WK 8- STI's Flashcards

1
Q

What is the most common STI in NQLD

A

Chlamydia

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2
Q

What pathogen causes chlamydia

A

Chlamydia trachomatis

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3
Q

What are the 3 different serotypes of chlamydia and what do each cause

A
  1. A, B & C – trachoma→ eye discharge, swollen eyelids, lymphadenopathy, photosensitivity
  2. D – K – genital infection & associated ocular and respiratory infections (particularly in newborns)→ pain on urination, penile and vaginal discharge, menstrual changes
  3. L1, L2 & L3 – LGV (systemic disease- Lymphogranuloma Venereum (Small, asymptomatic skin lesion followed by regional painful lymphadenopathy → systemic Disease)→ painful bowel movements, painless sores, lymphadenopathy
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4
Q

How is chlamydia transmitted

A

primarily sexually transmission→ enter through microabrasions in the mucosa (newborn can also get infected during birth

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5
Q

Is chlamydia intracellular or extracellular

A

Intracellular

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6
Q

What is the lifecycle of chlamydia

A
  • has 2 stage life cycle
  • Elementary body attaches and enters the cytoplasm of a susceptible host epithelial cell→ once attached to the cell it is taken up by an endosome→ once in endosome will form a reticulate body→ reticulate body will then undergo division and transform back to elementary bodies→ elementary bodies are then released from the infected cell and continue to infect other cells
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7
Q

How does a chlamydia infection spread within the body

A

Local infection – spread to adjacent cells when EBs released from infected cells
-May spread to distant sites via lymphatic system or blood

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8
Q

What are the symptoms of chlamydia

A
  • Conjunctivitis from chlamydia= adults (autoinoculation), neonates (acquired during birth)
  • Pneumonia= neonates inhale sexual fluid
  • Pharyngitis, Proctitis, Reactive arthritis, Perihepatitis, LGV (lymphogranuloma venereum)
  • In females→ Cervicitism (purulent endocervix), Crampy abdo pain, Menstrual changes, Pain on urination, Bleeding/spotting, Pain during or after sex, Change in vaginal discharge
  • In males→ Urethritis (non-gonorrheal uthritis), Epididymitism Prostatitis, Penile discharge, Pain on urination, Swollen & sore testes Proctitis – genital serovars or LGV serovars
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9
Q

What is the pathogenesis of symptoms in chlamydia

A

Clinical symptoms result from cell destruction and host inflammatory cell response

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10
Q

What serious complications arise from chlamydia

A

-Most are asymptomatic
Women→ PID, infertility, chronic pain, ectopic preg, neonatal infections
Men→ inflammation of testicles, infertility, chronic infection of urethra

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11
Q

What is lymphogranuloma vereneum

A
  • Genital ulcer disease with lymphadenopathy (due to spread to lymphatics)
  • Caused by L1, L2 & L3 serovars of C trachomatis
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12
Q

What pathogen causes gonorrhoea

-structure

A

Neisseria gonorrhea

-gram negative coccus (diploccoci) (gonococcus

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13
Q

What is the pathogenesis of gonorrhoea

4 stages of infection

A
  1. Attachment to host’s mucosal surface (by ‘pili’)
  2. Local penetration or invasion→ Engulfed by parasite-directed endocytosis
  3. Local proliferation
    → N gono multiply within intracellular vacuoles
    → Protected from host immune response
  4. Local inflammatory response or dissemination
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14
Q

How does gonorrhea cause symptoms/damage

A

Damage results from gonococcal-induced inflammatory responses

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15
Q

What are the 7 virulence factors of gonorrhoea

A
  • Pili – attachment to mucosa (allow it to not be washed away by urine/vaginal secretions & antigenic diversity
  • Por proteins – specific serotypes associated with virulence
  • Opa proteins – binding
  • Lipooligosaccharide – endotoxin activity
  • RMP proteins – inhibit bacteriocidal activity of serum
  • IgA protease – destroys IgA1
  • Capsule – resists phagocytosis
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16
Q

What complications can arise from gonorrhoea (male, female, MSM, neonates)

A

Complications in females→ PID (10-20% of untreated cases), Chronic pelvic pain, Infertility, Disseminated infection (1-3%)
Complications in males→ Rare
-Neonates→ Eye infection, Pharyngitis
-MSM→ Anorectal infection & Proctitis, Purulent discharge, MSM Joint infections Perihepatitis

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17
Q

What invasive infections can result from a gonorrhea infection

A

Invasive infections uncommon, but include disseminated gonococcal infection, endocarditis & meningitis, joint infections

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18
Q

What 2 antibiotics has gonorrhea shown resistance/developing resistance too

A

penicillins→ also emerging to cephalosporins

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19
Q

What symptoms accompany gonorrhoea

A

Males→ Infection is usually symptomatic, Urethral discharge, urethritis, Dysuria, epididymititis
Females→ 50% female cases mild or asymptomatic but still infectious (major reservoir of infection), Vaginal discharge, cervicitis, anorectal infection

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20
Q

What lab diagnostic tests are used from chlamydia and gono diagnosis

A
  1. PCR→ dry swabs only→ do genital, rectal, throat or eye swab→ rapid and reliable
  2. Urine for PCR→ good detection for STI as urethra often also gets colonized→ first catch is best
  3. Bacterial swab (swab of discharge) is also useful to grow the organism and allow you to determine if the organism is developing antibiotic resistance
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21
Q

What pathogen causes trichomoniasis

A

Trichomonas vaginalis

-protozoan parasite that has a flagella

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22
Q

What is the lifecycle of trichomoniasis

A

resides in female lower genital tract and male urethra/prostate→ no cyst form but replicates via binary fission

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23
Q

Without tx, how long can a trichomoniasis infection persist for

A
  • without treatment the infection can last for months/years

- in males is transient and only lasts a few weeks

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24
Q

What symptoms accompany trichomoniasis

A

vaginitis, frothy discharge in heavy infections, urethritis, infertility, ectopic pregnancy, pre-term delivery

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25
Q

What tests are used to diagnosis trichomoniasis

A

PCR with urine or a swab, can also be seen on a wet prep

  • PCR is highly sensitive and specific and can screen large numbers of specimens rapidly
  • Wet prep for T vaginalis→ smear on glass slide, add sterile saline, examine for motile trophozites
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26
Q

What is mycoplasma genitalum

-What is the pathology

A
  • Newly discovered STI which can be carried asymptomatically
  • attaches to mucosa an invades cells via adhesions→ can change antigens on it’s surface to manipulate the immune response
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27
Q

How is mycoplasma genitalum diagnosed

A

lab diagnosis using swab or urine for PCR

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28
Q

What is the treatment for mycoplasma genitalum

A

azithromycin→ increasing concern over possible emergence of antibiotic resistance

29
Q

What is the pathogen that causes syphilis

A

treponema pallidum

-it is a spirochaete

30
Q

How is syphilis transmitted

A

gains access to tissue via microabrasions in the mucosa

-most are acquired sexually, but can be transmitted vertically (from mother to child)

31
Q

What is the pathophysiology of syphilis

A
  • Evades the host immune system

- Has initial immune control but widespread dissemination still occurs leading to subsequent clinical manifestations

32
Q

what are the three stages of syphilis symptoms

A

primary, secondary, late

33
Q

What are the symptoms present in primary syphilis

A
  • Occurs 10-90 days after contact with infected individual
  • Commonly manifests on glans penis or vulva/cervix
  • Chancres: erythematous papules→erodes → central ulcer with slightly elevated edges
  • Resolves within 4-8wks with/without treatment
34
Q

What are the symptoms with secondary syphilis

A

-Commonly presents as mucocutaneous rash on soles and palms 2-10wks after first chancre – nonpruritic, bilateral + lymphadenopathy + malaise (general flu-like symptoms)

35
Q

What are the symptoms with tertiary syphilis

A

Manifest in different ways: Impaired balance, paresthesias, incontinence, impotence, tumours, periarteritis, endoarterities, Focal neurologic findings→ Dementia
Chest pain, back pain, stridor

36
Q

What is the pathogen responsible for donovanosis

A

Klebsiella granulomatis

37
Q

Where is donovanosis common

A

PNG, central america, sth africa

38
Q

What is the lab dx for donovanosis

A

Swab for PCR

39
Q

What is the tx for donovanosis

A

Cotrimoxazole, Doxycycline If untreated can cause chronic infection & scarring

40
Q

What are signs of congenital syphilis

A
  • appear within the first 5 wks of life→ include cutaneous lesions, jaundice, anemia, snuffles, hepatosplenomegaly, metaphyseal dystrophy and periostitis
  • Late manifestations: frontal bossing, short maxilla, interstitial keratitis, saddle nose
41
Q

In AUS, who is most at risk of contracting syphilis

A

ATSI men and women, individuals who have partners from high prevalence countries, MSM, those with HIV

42
Q

What types of human herpes virus are slow growing and found in lymphocytes

A

CMV, EBV, HHV-6, HHV-7, HHV-8

43
Q

What type of human herpes virus is lytic (fast growing) and found in neurons

A

HSV (herpes simplex virus) and VZV (varicella zoster virus)

44
Q

How is CMV (cytomegalovirus) transmitted

A

Saliva, Urine, Blood (need to screen in blood donors and organ donors), Transplanted organs, Semen & cervical secretions
-Virus may be shed intermittently

45
Q

What are the symptoms of CMV

A

Infection:

  • usually asymptomatic→ mild flu-like symptoms (fever, lethargy), mononucleosis syndrome
  • immunosuppression allows for reactivation of CMV
46
Q

Who are most at risk of severe symptoms from CMV

A

Immunocompromised and pregnant

47
Q

What is the pathogenesis of CMV and re-infection

A

CMV inhibits T cell responses–> initially controlled by cell mediated immunity but when immunosuppressed the virus can re-emerge

48
Q

What symptoms can arise in a fetus who’s mother becomes infected with CMV

A

IUGR (intrauterine growth restriction), microcephaly, thrombocytopaenia, hepatosplenomegaly, mental retardation, etc

49
Q

What symptoms occur in immunocompromised pt who gets infected with CMV

A

primary CMV infection serious & can be lethal in immunocompromised→ Often associated with organ rejection→ can cause pneumonia, or in those with HIV can cause retinitis/colitis

50
Q

How is CMV treated

A

gancylovir

51
Q

What is the pathology of EBV

A
  • Infects B cells
  • Infected B cells are often cleared by the host, but some B cells can be immortalised and act as a reservoir (oncogenic virus)
52
Q

What are the symptoms of EBV

A

symptoms are immune mediated
-include a self limited illness including fever, sore throat, lymphadenopathy, anorexia, splenomegaly and lethargy (glandular fever)

53
Q

What complications arise from EBV and why

A

After many decades (40-60yrs):

  • Nasopharyngeal carcinoma (EBV associated with 100% cases)
  • Hodgkin’s lymphomas (EBV associated with 50% cases)
  • Gastric carcinomas (EBV associated with 10% cases)
  • Endemic Burkitt’s Lymphoma – B-cell malignancy due to chronic infection of B cells (EBV associated with 100% cases)
54
Q

How is EBV diagnosed

A

Atypical lymphocytes seen in blood film

  • Detection of heterophile antibodies (“Monospot” test)→ RBC agglutination test
  • Serology for IgM and IgG
55
Q

What symptoms arise from a HHV-7 infection

A

-Asymptomatic or acute febrile respiratory disease +/- rash

exanthem subitum, pityriasis rosea, neurological manifestations & transplant complications

56
Q

What cell does HHV-7 reside in

A

T cells

57
Q

What is HHV-8 also called

A

Kaposi’s sarcoma-associated herpes virus (KSHV)

58
Q

What cell does HHV-8 reside in

A

lymphocytes

59
Q

What symptoms arise from HHV-8 infeciton

A

violaceous vascular lesions on skin, mucous membranes and/or viscera (e.g., GI tract, lungs)

60
Q

What disease does HHV-5 cause

A

CMV

61
Q

What disease does HHV-4 cause

A

EBV

62
Q

What is the gold standard of testing for syphilis

A

Serology

63
Q

What are the two serological tests for syphilis

A

Treponemal (specific for syphilis) and non-treponemal (not specific for syphilis but almost always positive in a syphilis diagnosis)

64
Q

What are the 3 types of treponemal tests and explain how each works

A

Total antibody test: screening assay for qualitative measurement of Ab to T pallidum in serum
TPPA/TPHA: Treponema pallidum particle agglutination assay / Treponema pallidum haemagglutinin assay→ detects antibodies against T pallidum
FTA→ Fluorescent treponemal antibody absorption test- add patient serum and fluorescence→ if organism is present then slide will fluoresce

65
Q

What are the advantages and disadvantages of treponemal testing

A

-Advantages of treponemal tests: specific and syphilis can remain positive for years even after antibiotic tx
Disadvantages: can’t be used to follow tx efficacy

66
Q

What Ig is looked for in a baby of a syphilis positive mother

A

IgM

67
Q

What are the 3 types of non-treponemal tests and how do they work

A

RPR: Rapid Plasma Reagin test→ measures anti-lipoidal anibotides→Patient serum is mixed with RPR antigen suspension (containing charcoal particles)
VDRL: Venereal Disease Research Laboratory test) Detects antibodies against lipoidal material→ only used for CSF for syphilis

68
Q

What are the disadvantages and advantages of non-treponemal tests

A

Advantages: Positive at 4-6 weeks post infection-Useful for monitoring progress of disease & therapy
Disadvantages: Not specific for syphilisNote: Positive results may occur when tissue damage has occurred due to other processes e.g. old age, lepto, pregnancy, autoimmune diseases, tuberculosis, malaria, etc (“biological false positive”)

69
Q

What is the most effective test for clarifying whether the ulcer on a patient is due to syphilis, herpes or donovanosis

A

A PCR