Sexually Transmitted Diseases (STDs)

Definition | Types | Aetiology | Risk Factors | Clinical Presentation | Investigations | Management | Prevention | When to Refer | References

Definition

Sexually Transmitted Diseases (STDs) are infections transmitted through sexual contact, caused by bacteria, viruses, parasites, or fungi. STDs can affect various parts of the body, but primarily the genital area. They can have significant health consequences if left untreated, including chronic pain, infertility, and an increased risk of certain cancers.

Types

STDs encompass a wide range of infections, including:

• Chlamydia: A bacterial infection that often presents with mild or no symptoms but can lead to serious reproductive complications if untreated.
• Gonorrhoea: A bacterial infection that can affect the genitals, rectum, and throat. If left untreated, it can cause infertility and systemic complications.
• Syphilis: A bacterial infection that progresses through stages and can lead to severe systemic complications, including neurological and cardiovascular damage, if not treated.
• Human Immunodeficiency Virus (HIV): A viral infection that attacks the immune system and can lead to Acquired Immunodeficiency Syndrome (AIDS) if untreated.
• Human Papillomavirus (HPV): A viral infection that can cause genital warts and is associated with an increased risk of cervical, anal, and other cancers.
• Herpes Simplex Virus (HSV): A viral infection that causes genital and oral herpes, characterised by painful blisters and ulcers.
• Trichomoniasis: A parasitic infection that can cause vaginal and urethral inflammation, often leading to symptoms such as discharge and irritation.
• Hepatitis B and C: Viral infections that affect the liver and can be sexually transmitted, particularly Hepatitis B.

Aetiology

STDs are caused by various pathogens, which are transmitted primarily through sexual contact, including vaginal, anal, and oral sex. Some STDs can also be transmitted through non-sexual means, such as from mother to child during childbirth (e.g., HIV, syphilis) or through shared needles (e.g., HIV, Hepatitis B, and C).

Risk Factors

Several factors increase the likelihood of contracting an STD:

• Multiple Sexual Partners: The more sexual partners, the higher the risk of exposure to STDs.
• Unprotected Sex: Not using condoms or dental dams increases the risk of STD transmission.
• Age: Young people, particularly those aged 15-24, are at higher risk of contracting STDs.
• Previous STD Diagnosis: A history of STDs increases the likelihood of future infections.
• Substance Abuse: Drug and alcohol use can impair judgement, leading to risky sexual behaviours.
• Men Who Have Sex with Men (MSM): This group is at higher risk for certain STDs, including HIV, syphilis, and gonorrhoea.

Clinical Presentation

The symptoms of STDs can vary widely depending on the specific infection. Common symptoms include:

• Genital Symptoms: Unusual discharge, sores, blisters, ulcers, warts, itching, or irritation in the genital area.
• Pain: Pain during urination (dysuria), painful intercourse (dyspareunia), or pelvic pain.
• Systemic Symptoms: Fever, swollen lymph nodes, rash, or general malaise, particularly in systemic infections like HIV or syphilis.
• Rectal Symptoms: Discharge, pain, bleeding, or irritation, particularly in infections like gonorrhoea, chlamydia, or HSV.
• Oral Symptoms: Sores, blisters, or ulcers in the mouth or throat, particularly in HSV or syphilis.

Many STDs can be asymptomatic, particularly in the early stages, which can lead to delayed diagnosis and treatment.

Investigations

The diagnosis of STDs typically involves a combination of clinical assessment and laboratory testing:

• Sexual History: A thorough sexual history is crucial to assess risk and guide testing.
• Swabs: Cervical, urethral, rectal, or throat swabs can be used to test for bacterial infections such as chlamydia and gonorrhoea.
• Blood Tests: Serological tests are used to diagnose HIV, syphilis, hepatitis B, and hepatitis C.
• Urine Tests: Used to detect chlamydia and gonorrhoea, particularly in men.
• Pap Smear and HPV Testing: Used to screen for cervical abnormalities and HPV infection.
• Microscopy: Can be used to diagnose trichomoniasis or bacterial vaginosis from vaginal discharge samples.

Management

The management of STDs involves appropriate antibiotic, antiviral, or antiparasitic treatment, depending on the infection:

• Antibiotics: Used to treat bacterial STDs such as chlamydia, gonorrhoea, and syphilis. Common antibiotics include azithromycin, doxycycline, and ceftriaxone.
• Antivirals: Medications such as aciclovir or valaciclovir are used to manage HSV infections, while antiretroviral therapy (ART) is essential for managing HIV.
• Antiparasitics: Metronidazole is commonly used to treat trichomoniasis.
• Partner Notification and Treatment: Sexual partners should be informed, tested, and treated to prevent reinfection and further spread of the disease.
• Follow-Up: Re-testing may be necessary to confirm the clearance of the infection, particularly for infections like chlamydia or gonorrhoea.

Prevention

Prevention strategies are crucial in reducing the spread of STDs:

• Condom Use: Consistent and correct use of condoms significantly reduces the risk of STD transmission.
• Regular Screening: Routine screening for STDs is recommended, especially for high-risk groups such as sexually active young people, MSM, and individuals with multiple partners.
• Vaccination: Vaccines are available for HPV and hepatitis B, which can prevent these infections.
• Safe Sexual Practices: Limiting the number of sexual partners and engaging in mutual monogamy with an uninfected partner reduces risk.
• Education: Raising awareness about STDs, their transmission, and prevention methods is key to reducing incidence rates.

When to Refer

Referral to a specialist, such as a genitourinary medicine (GUM) clinic, is warranted in the following situations:

• Complicated or severe cases of STDs that require specialist management, such as HIV or syphilis.
• Treatment-resistant infections or those requiring complex treatment regimens.
• Patients with recurrent or persistent symptoms despite appropriate treatment.
• High-risk patients requiring comprehensive sexual health management, including those with multiple STDs or co-infections.

References

1. NHS (2024) Sexually Transmitted Infections (STIs). Available at: https://www.nhs.uk/conditions/sexually-transmitted-infections-stis/ (Accessed: 26 August 2024).
2. National Institute for Health and Care Excellence (2024) Sexually Transmitted Infections: Diagnosis and Management. Available at: https://www.nice.org.uk/guidance/ng151 (Accessed: 26 August 2024).
3. British Medical Journal (2024) Sexually Transmitted Infections: Diagnosis and Treatment. Available at: https://www.bmj.com/content/359/bmj.j5225 (Accessed: 26 August 2024).

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