STD 1 Flashcards
What are STDs?
Diseases which are capable of being spread from person to person through sexual contact and not only
How can STDs be transmitted?
- Sexual Intercourse
vaginal
anal
oral - Blood-to-blood contact
- Sharing needles or other drug-use equipment
- Tattoo or body piercing
- Infected mother to her baby
Which body fluids are considered high risk for STD transmission?
- Semen
- Vaginal fluid
- Blood
- Fluid in sores or blisters
- Cerebrospinal fluid, Amniotic fluid, Pleural fluid, Synovial fluid, and Peritoneal and Pericardial fluids
Which fluids are considered low risk for STD transmission?
- Saliva
- Tears
- Sweat
- Urine
- Feces
- Ear wax
- Nasal secretion
What are the features of Trichomonas Vaginalis?
Anaerobic
Parasitic Protozoa
Pyriform/amoeboid shape
10-20um length x 2-14um width
4 flagellum pointing anterior, 1 posterior
What part does Trichomonas attach to and replicate?
Squamous epithelium of genital tract
-> replicates in lower genital tract, urethra, prostate
What happens when Trichomonas attaches to tissue?
Lyses host epithelial cells
Triggers immune response causing inflammation
Pathogenic disruption of vaginal bacteria
What area is Tricomoniasis most prevalent in?
Western pacific region
What percentage of patients with Trichomoniasis are asymptomatic?
Men- 77%
Females- 85%
What are the symptoms of Trichomoniasis in females?
- Heavy, unpleasant smelling green-yellow discharge
- Itching and burning at the outside of the opening of the vagina and vulva
- Painful and frequent urination
- Vulvar irritation and abdominal pain.
What are the symptoms of Trichomoniasis in males?
- Mild discomfort in urethra
- Minimal urethral discharge
- Dysuria
- Inflamed head of the penis.
-> Complications can also include epididymitis, prostatitis, and decreased sperm cell motility
What are the features of oral ulcers seen in patients with Trichomonas present?
Large- 1-1.5cm in diameter
Circumscribed with elevated edges
Necrotic centre- with yellowish colour
How is Trichomoniasis diagnosed?
Direct Microscopic examination- wet mount
Isolation- gold standard but higher cost
Rapid tests
-> OSOM
-> GeneXpert
-> Xenostrip
How is Trichomoniasis treated?
Avoid sexual intercourse and tell partners
Metroniazdole/Tinidazole- single dose 2g orally
Metronizadole- 400-500mg x 2 daily for 7 days
-> mostly for HIV patients
What must patients on metronidazole and tinidazole abstain from?
Alcohol
-> M- until 24 hours after last dose
-> T- until 72 hours after last dose
Prevents disulfiram reaction
What type of bacteria is Chlamydia?
Gram negative obligate anaerobe
What are the forms of Chlamydia?
Elementary body- 300nm, extracellular, metabolically inactive
Reticulate body- 400nm, intracellular, replicative
What happens to elementary body as it enters host cell?
It transforms it to Reticulate body form
-> it returns to EB form when released by host cell as a result of inclusion extrusion or lysis
What causes Chlamydia to become non-infectious persistent form?
Exposure to:
* IFN gamma
* Pencillin G
* Iron depletion
What is the incubation period in Chlamydia?
7-21 days
What are some of the symptoms that can occur in patients who have asymptomatic genital Chlamydia?
Fever
Weight loss
Lymphadenopathy
Fatigue
Diarrhoea
What are the female symptoms of Chlamydia?
Vaginal discharge (white or grey)
Burning with urination
Lower abdominal pain
Bleeding between menstrual periods
Cervicitis that can progress to pelvic
inflammatory disease
What are the male symptoms of Chlamydia?
Urethritis, or less commonly epididymitis
Discharge from the penis
Painful and burning urination
Burning and itching around the opening of the penis
Pain and swelling around the testicles
How may chlamydia present orally?
Tonsillopharyngitis
Oropharyngeal Lymphogranuloma
What tests can be done for Chlamydia?
PCR/SDA/TDA- high sensitivity, can be done from urine/vaginal swabs, automated
Cell culture
EIA
DFA
Serology- if other specimens not obtainable
How is Chlamydia treated?
Abstain from sex until regimen is completed
Azithromycin- single dose 1g orally
Doxycycline- 100mg x 2 daily for 7 days
What are the features of Neisseria Gonorrhoeae?
Gram Negative
Non-motile cocci
0.8um
Can be in pairs
What are the steps in the pathogenesis of gonorrhoea?
- Adherence to urogenital epithelium
- Competition with resident microbiota- colinsation and invasion of epithelium
- Release of peptidogylycan, LOS, OMVs- causes NOD/TLR activation , triggering innate immunity
- Cytokine chemokine and inflammatory transcription factor activation
- Influx of neutrophils causing phagocytosis
- Formation of neutrophil rich purulent exudate (facilitates transmission)
What is the incubation period for Gonorrhea?
2-8 days
What are the non-genital symptoms of Gonorrhea?
Fever
Chills
Nausea
Vomiting
Leukocytosis
Tonsillar infection
What are the female symptoms of Gonorrhea?
Cervicitis- discharge, bleeding, dysuria
Urethritis
Pelvic inflammatory disease
What are the male symptoms of gonorrhoea?
Urethritis
Urethral discharge
Dysuria
What are the complications for males of gonorrhoea?
Acute unilateral epididymitis
Penile oedema (“bull-headed clap”)
Penile lymphangitis
Periurethral abscess
Acute and chronic prostatitis
Seminal vesiculitis
Swollen testicles
What type of specimens can be used for Gonorrhea?
Urine
Urethral swab
Rectal swab
Pharyngeal swab
Conjunctival swab
What are the different testing methods for Gonorrhea?
Microscopy
Culture
Nucleic acid amplification- BEST
What treatment is used for Gonorrhea?
Ceftriaxone
What is Syphillis caused by?
Treponema Pallidum- spirochete bacterium
What are the features of Treponema Pallidum?
Helical shape
Micro-aerophillic bacterium
6-20um length, 0.1-0.18um in diameter
Central protoplasmic cylinder bound by cytoplasm membrane with overlying peptidoglycan then out membrane
Flagelar motors and filaments
Where is syphilis most incident?
Africa
How is syphilis spread?
Direct contact lesion
Blood transfer
Sexual contact
What are the steps in the pathogenesis of Syphilis?
Spirochetes adhere to epithelial cells or ECM allowing them to penetrate mucous membranes or enter through abrasions
Spirochetes then penetrate ECM and intercellular junctions- invasion
Tissue destruction occur due to immune response elicited by spirochetes
How long does the primary syphilitic lesion take to appear?
3 weeks after inoculation
How does primary syphillis present?
As a chancre
-> Painless ulcer or papule
-> Typically single
-> Lasts 3-6 weeks then heals on its on without scarring
Lympadenopathy
Resolves with tx
How does secondary syphilis present?
Occurs many weeks after primary infection
Fever
Weight loss
Fatigue
Myalgias
Athralgias
Sore throat
Headache
Hairloss
Rash- macular, papular, follicular, scarring
-> can occur orally
When does latent syphilis occur?
If primary and secondary manifestations resolve without treatment
What are the stages of the latent phase of syphilis?
Early latent- within first year
-> T.pallidum can be present in tissues and give recurrence
-> responds to tx
Late- after first year
-> does not respond to treatment
What occurs after the latent stage of syphilis?
Tertiary stage (15% of untreated patients)
What are the lesions that occur in tertiary syphillis?
Neurological
-> Meningeal syphilis
-> Meningovascular
-> General paresis
-> Tabes Dorsalis
CV
Muco-cutaneous
What are some of the signs and symptoms od early congenital syphilis?
Still birth
Lymphadenopathy
Anaemia
Leukopenia/leukocytosis
Rhinitis
Rash
Long bone lesions
Aseptic meningitis
Retinitis
What are the signs and symptoms of late congenital syphillis?
Hutchinson’s teeth
Mulberry Molars
Interstitial keratitis of eye
CN8 damage- deafness
Saddel nose
Impaired maxillary growth
What are the features of hutchinson’s teeth? (upper incisors)
Present at 6 years
Centrally notched
Widely spaced
Peg shaped
What are the features of mulberry molars?
Surface has poorly developed cusps giving dome shaped tooth
What are the differential diagnoses for Primary syphillis?
- HSV
- RAS
- Penile cancer
- TB
- Behcets
- LP
- Traumatic ulceration
- Reiters
- Scabies
What are the methods for diagnosis Syphilis? (detection of T.Pallidum)
Darkfield Microscopy
Direct fluorescent antibody staining
PCR
Immunohistochemisty
What are the types of serodiagnostic tests for syphillis?
Nontreponemal
-> measures IgM and IgG produced in response to lipoidal material released from bacterium/dying host cells
-> becomes positive 10-15 days after lesion
Treponemal- detects antibodies agains TP proteins (highly specific)
-> not useful for treatment effectiveness
-> Becomes positive 6-14 days after primary lesion
-> Good if missed by NTT
What treatment is used for Primary, Secondary, Early latent syphillis?
Penicillin- 2.4 million units of penicillin
-> 2 IM injections
Doxycycline- 100mg 2 x per day for 14 days
Tetracycline- 500mg 4 x per day for 14 days
What treatment is used for late latent, Cardiovascular, mucocutaneous syphillis?
Penillin- 7.2 million units IM
-> 2.4 at 7 day intervals for 21 days
Doxycycline- 100 mg x2 per day for 28 days
Tetracycline- 500mg x4 per day for 28 days
What is the treatment for symptomatic or asymptomatic neurosyphilis?
2-4 million units of aqueous penicillin G IV every 4 hours for 10 days
2-4 million units of procaine penicillin IM and probenecid 500mg x 4 daily for 10-14 days
Ceftriaxone- 2g IM or IV for 10-14 days
