50 - HIV and STIs Flashcards Preview

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Flashcards in 50 - HIV and STIs Deck (66):
1

in utero transmission

Trans placental

2

Peri-natal transmission

Passage through infected birth canal

3

Eye mucous membrane transmission

Conjunctivitis
Keratitis

4

Gonorrhoea - disease causing organism

Neisseria gonorrhoeae
Gram --ve coccus

5

Gonorrhoea - pathogensis

Pili on cell surface become virulent.

Ability to attach to mucosal epithelial cells

Primarily infect columnar/cuboidal epithelium

6

Gonorrhoea - where? incubation?

GU tract, rectum, oropharynx

2-5 days incubation

7

Gonorrhoea - presentation

60% women are asymptomatic

Urethral discharge

8

Gonorrhoea - local complications

Lots of -itis

Metastatic: disseminated gonococcal infection (DGI)

Bacteraemia, arthritis, dermatitis (meningitis)

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Gonorrhoea - microscopy

Urethral swab (male)
Endocervical (not high vaginal).

Culture created and tested for resistance.

PCR sometimes too

10

Gonorrhoea - treatment

B-lactams
Cephalosporins
Fluoroquinolones

11

Chlamydia - incubation, name type

Types D-K
1-2 weeks incubation period

Type of non-gonococcal urethritis

12

Chlamydia - diagnosis

NAAT for chlamydia

13

Chlamydia - target cells

Squamocolumnar epithelial cells of endocervix

Also, conjunctiva, urethra and rectum for M+F

14

Chlamydia - presentation

Often asymptomatic (f>M)

Urethritis - less purulent discharge then gonococcal

Cervicitis - mucopurulent

May have dysuria/frequency

15

Chlamydia - complications

PID (pelvic inflammatory disease (9.5% w/o Rx)
Tubal infertility (10.6%), ectopic pregnancy, chronic pain

Epididymitis (2%)

Neonatal + infant get conjunctivitis + infant pneumonia

Conjunctivitis
Reiter's syndrome: arthritis, conjunctivitis, urethritis, skin lesions

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Chlamydia - diagnosis

Histology
Cell culture

NAAT (superseded EIA)
99.7%

Serology

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Chlamydia - treatment

Azithromycin
Doxycycline

Paediatric: conjunctivitis, pneumonia, erythromycin (14 days)

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HPV - why important

12 high risk types are causally associated with cancer

19

HPV 6,11

90% genital warts

20

HPV 16, 18

Cervical carcinomas

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Gardasil

Vaccine for HPV 6, 11, 16, 18

22

Genital herpes -

Double stranded DNA viruses
HSV-2 more common in women than man

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Genital herpes - presentation

Pain, itching, dysuria, vaginal/urethral discharge

Bilateral vesicles / ulcers with viral shedding

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Genital herpes - pathogenesis

Latency - sensory neuron cells (sacral nerve ganglia)

Reactivated by: local trauma, menstruation, stress

25

Genital herpes - diagnosis

Clinical
PCR (HSV 1 or 2)
Histology

26

Genital herpes - treatment

Acyclovir (primary or recurrence)

If frequent consider suppression

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Genital herpes - complications

Dissemination
Meningitis
Encephalitis
Sacral nerve parasthesiae
Urinary retention

28

Syphilis - caused by

Spirochaete, Treponema pallidum

29

Syphilis - pathogenesis

Penetrates intact mucous membranes, disseminated within days via lymphatics/bloodstream

30

Syphilis - histology

Obliterative endarteritis (microvascular compromised)

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Syphilis - incubation time

21 days

32

Syphilis - primary chancre

Site of inoculation, painless indurated lesion

Heals spontaneously within 3-6 weeks

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Syphilis - secondary chancre

2-8 weeks post onset

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Syphilis - clinical presentation

Skin - rash, condylomata lata, mucous patches

Constitutional symptoms - fever, malaise, weight loss

Generalised lymphadenopathy

CNS involvement (40%), headache, meningismus

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Syphilis - prognosis and treatment

Spontaneous resolution 3-12 weeks

Latent: no clinical manifetation, positive serology

W/o treatment: 30% will develop late w/ tertiary syphilis

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Syphilis - tertiary

Neurosyphilis - meningovascular (hemiplegia, seizures)

Parenchymatous - paresis of cortex - personality, argyll robertson pupils

Tabes dorsalis - spinal cord - demyelinisation of cord, lightening pain in legs, loss of position/vibratory sense

CVS - aortic regurg, saccular aneurysm

Late benign syphilis - non-specific granulomatous rxn

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Argyll robertson pupils

Accommodate to near vision

Don't react to light

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Syphilis - neonates

Early signs: snuffles, rash, hepatosplenomegaly

Late: frontal bosses, saddle nose, sabre shins. Hutchinson's incisors

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Syphilis - diagnosis

Lack of culture
Direct detection by darkfield microscopy

PCR more sensitive than microscopy

40

Syphilis - indirect tests

Serology - specific: anti-treponemal antibodies

Non-specific: reaginic antibodies vs lipoidal antigens

41

Syphilis - treatment

Penicillin
Length/route IM IV

Jarish-Herxheimer rxn: commonest in 2* syphilis, fever, chills, myalgia, hypersensitivity rxn, self-limiting

Alternatives: amoxicillin, ceftriaxone, doxycycline

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Trichomoniasis - causative organism

Trichomonas vaginalis

Protozoa - lacks mitochondria

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Trichomoniasis - clinical presentation

Profuse greenish frothy vaginal discharge

Mucosal inflammation

Males may have urethritis but usually asymptomatic

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Trichomoniasis - diagnosis

Microscopy/culture (high vaginal swab)

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Trichomoniasis - treatment

Metronidazole

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Bacterial (anaerobic) vaginosis (BV) -

Reduced vaginal lactobacilli

Increased gardnerella vaginalis & anaerobes

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Bacterial (anaerobic) vaginosis (BV) - clinical presentation

Watery discharge
+ve KOH test (fishy odour)

Vaginal pH >4.5
Clue cells on microscopy

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Bacterial (anaerobic) vaginosis (BV) - treatment

Amoxycillin

Topical clindamycin

49

Candidiasis - two types

Thrush
Balanitis

50

Candidiasis - risk factors

Oral contraceptives, poorly controlled diabetes

Antibiotics - inhibition of normal flora

51

Candidiasis - clinical presentation

Vulval, vaginal and penile erythema w/ itching and irritation

Classically: thick/adherent discharge and white plaques

Maculopapular & fissuring lesions

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Candidiasis - investigations

Microscopy (10% KOH)

Culture

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Candidiasis - causative agent

Candida albians 85% cases - more susceptible but low risk of recurrence

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Candidiasis - uncomplicated

C albicans
Topical - clo-trimazole (Canesten)
Fluconazole: single 150mg oral dose

55

Candidiasis - complicated

Treatment for 10-14 days

Consider partner treatment

Long term suppressive if freq.

56

HIV - causative organism

Retrovirus - possesses reverse transcriptase script

converts viral RNA into linear DNA which is incorporated into host genome

error prone so high mutability rate

57

HIV - why causative organism so hard to fight

RNA-based means survival advantage with great genetic diversity

DNA intermediary - latent and can incorporate into host genome

CD4/macrophage tropic - reduction of host immune response

58

HIV - transmission routes

Sexual- genital or colonic mucosa

Infected fluid - blood

Mother to infant

59

HIV - how does it gain entry?

Viral glycoprotein gp120

Interacts w/ CD4 and chemokine receptor for virion to gain entry

60

HIV - WHO classification

Stage 1 - CD4 >500 cells/uL
Stage 2 - 349-499
Stage 3 - 200-349 (adv. HIV)
Stage 4

61

HIV - primary infection clinical presentation

Acute retroviral syndrome - fever, pharyngitis, lymphadenopathy, rash

Asymptomatic

Early: pulm TB, persistent oral candidiasis, chronic diarrhoea, persistent fever, severe bacterial infections

62

HIV - AIDS clinical presentation

HIV wasting syndrome (HIV encephalopathy)

Oesophageal candidiasis
Pneumocystis jirovecii pneumonia
CMV
CNS toxoplasmosis
Progressive multifocal leukoencephalopathy (PML)
Extra-pulm TB
Disseminated non-TB mycobacterial disease
Chronic cryptosporidiosis
Kaposi's sarcoma, lymphoma

63

HIV - diagnosis

25% undiagnosed

Universal testing - GUM clinics w/ TB or lymphoma. Also antenatal

64

HIV - investigations

Antibody testing

PCR - detects viral nucleic acid + copy #, genotypic mutations conferring drug resistance

65

HIV - treatment (drug types used)

Nucleoside reverse transcriptase inhibitors

Non-nucleoside reverse transcriptase inhibitors

Protease inhibitors (ritonavir)

Viral entry inhibitors

Integrase strand transfer inhibitors

66

HIV - treatment (methods)

Combinations
Highly active antiretroviral therapy (HAART)

Guidelines

Prophylaxis vs opportunistic infections

Decks in Clinical Pathology Class (65):