HIV & STIs Flashcards
What is vertical transmission?
- Mother to baby
- in utero: trans placental
- peri-natal: passage through infected birth canal
- Eye mucous membrane: conjunctivitis
What bacteria causes gonorrhoea?
- Neisseria gonorrhoeae= Gram negative
- N. meningitidis= non-pathogenic neisseria species
What type of cells does gonorrhoea infect? Where does it affect?
- Columnar/cuboidal epithelium
- GU tract, rectum, oropharynx
What are the 3 layers of gram negative bacteria cell envelopes?
- Outer cytoplasmic membrane
- Thin peptidoglycan cell wall
- Inner cytoplasmic membrane
What are complications of gonorrhoea?
- Local: epididymitis, prostatitis, barthonilitis, PID, peritonitis
- Metastatic: disseminated gonococcal infection
- pregnancy: premature labour, conjunctivitis in foetus (can lead to blindness), spent abortion
How is gonorrhoea diagnosed & treated?
- D: Culture, NAAT (PCR), microscopy
- T: β-lactams, cephalosporins, fluoroquinolones
What pathogens cause non-gonococcal urethritis?
- Chlamydia trachomatis
- Ureaplasma urealyticum (mycoplasma genitalium)
- Treat with doxycycline, macrolides
What 2 bodies does chlamydia trachomatis form? What cells does it target?
- Elementary body: Extracelullar infectious form
- Reticulate body: Intracellular replicative form
- Squamocolumnar epithelial cells of endocervix/upper genital tract in F
- Conjunctiva, uethra, rectum M&F
What are complications of chlamydia?
- PID
- Epididymitis
- Infant: pneumonia, conjunctivitis
- Reiter’s syndrome: skin lesions, urethritis, arthritis, conjunctivitis
Describe HPV
-HPV6,11= genital warts/Condylomata accuminata
-HPV 16,18= cervical carcinomas
-
What is the clinical presentation of genital herpes?
- Pain
- Itching
- Dysuria
- Vaginal/urethral discharge
- Bilateral vesicles/ulcers-viral shedding
What is the main cause of genital herpes?
- Herpes simplex types 1&2
- Double stranded DNA viruses
What are complications of genital herpes?
- Dissemination
- Meningitis
- Encephalitis
- Sacral nerve parasthesiae
- Urinary retention
Describe syphilis
- Spirochaete=Treponema pallidum
- slender, helical, tightly coiled cells
- Penetrates intact mucous membranes/abraded skin
- Disseminated within days via lymphatics/bloodstream
- Histology=obliterative endarteritis
What are the symptoms of syphilis?
- Rash= macular/maculopapular, trunk, limbs-palms/soles
- Condylomata lata= warm body areas, highly infectious, erythematous plaques
- Headache
- Generalised lymphadenopathy
- Fever, malaise, weight loss
- Meningismus
What are symptoms in the third stage of syphilis?
- Meningovascular: hemiplegia, seizures
- CV: aortitis, aortic regurgitation, saccular aneurysm
- Late benign syphilis: bone, skin, soft tissue, non-specific granulomatous reaction
- Parenchymatous: Tabes dorsalis (demyelination of DC), general paresis (personality change)
What are early & late signs of Spirochaetaemia in early syphilis?
- E: snuffles, rash, hepatosplenomegaly
- L: frontal bosses, saddle nose, sabre shins, Hutchinson’s incisors
How is syphilis diagnosed& treated?
- D-Indirect tests: Specific= anti-treponemal antibodies EIA, FTA non-specific= VDRL, RPR tests
- T-Penicillin (Jarish-Herxheimer reaction), amoxicillin, doxycycline, ceftriaxone
Describe trichomoniasis
- Trichomonas vaginalis protozoan (lacks mitochondria)
- Trophozoite transmission
- Humans only natural host
- Mucosal inflammation
- Profuse greenish frothy vaginal discharge
Describe bacterial vaginosis
- Anaerobic
- Reduced vaginal lactobacilli
- Increased gardnerella vaginalis & anaerobes
- Watery discharge
- Amoxicillin, topical clindamycin, metronidazole
Describe candidiasis
- Candida albicans
- Thrush, balanitis
- Oral contraceptives, poorly controlled diabetes, antibiotics inhibit normal flora
- Vulval/vaginal/penile erythema, itching/irritation
- Thick/adherent discharge, white plaques
- Maculopapular & fissuring lesions
What is viral glycoprotein gp120?
-Interacts with cellular receptor CD4 & chemokine receptor CCR5 for virion to gain host cell entry
Where does reverse transcription occur?
Cytoplasm
What are the 4 stages of CD4 count?
1: >500
2: 350-500
3: Advanced HIV 200-350
4: AIDS
What are the early symptoms of HIV?
- Pulmonary TB
- Persistent oral candidiasis
- Unexplained persistent fever/ chronic diarrhoea
- Severe bacterial infections
What is the primary HIV infection known as?
- Acute retroviral syndrome
- Fever, pharyngitis, lymphadenopathy, rash
What opportunistic infections are linked to AIDS?
- HIV wasting syndrome & encephalopathy
- Pneumonia
- CMV disease
- CNS toxoplasmosis
- Extra pulmonary TB
- Lymphoma & kaposi’s sarcoma
- Disseminated non-TB mycobacterial disease
- Chronic cryptosporidiosis
