic. *Neisseria gonorrhoeae* - This organism primarily causes **gonorrhea**, presenting as urethritis with purulent discharge, cervicitis, or pelvic inflammatory disease; it can also cause disseminated gonococcal infection. - Disseminated gonococcal infection can cause rash, but it is typically **pustular or vesiculopustular**, often on extremities, and not the diffuse macular rash described. *Borrelia burgdorferi* - This spirochete is the causative agent of **Lyme disease**, transmitted by ticks. - The classic rash of Lyme disease is **erythema migrans** (a bull's-eye rash), which is distinct from the macular trunk and palm rash seen in this patient.
Question 6: Which of the following STDs causes fetal abnormality?
- A. Syphilis (Correct Answer)
- B. Herpes
- C. Gonorrhea
- D. Hepatitis B
Explanation: ***Syphilis*** - **Congenital syphilis**, resulting from maternal infection, can lead to severe fetal abnormalities such as **bone deformities**, **saddle nose**, **Hutchinson's teeth**, and **neurological problems**. - It can also cause stillbirth, prematurity, or hydrops fetalis, emphasizing the importance of early detection and treatment during pregnancy. *Herpes* - While **neonatal herpes** can be life-threatening and cause neurological damage, it is typically acquired during passage through the birth canal and does not cause **fetal abnormalities** during gestation. - Herpes simplex virus primarily causes localized lesions and systemic infection in the neonate, not developmental defects. *Gonorrhea* - Gonorrhea primarily causes **ophthalmia neonatorum** (conjunctivitis) in newborns through exposure during birth, which can lead to blindness if untreated. - It does not typically cause **fetal abnormalities** or congenital defects through transplacental transmission. *Hepatitis B* - Hepatitis B can be transmitted to the fetus during birth, leading to **chronic hepatitis B infection** in the infant. - Although it causes a chronic disease, it does not typically result in **fetal abnormalities** or congenital malformations.
Question 7: A 22-year-old woman presents for STI screening. She reports multiple sexual partners and inconsistent condom use. What screening tests would be most appropriate?
- A. HPV DNA testing only
- B. Complete blood count and urinalysis
- C. HIV and syphilis testing only
- D. HIV, syphilis, gonorrhea, and chlamydia testing (Correct Answer)
Explanation: ***HIV, syphilis, gonorrhea, and chlamydia testing*** - This comprehensive panel screens for the most common bacterial and viral STIs in sexually active individuals with **multiple partners** and **inconsistent condom use**, as recommended by **NACO and WHO guidelines**. - **Gonorrhea and chlamydia** often present asymptomatically but can lead to serious reproductive health complications including pelvic inflammatory disease (PID) and infertility if untreated. - In high-risk populations, comprehensive screening is essential for early detection and prevention of transmission. *HPV DNA testing only* - **HPV DNA testing** is primarily for cervical cancer screening in women over 30 years or as a co-test with cytology; it doesn't cover other STIs. - While HPV is common, testing for other prevalent STIs like chlamydia, gonorrhea, syphilis, and HIV is crucial given her risk factors. *Complete blood count and urinalysis* - A **complete blood count (CBC)** assesses overall health and detects conditions like anemia or infection but is not a specific STI screening test. - **Urinalysis** checks for urinary tract infections or kidney issues and does not directly screen for STIs. - These are general screening tests and miss the targeted STI screening needed. *HIV and syphilis testing only* - Although **HIV and syphilis testing** are essential components of STI screening, this option misses other common and treatable bacterial STIs like gonorrhea and chlamydia. - Given the patient's risk factors (multiple partners, inconsistent condom use), a more comprehensive screening panel is warranted to prevent long-term reproductive complications.
Question 8: A 25 year old lady presented with curdy white discharge from the vagina is likely to be suffering from:-
- A. Trichomoniasis
- B. Gonococcal vulvovaginitis
- C. Chlamydia trachomatis
- D. Candida vaginitis (Correct Answer)
Explanation: ***Candida vaginitis*** - **Candida vaginitis** is characterized by a **curdy white vaginal discharge**, often described as cottage cheese-like. - This condition is caused by an overgrowth of *Candida* species, typically *Candida albicans*, and is associated with **vaginal itching, burning**, and **dyspareunia**. *Trichomoniasis* - **Trichomoniasis** typically presents with a **frothy, greenish-yellow discharge** and a **foul odor**. - It often causes **severe itching, redness, and irritation**, which differ from the curdy discharge described. *Gonococcal vulvovaginitis* - **Gonococcal vulvovaginitis** in women can cause a **purulent or mucopurulent discharge**, often yellowish. - While it can lead to vaginal irritation, a **curdy white discharge** is not its classic presentation. *Chlamydia trachomatis* - **Chlamydia trachomatis** often causes an **asymptomatic infection**; when symptoms occur, they may include a **mucopurulent discharge**. - A **curdy white discharge** is not a typical symptom of *Chlamydia* infection.
Question 9: A patient presents with genital grouped vesicles, as shown in the image. What is the most likely causative organism?
- A. Herpes simplex virus (Correct Answer)
- B. Haemophilus
- C. Klebsiella
- D. Treponema
Explanation: ***Herpes*** - The image shows **grouped vesicles** on an erythematous base, which is the classic presentation of **genital herpes** caused by the **Herpes simplex virus (HSV)**. - These lesions are typically painful and can recur, indicating a viral etiology. *Haemophilus* - *Haemophilus ducreyi* causes **chancroid**, which presents as **painful genital ulcers** with ragged borders and often associated with inguinal lymphadenopathy. - It does not present as grouped vesicles. *Klebsiella* - *Klebsiella granulomatis* causes **donovanosis (granuloma inguinale)**, characterized by progressive, **painless ulcerative lesions** that are highly vascular and bleed easily. - This organism does not cause vesicular lesions. *Treponema* - *Treponema pallidum* causes **syphilis**, which in its primary stage presents as a **painless chancre** (a solitary ulcer) or in secondary stage as a diffuse rash. - It does not cause grouped vesicles.
Question 10: Which one of the following statements best characterizes lympho-granuloma venereum (LGV)?
- A. It is most common in temperate regions
- B. The causative agent is C. trachomatis (Correct Answer)
- C. In the United States, it is more common among women
- D. Penicillin is effective in early treatment
Explanation: **The causative agent is *C. trachomatis*** - **Lymphogranuloma venereum (LGV)** is a sexually transmitted infection caused by specific serovars (**L1, L2, L2a, L2b, L3**) of *Chlamydia trachomatis*. [1] - These serovars are **invasive** and replicate in **mononuclear phagocytes** of lymphatic tissue, leading to the characteristic lymphadenopathy. [1] *It is most common in temperate regions* - LGV is **most common in tropical and subtropical regions**, particularly in parts of Africa, Southeast Asia, South America, and the Caribbean. - Its prevalence is much lower in temperate regions, though outbreaks can occur, especially in specific *high-risk populations*. *In the United States, it is more common among women* - In developed countries like the United States, LGV primarily affects **men who have sex with men (MSM)**, particularly those who are HIV-positive. [1] - While it can occur in women, its incidence is **significantly lower** in this population. *Penicillin is effective in early treatment* - LGV is caused by *Chlamydia trachomatis*, which is a **bacterium that lacks a peptidoglycan cell wall**, making it inherently resistant to penicillin. - The recommended treatments for LGV are **doxycycline** or **erythromycin**, not penicillin.
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