ID Flashcards
What causes neurocysticerosis?
Taenia solium
Ingested larvae from undercooked pork
Treatment for cysticercosis
Praziquantel
Treatment for neurocysticerosis
Albendazole
Cause of hydatid cysts in liver and lungs?
What occurs when they rupture
Echinococcus granulosus
If hydatid cysts rupture can cause anaphylaxis
Tx Albendazole
What does clononchis sinesis increase risk of?
Cholangiocarcinoma
Schistosomas can cause which type of inflammatory disease?
Granulomatous disease
Why in acute schistosomiasis do you have severe fever, uricaria, angiooedema, myalgias and arthralgias 3-8 weeks post infection
Period of egg production, increased Antigen production causing hypersensitivity
Chronic schistosomasis leads to increased risk of?
SCC of bladder
Pulmonary HTN
Treatment for schistosomaiasis
Praziquantel
Corticosteroids
Treatment of scabies
Permethrin cream
Oral ivermectin
What is genetic recombination
Viruses exchange genetic material
What are the ESCAPPM organisms?
Enterobacter
Serratia
Citrobacter
Aeromonas
Proteus
Providencia
Morganella
MoA of penicillin
D-ala-D-ala structural analogue that Binds penicillin binding proteins -> blocks cross linking of peptidoglycan wall
MRSA resistance mechanism
Altered penicillin binding proteins
What are penicillinase sensitive penicillins and what use do they have?
Amoxicillin and ampicillin
Extended spectrum penicillin HHEELPSS
H influenza h pylori e coli enterococci listeria proteus salmonella shigella
Penicillin toxcitities
Direct coombs positive haemolytic anaemia
Drug induced interstitial nephritis
C diff pseudomembranous colitis
Hypersensitivity
Moa of vancomycin
Inhibition of peptidoglycan formation by binding to d ala d ala
Aminoglycoside moa
Irreversible inhibition of ribosome initiation complex Binds 30s subunit, needs o2 so no anaerobic activity
Aminoglycoside mechanism of resistance
Bacterial transferase enzymes inactivate the drug via acetylation, phosphorylation or adenylation
Linezolid moa
Inhibits ribosome 50s unit and prevents initiation complex
Linezolid resistance
Point mutation of ribosome rna
What are the macrolides
Azithromycin, erythromycin, clarithromycin
Macrolide moa
Inhibit translocation in the ribosome so proteins cannot be produced, bacteriostatic
Macrolide uses
Atypical mycoplasma, chlamydia, legionella, Gram +ve cocci
Macrolide resistance
Methylation of 23s rRNA binding site, drug can’t bind
Macrolide side effects
MACRO
gi motility, arrthymia (qt prolongation) cholestatic hepatitis, rash, eosinophilia
Linezolid also inhibits
MAO inhibitor, causes serotonin syndrome
Linezolid ADRs
Thrombocytopenia, peripheral neuropathy, serotonin syndrome, lactic acidosis
Tetracyclines and moa
Doxycycline
Binds to 30s subunit, prevents trna attachement
Doxycycline resistance
Reduced uptake or increased removal from cell by Plasmid encoded transport pump
Type of bacteria doxycycline best against
Intracellular
Rickettsia and chlamydia
Use in atypicals
Clindamycin moa
Blocks tranlocation of peptides at 50s ribosome subunit
Clindomycin uses
Aneorobes above the diaphragm
Clindamycin adrs
C diff
Sulfonamides and their moa
Sulfamethoxazole
Inhibit DHF synthesis, inhibits foliate synthesis, bacteriostatic
Sulfonamides adr
Hypersensitivity
If g6pd def then haemolysis
Tubulointerstitual nephritis
SJS
Displaces other drugs from alb (warfarin)
Sulfonamides resistance
Altered enzyme leads to decreased uptake or increases PABA synthesis
Dapsone moa
Inhibit DHF synthesis, inhibits foliate synthesis, bacteriostatic
Dapsone adrs
Methhaemoglobulinaemia, agranulocytosis, hameolysis if g6pd def
Trimethoprim moa
Inhibits bacterial dihydrofolate reductase, bacteriostatic
Trimethoprim adrs
HyperK, megaloblastic anaemia, leukopenia, granulocytopenia
Daptomycin moa
Creates transmembrane channels in Gram +ve cocci
What is dapsone used in
S aureus skin infections
Can’t use in lungs, inactivated by surfactant
Dapsone adrs
Myopathy, rhabdo
Metronidazole moa
Forms toxic free radical metabolites in bacteria which kills it
Also kills protozoa
Metronidazole adrs
Red Man syndrome (disulfram like reaction, severe flushing, tachy, low bp) with alcohol, headache, metallic taste
Metronidazole used for
Get gap on the metro
Giardia
Entamoeba
Trichmonas
Garderella vaginalis
Anaerobes
Fluroquinolones and moa
Ciprofloxacin, moxifloxacin
Inhibits prokaryotic enzymes topoisomerase 2 and 4 (DNA gyrase inhibition)
Fluroquinolones adrs
GI, superinfections, rash, headache, dizziness, rarely myalgias, cramping, tendon rupture
Fluroquinolones resistance
Mutation in DNA gyrase
Plasmid medicated resistance
Efflux pumps
Rifampin moa
Inhibit bacterial rna polymerase -> reduced mrna synthesis
Rifampin adrs
Hepatotoxicity, cypP450 inducer
Red-orange body fluids
Isoniazid moa
Inhibits mycolic acts synthesis and reduces cell wall synthesis
Needs bacterial catalase peroxidase in order to convert to active form (encoded by KatG)
Isoniazid resistance
Needs bacterial catalase peroxidase in order to convert to active form (encoded by KatG)
Mutations in katG
Insoniazid causes what deficiency
Vit B6 (pyridoxine)
Isoniazid adrs
B6 def, hepatotoxicity, cypP450 inhibition, drug induced lupus, overdose causes seizures
Pyrazinamide adrs
Hepatotoxicity, hyperuricaemia
Ethambutol moa
Inhibits arabinosyltransferase, reduces arabinogalactan synthesis and reduces cell wall synthesis
Ethambutol adrs
Optic neuropathy (red-green colour blindness and decreased visual acuity)
Usually reversible
Treatment of TB leprosy
Dapsone and rifampin
Add clofazimime for lepromatous form
Amphotericin B and nystatin MoA
Binds ergosterol and forms membrane pores which leak electrolytes
Treatment considerations when using amphotericin B
supplement K and Mg due to altered renal tubule permeability
Amphotericin B ADRs
nephrotoxicity, arrthymias, anaemia, phelbeitis, fever/chills, hypotension
MoA of Flucytosine
Antifungal
Inhibts DNA and RNA synthesis by converting to 5FU through cytosine deaminase
ADR of Flucytosine
Myelosuppression
What are the azoles
clotrimazole, fluconazole, voriconazole, ketoconazole
MoA of Azoles
Inhibits fungal ergosterol synthesis by inhibiting CYP450 (usually converts lanosterol to ergosterol)
Azole ADRs
Testosterone synthesis inhibition (gynocomastia), liver dysfunction, QT prolongation
Terbinafine MoA
Inhibits fungal enzyme squaline epoxidase, stops lanosterol synthesis
What are the Echinocandins
Anidulafungin, caspofungin, micafungin
MoA echinocandins
inhibits Beta-glucan synthesis which inhibits cell wall synthesis
Griseofulvan MoA
interferes with microtubule function, accumulates in nails
Griseofulvin ADRs
teratogenic, carcinogenic, confusion, headaches, disulfram-like reaction, increased CYP450 and warfarin metabolism
What is a disulfiram-like reaction
adverse reaction to alcohol (N+V, headache, dizziness, hangover) caused by accumulation of acetaldehyde
Cephalosporins, macrolides, sulfonureas
Oseltamivir MoA
Inhibits influenza neuramindase, reduces viral progeny release
Remdesivir MoA
prodrug of ATP analogue
inihibts viral RNA-dependent RNA polymerase and evades viral proof-reading, reducing viral RNA production
Aciclovir, Famiciclovir, valaciclovir MoA
guanosine analogues
phosphorylated by HSV/VZV viral thymidine kinase (not activated in uninfected cells and in CMV), inihibits viral RNA polymerase
Valacyclovir is aciclovir prodrug, has beeter oral biovailability
Aciclovir, Famiciclovir, valaciclovir ADR
obstructive crystalline nephropathy and AKI if not hydrated enough
Aciclovir, Famiciclovir, valaciclovir resistance
mutated viral thymidine kinase
Ganciclovir MoA
Guanosine analoug
phosphorylated by CMV viral kinase, inhibits DNA polymerase
Valganciclovir is prodrug, has better bioavailability
Foscarnet MoA
Viral DNA/RNA prolymerase inhibitor and HIV reverse transcriptase inhibitor
Foscarnet ADRs
Nephrotoxicity
Electrolyte disturbance
Cidofovir MoA and ADR
Inhibits viral DNA polymerase
ADR: nephrotoxicity (use with probenicid and saline to reduce toxicity)
Common combo of HIV therapy
2 NRTIs and an integrase inhibitor
Therapy used for HIV PrEP
Tenofovir and emtricitabine
NRTIs MoA
abacavir, tenofovir
inhibit nuceloside binding to reverse transcriptase to terminate DNA chain
NRTI ADRs
myelosuppression, nephrotoxicity
When is abacavir contraindicated?
HLAB5701 mutations, increases hypersensitivity
NNRTIs ADRs
rash, hepatoxocitity
Integrase inhibitor MoA
inhibiting integrase prevents HIV genome integration into host cell chromosome
Integrase inhibitors ADRs
raised CK, weight gain
Protease inhibitors all need to be prescribed with
ritonavir or cobicistat
Protease inhibitors MoA
protease usually cleaves RNA into functional parts, if inhibited prevents maturation of new virions
Protease inhibitor ADRs
hyperglycaemia, nausea and diarrhoea
MoA of enfuvirtide
binds gp41, inhibiting entry
Fusion inhibitor
Maraviroc MoA
binds CCR5 and inhibits interaction with gp120
NS5A inhibitors MoA (hep C therapy)
end in pasvir
is a viral phosphorylase which plays key role in RNA replication
NS5B inhibitors MoA
end in buvir
RNA-dependent RNA polyermerase, prevents viral replication
NS3/4A inhibitors MoA
end in previr
inhibit viral protease, prevents replication
Ribavirin MoA
inhibits guanine synthesis
Treatment for acyclovir resistant HSV
Foscarnet or Cidofovir
Extrahepatic manifestations of Hep C
DM
Autoimmune hypothyroidism
Membronous/membranoproliferative GN
Lichen planus
Empiric treatment for sepsis in splenectomy
Ceftriaxone and vanc
mortality in sepsis and splenectomy
50%
Most common organisms causing sepsis in splenectomy pt
strep pneumoniae
H influenza
Neisseria meningiditis
empiric sepsis tx pre hospital
ceftriaxone
empiric tx community acquired
Gent and fluclox
add vanc is MRSA
add ceftriaxone if meningitis
(cefazolin if allergic)
empiric tx of hospital sepsis
PipTaz
What is ecthyma gangrenosum and what caused by
rash with haemorrhagic vesicles, rim of erythema and central necrosis
Caused by pseudomonas
What causes sepsis after ingesting raw shellfish (US) -> sudden malaise, fever, hypotension
bullous haemorrhagic lesions
occurs in liver disease, DM, renal insuff, cancer
vibrio vulnificus
Most common causitive organisms of nec fasc
group a strep
clostridium perfringins
empriric treatment for nec fasc
meropenam or pip/taz plus vancomycin plus clindamycin
if water associated wound add ciprofloxacin
Pneumovax dosing for adults
1 dose when non indigenous 70yo
aborginal >50yo 3 doses
pneumovax 23 better at preventing adult infections