HIV & STIs

Question 1

What is vertical transmission?

Answer 1

• Mother to baby
• in utero: trans placental
• peri-natal: passage through infected birth canal
• Eye mucous membrane: conjunctivitis

Question 2

What bacteria causes gonorrhoea?

Answer 2

• Neisseria gonorrhoeae= Gram negative

- N. meningitidis= non-pathogenic neisseria species

Question 3

What type of cells does gonorrhoea infect? Where does it affect?

Answer 3

• Columnar/cuboidal epithelium

- GU tract, rectum, oropharynx

Question 4

What are the 3 layers of gram negative bacteria cell envelopes?

Answer 4

• Outer cytoplasmic membrane
• Thin peptidoglycan cell wall
• Inner cytoplasmic membrane

Question 5

What are complications of gonorrhoea?

Answer 5

• Local: epididymitis, prostatitis, barthonilitis, PID, peritonitis
• Metastatic: disseminated gonococcal infection
• pregnancy: premature labour, conjunctivitis in foetus (can lead to blindness), spent abortion

Question 6

How is gonorrhoea diagnosed & treated?

Answer 6

• D: Culture, NAAT (PCR), microscopy

- T: β-lactams, cephalosporins, fluoroquinolones

Question 7

What pathogens cause non-gonococcal urethritis?

Answer 7

• Chlamydia trachomatis
• Ureaplasma urealyticum (mycoplasma genitalium)
• Treat with doxycycline, macrolides

Question 8

What 2 bodies does chlamydia trachomatis form? What cells does it target?

Answer 8

• 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

Question 9

What are complications of chlamydia?

Answer 9

• PID
• Epididymitis
• Infant: pneumonia, conjunctivitis
• Reiter’s syndrome: skin lesions, urethritis, arthritis, conjunctivitis

Question 10

Describe HPV

Answer 10

-HPV6,11= genital warts/Condylomata accuminata
-HPV 16,18= cervical carcinomas
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Question 11

What is the clinical presentation of genital herpes?

Answer 11

• Pain
• Itching
• Dysuria
• Vaginal/urethral discharge
• Bilateral vesicles/ulcers-viral shedding

Question 12

What is the main cause of genital herpes?

Answer 12

• Herpes simplex types 1&2

- Double stranded DNA viruses

Question 13

What are complications of genital herpes?

Answer 13

• Dissemination
• Meningitis
• Encephalitis
• Sacral nerve parasthesiae
• Urinary retention

Question 14

Describe syphilis

Answer 14

• Spirochaete=Treponema pallidum
• slender, helical, tightly coiled cells
• Penetrates intact mucous membranes/abraded skin
• Disseminated within days via lymphatics/bloodstream
• Histology=obliterative endarteritis

Question 15

What are the symptoms of syphilis?

Answer 15

• Rash= macular/maculopapular, trunk, limbs-palms/soles
• Condylomata lata= warm body areas, highly infectious, erythematous plaques
• Headache
• Generalised lymphadenopathy
• Fever, malaise, weight loss
• Meningismus

Question 16

What are symptoms in the third stage of syphilis?

Answer 16

• 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)

Question 17

What are early & late signs of Spirochaetaemia in early syphilis?

Answer 17

• E: snuffles, rash, hepatosplenomegaly

- L: frontal bosses, saddle nose, sabre shins, Hutchinson’s incisors

Question 18

How is syphilis diagnosed& treated?

Answer 18

• D-Indirect tests: Specific= anti-treponemal antibodies EIA, FTA non-specific= VDRL, RPR tests
• T-Penicillin (Jarish-Herxheimer reaction), amoxicillin, doxycycline, ceftriaxone

Question 19

Describe trichomoniasis

Answer 19

• Trichomonas vaginalis protozoan (lacks mitochondria)
• Trophozoite transmission
• Humans only natural host
• Mucosal inflammation
• Profuse greenish frothy vaginal discharge

Question 20

Describe bacterial vaginosis

Answer 20

• Anaerobic
• Reduced vaginal lactobacilli
• Increased gardnerella vaginalis & anaerobes
• Watery discharge
• Amoxicillin, topical clindamycin, metronidazole

Question 21

Describe candidiasis

Answer 21

• 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

Question 22

What is viral glycoprotein gp120?

Answer 22

-Interacts with cellular receptor CD4 & chemokine receptor CCR5 for virion to gain host cell entry

Question 23

Where does reverse transcription occur?

Answer 23

Cytoplasm

Question 24

What are the 4 stages of CD4 count?

Answer 24

1: >500
2: 350-500
3: Advanced HIV 200-350
4: AIDS

Question 25

What are the early symptoms of HIV?

Answer 25

• Pulmonary TB
• Persistent oral candidiasis
• Unexplained persistent fever/ chronic diarrhoea
• Severe bacterial infections

Question 26

What is the primary HIV infection known as?

Answer 26

• Acute retroviral syndrome

- Fever, pharyngitis, lymphadenopathy, rash

Question 27

What opportunistic infections are linked to AIDS?

Answer 27

• HIV wasting syndrome & encephalopathy
• Pneumonia
• CMV disease
• CNS toxoplasmosis
• Extra pulmonary TB
• Lymphoma & kaposi’s sarcoma
• Disseminated non-TB mycobacterial disease
• Chronic cryptosporidiosis