Flashcards in Exam 2 -- Infectious Disease Deck (164):
Which disease in the US is the leading vector borne disease?
True or false: for every case of Lyme disease reported, the CDC estimates that there is another case, unreported.
False; CDC estimates that there are 10 cases of Lyme for every one reported.
Name the gender prevalence, if any, for the following diseases, as discussed in class:
-West Nile Virus
-West Nile Virus: none
-HIV/AIDS: male? (63% of new HIV infections is MSM)
Name the age prevalence, if any, for the following diseases, as discussed in class:
-West Nile Virus
-Lyme: bimodal; 5-19 and 45-50
-West Nile Virus: none
-Syphilis: 20-30 for male and female
-Chlamydia: 20-30 for male, 15-25 for female
-Gonorrhea: 20-30 for male, 15-25 for female
-HIV/AIDS: 13-24? (26% of new HIV infections)
-Toxocariasis: children? (up to 30% infected)
95% of cases of Lyme disease in the US come from these geographic regions.
What are the Northeast, Wisconsin, and Minnesota?
Name both the spirochete which causes Lyme disease, as well as the organism that is its vector.
Borrelia burgdorferi is the spirochete, and the black legged tick (ixodes scapularis; in the east) and deer tick (ixodes pacificus; in the west) are the vector.
The ticks that transmit Lyme disease have three life stages after they hatch: larva, nymph, and adult. Which is the stage which most commonly affects human beings? What reasons were given in class for this?
Nymph; they're smaller (less noticeable) than adults. They also outnumber adults 10:1, and they're outside during spring and summer, which is when we are outside most.
The most common sign of the early/localized Lyme disease infection is erythema migrans (average of 7 days post bite). Which of the following descriptors usually apply to EM?
For bonus points, what is the CDC definition of EM?
EM can feel warm, but typically involves no pain and no itch.
CDC definition of erythema migrans
-at least 5 cm in size
->1 week in duration
If the early/localized form of Lyme disease is untreated, early disseminated infection can develop days to weeks after the bite. This stage can include more erythema migrans as well as the following three categories of symptoms:
What percentage of patients in the early disseminated form experience each of these categories? What specific symptoms occur in these stages?
Rheumatoid = 30%
-arthalgia with swelling
-CN palsies (especially Bell's palsy with a fever)
-acute febrile polyneuritis
-AV conduction defects or tachyarrythmias
Late disseminated Lyme disease occurs after 4 months on average. What symptoms occur in this stage?
Lyme arthritis (in 60% of patients)
Chronic neurologic (in 5%)
-Encephalopathy, low grade CNS inflammation, paresthesias, "stocking glove" pattern shooting pain
What ocular signs might occur in a patient with early Lyme disease?
Follicular conjunctivitis, episcleritis, perioribital edema
What ocular signs might occur in a patient with late Lyme disease?
Pupil abnormalities, CN palsies of III, IV, VI, pars planitis, choroiditis, granulomatous anterior uveitis, and unilateral or bilateral disc edema.
The CDC allows diagnosis of and treatment for Lyme disease based on their definition of EM and known exposure. Serological "two-tiered" testing is another way to try and diagnose this condition. Briefly describe two-tiered testing.
Start with an enzyme immunoassay (EIA) or an immunofluorescence assay (IFA). If negative, consider another diagnosis. If positive, continue to a Western Blot (for IgM and IgG if S/S less than 30 days, for IgG only if S/S for more than 30 days).
What sorts of conditions might cause two-tiered testing for Lyme disease to give false positives?
Autoimmune diseases, mono, malaria, syphilis, etc.
True or false: since two-tiered testing looks for antibodies, it can be used to determine success of treatment.
False; the organism can hide outside of the blood supply, so treatment success cannot be measured with serologic testing.
FYI: non-treponemal testing for syphilis is the only test discussed in class can be used to determine treatment success.
What treatments are used for early Lyme disease when the symptoms include EM, Carditis, Facial Nerve Palsy, or arthritis?
Oral doxycycline*, amoxicillin, or cefuroxime axetil for 14 days (28 days if arthritis)
Note: if patient is a child, no doxy
What treatments are used for early Lyme disease when the symptoms include meningitis or acute febrile polyneuritis?
IV Ceftriaxone or Penicillin G for 14 days (oral doxy for 28 days if allergic)
What treatments are used for late Lyme disease when the symptoms include arthritis?
Treat as in the early stage; if patient doesn't respond, retreat with another 28 day course of oral meds or switch to IV ceftriaxone for 14-28 days. If still no response, treat with anti-inflammatories (NSAIDs, corticosteroids, DMARDs).
What treatments are used for the neurological symptoms of late Lyme disease?
IV ceftriaxone for 14-28 days
Post-treatment Lyme disease is a very serious condition that features continuing pain, sleep disturbance, and cognitive dysfunction. It occurs in 10-20% of patients with Lyme disease.
True or false: although spraying clothes with permethrine and >20% DEET are among some of the most effective things you can do to reduce your chances of being bitten by a tick, the overall best thing you can do is sit down with the ticks, make friends, and sing kumbaya.
False (well, the last part at least).
How is West Nile Virus transmitted to humans?
Typically through mosquitoes (they bite infected birds then pass it on to humans), though it can occur through blood transfusions or organ transplantations, breast milk, transplacentally.
There is an incubation period typically of 2-6 days for West Nile Virus before symptoms start to appear. What type of non-ocular symptoms are there? How many people infected with WNV experience these symptoms?
Only 20%; it's known as West Nile Fever at this stage. Early symptoms include flu-like symptoms, rash on trunk.
Although the ocular symptoms of West Nile Fever occur less commonly, they generally last longer than the non-ocular symptoms (2-3 weeks compared to about 1 week). What ocular signs/symptoms are there?
Conjunctivitis, photophobia, eye pain, floaters, vasculitis. May notice a linear pattern on the retina due to choroiditis.
What percentage of patients who are infected with WNV develop the neuroinvasive form? What symptoms can occur in this stage?
Less than 1%; symptoms may include meningitis, encephalitis, acute flaccid paralysis, and rarely optic neuritis or CN abnormalities.
What two findings were discussed in class that should make WNV rise to the top of your list of possible diagnoses?
Linear choroidal pattern on the retina and paralysis plus muscle weakness.
True or false: the neurologic effects of neuroinvasive WNV are usually short-lived.
False; they can be permanent, or last a very long time.
What is the overall fatality rate for patients who develop neuroinvasive WNV? Is it higher or lower in meningitis as compared to encephalitis?
10% is the overall, and it is higher in encephalitis than in meningitis.
Late manifestations of WNV occur months to more than a year after the diagnosis of WNV. What percentage of patients infected with WNV will develop late manifestations? List some of the manifestations.
About 50%; symptoms include fatigue/malaise/weakness (in 49% of these patients), memory problems, HA, depression (in 24%), and new tremor (in 20%).
What factors are taken into account when considering WNV as a diagnosis?
Symptoms consistent with the disease, having visited or lived in a high risk state.
If you have a patient and you suspect they have meningitis or encephalitis due to WNV, what lab screening tests could you send for? What situations may cause false positives?
Antibody tests (EIA, IFA, Western Blot) looking for IgM in the serum or the CSF (CSF preferred, since IgM in the CSF indicates presence of the virus in the CSF too).
St. Louis encephalitis virus or yellow fever vaccination can cause false positives.
If your patient tested positive for WNV on a screening test, what confirmatory tests could you run?
Plaque reduction neutralization test (take live WNV, add to a sample of the patient's serum--positive if no growth, negative if growth) -- this is the gold standard to differentiate WNV from St. Louis encephalitis virus
RT-PCR (detects viral RNA--positive confirmed the infection, negative does not rule out the infection)
Unfortunately, there is no specific treatment for WNV, there are only supportive therapies. What can you do to help the patient?
Pain control, IV fluids (due to N&V), respiratory support (from the flaccid paralysis), antibiotics (prevent secondary infections), anti-inflammatory meds, osmotic agents (decrease ICP caused by brain swelling).
Protective measures against mosquitoes is very similar to those against ticks. What additional things could you do to protect against mosquitoes?
Don't go outside at dawn and dusk (this is when they most commonly feed) and drain any standing water (this is where they lay their eggs).
True or false: there are an estimates 20 million new STIs each year in the US, with about half of them occurring in the age range of 20-30
Half true--there are indeed 20 million new STIs each year in the US, but half of them occur in the 15-24 age range.
STDs are a major cause of infertility in women in the US. Which STD discussed in class is the main concern for female infertility?
It is estimated that only 50% of individuals get recommended screening for STIs. What is the chlamydia screening recommendation for non-pregnant women?
Annual chlamydia screening if:
-25 and under
-New or multiple sex partners
It is estimated that only 50% of individuals get recommended screening for STIs. What is the gonorrhea screening recommendation for non-pregnant women?
Annual gonorrhea screening if:
-New or multiple sex partners/Those living in communities with high burden of disease
It is estimated that only 50% of individuals get recommended screening for STIs. What is the screening recommendation for pregnant women?
Syphilis/HIV/Chlamydia/HBV screening if:
Gonorrhea screening at first prenatal visit if:
-At-risk and pregnant
It is estimated that only 50% of individuals get recommended screening for STIs. What is the screening recommendation for men?
Annual syphilis/chlamydia/gonorrhea/HIV screening if:
-Sexually active gay, bisexual, or other MSM
If multiple/anonymous partners, screen every 3-6 months.
If illicit drug user (or if partner is), screen even more frequently.
Syphilis incidence peaked in 1946, then had a huge decrease by 1956 due to what treatment?
Though the incidence of syphilis decreased steadily in the latter half of the 20th century, there was a dramatic rise from 1986-1990. What caused this increase?
HIV, birth control pills, drug culture
True or false: although there is a higher rate of syphilis among men as compared to women, the difference is minimal.
False; the rate of syphilis among men is more than 10x that in females.
What is the name of the organism that causes syphilis? About what ratio of exposed individuals will acquire the organism?
Treponema pallidum; about 1/3 exposed individuals acquire the organism.
Treponema pallidum can enter intact mucous membranes.
Syphilis is hard to diagnose partly because of the fact that the disease has episodes of activity and periods of latency. About how long is the average incubation period (time from initial infection to symptoms)?
There are four classic stages to syphilis. What are the signs/symptoms of primary syphilis?
Regional lymphadenopathy (caused by immune response in the location of first exposure), and chancre (due to local infiltration of PMNs, also in the area of first exposure)
Describe the chancre found in primary syphilis.
It starts 2-6 weeks after exposure, as a red painless papule (0.5-1.5 cm in size). It ulcerates "cleanly" in 1-2 days, then heals in 3-6 weeks.
True or false: though most untreated individuals with primary syphilis will progress to secondary, there are a few whose genetic make up seem to protect them from progression to secondary.
False; 100% of untreated individuals with primary will progress to secondary.
In which gender is secondary syphilis more likely, and why?
Females; the ulcers that occur in primary syphilis are more likely to be noticed by men, which means men are more likely to be treated for primary syphilis than are women.
What are the non-ocular signs and symptoms of secondary syphilis?
Cutaneous lesions (rash on trunk/extremeties), mucous membrane lesions (small superficial ulcerated areas), condylomata lata (moist, wart-like papules in warm intertriginous [skin-on-skin] areas), alopecia (including eyebrows, eyelashes, and facial hair), and flu-like symptoms.
The cutaneous lesions of secondary syphilis are most obvious on the palms, hands, and soles of feet and DO NOT ITCH. Which other disease discussed in class features a maculopapular rash that SPARES the palms and soles? Which features a rash that DOES itch?
Acquired toxoplasmosis spares the palms and soles.
HIV can feature an itchy rash.
What are the ocular signs and symptoms of secondary syphilis?
Madarosis, iris nodules, disc edema, exudative RD, plus just about any type of "itis" you can think of.
If untreated, secondary syphilis lasts for about 4-8 weeks before the patient becomes symptom-free and enters the latent period, which consists of an early period and a late period. Classify each of the following bullet points as "early" or "late" according to which portion of the latent period it pertains to.
-Patient still sexually infectious
-Organism can be passed by mother to fetus
-Within one year of infection (or relapse)
-Not considered sexually infectious
-Relapse is rare
-More than one year after infection (or relapse)
-25% of these patients relapse to secondary
-Patient still sexually infectious: early
-Organism can be passed by mother to fetus: early AND late
-Within one year of infection (or relapse): early
-Not considered sexually infectious: late
-Relapse is rare: late
-More than one year after infection (or relapse): late
-25% of these patients relapse to secondary: early
What two categories of symptoms occur in tertiary syphilis? How long after initial infection does each occur?
Benign (10-15 years post infection): gummas (localized soft granulomas), chronic inflammation, fibrosis of tissue/destruction of cartilage.
Cardiovascular (20-30 years post infection): aortic aneurysm, aortic valve insufficiency/regurgitation, CAD, MI, HF, strokes, seizures.
What causes the cadiovascular symptoms of tertiary syphilis?
Damage caused by immune process causes cellular debris to be released into the blood. Antibodies known as reagin tag a cardiolipin-cholesterol-phospholipid antigen made from the debris. The immune system targets these antigens and causes inflammation and even more damage to heart tissue.
In early neurosyphilis, what symptoms are possible? About how long after infection does early neurosyphilis tend to occur?
CN involvement (all but CN V; also, Bell's palsy could be accompanied by a fever), meningitis, strokes/seizures, tingling/weakness of legs, loss of vibratory sense, auditory/ophthalmic involvement.
Occurs within one year of infection.
About how long after infection does late neurosyphilis tend to occur?
In late neurosyphilis, symptoms can be motor-based or sensory-based. Which motor symptoms are possible?
In late neurosyphilis, symptoms can be motor-based or sensory-based. Which sensory symptoms are possible?
Acronym OD LUAU
Decreased peripheral reflexes
Lightning pains in extremeties
Urinary and fecal incontinence
Syphilis can cause stillbirth or miscarriage. What are the chances of syphilis transmitting to the fetus if the mother is in the primary or secondary stage? Early latent? Late latent?
Early latent: 40%
Late latent: 10%
Early congenital syphilis has manifestations prior to age two. What manifestations can occur?
Mucocutaneous lesions like those in secondary syphilis, as well as a bilateral rash with vesicles on the palms and feet, and inflammation of cartilage and bone (very painful, child may not move much).
Late congenital syphilis has manifestations between ages five and twenty. What manifestations can occur?
Hutchinson triad (defective adult teeth, interstitial keratitis, deafness), poorly formed bones, neurosyphilis possible.
Serological testing for syphilis falls into the category of non-treponemal and treponemal. Categorize each of the following bullet points according to which type of test it pertains to.
-Cannot be used to check success of treatment
-Qualitative and quantitative
-Most common test is FTA-ABS
-Targets antibody against T. pallidum
-Can be used to check success of treatment
-Most common tests are VDRL and RPR
-Qualitative and quantitative
-Can be used to check success of treatment
-Most common tests are VDRL and RPR
-Targets antibody against T. pallidum
-Cannot be used to check success of treatment
-Most common test is FTA-ABS
What are the advantages of non-treponemal serological testing for syphilis?
Rapid and inexpensive, easy to perform, quantitative and qualitative, can be used to monitor success of treatment, as well as evaluate for possible reinfection.
What are the disadvantages of non-treponemal serological testing for syphilis?
Possibly insensitive in very early or very late stages, must be followed by treponemal testing due to non-specificity, false negatives if testing too soon (not enough reagin) or if very high reagin levels (too many antibodies and they may clump up and not respond to the test very well)
Name the possible indicators of need for a lumbar puncture, if you are suspicious of neurosyphilis.
Neurological S/S, ophthalmic S/S, HIV infection, failure of treatment, and children with syphilis.
List the treatment for primary, secondary, or early latent syphilis. (No neurological involvement.)
Penicillin G benzathine, 2.4 million U IM one time
If allergic to penicillin and not pregnant
-Doxy 100 mg po bid for 14 days
-Tetracycline 500 mg po qid for 14 days
List the treatment for late latent or tertiary syphilis. (No neurological involvement.)
Penicillin G benzathine, 2.4 million U IM q1week for 3 weeks
If allergic to penicillin and not pregnant
-Doxy 100 mg po bid for 28 days
-Tetracycline 500 mg po qid for 28 days
List the treatment for neurosyphilis, or syphilis with ophthalmic involvement.
Penicillin G aqeous, 18-24 million U IV for 10-14 days (divided into q4h)
Procaine penicillin 2.4 million U IM qd with probenicid 500 mg po qid for 10-14 days
If allergic to penicillin and not pregnant
-Ceftriaxone 2 g qd IM or IV for 10-14 days
True or false: you should always avoid the use of penicillin in treating syphilis if the patient is penicillin sensitive.
False; in pregnant patients, penicillin is still the treatment used (even if the patient is sensitive) because it's the only drug effective against syphilis that crosses the placental barrier.
Treatment of syphilis is considered successful after 6 months if....
...the dilution of a non-treponemal test has decreased by a factor of 4 (i.e., from 1/64 to 1/16, or from 1/32 to 1/8)
Which two of the STIs discussed in class are in the top two of most commonly reported notifiable diseases?
Chlamydia is #1, gonorrhea is #2
Jeopardy style: This is the rate at which chlamydia occurs in females as compared to males.
What is 2.5 times more?
List the two facts about the microbiology of chlamydia trachomatis that makes it
1) more likely to infect women
2) more likely to cause infertility in women
It infect columnar epithelial cells, which are more common in the vagina than in the penis.
It is an obligate intracellular organism that destroys the host cell when it dies, resulting in scarring that could lead to infertility (and since it preferentially infects columnar epithelial cells, scarring is more common in women)
What are the two forms of chlamydia trachomatis? Which is the infectious form, and which is the duplicating form?
The elementary body is the infectious form.
The reticulate body is the duplicating form.
The incubation period for chlamydia is around 7-21 days. How is the disease transmitted? What is the co-infection rate?
Transmitted by direct contact with urine or genital secretions.
50% co-infection rate
The three types of clinical syndromes caused by chlamydia trachomatis are local, complications and sequelae. What are the findings of local infection for men, women, and children?
Men: conjunctivitis, urethritis, prostatitis
Women: conjunctivitis, urethritis, cervicitis, proctitis
Children: conjunctivitis, pneumonitis, pharyngitis, rhinitis
The three types of clinical syndromes caused by chlamydia trachomatis are local, complications and sequelae. What are the findings of complications for men, women, and children?
Men: reactive arthritis, epididymitis
Women: endometritis, salpingitis, perihepatitis, reactive arthritis
Children: chronic lung disease
The three types of clinical syndromes caused by chlamydia trachomatis are local, complications and sequelae. What are the findings of sequelae for men, women, and children?
Men: chronic arthritis (rare), infertility (rare)
Women: Infertility, ectopic pregnancy, chronic pelvic pain, chronic arthritis (rare)
Children: Rare, if any
What is the most common manifestation of chlamydia in men? In women? What are the symptoms for each?
Men: urethritis (occurs in 50%); mucoid or clear discharge, dysuria, urethral pruritis, meatal erythema/tenderness
Women: cervicitis (occurs in 20-30%); mucopurulent discharge, cervix bleeds easily from minor trauma
What is the main complication of chlamydia?
Reactive arthritis (urethritis, arthritis, conjunctivitis, rash)
What ocular or case history findings might make you suspect that your adult patient's conjunctivitis was caused by chlamydia (adult inclusion conjunctivitis)?
Case history indicates new sexual partner
1-2 weeks post infectious opportunity (i.e., sex with new partner)
Conjunctivitis is prolonged and unresponsive to topical antibiotics
Papillae and follicles
What ocular findings might you find in a neonate that would indicate neonatal inclusion conjunctivitis?
5-14 days after birth
Papillae, no follicles
What is the main possible complication for newborns with chlamydia?
Pneumonia; occurs 4-12 weeks after birth, no fever
(FYI: otitis and vaginal or rectal infections also possible)
Three types of laboratory tests were discussed in class for diagnosis of chlamydia. Which is recommended by the CDC? Briefly describe this test.
NAAT is CDC recommended. Sample required is vaginal swabs for women and urine for men. Gonorrhea will usually be concurrently tested for.
Three types of laboratory tests were discussed in class for diagnosis of chlamydia. Which is the historical standard? When would this test be used?
McCoy cell tissue culture. It has high specificity and so is used in court for cases of suspected sexual abuse.
Three types of laboratory tests were discussed in class for diagnosis of chlamydia. Which is used for detecting ocular infection? Briefly describe this test.
Direct fluorescent antibody (DFA): take a sample from the patient, add fluorescein-tagged antibodies from the lab, and see if there is fluorescence.
Warning: if you're planning on doing this test on a patient, don't do it right after putting fluorescein in their eye.
Describe the treatment for genital chlamydial infections. When would you follow up with the patient to check how treatment went?
Azithromycin 1 g po single dose OR
Doxy 100 mg po bid for 1 week
F/U in 3 weeks if pregnant, 3-4 months if not
Describe the treatment for inclusion conjunctivitis.
If over 8 years old OR above 45 kg
-Azithromycin 1 g po single dose OR
-Doxy 100 mg po bid for 1 week
If under 8 years old AND below 45 kg
-Erythromycin or ethylsuccinate solution 50 mg/kg/d (divided into 4 doses) po for 2 weeks
What is expedited partner therapy? For which conditions discussed in class can it be done (depending on the state where you are practicing)?
It means you can write a prescription for your patient's sexual partner without ever having examined that person. It can only be done for chlamydia.
Gonorrhea is asymptomatic early on in 10% of men and 50% of women, and is often concurrent with other STIs.
What clinical syndromes can occur with gonorrhea?
Local and complications/sequelae
What is the common clinical manifestation of gonorrhea?
How many days after birth does congenital gonorrhea cause conjunctivitis? How does this compare with conjunctivitis due to congenital chlamydia?
Gonorrhea: 2-5 days
Chlamydia: 1-2 weeks
What is a major concern of gonorrheal conjunctivitis?
Possible corneal perforation and blindness.
What lab tests are available for the diagnosis of gonorrhea? Which is preferred by the CDC, and what kinds of samples can be used for it?
Gram stain, culture, NAAT
NAAT is preferred by the CDC; can use urine or urethral or cervical swabs.
What is the treatment for adults for non-ocular gonorrhea?
Ceftriaxone 250 mg in one IM dose plus Azithromycin 1 g PO single dose (or Doxy 100 mg po q12h for 7 days)
What is the treatment for adults and children over 45 kg for ocular gonorrhea?
Ceftriaxone 1 g in one IM dose plus Azithromycin
What is the treatment for children under 45 kg for ocular gonorrhea?
Ceftriaxone 25-50 mg/kg in one IM or IV dose (don't exceed 125 mg)
What is ophthalmia neonatorum prophylaxis?
Prophylactic instillation of erythromycin 0.5% ointment in neonate eyes immediately after deliver for potential gonorrheal conjunctivitis.
With 35 million international infections (1.2 million in the US), what disease is the leading infectious killer?
Jeopardy style: At only 2% of the US population, this group makes up 63% of new HIV infections in the US.
What ethnic group, though only 12% of the US population, makes up 44% of new HIV infections in the US?
What age group (comprising 16% of the US population) makes up 26% of new HIV infection in the US?
Though HIV was first brought into the US in the 1970s, AIDS wasn't first recognized as a disease until what year? When was HIV first isolated?
Recognized in 1981
Isolated in 1983
HIV transmission can occur through exposure to any bodily fluids except _______.
FYI: there hasn't yet been a documented case of transmission through tears, but it's still on the list.
HIV is a retrovirus. What three enzymes does it carry in its capsid? What does each do?
Reverse transcriptase: makes viral DNA from viral RNA
Integrase: pulls viral DNA into cell nucleus and integrates it into host DNA
Protease: clips resultant viral protein to form more viral enzymes
What two receptors are needed for HIV to invade a host cell?
CD4 and CCR5
T-cell to T-cell transfer is a far more effective way for HIV to spread throughout a body than spreading through the blood. Briefly describe why this mode of transfer is likely responsible for most CD4 T-cell death.
Most CD4 T-cells are at rest and stop the productionof HIV at the chain elongation phase of reverse transcription. Incomplete viral DNA activates enzymes in the cell that lead to pyroptosis.
The initial stage HIV infection occurs 2-4 weeks after infection, and usually consists only of mild flu-like symptoms. An skin rash can occur as well.
FYI: compare the itchy rash of early HIV infection to the non-itchy rash of secondary syphilis.
The chronic stage of HIV infection lasts for months to years and exhibits only mild constitutional changes (if any). What two markers are used to manage and monitor the disease?
The viral load (HIV RNA in the blood) and CD4 T-cell count.
CD4 cell count provides information on the overall immune function of an HIV+ patient. What level indicates an increased risk for opportunistic infections?
Less than 200 cells/mm3
Fill in the blank: viral load is measured in log units (3.0 log units is 1000 RNA units/mm3) and is used to monitor ____________.
Response to antiretroviral therapy.
The crisis or final stage of HIV infection features a decreased CD4 cell count, increased viral load, and includes what S/S?
Constitutional symptoms, CNS involvement (dementia, memory loss, depression, seizures, social withdrawal), opportunistic infections.
A CDC diagnosis of AIDs is made whenever a person is HIV+ and ______________ (list all that apply)
CD4 cell count below 200/mm3
CD4 T-cell % of total lymphocytes below 14%
Development of an AIDS defining illness (huge list, pneumocystis jirovecii pneumonia is the most common cause of death in AIDS patients)
What sorts of ocular opportunistic infections can occur with an HIV infection?
CMV, herpes (zoster or simplex), varicella-zoster, M. tubuerculosis, histoplasmosis, candidiasis, toxoplasmosis, molluscum contagiosum.
What ocular findings NOT directly related to an infection might a patient with HIV have?
KCV sicca, immune recovery uveitis/vitritis, kaposi sarcoma, HIV retinopathy, and neuro-ophthalmic abnormalities.
HIV rapid tests look for antibodies and so are dependent on the patient's immune response. Each of the following rapid tests had one feature that was highlighted in class. Name said features.
OraQuick ADVANCE: can use oral fluid
Reveal G-3: 3-5 minutes for the entire test
MultiSpot: differentiates HIV-1 from HIV-2
Alere Determine: also looks for an HIV-1 antigen
True or false: the FDA requires Western Blot or IFA to confirm initial positive HIV immunoassay results.
False; they used to require confirmation, but not anymore.
Briefly outline the recommended lab HIV testing algorithm.
Do HIV-1/2 antigen/antibody combination immunoassay
-If negative, true negative
-If positive, continue to HIV-1/2 antibody differentiation immunoassay
HIV-1/2 antibody differentiation immunoassay
-If positive, diagnosis is according to whichever type of antibodies you found (HIV-1, HIV-2, or both)
-If negative or indeterminate, run an HIV-1 NAAT
-If positive, acute HIV-1 infection
-If negative, true negative for HIV-1
Guidelines for starting ART are rated based on the recommendations and the evidence. What is the scale for rating recommendations?
B= moderate recommendation
Guidelines for starting ART are rated based on the recommendations and the evidence. What is the scale for rating evidence?
I=Data from randomized controlled trial
II=Data from well-designed nonrandomized trials or observational cohort studies with long-term clinical outcomes
III = Expert Opinion
In terms of reducing risk of disease progression, what guidelines are in place for when to start ART? How are these guidelines rated?
Based on CD4 cell count:
Less than 350 cells per mm3, AI
350-500 cells per mm3, AII
More than 500 cells per mm3, BIII
In terms of preventing disease transmission, what guidelines are in place for when to start ART? How are these guidelines rated?
Based on transmission risks:
There are five classes of HIV medications (plus pharmacokinetic enhancers). Describe what entry/fusion inhibitors do, as well as any specific points made during class about this class of medication.
Inhibit fusion with or entry of the virus into the cell. This class is used when other medications have failed.
There are five classes of HIV medications (plus pharmacokinetic enhancers). Describe what NRTIs (nukes) do, as well as any specific points made during class about this class of medication.
They provide faulty versions of viral DNA nucleotides/nucleosides, stopping reverse transcriptase.
There are five classes of HIV medications (plus pharmacokinetic enhancers). Describe what NNRTIs (non-nukes) do, as well as any specific points made during class about this class of medication.
They attach to and stop reverse transcriptase. Nevirapine is used for infants and pregnant women.
There are five classes of HIV medications (plus pharmacokinetic enhancers). Describe what INSTIs (integrase strand transfer inhibitors; integrase inhibitors) do, as well as any specific points made during class about this class of medication.
They block integrase, keeping the viral DNA from being inserted into the host cell DNA. This class has been associated with SJS.
There are five classes of HIV medications (plus pharmacokinetic enhancers). Describe what protease inhibitors do, as well as any specific points made during class about this class of medication.
They inhibit protease, keeping it from activating new copies of viral enzymes.
There are five classes of HIV medications (plus pharmacokinetic enhancers). Describe what pharmacokinetic enhacners do.
They increase the amount of medication in the blood, and prevent the breakdown of protease inhibitors by the body.
There are three preferred regimens of ART. List them.
-Two different NRTIs with a PI and pharmacokinetic enhancer
-Two different NRTIs with an INSTI
-Two different NRTIs with an NNRTI
Combination medications are available for HIV treatment. What are the main advantages and disadvantages of combo meds?
Advantage: decreases the complexity of medication regimen
Disadvantages: more expensive, and decreases overall effectiveness of the individual medications regimen (if it were perfectly followed)
All of the combo medications for HIV involve three medications. What is the one exception, and for what is it used?
Truvada contains only two nukes, and is used for pre-exposure prophylaxis.
Who should get pre-exposure prophylaxis for HIV?
MSM, heterosexuals with risky behaviors, partners with one HIV+, injectable drug users.
Find the one false statement about toxoplasmosis:
-60 million infected in US
-2 billion infected worldwide
-organism completes life cycle in dogs
-leading cause of foodborne illness
False--Organism does not complete its life cycle in dogs; it completes it in cats.
What kind of geographic climate is likely to have a higher prevalence of toxoplasmosis?
Warm, moist, and lower altitude
How does toxoplasmosis get from your cat into you?
Organism appears in cat feces and gets lodged in muscles of animals that root around in the dirt (pigs, sheep; can also appear on fruits and veggies). Eating the undercooked meat or unwashed fruits/veggies gets the organism into our bodies.
What is the active form of the toxoplasmosis parasite called? Where in the body does it lodge before reverting to its dormant form (due to immune system)?
Tachyzoites are the active form which lodge in muscles, myocardium, brain, and eyes. Bradyzoites are the dormant form.
What is the most common symptom of acquired toxoplasmosis?
Non-tender cervical lymphadenopathy
Acquired toxoplasmosis can feature flu-like symptoms. What makes these flu-like symptoms stand out?
They can last for a month
Acquired toxoplasmosis can feature maculopapular rash. What makes this rash different from the rash that appears in another condition mentioned in class?
This rash spares the palms and soles, whereas the rash of secondary syphilis does NOT spare the palms and soles.
Transmission of toxoplasmosis can be as high as 60%. True or false: the earlier in the pregnancy the mother is infected, the worse the manifestations in the fetus (if the fetus is indeed infected).
What symptoms are possible with congenital toxoplasmosis?
Stillbirth, miscarriage, hydroencephaly, microcephaly, endocrine disorders, cerebral calcifications, rash, fever, psychomotor retardation, jaundice, enlarged spleen, CSF abnormalities.
Ocular: chorioretinitis, potentially leading to macular scarring, strabismus, and optic nerve problems.
True or false: we as optometrists are less concerned about congenital toxoplasmosis because only 20% of children develop ocular complications later in life.
False; we are very concerned about it because 80% of children with congenital toxoplasmosis go on to develop ocular complications later in life.
Toxoplasmosis in the immunosuppressed features the same types of symptoms as acquired toxoplasmosis (but more severe), plus confusion, seizures, nausea, poor coordination, encephalitis, pneumonitis, myocarditis, retinochoroiditis.
What is the ocular finding that occurs in less than 1% of patients with acquired toxoplasmosis but more than 80% of patients with congenital toxoplasmosis?
Chorioretinitis (inflammation from the tachyzoite in retinal cells; tends to occur in the macula but can be in the periphery; can cause optic nerve problems and strabismus; also tends to be unilateral in acquired and congenital but bilateral in immunocompromised).
FYI: toxoplasmosis is the most common cause of human retinochoroiditis.
You can use EIA or IFA in terms of serological testing for toxoplasmosis. Which antibody do you look for first?
Usually IgG and then IgM (this is backwards from tests for other conditions--because IgG appears so quickly with toxoplasmosis, look for it first, then you can look for IgM to decide if the infection is acute)
If a woman is pregnant and is diagnosed with toxoplasmosis, what test will be run to help determine the time of infection?
IgG avidity test
What can cause false positives in serological testing for toxoplasmosis? False negatives?
False positives: RF/ANA
False negatives: decreased immune response
The Sabin-Feldman dye test is the gold standard for toxoplasmosis. Does staining indicate a positive or negative test?
Staining indicates a negative test--organism must be intact for staining to occur. It patient has antibodies, organism will not be intact.
True or false: you should treat all patients with toxoplasmosis
False; immune competent, non-pregnant patients are usually not treated. If a patient is a newborn or immunocompromised, or if there is an ocular lesion threatening the macula, optic nerve, or papillomacular bundle, then treatment is usually pursued.
What is the classic triple therapy for toxoplasmosis? What alternatives exist?
Classic: Pyrimethamine, sulfadiazine, and leucovorin calcium.
-Trimethoprim, sulfamethoxazole, leucovorin calcium
-Pyrimethamine, clindamycin, leucovorin calcium
What are the adverse effects of pyrimethamine?
Rash, asplastic anemia, anorexia, dry mouth, plus non-specific.
What are the adverse effects of sulfa drugs?
SJS, aplastic anemia, hepatitis, ARF, pruritus, photosensitivity, hematuria, plus non-specific
True or false: toxocara canis is transferred to puppies through their mother.
Where in the US is toxocariasis more common?
South central and southeastern; due to poor soil conditions.
True or false: toxocara canis completes its life cycle in humans.
False; it stays a larva while in humans.
True or false: most people with toxocariasis need to undergo treatment for the symptoms.
False; most individuals do not have symptoms and do not require treatment.
There are two major forms of toxocariasis: visceral larva migrans and ocular larva migrans. Visceral larva migrans involves some general non-specific symptoms and non-specific pulmonary symptoms, as well as what not so general symptoms?
Enlargement of spleen and liver, and seizures or epilepsy.
True or false: visceral larva migrans is more common in kids.
What symptoms can occur in ocular larva migrans?
The larva enters the eye through choroidal circulation and can cause a granuloma, potentially leading to a retinal detachment; also chorioretinitis, uveitis, endophthalmitis, optic neuritis. This is usually unilateral.
Though the definitive diagnosis for toxocariasis is tissue biopsy, this is not often done. What other test is done, and which form of the disease is it more useful for?
ELISA; it is more useful for VLM than OLM since there aren't many antibodies in the eye.