GUM Flashcards
What type of virus is HPV?
Double-stranded DNA virus
What proportion of PID cases are caused by CT?
14-35%
What is the estimated transmission risk of CT with a single episode of UPSI?
10%
What proportion of women with CT will develop SARA?
<1%
What proportion of patients with untreated CT will spontaneously clear by 12 months?
50%
What are rates of concordance when one partner is diagnosed with CT?
75%
What is the first-line management of uncomplicated CT?
Doxycycline 100mg bd for seven days
or
Azithromycin 1g orally as a single dose, followed by 500mg once daily for two days
If first line management options are contraindicated in CT, what should be used instead?
Erythromycin 500mg bd for 10–14 days
or
Ofloxacin 200mg bd or 400mg od for seven days
What are the management options for uncomplicated CT in pregnancy?
Azithromycin 1g orally as a single dose, followed by 500mg once daily for two days
or
Erythromycin 500mg four times daily for seven days
or
Erythromycin 500mg twice daily for 14 days
or
Amoxicillin 500mg three times a day for seven days
In whom should a TOC be performed for re: CT?
- Pregnancy
- Where poor compliance is suspected
- Where symptoms persist
Co-infection of M.gen is reported in what proportion of CT infections?
3%-15%
What type of bacteria is chlamydia trachomatis?
Gram negative
How does chlamydia trachomatis replicate?
WITHIN a cell
Which CT serovars account for trachoma?
A-C
Which CT serovars account for genital infection?
D-K
Which CT serovars account for LGV?
L1-L3
What is the lifecycle of CT?
Elementary bodies (EB) are the infectious forms of CT and are spore like structures with a hard cell wall allowing its survival in the environment outside the cell.
They are 200-400 nanometres in size.
An EB attaches to the new host cell and enters the cytoplasm surrounded by a vacuole called an inclusion.
Within this inclusion, the EB transforms into a Reticulate body (RB) and rapidly replicates by binary fission.
RB’s transform back into EB’s with increasing expansion of the inclusion within the host cell cytoplasm.
The host cell ruptures causing expulsion and release of the EB’s into the environment before they re-infect further epithelial cells.
What are the risks of CT in a pregnant pt?
- Neonatal conjunctivitis
- Pre-term labour
Where is LGV endemic?
Southern Africa, West Africa, Madagascar, India, South-East Asia and the Caribbean
What is the most common serovar of CT associated with LGV infection?
L2
What is the incubation period of LGV?
3-30 days
What is the primary manifestation of LGV in MSM?
Haemorrhagic proctitis - 96% of cases in Western Europe
Can LGV cause systemic symptoms?
Yes - fever and malaise
What is ‘groove’ sign in LGV?
When both inguinal and femoral lymph nodes are involved, they may be separated by the so-called ‘‘groove sign,’’ which consists of the separation of these two lymph node systems by the inguinal ligament
What proportion of LGV cases display ‘groove sign’?
15-20% (although considered pathognomonic of LGV)
What are the long-term consequences of LGV?
Destruction of LNs may result in genital lymphoedema (elephantiasis) with persistent suppuration and pyoderma
Chronic inflammation and destruction of tissue may lead to proctitis, proctocolitis mimicking Crohn’s disease, fistulae, strictures and chronic granulomatous disfiguring fibrosis and scarring of the vulva with esthiomene (Greek word meaning ‘‘eating away’’). All more frequent in women, reflecting the involvement of retroperitoneal lymphatics.
What may be seen on microscopy in LGV?
Rectal polymorphonuclear leucocytes (PMNLs) from rectal swabs is predictive of LGV proctitis, especially in HIV-positive MSM, with levels of >10 and >20 PMNLs per high-power field both shown to be significant
How is LGV treated?
Doxycycline 100 mg twice daily orally for 21 days
2nd choice: erythromycin 500mg four times daily orally for 21 days
What is the ‘look-back’ period for LGV?
4 weeks prior to the patient’s symptoms, or the last 3/12 if asymptomatic LGV is detected
If TOC required in LGV (e.g. if pregnant), when can it be performed?
2 weeks after treatment
Who is most likely to be diagnosed with LGV in the UK?
HIV +ve MSM
What is the smallest known smallest known self-replicating bacterium?
M.gen
What is the 2nd most common cause of NGU?
M.gen
Whom should be tested for M.gen
Recommend testing:
- NGU
- PID
Consider:
- Muco-purulent cervicitis +/- PCB
- Epididymitis
- Sexually-acquired proctitis
In whom should a TOC be performed in M.gen?
All patients
What is the treatment for uncomplicated M.gen (urethritis/cervicitis)?
Doxycycline 100mg bd for seven days followed by azithromycin 1g orally as a single dose then 500mg orally once daily for 2 days where organism is known to be macrolide-sensitive or where resistance status is unknown
Moxifloxacin 400mg orally once daily for 7 days if organism known to be macrolide-resistant or where treatment with azithromycin has failed
What is the treatment for complicated M.gen (PID/EO)?
Moxifloxacin 400mg orally once daily for 14 days
How is M.gen treated in pregnancy?
A three-day course of azithromycin can be used for uncomplicated M. genitalium infection detected in pregnancy
What is the partner treatment for M.gen?
Only current partner(s) (including non-regular partners where there is likely to be further sexual contact) should be tested and treated if positive
How is NGU diagnosed?
Confirmed by demonstrating five or more PMNLs per high power (x1000) microscopic field (averaged over five fields) on a smear obtained from the anterior urethra
Sampling with a 5-mm plastic loop or cotton tipped swab which should be introduced about 1cm into the urethra. A 5-mm plastic loop is less painful than a Dacron swab which is less painful than a Rayon swab
What is the most common cause of NGU?
C. trachomatis
What is the recommended 1st line treatment for NGU?
Doxycycline 100mg twice daily for 7 days
What are the alternative treatments for NGU?
Azithromycin 1g stat then 500mg once daily for the next 2 days (three days total treatment)
or
Ofloxacin 200mg twice daily, or 400mg once daily, for 7 days
For how long should people abstain in NGU?
14 days from start of treatment
What proportion of patients experience persistent NGU?
15-25%
What is recurrent NGU?
Symptomatic urethritis occurring 30-90 days following treatment of acute NGU
In what proportion does recurrent NGU occur?
10-20%
What is the positive predictive value of clinical Dx PID (compared to laparoscopic diagnosis)?
65-90%
What is the negative/positive predictive value of endocervical pus cells for PID?
Negative predictive value - 95%
Positive predictive value - 17%
What is the ‘lock-back’ period with PID?
6 months
What is scabies caused?
Sarcoptes scabiei var hominis
How long is the life cycle of Sarcoptes scabiei?
4-6 weeks
How long is the ‘moulting’ period in scabies (eff to adult)?
10-15 days
How long can scabies live off a host?
24-36 hours
What type of hypersensitivity reaction causes itching in scabies?
Delayed type-IV hypersensitivity
How soon do scabies symptoms start?
Symptoms begin 3-6 weeks after primary infestation, but occurs earlier at 1-3 days in a reinfested person probably due to prior sensitization to the mite and mite products
Scabies is
therefore infectious before the rash develops
What proportion of crusted scabies cases has no identifiable risk factor, e.g. immunocompromise?
40%
What are the treatment options for scabies?
- Permethrin 5% cream
- Malathion 0.5% aqueous lotion
- Ivermectin
After how long should permethrin be washed off?
8-12 hours
After how long should malathion be washed off?
24 hours
How long may post-scabetic itch last?
2 weeks
Where do scabies live on the skin?
The mites burrow into the upper layer of the skin but never below the stratum corneum
How many eggs per day do scabies lay?
2-3/day
Scabies may live for 1-2 months, and 10% of her her eggs survive
What type of organism is MC?
A large DNA
virus
Molluscum contagiosum belongs to the Poxviridae
family and Molluscipox genus
How many subtypes of MC are there?
4
What are the most common subtypes of MC?
MC-1 - most prevalent
MC-2 - relatively commoner in immunocompromise/HIV, and with increasing age and thus genital infection
By when does MC usually spontaneously resolve?
12-18 months
How can MC in severe immunocompromise (e.g. HIV) present?
Molluscum
lesions can affect the eyelids and cause chronic conjunctivitis due to a FB-type reaction
What type of virus is the poxvirus?
Double-stranded DNA viruses
What is the definition of recurrent VVC (thrush)?
At least four episodes per 12 months with two episodes confirmed by microscopy or culture when
symptomatic (at least one must be culture)
Do male partners require treatment when a woman has been diagnosed with VVC?
Asymptomatic male sexual partners do not need treatment if their female partner has either uncomplicated or recurrent candidiasis.
Does nystatin (used in the treatment of VVC) damage latex?
No, but some anti-fungals do
What type of organisms are yeasts?
Yeasts are eukaryotic, unicellular microorganisms which have the ability to develop multicellular characteristics by forming pseudohyphae and biofilms
Can contraception increase the risk of recurrent VVC?
Oestrogen containing contraceptives increases recurrence risk. There may be a possible risk that yeast may form a biofilm on Cu-IUD causing treatment resistance however there is no consistent evidence.
What proportion of VVC cases are caused by C. albicans?
80-89%
Aside from C.albicans, what other organisms can be responsible for thrush?
- C. glabrata,
- C. tropicalis
- C. krusei
- C. parapsilosis
- Saccharomyces cerevisiae
What proportion of women will have a) at least one episode and b) two or more episodes of VVC?
a) 75%
b) 40–45%
What genotype may be associated with increased susceptibility to recurrent or acute VVC?
Mannose binding lectin (MBL) deficiency is a genetic condition that affects the immune system. Several studies have shown that MBL codon 54 gene polymorphism (in particular, possessing the MBL variant allele B heterozygous genotype) is associated with recurrent and acute VVC
What microscopic features are suggestive of candida?
- Blastospores
- Pseudohyphae
- Neutrophils
What microscopic features are suggestive of C. glabrata specifically?
Blastospores and neutrophils ONLY
In the context of recurrent VVC, what medium should be used for direct plating?
A solid fungal growth medium (Sabouraud plate)
What is the benefit of direct plating in recurrent VVC?
Quantification of candida
Why can candida not be quantified from other fungal transport mediums?
If kept in transport medium for
more than 12 hours, quantification is unreliable due to continued growth