Exam #2 Flashcards
Which organism is heat sensitive = killed by pasteurization?
MTB
Transmission of MTB vs. MAC?
- MTB: person to person
- MAC: contaminated water/food (NOT person to person)
What organism has mycolic acids, cord factor, LAM?
MTB
What organism shows as IFN-gamma on blood test?
MTB
Three groups most affected by MTB?
- IC
- Children
- HIV/AIDS
Which organism is ubiquitous, acid fast, weak G+?
MAC
What is the leading cause of NTM in HIV+ population?
MAC
What two “characters”/populations are described with MAC? How does each present on CXR?
- Middle-aged/old man, smoker = cavitary
- “Lady Windermere” aka elderly woman, NON-smoker = patchy/nodular
What is important when obtaining a sample for MAC? What is seen on PCR?
STERILE SITE
- PCR shows 16s rRNA sequence
What population is Mycobacterium abscessus seen?
CF
What vaccination is associated with false+ in MTB?
BCG vaccine
What population is Measles most common in? What two risk factors further increase risk?
Children
- Severe is malnourished or Vitamin A deficient
What two findings are pathognomonic for Measles? What other two symptoms often follows these findings?
- Prodrome
- 3 C’s (cough, coryza, conjunctivitis)
- Koplik spots - RASH + FEVER (head to toe)
What two complications are associated with Measles?
- PNA = most common cause of death
- Acute symptomatic encephalitis = high fatality
What two preventions can be used for Measles?
- MMR II
- BayGam (immunoglobulin) for exposed non-vaccinated
Which condition is NOT associated with children and caused by close/prolonged contact?
Rubella
What complication is associated with Rubella, and when does it often present?
CRS in 1st trimester of pregnancy
What condition can infect the CNS AND can be latent?
Herpes Simplex Virus (HSV)
What condition has lifelong immunity but possibility of recrudescence?
Herpes Simplex Virus (HSV)
For Herpes Simplex Virus (HSV), when is recrudescence risk increased?
If initial outbreak was larger/more extensive
Is asymptomatic shedding of Herpes Simplex Virus (HSV) possible?
YES
Differentiate HSV-1 from HSV-2.
- HSV-1: common in early in life = oral
- HSV-2: seen later in life, associated with sex = GENITAL
What diagnostic tool is used for Herpes Simplex Virus (HSV), and what will is how? What other finding may be seen?
Tzanck smear shows large/fused cells
- Ballooning pathology
What is the treatment for Herpes Simplex Virus (HSV)?
Acyclovir
What cancer is associated with Human Papillomavirus Virus (HPV), and what is the prevention (what ages)?
Cervical CA
- Gardasil vaccination in ages 9-45 years
What two conditions are associated with VZV?
- Chickenpox = Varicella
- Shingles = Herpes Zoster
When is peak occurrence of Chickenpox, and in what population is it most seen?
Winter/Spring peak
- Ages 5-9 years
Where does Chickenpox replicate for its first and second viremia?
- Replicates in lymph nodes = primary viremia
2. Replicates in liver and spleen = secondary viremia
What condition involves prodrome symptoms in older children/adult, but NOT seen in young children?
Chickenpox
Is treatment necessary for Chickenpox?
2
NO…
- But if needed, Acyclovir
What medication should NOT be administered in a patient with Chickenpox, and why?
ASA = possible Reyes Syndrome
What type of VZV is associated with significant disease/damage, and how would you treat?
Congenital/Neonate VZV
- VariZig for high-risk exposed to infection
What is the prevention for Chickenpox? What is the prevention for Shingles (2)? How are the two related?
- Chickenpox: Varivax
- Shingles: Zostavax, Shingrix
Zostavax is the same virus used in Varivax, but higher potency for Shingles
What is the primary symptom associated with Shingles? What system is sometimes affected by Shingles?
PAIN (searing, burning, stabbing) +/- rash in unilateral dermatomal pattern
- Consider involvement of ophthalmic branch of CN V
NOTE: pain can precede rash by days/weeks
How do you treat Shingles?
What complication is associated with Shingles?
NO treatment (self-limited) - Comp: post-herpetic neuralgia
What is another name for Human Herpes Virus 6 (HHV-6), and how does it present? What population is it common in?
Roseola Infantum
- Fever the rose-colored rash
- Common in children
What is the treatment for HHV-6?
NONE = self-limited
What is the treatment for Parvovirus 19?
NONE = self-limited (NSAIDs)
What is another name for Parvovirus 19, and how does it present in children? In adults?
Fifth Disease
- Slapped cheek rash then maculopapular rash
- ADULTS: may be only arthritis/arthralgia
What condition is caused by a G+, anaerobic rod organism found in skin/sebaceous glands?
Acne Vulgaris
What is the progression of symptoms seen with Acne Vulgaris (3)? Which part is inflammatory?
Papules → Pustule → Nodule (severe)
- Pustules and Nodules inflammatory
What are the two organism that cause Folliculitis? Are they G+ or G-? How does each present symptomatically?
Staph aureus = G+
- Pustules/nodules
P. aeruginosa = G-
- Maculopapular rash (itchy)
What are the two treatments for Staph aureus Folliculitis?
- Clindamycin ointment
- Benzoyl Peroxide wash
What organism causes “Hot Tub” Folliculitis? Tell me about it (3)?
P. aeruginosa
- G- RODS
- Pyoverdin/Pyocyanin
- Opportunistic
Are Furuncles or Carbuncles typically recurrent?
Furuncles = recurrent
What organism causes Furuncles/Carbuncles?
Staph aureus (G+)
What three populations are most affected by Furuncles/Carbuncles?
- Obese
- IC
- DM
What is the treatment for BOTH Furuncles/Carbuncles? How is treatment different between the two?
BOTH: drain abscess
- Furuncles: MRSA-effective abx
- Carbuncles: MRSA-effective abx + RIF
How is Impetigo different from Ecthyma?
- Impetigo: superficial
- Ecthyma: deep/ulcerative
What are the two subtypes of Impetigo, and what organisms cause each?
- Non-bollous: Staph aureus (G+) or Strep pyogenes = GAS (G+)
- Bollous: Staph aureus (G+) ONLY
What two organisms cause Ecthyma?
- Staph aureus (G+)
- Strep pyogenes = GAS (G+)
What specific organism causes Staphylococci Scalded Skin Syndrome?
Staph TOXIN (not the bacteria itself)
What condition involves sterile bullae?
Staphylococci Scalded Skin Syndrome
What condition involves a positive NIkolsky’s sign?
Staphylococci Scalded Skin Syndrome
What is the treatment for Staphylococci Scalded Skin Syndrome? What if it is severe?
Penicillinase-resistant, anti-Staph abx
- If severe, treat as burns
How is Erysipelas different from Cellulitis?
- Erysipelas: superficial; raised lesions with sharp borders
- Cellulitis: deeper; indistinct borders with spreading
What condition involves +/- wound; deeper; indistinct borders with spreading?
Cellulitis
What organism causes Erysipelas?
Strep pyogenes = GAS (G+)
What two organisms cause Cellulitis?
- Strep pyogenes = GAS (G+)
- Staph aureus (G+)
What medication should be avoided in the treatment of Erysipelas and Cellulitis, and why?
NSAIDs
- Can mask pain of myonecrosis
What is the primary cause of Pasteurella multocida?
CAT BITE
What condition involves draining pus, fluctuance, white/yellow center with head?
MRSA
What two diagnostic tests can be used to diagnose MRSA, and what is seen with each?
- mecA gene on PCR
- MecA protein with latex agglutination
What condition involves deeper tissue and mixed aerobe + anaerobe?
Necrotizing Fasciitis
What condition involves pain out of proportion and NO PUS?
Necrotizing Fasciitis
What two conditions involves HEET?
- Cellulitis
- Necrotizing Fasciitis
What condition spreads along the fascia? What is often spared, and why?
Necrotizing Fasciitis
- Muscle spared because good blood supply
What are the two types of Necrotizing Fasciitis, and what organisms cause each?
In what population is each seen?
Type 1: polymicrobic (anaerobe + aerobe/anaerobe)
- DM
Type 2: monomicrobic (Strep pyogenes (G+))
- HEALTHY
What bacterial skin infection is considered an emergency? How is it treated? What other tx may be considered?
Myonecrosis
- Treated with SURGERY (HBOT?)
What organism causes Myonecrosis, and what symptom is pathognomonic?
Clostridium pefringens Type A
- Sxs: crepitus
What two organisms cause Toxic Shock Syndrome, and in what population does each present? What symptom is often common for both?
EXOTOXIN SUPERANTIGENS
- Strep pyogenes = GAS (G+): already ill (bacteremic +NF)
- Staph aureus (G+): HEALTHY (surgery or menstrual)
Sunburn-like rash of whole body for both
What is required for growth of Dermatophytes?
Keratin
What two virulence factors are associated with Trichophyton Dermatophytes? Describe each.
- Galactomannan peptide
- Crude antigens (CHO = immediate, peptide = delayed)
What diagnostic tool is used for Dermatophytes? What is seen?
DTM = selective and differential
- pH change = red color change
What three fungal elements are seen in Dermatophytes?
- Arthrospores
- Microconidia (asexual spore)
- Macroconidia (asexual spore)
What is a Dermatophytid?
ALLERGIC RXN to Dermatophytes
How can you differentiate Trichophyton Dermatophytes from Microsporum Dermatophytes?
- Trichopyton = NOT fluorescent
- Microsporum = fluorescent
What three virulence factors are seen with both Trichophyton Dermatophytes AND Microsporum Dermatophytes?
- Hyphae
- Microconidia (asexual spore)
- Macroconidia (asexual spore)
What is the most common Trichophyton Dermatophyte?
Trichophyton mentagrophytes
What two organisms can cause Tinea Capitis, and what is specific of each?
- M. canis = ectothorix (around hair follicle)
- T. tonsurans = endothorix (within hair follicle)
How are Tinea Corporis and Tinea Cruris transmitted (2)? What three risk factors are associated with both?
Transmitted via direct AND indirect contact
- RF: DM, obesity, excessive sweating
What condition is often associated with Candida co-infection?
Tinea Unguium (Onychomycosis)
What is the most common opportunistic fungal infection worldwide?
CANDIDA
What five causes are associated with Candida spread (i..e possible risk factors)?
- Absence of normal flora
- Intro into abnormal site
- “Pathologic” change
- Immune defect
- Use of broad-spectrum abx
What are all species of Candida capable of, and which type is better at this?
ATTACHMENT
- Germ tube is more adhesive (than yeast cells)
G+ cells, yeast cells, pseudohyphae and true hyphae are indicative of what organism?
CANDIDA
How can you differentiate between types of Candida infection, and what two forms involve germ tubes?
Chromagar can diff.
- Germ tubes ONLY seen with C. albicans and C. dubliniensis
What is another name for Malassezia furfur, and how does it present on microscopy/KOH?
Tinea Versicolor
- “Spaghetti & meatballs” on KOH
What is required for growth of Malassezia furfur?
Lipophilic growth factor = FAT
What is another name for Hortaea werneckii, and how does it present on microscopy/KOH?
What is another key characteristic of Hortaea werneckii?
Tinea nigra
- DIMORPHIC on KOH (yeast and mold)
It is an extreme halotolerant
What organism is a small mite with short legs?
Sarcoptes scabiei (Scabies)
What condition involve pruritus worse at night?
Sarcoptes scabiei (Scabies)
What two populations often present with Sarcoptes scabiei (Scabies)?
- Children
- Elderly
In what population is Norwegian Scabies most prevalent?
HIV
- Crusted/very itchy lesions
How does Pediatric Scabies present?
Blood-filled lesions
What organism is larger than Scabies?
Phthirus pubis (Crabs)
What condition is caused by a “blood-sucking parasite” that cements itself to hair/clothing fibers?
Pediculosis (Pediculus humanus)
What condition is associated with “Vagabonds disease”, and what is this?
Pediculosis (Pediculus humanus)
- Darkened skin with LONG-TERM exposure
What organism is a parasite that NEEDS blood, but does NOT live on humans?
Pulex irritant (Human Flea)
What organism has short spikes on its legs, and what do these allow for?
Pulex irritant (Human Flea) - Allows for attachment to host
What organism CAN JUMP and symptomatically presents as linear bites on the lower extremities?
Pulex irritant (Human Flea)
What organism causes RMSF, and what are two characteristics of this?
Rickettsia rickettsii
- G-
- Obligate intracellular
What symptoms are associated with RMSF (3)?
Fever, HA
- THEN RASH (macular and painless to petechial/painful)
What condition involves macular and painless rash that progresses to a petechial and painful rash?
RMSF
What diagnosis is used for RMSF?
Indirect immunofluorescence
What organism causes Chagas disease, and what is one virulence factor is contains?
Trypanosoma cruzi
- Flagella (it is a protozoa)
What two symptoms are seen with ACUTE Trypanosoma cruzi (Chagas disease)?
- Romaña’s sign
- Chagoma
What condition involves Romaña’s sign?
ACUTE Trypanosoma cruzi (Chagas disease)
Are fleas or scabies contagious?
SCABIES = contagious (spread by direct contact)
What will be seen diagnostically for ACUTE Trypanosoma cruzi (Chagas disease)? What about CHRONIC? What tool is used for each?
- ACUTE: Trypomastigotes = blood smear
- CHRONIC: Amastigotes = biopsy
What is linked with IM/EBV?
Burkett’s Lymphoma
What is the peak age associated with IM, and how can this affect diagnosis? How is it diagnosed, and what is seen?
17-25 years: use Monospot and see Heterophile Ab
- If peds (younger), have to use IgM anti-VCA
What condition involves Heterophile Antibodies on diagnosis?
IM/EBV
What condition involves “Downey Cells” on diagnosis?
IM/EBV
IM/EBV and CMV are very similar, so how can you differentiate the two?
CMV = NO Heterophile Antibodies
What three populations are most affected by CMV?
- Pregnant
- IC
- Transplant patients
What is the prevention for Mumps, and when is it contraindicated (2)?
MMR II vaccine
- NOT if egg sensitivity or Neomycin sensitivity
What organism causes Lyme Disease, and what two characteristics are exhibited by the vector/what is the vector?
Borrelia burgdorferi
- TICKS (nymphal stage, questing)
What symptom is seen with ACUTE Lyme Disease?
Erythema Migrans (bullseye rash)
What symptom is seen with subacute or chronic Lyme Disease?
Asymmetric arthritis
What two diagnostic tools are used for Lyme Disease?
EIA then Western Blot
Which four conditions can cause false+ on EIA when diagnosing Lyme Disease?
- Syphilis
- EBV
- SLE
- RA
What types of Hepatitis are associated with a shorter incubation period?
A, E
- ALSO only acute and fecal-oral transmission
What type of Hepatitis does NOT have a vaccine for prevention?
HCV
What is a major reservoir of HBV, and why?
Chronic HBV
- Can still shed even if asxs
What is a major complication of HBV?
Primary hepatocellular carcinoma
How is Hepatitis A transmitted?
Contaminated food or water
How is Hepatitis B transmitted (3)?
- Needle-sharing
- Sex
- Mother to fetus
How is Hepatitis C transmitted (5)?
- Transfusions
- Transplants
- IDIOPATHIC
- IVDU
- Sex
What is the hallmark of Hepatitis C?
CHRONICITY
What can increase the severity of Hepatitis B, and is fairly common?
Hepatitis D co-infection (COMMON)
What is the primary treatment for Hepatitis C (2)?
DAAs +/- interferon
Why can’t you treat Hepatitis C with DAAs if you also have a Hepatitis B co-infection?
DAAs can inhibit Hepatitis C BUT ACTIVATE HEP B
What is the primary recommendation for Hepatitis A?
EDUCATE
What three characteristics can differentiate HIV-1 form HIV-2? How is HIV-2 generally treated?
HIV-2 is…
- Less transmitted
- Has slower progression to AIDS
- Resistant to NNRTIs
NEEDS COMBO THERAPY
What are the five possible transmission routes for HIV?
- Sex
- Parenteral
- Perinatal
- Transplant
- Occupational (HC)
With sexual transmission of HIV, what two conditions can create further increased risk for HIV contraction?
- HSV
- Syphilis
What constitutes HIV progression to AIDS?
CD4 T cell count <200
What are four “AIDS-defining” conditions?
- Kaposi’s sarcoma
- PCP
- PNA
- MAC infection
What is the diagnostic plan for HIV (2)?
EIA then Western Blot
What can be used to test HOW much HIV virus is present?
NAT
What is the most effective treatment for HIV?
RTI + PI in HAART
What should be used to evaluate the effectiveness of HIV treatment?
TRENDS of viral load (effective treatment = viral load decreases)
What does U = U mean, and for what condition is it used?
Undetectable = Untransmittable so if viral load is low enough, HIV is not contagious
What is the asexual stage of Malaria? What is the sexual stage?
- Asexual: trophozoites
- Sexual: gametocytes
What two things are released by humans to cause symptoms of Malaria?
- Pyrogens = fever/chills
- Tissue Necrosis Factor (TNF) = intensifies sxs
What three symptoms are often associated with Malaria?
- HIGH FEVER
- Anemia
- Hypotension
What two conditions/things are associated with host resistance of P. vivax?
- Sickle Cell Anemia
- Presence of/expressed Duffy gene
What specific organism does the Malaria vaccine act on, and what is the vaccine called?
Mosquirix
- Acts on P. falciparum
What Malaria organism infects young erythrocytes?
P. vivax
What diagnostic tool is used in Malaria?
Giemsa stain
What Malaria organism presents as enlarged RBCs with Schuffner’s dots?
P. vivax
How does P. vivax differ from P. falciparum in terms of cells infected?
- P. vivax = few infected
- P. falciparum = MANY infected
Which two Malaria organisms CAN relapse, and how?
Activation of liver hypnozoites
- P. vivax
- P. ovale
What Malaria organism infects ALL erythrocytes?
P. falciparum
What Malaria organism can cause possible capillary obstruction, and how?
P. falciparum
- infected RBCs stick to capillary linings = clots
What Malaria organism presents as RBCs with double or multiple ring stages?
P. falciparum
What Malaria organism presents with Maurer’s clefts?
P. falciparum
What Malaria organism infects older erythrocytes?
P. malariae
What Malaria organism presents as basket or band-shaped, and what is this?
P. malariae
- Trophozoites
What Malaria organism presents as rosette-shaped, and what is this?
P. malariae
- Schizonts
What is the primary reason behind multidrug resistance for treatment of Malaria? What is another possible cause?
Efflux pumps
- P is becoming increasingly independent of binding Duffy antigen
What condition involves “cross-like” morphology of RBCs?
Babesia microti
What organism causes Babesia microti?
Deer tick bites