Sexually Transmitted Infections and Urinary Tract Infections Flashcards
What is chlamydia
An obligate intracellular bacterial pathogen. Full name- chlamydia trachomatis
What are the three different biovars (forms) of chlamydia
- Causes trachoma infection of the eyelids (leading cause of blindness worldwide). 2. Causes STI. 3. Causes Lymphogranuloma veneruem (infection of the lymph nodes and the lymphatic system, rare in the western world)
What is gonorrhoeae
Gram negative diplococcus. Full name- neisseria gonorrhoeae
What is syphillis
A bacterial infection causes by treponema pallidum
How is syphillis spread
By skin and mucous membranes following direct contact
What is genital herpes caused by
Herpes simplex virus
Describe Type 1 herpes
Classic cause of oral cold sore
Describe Type 2 herpes
Historically more associated with STI
Where does genital herpes remain laten
In sensory root ganglia
What can herpes be
Primary or recurrent
What is genital warts caused by
Human papilloma virus (HPV)
What are the symptoms of chlamydia
Urethritis, epididymitis, cervicitis, proctitis . Commonly asymptomatic (80%)
What are the symptoms of gonorrhoea
Urethritis, proctitis and discharge (vaginal, anal and urethral). Pharangitis and eye infections. May be asymptomatic (10%) particularly in men
What are the 3 stages of syphilis
Primary syphilis, secondary syphilis and tertiary syphilis
Describe primary syphilis
Painless but highly infectious sore (chancre) lasts 2-6 weeks
Describe secondary syphilis
Skin rash (affects palms of the hands and soles of the feet), fever and sore throat- few weeks
Describe tertiary syphilis
33% of untreated patients develop tertiary syphilis. Gummatous (15%)- soft inflammatory masses involving bone, skin and liver. Cardiovascular (6%)- aorititis and aneurysm. Neurological (10%)- dementia, psychosis, paresis (tabes dorsalis, general paralysis of the insane)
What are the symptoms of genital herpes
Can by symptomatic or non-symptomatic: intermittent viral shedding occurs in both. Painful genital vesicles and ulcers
What are the symptoms of genital warts
Could take 1-2 months to develop or 9 months or incubate depending on the speed of cellular replication or the quantity of the virus. May not be visible. Will cause a visible, painless soft fleshy growth in or around the genitalia. Does not always cause visible signs and symptoms
What are the consequences of chlamydia
Pelvic inflammatory disease (15%), ectopic pregnancy (1 in 10), tubal infertility (1 in 5), chronic pain (1 in 5), increased HIV transmission 3-5 fold, Reiter’s syndrome, transmission to baby during birth- conjunctivitis and neonatal pneumonia
What are the consequences of gonorrhoea
PID, may spread to blood stream and cause bone and soft tissue infections, neonatal infection (conjunctivitis), global resistance to antibiotics emerging
Describe early congenital syphilis
Rash, snuffles, perostitis, hepatosplenomegaly, generalised lymphadenopathy, neurological or occular movement
Describe late congenital syphilis
Stigmata- Clutton’s joints, Hutchinson’s incisors, mulberry molars. Facial deformities- high palatal arch, frontal bossing, short maxilla, protuberance of mandible, saddlenose (due to collapsed cartilage). Neurological or gummatous involvement
What are the consequences of genital herpes
Recurrent disease more likely with HSV type 2. Can affect newborns- if primary infection is acquired late in pregnancy, baby is premature
What are the consequences of genital warts
First infects the DNA of the skin a mucous membranes. Then replicates and causes a cellular abnormality that is spread through the area. If the correct variation of HPV is contracted a genital wart abnormality will develop from these infected epithelial tissues
How do you investigate/ diagnose chlamydia
Performed when symptomatic- urethritis, PID, Reiter’s syndrome. Early detection and treatment of asymptomatic infection requires screening. Microscopy, fluorescent antibody tests ELISA, all relatively insensitive- genital swabs. Nucleic acid amplification tests most sensitive and specific (NAAT testing). Genital swabs and/or urine specimens
How do you investigate/ diagnose gonorrhoea
Presence of gram negative diplococci in pus. Culture from swabs and pus speciemens- need to distinguish from other neisseria that man colonise mucous membranes N.menigitidis, N.lactamia (sugar fermentation and biochemical tests). NAAT testing
How do you investigate/ diagnose syphilis
Microscopy- dark ground illumination. Serology- specific tests detect T. pallidum IgG and/or IgM (enzyme immunoassay (EIA) T. pallidum haemagglutination assay (TPHA), T. pallidum particle, agglutination assay (TPPA), fluorescent treponemal antibody absorbed test (FTA)), cross react with other treponemal infections (Yaws, Pinta). Non treponemal tests- detect anticardiolipin antibodies (VDLR, Reagin test (RPR)). Can be quantified and becomes negative with successful treatment. Use one test to screen and another to confirm. Monitor response with VDRL/RPR
Describe how you investigate/ diagnose genital herpes
Diagnoses by immunofluorescence/ PCR on vesicular fluid
Describe how you investigate/ diagnose genital warts
May not be visible and therefore must be diagnosed through a colposcopic exam of the cervix or vagina because the genital warts may be located on the vaginal walls and the cervix
Describe the national chlamydia screening program
Targets 14-24 year olds including anal screening and when change of sexual partner. Also offered during pregnancy and TOP.
Describe the use of NAAT in chlamydia
Fully automated extraction, amplification and detection systems (rapid and widely available), do not require viable organisms, swab (urethral, cervical, rectal) or urine all validated, can detect chlamydia and gonococcus in same sample
What is the treatment for chlamydia
Easily treated, drugs readily available azithromycin (single dose) and doxycycline (a longer course, usually two capsules a day for two weeks), screen for other STIs, screen and treat contacts
What is the treatment for gonorrhoea
Increasing resistance leads to treatment failures. Combination therapy now reccomended ceftriaxone 500mgx1 IM, plus azithromycin 1gx1 orally. Test of cure recommended, screen for other STIs and screen contacts
Describe the use of mercury in the treatment of syphilis
Long used to cure all ailments, used widely in treatment of syphilis, very toxic- renal failure, skin ulcers, tooth loss and death
Describe the use of arsenic in the treatment of syphilis
Antisyphilitic effects of arsenic discovered 1910, Salvarsan developed
Describe the use of fever therapy in the treatment of syphilis
Giving patients malaria moderately effective after quinine discovered
What is the treatment for early (primary or secondary) syphilis
Benzathine penicillin G 2.4 MU i.m. single dose and procaine penicillin 600,000 units i., o.d. for 10 days
What is the treatment for latent, cardiovascular or gummatous syphilis
Benzathine oenicillin G 2.4 MU i.m. weekly for 3 doses and procaine penicillin 600,000 units i.m. o.d. 17 days
What is the treatment for neurosyphilis
Procaine penicillin 1.8-2.4 MU i.m. o.d. plus probenecid 500mg po q.d.s for 17 days.
Describe the treatment of genital herpes
Treated with aciclovar
Describe the treatment options for genital warts
Surgery, freezing, chemical
Describe surgery of genital warts
By surgical incision around the site or with laser surgery to cauterize and remove
Describe freezing of genital warts
Small warts can be removed by freezing (liquid nitrogen)
Describe chemical treatment of genital warts
Imiquimod a 5% cream that is an interferon inducer or a 25% podophyllin solution which is applied to the affected area and washed off after several hours
Name lower UTIs
Urethritis and cystitis
Name upper UTIs
Prostatitis, pyelonephritis, intrarenal and perinephric abscesses
What is the leading cause of sepsis
UTIs
Who are UTIs more common in
Females as have a shorter urethra
What are the sources of a UTI
Bowel, heamatogenous spread, instrumentation
What are the bowel sources of UTIs
E. coli, Proteus, Enterococci
Describe the haematogenous spread of UTIs
Staphylococcal aureus, Streptococci
Describe the instrumentation sources of UTIs
Catheterisation, cytoscopy= MRSA, Candida, Pseudomonas
What is the commonest health care associated infection
Catheters becoming colonised, this is an indication for removal not necessary treatment
What is pathogenicity
It takes two to make a pathogen- host response and microbial virulence
What are host factors associated with UTIs
Flushing effect of voiding urine. Antibacterial effects of urine (low pH, high urea, high osmolality), secreted IgA, secretory bactericidial peptides, blood group (ABO blood group secretor status)- blood group related carbohydrate antigens reduce availability of urethral receptors
What are predisposing factors of a UTI
Female sex, dehydration, obstruction- stone, urethral valve, enlarged prostate, pregnancy, sexual intercourse, inadequate bladder emptying- neurogenic bladder, enlarged prostate, hydronephrosis and reflux
What are microbe factors of UTIs
Numbers- gut contains 10 to the 12 bacteria, many are motile, oissess fimbria (E.coli)- specific receptors on certain serotypes adhere to uroepithelim. Possess urease (proteus)- splits urea, alters pH leads to stone formation
Describe symptoms of urethritis
Dysuria, smelly cloudy urine, urgency, frequency
Describe symptoms of cystitis
Dysuria, smelly cloudy urine, urgency, frequency, subrapubic tenderness, haematuria
Describe symptoms of an upper UTI
Dysuria, smelly cloudy urine, urgency, frequency, subrapubic tenderness, haematuria, loin pain, fever, chills
What can an upper UTI progress to
Septicaemia, sepsis, septic shock, death
Why do you need a midtream urine sample
Urine for microbial analysis should be free of external contaminant
Describe the procedure for collecting a midstream urine sample
Collected aseptically, urethral meatus cleaned first, intitial and terminal portion of urine discarded, middle portion collected into sterile conatined (often heavily contaminated with perineal and bowel flora)
What does interpretation of a midstream urine sample require
Microscopy for presence of pus cells (and absence of epithelial cells). Quantitative culture of bacteria, >100,000 CFU/ml indicative if infection (contamination is common), asymptomatic if bacteriuria exist (not indication for treatment in pregnancy)
What does a urine dipstick test for
Nitrite and leucocyte esterase
What does presence of nitrite indicate
Presence of bacteria
What does presence of leucocyte esterase indicate
Presence of white blood cells
What urine dipstick results should you treat
If both nitrite and leucocyte esterase are positive
In what situations is a midstream urine sent to labatory
In pregnant women, children under 2, men, pylenonephritis, relapse/ failed antibiotic treatment, renal impairment
When do you treat a UTI
If someone has 3 or more symptoms
What is the empiricle treatment for UTIs
Encourage fluids (cranberry juice)
What do you use to treat uncomplicated UTIs
Trimethprim
What do you use to treat complicated UTIs
Amoxycillin +/- gentamicin
What are complicated UTIs
Children under 5 years, men; pregnancy; pyelonephritis or urosepsis; relapseed, recurrent or refractory infection; renal tract abnormality, obstruction, recent instrumentation; renal impairement, immunocompromised
When is furtehr investigation warrented
In children under 5 years or recurrent UTI
What are common implications (complications) of UTI
Sepsis. Recurrent UTI lead to renal scarring- particularly in children less than 2 years, chronic renal failure (need for dialysis/ transplantation), stones. May require prophylactic antibiotic treatment. Antibiotic resistance an increasing problem
