Endo Flashcards
1
Q
STDs
A
- Genital discharge of urethritis in men due to N gonorrhoeae, C trachomatis, and Ureaplasma urealyticum
- Endocervicitis in women caused by N gonorrhoeae and C trachomatis
- Genital sores associated with herpes simplex, less commonly syphilis or chancroid, uncomonly lymphogranuloma venereum
2
Q
Neisseria gonorrhoeae
A
- Aerobic, Gram-negative, diplococci (resemble coffee beans)
- All species are oxidase POSITIVE and most are catalase POSITIVE
- Grow it on Chocolate Agar
- Lack of immunity to reinfection: antigenic variation among the pilin proteins and phase variation in Pilin expression
- Gonorrhea occurs naturally only in humans and is transmitted primarily via sexual contact
- N gonorrhoeae is a leading cause of purulent arthritis in adults
- Stained smear of a urethral or a cervical exudate that shows Intracellular Gram negative diplococci is strongly suggestive of Gonorrhea
- Sensitivity is only 50% in women (90% in men), so get a nucleic acid amplification test in addition to the stained smear
- Table 29-1 (murray p.294) for virulence factor info (Pilin, Por protein, Opa protein, Rmp protein, Transferrin-binding proteins, Lactoferrin-binding proteins, Hemoglobin-binding proteins, LOS, IgA1 protease, B-Lactamase)
3
Q
Treponema
A
- T pallidum are thin, tightly coiled spirochetes with pointed, straight ends
- Three periplasmic flagella are inserted at each end
- Anaerobic and are extremely sensitive to oxygen toxicity
- Catalase NEGATIVE and Superoxide Dismutase NEGATIVE
- Clinical course evolves through 3 phases:
1) Primary phase: characterized by one or more skin lesions (chancres) at the site where the spirochete penetrated
2) Secondary phase: Disseminated disease, with prominent skin lesions dispersed over entire body surface
3) Late phase: Virtually all tissues may be involved (granulomatous lesions (Gummas) may be found in bone, skin, and other tissues) - Natural syphilis is exclusive to humans and has no other known natural hosts
- Dark-field or immunofluorescence examination of tissue fluid expressed from the base of the chancre may reveal typical T pallidum
- A positive treponemal antibody test, T pallidum particle agglutination, or the newer Treponema EIAs and chemiluminescence assays PROVES syphilitic infection
- Penicillin is drug treatment of choice (Tetracycline and doxycycline if penicillin allergy)
- Penicillin is the only thing used for neurosyphilis and pregnant women regardless of allergies
4
Q
Urethritis, Endocervicitis, and Pelvic Inflammatory Disease (Case 12)
A
“A 19 y.o. woman came to the clinic because of lower abdominal pain of 2 days’ duration and a yellowish vaginal discharge first seen 4 days previously on the day following the last day of her menstrual period. The patient had had intercourse with two partners in the previous month, including a new partner 10 days before presentation.”
- Yellowish micropurulent discharge from cervical os
- Mild fever
- Cervical motion tenderness and adnexal tenderness more severe on left than right (via bimanual exam)
- Nucleic acid amplification test that detects N gonorrhoeae and C trachomatis performed on cervical swab is positive for C trachomatis
- Diagnosis: Pelvic Inflammatory Disease (PID)
- Treatment: Single IM dose of ceftriaxone plus doxycycline for 2 weeks
5
Q
Pelvic Inflammatory Disease (PID)
A
- AKA salpingitis
- Inflammation of uterus, uterine tubes, and adnexal tissues that is not associated with surgery or pregnancy
- Major consequence of endocervical N gonorrhoeae and C trachomatis infections
- Lower abdominal pain is the common presenting symptoms
- Major complication of PID is infertility due to uterine tubal occlusion
6
Q
Genital Sores (Case 14)
A
“A 21 y.o. man came to the clinic with a CC of a sore on his penis. The lesion began as a papule about 3 weeks earlier and slowly progressed to form the ulcer. It was painless, and the patient noticed no pus or discharge from the ulcer. The patient was seen previously because of a STD and was suspected of trading drugs for sex.”
- 1-cm ulcer on left side of penile shaft
- Ulcer had clean base and raised borders with moderate induration
- Little pain on palpation
- Left inguinal lymph nodes 1-1.5 cm in diameter were palpable
- Multiple spirochetes were seen after dark-field microscopy
- Rapid plasma reagin (RPR) screening serologic test for syphilis was positive at 1:8 dilution
- Confirmatory treponeme-specific fluorescent treponemal antibody-absorbed (FTA-ABS) test was also positive
- Treatment: Single dose of benzathine penicillin
7
Q
Other Treponemes
A
- Other 3: endemic syphilis (bejel), yaws, pinta
- Endemic syphilis caused by subspecies endemicum (caused by direct contact or via contaminated eating utensils)
- Oral papules and mucosal patches
- Present in desert and temperate regions of N. Africa and Middle East and is primarily disease of children
- T. pertenue is etiologic agent of yaws, a granulomatous disease in which patients have skin lesions early in the disease and then late destructive lesions of the skin, lymph nodes, and bones (spread by direct contact with infected skin lesions)
- Present in S. America, Central Africa, and Indonesia
- T. carateum causes pinta, a disease that primarily affects the skin
- Small pruritic papules develop on the skin surface after 1-3 wk incubation
- These lesions enlarge and persist for months to years before resolving (scarring and disfigurement)
- Tropical areas of Central and S. America and is spread by direct contact with infected lesions, and is a disease of young adults
8
Q
Chlamydia trachomatis
A
- Small, Gram negative rods w/ no peptidoglycan layer in cell wall
- Obligate intracellular parasites that have a unique developmental cycle, forming metabolically inactive infectious forms (elementary bodies [EBs]) and metabolically active, noninfectious forms (reticulate bodies [RBs])
- Elementary bodies penetrate (because they’re infectious) and once inside turn into reticulate bodies (because these can replicate)
- Energy parasites because they use the host ATP
- Infection doesn’t confer long-lasting immunity; rather it induces a more vigorous inflammatory response that can lead to vision loss and/or scarring with sterility and sexual dysfunction
- Trachoma is the LEADING CAUSE of PREVENTABLE BLINDNESS***
- C. trachomatis is thought to be the MOST COMMON sexually transmitted bacterial disease in the United States
- Diagnose with Nucleic acid amplification tests (NAATs)
- Treatment: Doxycycline (Erythromycin for children or pregnant women)
9
Q
Clinical Diseases of C. trachomatis
A
Trachoma***
- A chronic disease that initially presents with follicular conjunctivitis with diffuse inflammation that involves the entire conjunctiva (conjunctiva become scarred as the disease progress, causing patient’s eyelid to turn inward)
- This inward turn of the eyelid makes eyelashes abrade cornea, eventually resulting in corneal ulceration, scarring, pannus formation, and blindness
Lymphogranuloma Venereum***
- Primary lesion appears at site of infection (penis, urethra, glans, scrotum, vaginal wall, vervix, vulva)
- The lesion (either a papule or an ulcer) is small, painless, and heals rapidly
- Second stage of infection is marked by inflammation and swelling of lymph nodes (become buboes) draining the site of initial infection
- Proctitis is common in women with LGV, resulting from lymphatic spread form the cervix or vagina
Adult Inclusion Conjunctivits
- Mucopurulent discharge, keratitis, corneal infiltrates, and occasionally some corneal vascularization
Neonatal Conjunctivitis
- Eye infection in infants exposed to C. trachomatis at birth
- Eyelids swell, hyperemia occurs, and copious purulent discharge appears
- Conjunctival scarring and corneal vascularization
Infant pneumonia
- Rhinitis is initially observed in such infants, after with a distinctive staccato cough develops
Urogenital infections
- Reiter syndrome (urethritis, conjunctivitis, polyarthritis, and mucocutaneous lesions) is initiated by genital infection with C. trachomatis
- Usually occurs in young white men
10
Q
Haemophilus ducreyi
A
- Gram-negative rods that causes chancroid
- Specimens for the detection of H ducreyi should be collected with a moistened swab from the base or margin of the ulcer
- Fastidious and require specialized growth conditions (gonococcal (GC) agar supplemented with hemoglobin, fetal bovine serum, IsoViteleX enrichment, and vancomycin)
Treatment: Erythromycin
11
Q
Candida
A
- Candida albicans is an oval yeast with a single bud
- A part of the normal flora of mucous membranes of the female genital tract
- Carbohydrate fermentation differentiate it from other Candida species (Also forms Germ tubes)
- Vaginitis with itching and discharge is favored by pregnancy, oral contraceptive use, high pH, diabetes, or use of antibiotics (because antibiotics suppress normal flora Lactobacillus, which keep pH low)
- Vaginal pruritus is the most common and specific symptom
- Can see discharge that may resemble “cottage-cheese”
- Very rarely has smell (that’s bacterial rather than yeast)
- If immunocompromised, Candida can disseminate to many organs or cause chronic mucocutaneous candidiasis (CMC)
- Appear Gram-positive and can be visualized using calcofluor-white staining (adding KOH improves microscopy sensitivity and specificity)
- Treatment: topical (intravaginal) azole drugs such as clotrimazole or miconazole, or with oral fluconazole (unless pregnant)
12
Q
Trichomonas vaginalis
A
- A flagellate with four flagella and a short, undulating membrane that are responsible for motility
- Exists only as a trophozoite and found in urethras and vaginas of women and urethras and prostate glands of men
- Sexual intercourse primary mode of transmission
- Most infected women are asymptomatic or have a scant, watery vaginal discharge (but vaginitis can occur)
- Strawberry cervix with inflammatory cells
- Men are primarily asymptomatic carriers who serve as a reservoir for infections in women
- Treatment: Metronidazole (recently, tinidazole approved by FDA)
13
Q
HSV-2
A
- Pathogenesis is the same as HSV-1; infect, replicate in mucoepithelial cells, cause disease at the site of infection, and then establish latent infection of innervating neurons
- Cowdry type A acidophilic intranuclear inclusion bodies are produced
- CD8 T cells and interfereon gamma are important to maintain HSV in latency
- Reactivation can by unapparent or may produce vesicular lesions (which contain infectious virions)
- Reactivation caused by various stimuli occurs via promoting replication of the virus in the nerve, by transiently depressing cell-mediated immunity, or by inducing both
- Enveloped virus and thus transmitted in secretions and by close contact
- Classic manifestation is that of a clear vesicle on an erythematous base (dewdrop on a rose petal) and then progresses to pustular lesions, ulcers, and crusted lesions
- Can cause significant morbidity and mortality on infection of the eye or brain and on disseminated infection of an immunosuppressed person or a NEONATE (because no cell-mediated immune response)
- Neonatal infection usually results from the excretion of HSV-2 from the cervix during vaginal delivery (prevent via cesarean section)
- Diagnose via Tzanck smear or Pap smear*
- Treatment: Acyclovir
14
Q
Cytomegalovirus
A
- Most common viral cause of congenital defects***
- Congenital defects include small size, thrombocytopenia, microcephaly, intracerebral calcification, jaundice, hepatosplenomegaly, and rash (cytomegalic inclusion disease)
- Unilateral or bilateral hearing loss and mental retardation are common consequences of congenital CMV infection (mom harbors in cervix at term)
- Highly cell-associated and is spread throughout the body within infected cells, especially lymphocytes and leukocytes
- An opportunistic disorder, rarely causing symptoms in the immunocompetent host but causing serious disease in an immunosuppressed or immunodeficient person (AIDS or neonate)
- Disease of the lung in immunocompromised patients often leads to pneumonia (most common manifestation)
- CMV is responsible for the failure of many kidney transplants
- A sexually transmitted disease
- Patients may show a heterophile-negative mononucleosis syndrome*
- Histologic hallmark: Cytomegalic cell which is enlarged with a dense, central “owl’s eye” basophilic intranuclear inclusion body
- Treatment: Ganciclovir, valganciclovir, cidofovir, and foscarnet
15
Q
Human Papilloma Viruses (HPV)
A
- Cause warts and several genotypes are associated with cancer (e.g. cervical carcinoma)
- Icosahedral capsid; HPV genome is CIRCULAR ds DNA
- HPV replication is controlled by the host cell’s transcriptional machinery
- Accesses basal cell layer through break in skin, early genes stimulate cell growth, this facilitates replication of viral genome by host cell DNA pol when cells divide, and finally this increase in cell number causes the basal and stratum spinosum to thicken (wart or papilloma)
- HPV-16 and HPV-18 cause CERVICAL CARCINOMAS and dysplasia* (HPV-6 and HPV-11 = Condyloma Acuminatum)*
- The E6 and E7 proteins of HPV-16 and HPV-18 are ONCOGENES*** because they bind and inactivate p53 and p105RB respectively
- There’s a quadravalent vaccine! It’s known as Gardasil and consists of the L1 major capsid protein assembled into viruslike particles from HPV 6, 11, 16, and 18 (A series of 3-shots recommended for girls AND BOYS starting at age 9Females or 11Males (Much stronger response to vaccine because antigen rapidly enters blood rather than being shed with skin cells, thus providing immunity where it cannot naturally occur)
