Infectious Diseases Flashcards
Aedes aegyptes is the mosquito that transmits _____
Zika and Dengue
Anopheles mosquitos transmit _______
Malaria - Falciparum
Tsetse flies transmits _______
Sandflies transmit _________
Ixodes ticks transmit ________
Tsetse flies transmits trypanosomiasis.
Sandflies transmit leishmaniasis.
Ixodes ticks transmit Lyme disease.
Toxoplasmosis crosses the placenta ______ weeks after maternal infection
4-8 weeks
If mother get Toxoplasmosis during the pregnancy what do you treat her with?
And if amniotic fluid is positive?
Spiramycin
Pyrimethamine plus Sulphadiazine (supplement with folonic acid)
What are the most common clinical findings in a newborn with congenital Toxoplasmosis?
85% of congenitally infected infants appear normal at birth
85% of these will suffer one or more episodes opf chorioretinitis if left untreated
Hearing loss in 10-30%
Developmental delay in 20-75%
How long and what do you treat a newborn with confirmed diagnosis of congenital toxoplasmosis?
Pyrimethamine + Sulfadiazine + Folonic acid
Treat until 12 months of age (immune competent)
Are the risks of meningitis higher in EOS or LOS?
LOS
Perinatal syphillis can present in various ways - list atleast 5/7 of common signs seen?
- Osteochondritis/periostitis
- Snuffles, haemorrhagic rhinitis
- Skin changes: bullous lesions, palms/soles involved
- Unexplained enlarged placenta
- Nephrotic syndrome (rare, usually at 2-3 months of age)
- Hepatosplenomegaly +/- splenomegaly jaundice
- Non immune hydrops fetalis
Darkfield microscopy for spirochetes is seen in ______
Syphillis
If a mother is HBsAg positive and maternal HBeAg is positive - the rate of transmission:
- with treatment?
- without treatment?
- With treatment - 7-28%
- Without treatment 90%
RIsk of congenital rubella infection:
<8 weeks: XX
8-12 weeks: XX
12-20 weeks: XX
>20 weeks: XX
<8 weeks: 100%
8-12 weeks: 50%
12-20 weeks: 20%
>20 weeks: <1 %
Vaccine related birth defects in 1% if vaccine given first 4 weeks of pregnancy
Congenital XX syndrome:
SNHL (58%) + Eyes (cataracts, retinopathy, micropthalmia 43%), Cardiac (PDA, PS stenosis) + neurodevelopmental disability
Congenital rubella syndrome!
What time period of neonatal exposure to maternal varicella warrants treatment with ZIG?
If mother develops Varicella 7 days before delivery or 7 days after delivery
When is varicella normally infectious?
Varicella (chickenpox) is infectious from 48 hours before rash until crusting of all lesions has occurred (usually 5 days after rash starts).
Multiple plasmodium in an RBC is indicative of _______
Falciparum
Strep on agar plate with green haemolysis seen?
Alpha haemolytic
Three viruses with high R0 value?
Measles, pertussis, polio
What meningococcal vaccines are available?
Meningicoccal C conjugate
Meningicoccal conjugate vaccine - ACWY
(Above funded in australia)
Meningicoccal B vaccine
- there is a new 4C meningicoccal B vaccine
Which meningicoccal strain is on the rise?
W
Which vaccinations should be given in pregnancy?
Influenzae and pertussis
When during the pregnancy is the immunisation recommended?
Funded from 13 weeks gestation (recommended in second trimester)
HBIG can be administered upto ____ days after delivery
7 days
Check the Hep b status of babies with infected mothers at ___ months
at 9 mo
Check HbsAg and HBsAb
Vaccination prior to immunosuppression?
- complete all age appropriate vaccinations according to schedule
- Live viral vaccines are recommended prior to planned immunosuppression - if time permits
- Immunosuppression should not be delayed
If a patient is on high dose Azathioprine (>3mg/kg), 6-MP (>1.5mg/kg) or Methotrexate (>0.4mg/kg) how long do you delayed the administration of live vaccines?
Delay for 3 months after discontinuation
How long do you delay live vaccines after Leflunomide, teriflunomide?
6 months after discontinuation
How long after IVIG do you delay live vaccines?
?10 months
How long do you delay vaccines if a patient is on Sirolimus?
6 months
How much do you delaye vaccines for most biologics?
12 months
AUC/MIC is important in prescription of which anitbiotics
Vancomycin, azithromycin, fluoroquinolone, aminoglycosides
CMax/MIC is imporrtant in prescription of which antibiotics?
Aminoglycosides and fluoroquinolones
Vancomycin has no effect on ______-
Gram negatives
P. Aerigunosa is intrinsically resistant to ______
Cefotaxime (and other first and second Gen Cephs)
Enterococci have intrinsic resistant to ______
Cephalosporins
E. Faecalis - need to use Pen or Amox; or vanc
How does Clavulonic acid work?
Inhibits beta lactamase
Cephalosporins are resistant to ________ produced by Staph Aureus
Penicillinase (beta-lactamase)
Ceftriaxone, Cefotaxime and Ceftazidime are ______ generation cephalosporin
Cefepime is a _____ generation cephalosporin
3rd generation
4th Generation
Which cephalosporins will have some pseudomonas cover?
Ceftaroline and Cefepime
How do beta lactams work?
PBP (penicillin binding protein) normally connect and help form the bacterial cell wall - Beta lactams help bind onto PBP’s
What are the narrowest penicillin?
Pen V and Pen G
What bacteria are 1st generation cephalosporin effective against?
Stretococci
Staphylococci
Proteus
Escheria Coli
Klebsiella
Which Cephalosporin can treat Pseudomonas?
Ceftazidime
Which Cephalosporin can cross BBB?
Cefepime (4th) and Ceftazidime/Cefotaxime/Ceftriaxone (3rd gen)
How do Tetracyclines work?
Inhibit bacterial ribosomes and prevent protein synthesis
Bind to 30S subunit of ribosomes
What are side effects of Tetracycline?
Phototoxicity
Tinnitus
Accumulate in teeth and ones - permanent teeth discoloration
Not Doxy!
How do carbapenem work?
They bind to PBP’s and are resistant to beta lactamases
Cover Gram +ve, Gram -ve, Anaerobic species
How does Vancomycin work?
Latch onto the tetrapeptide chain (do not actually bind to the PBP)
How is Vancomycin resistance to Staph developing?
The Staph bug, puts a D-Lactate on tetra-peptides
What antibiotic is effective against ESBL?
Carbapenems
Which antibiotic lowers seizure threshold?
Carbapenem (Imipenem)
How is pneumococcal resistance to penicillin developing?
Changes in PBP which leads to decrease affinity of penicillin
Ciprofloxacin is a good or bad agent for Staph?
Bad!
Prolonged high dose of Fluxcloxicillin can have adverse event including….
Bone marrow suppression (neutropenia)
How does MRSA get it’s resistance?
Alteration to PBP site which prevents it binding to all penicillins and Cephalosporins (except Ceftaroline)
What is Ecthyma gangrenosum associated with?
Pseudomonas septicaemic - appears as skin lesions
How do you treat Strenotrophomonas maltophilia?
Co-Trimoxazole
Galactomannan antigen can be done on bronchial wash do diagnose….
Aspergillosis
First line agent for Aspergillus?
Voriconazole
2nd line - Caspofungin
(resistant to Fluconazole)
How do Polyenes work? (Amphotericin/Nyastatin)
Make holes in cells
How do the -Azoles work? (Antifungal)
Interfere with cell membrane synthesis (Ergosterol)
How does Echinocandins work? (Caspofungin/micafungin)
Inhibit cell wall synthesis by targetting Beta 1,3 D glucan synthesis
1st line empiric antifungal?
Amphotericin
Does Caspofungin penentrate urine/CSF?
NO
Side effects of Co-trimoxazole?
Neutropenia
HHV 5 is ….
CMV
What are the effects of CMV in a immunocompromised person?
Pancytopenia, colitis, pneumonitis, retinitis, encephalitis, myocarditis
First line for CMV treatment in HSCT?
Gancyclovir (IV)
How can you treat RSV in an immunocompromised patient?
Ribavirin
How do you treat Adenovirus in immunocompromised?
Cidofovir
Before commencing TNF alpha antibody?
It puts you at risk of TB - thus important to do IGRA and CXR
If starting Eculizumab (anti-terminal complement 5) what should you vaccinate for?
Meningicoccal vaccination (add oral amoxicillin for two weeks if urgent)
The predominant organisms isolated from anaerobic empyemas are Fusobacterium nucleatum, Prevotella sp, Peptostreptococcus, bacteroides fragillis
- what might be a good antibitoics to treat?
Clindamycin
What is the MIC cut off for Penicillin and Cef in bacterial meningitis?
Penicillin MIC <0.125
Cef MIC <1
How do you treat Malaria?
IV Artesunate and fluid boluses ARE NOT recommended
What are the two malaria types that can lay dormant in the liver before becoming active?
Plasmodium Vivax and Ovale
Erythrocytes lacking Duffy blood group antigen are relatively resistant to _______, and erythrocytes containing hemoglobin F (fetal hemoglobin) and ovalocytes are resistant to ________
Erythrocytes lacking Duffy blood group antigen are relatively resistant to P. vivax, and erythrocytes containing hemoglobin F (fetal hemoglobin) and ovalocytes are resistant to P. falciparum
While the rupture of schizonts that occurs every 48 hr with ______ and ______and every 72 hr with ________ can result in a classic pattern of fevers every other day or every 3rd day (as it is related to when the bug breaks out of the erythrocyte
While the rupture of schizonts that occurs every 48 hr with P. vivax and P. ovale and every 72 hr with P. malariae can result in a classic pattern of fevers every other day (P. vivax and P. ovale) or every 3rd day (P. malariae)
Most severe form of malaria is ______
Falciparum - shorter incubation and higher parasite load
Childhood herpes zoster has several recognised risk factors, which include the following:
- Acute lymphocytic leukaemia and other malignancies
- Immunocompromised state as a result of treatments or human immunodeficiency virus (HIV)
- In utero varicella exposure
- Primary VZV infection that occurred in the first year of life
- Antitumor necrosis factor-alpha agents (may pose an increased risk)
Parovirus B19 causes….
Slapped cheek - erythema infectiosum
How do you treat Kingella?
Cefazolin
If an infant receives the MMR vaccine early (6-11mo) - what should be the further follow up/vaccine schedule?
Infants who receive a dose of MMR vaccine at 6 through 11 months of age should receive
two additional doses, separated by at least 28 days, beginning at age 12 to 15 months.
Properidin deficiency is associated with ______
N. meningitidis meningitis
What are the four minor manifestations in Rheumatic fever?
The four minor manifestations are:
1. Arthralgia
2. Fever
3. Elevated acute phase reactants (erythrocyte sedimentation rate [ESR], C-reactive
protein [CRP])
4. Prolonged PR interval on electrocardiogram
What are the five major manifestations of Rheumatic fever?
- Carditis and valvulitis (e.g., pancarditis) that is clinical or subclinical – 50 to 70
percent - Arthritis (usually migratory polyarthritis predominantly involving the large joints) –
35 to 66 percent - Central nervous system involvement (e.g., Sydenham chorea) – 10 to 30 percent
- Subcutaneous nodules – 0 to 10 percent
- Erythema marginatum
What are the four minor manifestations in Rheumatic fever?
The four minor manifestations are:
1. Arthralgia
2. Fever
3. Elevated acute phase reactants (erythrocyte sedimentation rate [ESR], C-reactive
protein [CRP])
4. Prolonged PR interval on electrocardiogram
What are the five major manifestations of Rheumatic fever?
- Carditis and valvulitis (e.g., pancarditis) that is clinical or subclinical – 50 to 70
percent - Arthritis (usually migratory polyarthritis predominantly involving the large joints) –
35 to 66 percent - Central nervous system involvement (e.g., Sydenham chorea) – 10 to 30 percent
- Subcutaneous nodules – 0 to 10 percent
- Erythema marginatum
Urease-producing bacteria (mnemonic PUNCH):
Proteus, Klebsiella - predispose to struvite stone production (UTI) Ureaplasma urealyticum Nocardia Cryptococcus Helicobacter pylori
What is the triad seen in infant botulism?
1) Acute onset of a symmetric flaccid descending paralysis with clear sensorium
2) No fever
3) No paresthesias
How do you diagnose infant botulism?
Presence of botulinum toxin in serum
C. botulinum toxin or organisms in wound material, enema fluid, or feces
How do you treat infant botulism?
Human botulism immune globulin, given intravenously
When is measles most infectious?
3 days before rash to 6 days after rash onset
3 week, non-bloody diarrhea post bali
Giardia (chronic, non-bloody diarrhea)
Patient should be tested for latent TB before commencing which immunosupressant?
TNF-alpha inhibitor
What is the primary site of action of clindamycin?
50S ribosomal RNA
What is the gram stain appearance of Listeria monocytogenes?
Gram positive rod
Why is enterobacter cloacae resistant to cephalosporins?
Upregulation of chromosomal beta-lactamase
Precautions for chickenpox?
Airborne
Hypotension, interstitial pneumonitis, aseptic meningitis and associated hepatosplenomegaly with jaundice
Leptospirosis
By which mechanism do super antigens work?
T cell stimulation?
Vancomycin is similar to which antibiotic?
Teicoplanin
What sort of bug is Kingella?
And what should you treat with?
Gram-negative facultative anaerobic β-hemolytic coccobacilli
Often Kingella is more indolent
Treat with - Cefazolin, ceftriaxone
Is MRSA sensitive to Bactrim?
Yes
What antibiotics would you use for GAS toxic shock?
Penicillin + Clindamycin!