DIT review - Micro 6 Flashcards
1
Q
Patients with what diseases should you be cautious giving beta-blockers to?
A
Diabetics (masks hypoglycemia)
Asthma (exacerbates asthma)
CHF (depression of cardiac contractility)
2
Q
Most common viral causes of meningitis
A
- Enterovirus (most common) – Coxsackievirus, Echovirus, Poliovirus
- Arbovirus
- Herpes simplex virus type 2
3
Q
Most common bacterial cause of meningitis is neonates
A
- Group B strep
- Gram negative bacilli (E. coli)
- Listeria
4
Q
Most common bacterial cause of meningitis in adults
A
- Strep pneumoniae
- Neisseria meningitides
- H. flu type B
5
Q
Most common cause of bacterial meningitis in elderly
A
- Strep pneumonia
- Gram (-) rods
- Listeria
6
Q
Describe CSF findings of fungal/TB meningitis (opening pressure, WBC predominance, protien, glucose)
A
Same as bacterial except for WBC predominance:
- Elevated opening pressure
- Lymphocyte predominance (only difference between bacterial)
- Increased protein
- Low glucose
7
Q
MOA of Sulfonamides and Trimeothoprim
A
- Sulfonamides:
- Inhibits dihydropteroate synthase (PABA à dihydrofolic acid)
- Same mechanism as Dapsone (used for Leprosy)
- Inhibits dihydropteroate synthase (PABA à dihydrofolic acid)
- Trimethoprim:
- Inhibits dihydrofolate reductase (dihydrofolic acid à THF)
- Bacteridical when used together
8
Q
Uses of TMP/SMX
A
- UTI’s, MRSA, Nocardia, Pneumocystis jirovecci
- Prophylaxis:
- PJP CD4 < 200
- Toxoplasmosis CD4 < 100
9
Q
Adverse effects of both TMP/SMX
A
- Pancytopenia (due to folate deficiency)
- Megaloblastic anemia
- Teratogenic (neural tube defects)
10
Q
Adverse effects of sulfa drugs
A
- Sulfa-allergy – fever, rash, urticarial
- Hemolytic anemia in G6PD deficiency
- Stevens-Johnson syndrome
- Type IV RTA
- Interstitial nephritis
- Photosensitivity
- Kernicterus of neonate
- Displace other drugs from albumin (e.g. Warfarin)
- Drug-induced lupus
11
Q
MOA of fluoroquinolones
A
- Inhibits topoisomerase (e.g. DNA gyrase which normally relieves supercoiling)
- Bactericidal
- Decreased absorption when taken with divalent cations
- Do not take with milk, antacids, or iron supplements
12
Q
Uses of Fluoroquinolones
A
- Mostly gram (-)
- UTI’s (E. Coli, Proteus, Psuedomonas)
- Pyelonephritis
- GI bugs (Shigella, Salmonella, E. coli, Campylobacter)
- Osteomyelitis (Salmonella)
- Some gram (+)
- Bacillus anthracis
- Pneumonia (Strep pneumo, Mycoplasma pneumonia, legionella)
13
Q
Adverse effects of fluoroquinolone
A
- Prolonged QT interval
- GI distress (N/V/D)
- Tendon and cartilage damage
- Tendon rupture in elderly and those taken steroids
- Teratogenic
14
Q
MOA of Metronidazole
A
Forms toxic free radical metabolites in the bacterial cell that damage DNA
15
Q
Uses of Metronidazole
A
- THINK: GET GAP on the Metro:
- Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobes (bacteroides, C. Diff), H. Pylori
- Anaerobes below the diaphragm
16
Q
What is the DNA virus that does not replicate in the nucleus
A
Poxvirus
17
Q
What is the RNA virus that does not replicate in the cytoplasm
A
Influenza and retrovirus
18
Q
What is the only ssDNA virus
A
Parvovirus
19
Q
What is the only dsRNA virus
A
Reovirus
20
Q
What is viral recombination
A
- Exchange of genes between 2 chromosomes by crossing over within region of significant base sequence homology
21
Q
What is viral reassortment
A
- When viruses with segmented genomes (BOAR) exchange genetic material
22
Q
What is viral complementation
A
- When 1 of 2 viruses that infects the cell has a mutation that results in a nonfunctional protein, the nonmutated virus “complements” the mutated one by making a functional protein that serves both viruses
23
Q
What is viral phenotypic mixing
A
- Occurs wit simultaneous infection of a cell with 2 viruses; genome of virus A can be partially or completely coated with the surface proteins of virus B; Type B protein coat determines the tropism (infectivity) of the hybrid virus; however, the progeny from this infection have type A coat encoded by type A genetic material
24
Q
What are the different Herpesviruses?
A
HSV1
HSV2
VZV (HHV3)
EBV (HHV4)
CMV (HHV5)
Roseola (HHV6)
Kaposi (HHV8)
25
What is a Tzank smear and what pathogens will have a positive Tzank smear
* Scrape base of lesion and look under microscope for multinucleated giant cells
* Can detect HSV-1, HSV-2, or VZV but cannot differentiate between the three
26
What are Cowdry bodies and what disease are they seen in?
* Intranuclear eosinophilic inclusions
* Seen in HSV-1, HSV-2, and VZV
27
Severe presentation of VZV primary infection in adults
Encephalitis, pneumonia
28
Describe the role of B-cells and T-cells in EBV
* Infects B-cells via CD21 then amounts a large CD8 T-cell response (atypical lymphocytes)
29
What are Downey cells and what disease are they seen in?
* T-cells that are responding to EBV
* Have a foamy appearance
30
What is the fear of confusing EBV with strep throat
* Giving Aminopenicillins (Amoxicillin) will cause maculopapular rash on trunk and extremities)
31
Describe presentation of CMV in the following populations:
* Immunocompetent
* Transplant patients
* AIDs
* Congenital
* Immunocompetent patients:
* Monospot (-) mononucleosis – sore throat, lymphadenopathy, fatigue
* Immunocompromised patients:
* Transplant patients – pneumonia
* AIDs patients – Retinitis, esophagitis, colitis
* Congenital:
* Blueberry muffin rash, hepatosplenomegaly, jaundice, hearing loss, ventriculomegaly, ventricular calcifications, mental retardation, seizures
32
In what cells does CMV maintain dormancy and what is the characteristic feature of infected cells
* Latent in mononuclear cells (lymphocytes, monocytes, macrophages)
* Infected cells have “owl eye” inclusions
33
Describe presentation of HHV-6
* Causes Roseola in children (aka exanthema subitum)
* 3-5 days of high fever followed by diffuse maculopapular rash that spares the face
* Can cause febrile seizures
34
Transmission of HHV6
Saliva
35
Transmission of HHV8
Kaposi
Sexual contact
36
MOA, activation, and uses of Acyclovir
* MOA:
* Guanosine nucleoside analog
* Incorporates into replicating DNA and inhibits viral DNA polymerase via chain termination
* Activation:
* Mono-phosphorylated by HSV/VZV thymidine kinase
* Only effective in HSV/VZV
* Only effective against infected cells
* 2nd and 3rd phosphorylation via cellular kinases
* Uses:
* Treats symptoms of HSV but does not affect recurrence (treats encephalitis)
* VZV (Famciclovir and Valacyclovir are preferred)
37
Adverse effects of Acyclovir and related drugs
* Intersitial nephritis, crystalline nephropathy
* CNS effect – Delirium, confusion, vertigo, hallucination
38
Uses of Valacyclovir
* Prodrug of Acyclovir – same MOA
* Better oral bioavailability
* Uses:
* Same as Acyclovir
* Can be used as suppressive therapy for recurrence
* Preferred over Acyclovir for VZV
39
Uses of Famciclovir
* MOA = same as Acyclovir
* Uses:
* Same as Acyclovir
* Preferred over Acyclovir for VZV
40
MOA, activation, uses, and adverse effects of Ganciclovir
* MOA:
* Guanosine nucleoside analog
* Incorporates in to viral DNA, inhibiting viral DNA polymerase
* Activation:
* Mono-phosphorylated by CMV viral kinase
* 2nd and 3rd phosphorylation via cellular kinase
* Uses:
* CMV (especially in immunocompromised)
* Adverse effects:
* Myelosuppression
41
MOA and uses of Foscarnet
* MOA:
* Directly inhibits viral DNA/RNA polymerase
* Does not require intracellular activation/phosphorylation
* Uses:
* CMV when Ganciclovir fails
* Acyclovir-resistant HSV
42
Adverse effects of Foscarnet
* Adverse effects:
* Nephrotoxicity, hypocalcemia, hypomagnesemia, hypokalemia, seizures (from electrolyte disturbance)
43
MOA and uses of Cidofovir
* Cidofovir
* MOA:
* Directly inhibits viral DNA/RNA polymerase
* Does not require intracellular activation/phosphorylation
* Uses:
* CMV retinitis
* Acyclovir-resistant HSV
44
How do you prevent adverse effects of Cidofovir
* Adverse effects:
* Nephrotoxicity
* Administer with **Probenecid** to block the tubular secretion of Cidofovir
45
