Infection Flashcards
What CT changes do you see in hepatitis encephalitis
Changes in temporal lobes
What infection is seen in people who keep snakes?
Salmonella
Which pathogen grows in 0-4 degrees?
Listeria monocytogenes
What is the structure of a virus?
Core nucleic acid surround ed by protective protein coating known as the capsid
Capsid mediates the attachment of the virus to specific host cell receptors
Can viruses synthesis their own energy?
No - dependent on host cell to replicate
What is bacterial classification based on?
Gram reaction
Bacterial shape
Growth requirement
Presence of spores
What is the structure of bacteria?
Cytoplasm surrounded by cell wall
DNA is free within the cytoplasms as a single chromosome of circular dNA and plasmids
What does gram positive bacteria have?
Thick peptidoglycan layer with no outer membrane
What do gram negative bacteria have?
Thin peptidoglycan layer surrounded by an outer lipid membrane
Endotoxin on outer layer
Name beta-lacetam agents
Penicillins
Cephalosporins - ceftriaxone, cefuroxime
Carbapenems - meropenam
Name examples of macrolide
Erythromycin
Azithryomycin
Clarithryomycin
Name example of tetracycline
Doxycycline
Name example of aminoglycosides
Gentamycin
Name example of glycopeptide
vancomycin
teicoplanin
Which ABX cause disruption of bacterial cell wall?
B-lactams
Glycopeptide
What Type of infections are B-lactams used for?
Gram positive
What can 3rd generation - cephalosporins the used for?
Gram positive and gram negative
What can glycopeptides be used for?
Gram positive
Which class of ABX inhibit protein synthesis?
Macrolides
Tetracyclines
Aminoglycosides
Clindaymycin
What are aminoglycosides good for?
gram negative
Which ABX cause inhibition of DNA replication?
Fluroquinolones - ciprofloxacin
What is the most common parasite to cause malaria ?
P.falciparum
Worldwide in sub and tropical areas
What are other parasites that cause malaria?
Plasmodium vivax - Asia, South America, some African
Plasmodium ovale- West africa, western pacific
Plasmodium malaria
What is released into the blood stream when an infected mosquito bites?
Sporozoites are released into blood stream and move to liver cells
What do sporozoites involve in to?
Schizonts (mature sporozoites in liver)
How does malaria spread in the body?
Schizonts rupture and release meroziotes
Meroziotes infect the blood and replicate
Red blood cells rupture and release more meroziotes into the system
How long until malaria is present post visiting an infected country?
P.falciparum - 3 months (10-28 days)
P.vivax and P.ovale - 6 months - HYPOZOITES represent dormant stage in liver
How many negative films are required to exclude malaria?
3 negative within 12-24 hours apart
How is chronic granulomatous disease inherited
X linked disease
What is the pathophysiology of chronic granulomatous disease?
Phagocytes lack the ability to produce microbicidal reactive oxygen species so bacteria aren’t killed or digested properly
Mainly catalase-positive bacteria
When do you suspect CGD?
Recurrent pnuemonias
Lymhphadenitis
Hepatic / subcutaneous or other abscesses
Osteomyelitis at multiple sites
Name catalase-positive bacteria
Stapylococcus, salmonella
Pseudomonas
Aspergillus
Canidida
Enterobacteriacae (E.coli, klebsiella, salmonella, serratia)
How is CGD diagnosed?
Using DHR test
What are symptoms of IgE mediated allergies?
Immediate
Urticaria
Angiooedema
upper resp. tract infection
anaphylaxis
What are non IgE mediated reactions?
Usually delay - 72 hours post exposure
Bloody diarrhoea
Constipation
Colic prdominate
How do you test for IgE mediated reactions?
skin-prick test
specific serum IgE testing
How do you test for non-IgE mediated reactions?
dietary exclusion
Pathophysiology of HIV
RNA retrovirus - enzyme reverse transcriptase
Enters CD4 lymphocytes (helper T cells) via fusion of viral cell membrane to host cell membrane
Migrates to lymphoid tissue and replicates
HIV transcribed into host dNA
What secretes T.gondii oocysts
Excreted in cat feaces
What are tachyzoites?
Active proliferating cause of T.gondii
Neonatal toxoplasma infection features
Hydrocephalus
Microcephaly
Chorioretenitis
Intracranial calcifications
TORCH
Toxoplasma gondii
Other agents - HIV, parvovirus, VZV
Rubella
CMV
Herpes simplex virus
Characteristics of toxoplasma gondii
Intracranial calcifications
Inflammation of choroid and retina
Hydrocephalus
Rubella characterised
Deafness
Rash
Cataracts
Heart defects
Characteristics of CMV
Microcephaly
periventricular calculations
Chorioreteinitis
HSV
Type 1 - oral herpes
HSV 2 - STI
Congenital syphilis - What is the bacterium that causes it
Treponema pallidum
Signs of congenital syphilis
Craniofacil malformation
Rash
Deadness
What is most common vector for leishmaniasis
sand fly
Stage 1 of early Lyme disease
erythema migrans
Stage 2 - disseminated Lyme disease
Flu-like symptoms
Neurological disorders - facial nerve palsies
Myopericarditis
Stage 3 - late manifestations of Lyme disease
arthritis
Acrodermatitis chronia atrophicans
Post lyme syndrome - fatigue
Treatment of Lyme disease
doxycycline 21 days
amoxicillin if doxy not appropriate
azithromycin fo 17 days
When can a HIV +ve mum breast feed
if viral load undetectable
top up formula feeds can’t be used
When would you start treatment in a HIV +VE child
all children with confirmed HIV should be started on antiviral therapy irrespective of CD4 count
if child > 6 weeks and <12 months -start co-trimoxazole respective of Cd4 COUNT
1-4 years - only start co-trimoxazole if cd4 <15% or <500
5 years <15% or <200
hereditary angioedema - C1 levels?
low c1 inhibitor
What causes cat scratch disease
Bartonella henselae
What type of hypersentiivty reaction is contact dermatitis
Type 4 -T lymphocytes reacting with a previous sensitised antigen
