Infectious Diseases Flashcards
1
Q
Mechanisms of resistance
A
Antibiotic inactivation
- Beta lactamases
- Pneumococcus and macrolides
- Enzymatic modification of aminoglycosides
Alteration of antibiotic target
- Pneumococcus and penicillin
- Staph aureus and methicillin like antibiotics
Decreased uptake
- Reduced penetration
- Antibiotic effluc
2
Q
MRSA mechanism of resistance
A
Penicillin-binding protein mutation coded by the mecA gene on a transposon
3
Q
MRSA treatment
A
Vancomycin
Teicoplanin
Rifampicin
Fusidic acid
Ciprofloxacin
Clindamycin
4
Q
VISA mechanism of resistance
A
Genes code for factors such as additional peptidoglycan synthesis and reduced need for peptidoglycan cross-linking
5
Q
VISA management
A
Teicoplanin
Linezolid
Quinupristin-dalforpristin
Cotrimoxazole
6
Q
VRE pathogens
A
E faecium
E faecalis
7
Q
VRE mechanism of resistance
A
- penicillin-binding protein mutations
- beta-lactamase production
- aminoglycoside-modifying enzymes
- antibiotic drug efflux pumps
- alterations in cell wall components coded by transposons (Van A to F phenotypes)
8
Q
Treatment of VRE
A
Teicoplanin
Linezolid
Daptomycin
Tigecycline
Van A: resistant to vancomycin and teicoplanin
Van B: resistant to vancomycin, teicoplanin may be effective but resistance likely to emerge with prolonged use (use linezolid, tigecycline, dalfopristin-quinapristin, daptomycin)
Van C: partly resistant to vancomycin
9
Q
ESCAPPM organisms
A
Enterobacter species
Serratia species
Citrobacter freundi
Aeromonas
Proteus vulgaris (non-mirabilus) + Pseudomonas
Providencia
Morganella morganii
10
Q
ESCAPPM resistance and mechanism
A
Resistance to cephalosporins (especially third generation) due to overexpression of induceable chromosomal AmpC/β-lactamase enzymes.
11
Q
Treatment of ESCAPPM
A
Carbapenems
Fourth generation cephalosporins
Ciprofloxacin
Aminoglycosides
12
Q
Mechanism of penicillin resistance in staph aureus
A
- Production of beta-lactamase, conferred by the gene blaZ - inactivates penicillin by hydrolyzing the beta-lactam ring
- Altered penicillin-binding protein, PBP2a, encoded by mecA
13
Q
Classes of beta lactamase enzymes
A
A - penicillinases (TEM, SHV, CTX-M)
B - metalloenzymes (NDM, VIM, IMP)
C - cephalosporinases (AmpC)
D - oxacillinases (OSA)
14
Q
ESBL mechanism of resistance
A
Arise by
- mutations in old beta lactamase genes (i.e. TEM, SHV)
- Plasmid mediated transfer
15
Q
ESBL organisms
A
Klebsiella
E coli
Salmonella
Proteus
Enterobacter
Citrobacter
Serratia
Pseudomonas
16
Q
Treatment of ESBL
A
Carbapenems
Colistin
Amikacin
Ciprofloxcin
17
Q
Metallo betalactamases organisms
A
Pseudomonas
Acinetobacter
18
Q
Metallo betalactamases mechanism of resistnace
A
New Delhi metallo-Clactamase 1 (NDM-1) - an enzyme that produces resistance to a broad-range of beta-lactam antibiotics
produces a carbapenemase
19
Q
Treatment of metallo-beta-lactamases
A
Tigecycline
Colistin
20
Q
Linezolid mechanism
A
Activity against gram positive (+ mycobacteria, nocardia spp.)
Inhibits protein synthesis
21
Q
Side effects of linezolid
A
GI upset
Cytopenias
Neuropathy
MAO inhibition (avoid SSRIs, tramadol, pethidine)
22
Q
Daptomycin mechanism
A
Cyclic lipopeptide
Binds to cell membrane and leads to inhibition of synthesis of DNA, RNA and protein
Bactericidal activity against most gram positive
23
Q
Tigecycline mechanism
A
Protein synthesis inhibitor
Bacteriostatic
24
Q
Tigecycline targets
A
MRSA, MSSA, VISA, VRE - low MICs required
Active against gram negatives (except pseudomonas)
25
Ceftaroline/ceftobirole mechanism and targets
Novel cephalosporins
Active against MRSA
Not good for VRE
26
Colistin mechanism
Binds lipopolysaccharides and phospholipids in outer cell membrane
Leads to disruption of outer cell membrane, leakage and cell death
27
Colistin targets
Pseudomonas
Acinetobacter
E Coli
Enterobacter spp
Klebsiella
Salmonella
Stenotrophomonas
28
Fosfomycin mechanism
Inhibits MurA enzyme and bacterial cell wall biogenesis
Bactericidal
29
Fosfomycin targets
Targets gram -ve and +ve resistant cystitis UTIs
Not pseudomonas or morganella
30
Cefiderocol mechanism
Siderophore cephalosporin that binds to iron
Actively transported into bacterial cells
31
Cefiderol targets
Multi-resistant gram negatives
ESBL
Pseudomonas
Acinetobacter
Stenotrophomonas
Burkholderia
32
Prophylaxis for C-section, H&N, thoracic, neck, ortho
1st line - cefazolin 2g
2nd - vancomycin 25mg/kg
33
Prophylaxis for colorectal surgery, biliary, hysterectomy, major ENT, infrarenal vascular surgery
1st line - cefazolin + metronidazole
2nd line - vanc + gent
34
Prophylaxis for amputation
1st line - benzylpenicillin
2nd - metronidazole
35
Prophylaxis for ERCP
1st line - gentamycin
2nd line - cefazolin
36
Indications for dental prophylaxis
Mechanical valve
Prior IE
Congenital heart disease
Rheumatic heart disease
Heart transplant
37
Standard therapy for TB
2 weeks of isoniazid, rifampicin, ethambutol, pyridazinamide
4 weeks of isoniazid and rifampicin
38
Greatest risk of reactivating TB
HIV
39
Growing resistance to which antimicrobial in TB
Isoniazid > Rifampicin
40
Features of paradoxical reactions in TB
Clinical or radiological deterioration of pre-existing lesions or appearance of new lesions whilst on therapy
Presents with fever, nodes, respiratory failure, neuro deterioration, sinus formation
41
Treatment of paradoxical reactions in TB
Corticosteroids
Aspiration of pus
Excision
Continue anti-TB therapy
42
Mechanism of action of quantiferon gold assay
Exposes whole blood to TB antigens
Sensitised lymphocytes release measurable cytokines in response
Unable to differentiate latent vs active TB
43
Features of nodular bronchiectasis
Presents in elderly women with chronic suppressed cough
Affects RML and lingular segment
44
Features of fibronodular bronchiectasis
Middle-aged, male smokers/drinks
Presents with productive cough positive with MAC
45
Antibiotic guidelines of CAP
Mild CAP - doxycycline or amoxicillin (or clarithromycin)
Moderate CAP - Benzylpenicillin + doxycycline
Severe CAP - ceftriaxone + azithromycin
46
Indications to treat aspiration pneumonia with metronidazole
Terrible gums, foul smelling sputum
Severe EtOH abuse
Lung abscess with fluid level
Empyema or complete white out
47
Mechanisms of oseltamivir
Neuraminidase inhibitor
Reduces duration of flu symptoms by 1-2 days
More effective for Flu A than Flu B
48
Causes of avian influenza
Bird exposure
49
Features of pertussis
Incubation period: 1-4 weeks
Catarrhal phase (1-2 weeks) - non specific URTI features
Paroxysmal phase (2-6 weeks) - intense paroxysmal coughing
Convalescent phase - progressive reduction in symptoms
50
K1 Klebsiella pneumoniae features
Novel strain associated with community acquired liver abscesses, bacteraemia and endophthalmitis
More common in diabetes
Susceptible to ceftriaxone (unless ESBL)
51
Indications for surgery in endocarditis
Absolute
- Severe AR or MR
- Cardiac failure (related to valve dysfunction)
- Fungal or highly resistant organisms
- Perivalvular abscess or fistula
- Prosthetic valve endocarditis
Relative
- Multiple or severe embolism
- Uncontrolled infection (e.g. MSSA, pseudomonas, Q fever)
- Size of vegetation
52
Necrotising fasciitis bacteria and treatment
Usually group A strep, may be polymicrobial in diabetes
Treatment with penicillin, clindamycin, pip/taz +/- gent +/- IVIG
Surgery
53
Mycobacterium ulcerans features
From Bairnsdale, Phillip Island, Point Lonsdale, Daintree
Treatment with rifampicin + clarithromycin (or moxifloxacin)
54
Neisseria gonorrhoeae triad
Tenosynovitis, dermatitis and polyarthralgias without purulent arthritis
55
Features of Bartonella
Cat scratch disease - B. henselae and B. quintana
Cutaneous lesion at bite site after 3-10 days
Resolves in 1-4 months, sometimes longer
May have ocular features, encephalopathy, radiculitis, myelitis, cerebellar ataxia, granulomatous hepatitis or splenitis, or bone lesions
56
Types of tick-borne rickettsial infections
R. australias - Australian tick typhus
R. honei - Flinders Island spotted fever
R. rickettsi - Rocky Mountain SF
R. africae - African tick bite fever
57
Treatment for Rickettsia
Doxycycline
58
Anthrax features
Bacillus anthracis - gram positive spore forming bacterium
Clinical syndromes
- Inhalation
- Cutaneous
- GI
59
Features of Inhalational anthrax
Flu-like symptoms for two days
Sudden deterioration - severe SOB and hypoxia
Haemorrhagic mediastinum
Can cause pleural effusion, meningitis, low BP
60
Plague features
Yersinia pestis (enterobacteriae)
Reservoir - rats, gerbils, prairie dogs, other rodents
Transmission via infected fleas
Types
- Bubonic
- Pneumonia (primary or secondary)
- Septicaemic
- Meningitis, pharyngitis
Treatment with streptomycin, doxycycline, ciprofloxacin
61
Features of tularaemia
Francisella tularensis
Incubation 2-10 days
Sudden onset fever, chills
Headache
Malaise
Treatment with streptomycin, tetracycline or chloramphenicol
62
Features of botulism
Toxins A, B and E
Binds to pre-synaptic nerves to prevent release of acetyl choline
Affects CN than symmetrically descends
No sympathetic or sensory involvement
Food history
EMG
Supportive treatment +/- antitoxin or penicillin
63
Infections to suspect with red eyes
Leptospirosis
Measles
Dengue
Kawasaki
Adenovirus
Stevens-Johnson
64
Causes of nodular lymphangitis
Sporotrichosis (Sporothrix schenckii)
Nocardia spp
Mycobacterium marinum
Leishmania braziliensis
Francisella tularensis
65
Features of Whipples disease
Tropheryma whipplei, an intracellular gram-positive bacteria
Abdominal pain, intestinal malabsorption
Enteropathic arthritis
Cardiac symptoms
Neurological symptoms i.e. myoclonus, ataxia, oculomotor impairment
66
Vancomycin targets
Most gram positive
67
Carbapenem targets
Most gram positive, gram negative, anaerobes
68
Fluoroquinolones targets
Older (cipro, norflox) - most aerobic gram negatives (including pseudomonas)
Newer (moxiflox) - most gram positive, gram negative (not pseudomonas), anaerobes, TB, atypicals
69
Ceftriaxone targets
Streps
Gram negatives
Weak for staph and anaerobes
70
Penicillin targets
Streps
Enterococcus faecalis
Syphilis/spriochaetes
Meningococcus
71
Aminoglycosides targets
Gram negatives
Some gram positives
Not anaerobes
72
Macrolide targets
Atypicals
G+C
G-C
Non-enteric G-B
Mycobacteria
H. pylori
73
Clindamycin targets
Gram positive
Anaerobes
74
Doxycyline targets
Gram positive and gram negatives
Atypicals
Spriochaetes (lyme)
Rickettsia
Malaria
75
Co-trimaxazole
Aerobic G-B
Staph including NORSA
Nocardia
Listeria
Meliodosis
76
Rifampicin drug interactions
Induction of CYP450
Warfarin
Voriconazole
Protease inhibitors
AEDs
Methadone
Tamoxifen
SSRIs
CyA
Tacrolimus
Corticosteroids
77
Quinolone drug interactions
Reduced absorption with Ca, Fe, Zn, antacids
78
QT prolonging drugs
Voriconazole
Macrolides
Moxifloxacin
Pentamidine
Mefloquine
Bedaquiline
79
Cells infected by HIV
CD4+ T lymphocytes
Monocytes and macrophages
Dendritic cells
Astrocytes
Thymic progenitor cells
CD34+ progenitor cells
80
HIV lifecytle
1) Attachment and fusion
2) Reverse transcription
3) Integration
4) Transcription
5) Translation
6) Budding and maturation
81
Natural history of untreated HIV disease
Primary infection - rise in HIV viral load with wide dissemination of virus seeding of lymphoid organs
Clinical latency - decrease in HIV viral load and blood CD4 T cells
Fall in CD4 T cells - opportunistic diseases, rise in HIV viral load and death
82
Classes of HIV ART
1) Reverse transcriptase inhibitors - nucleoside/nucleotide analogues
2) Integrase inhibitors
3) Reverse transcriptase inhibitors - non-nucleoside reverse transcriptase inhibitors
4) Protease inhibitors
5) Entry inhibitors
83
Examples of NRTIs
Nucleoside analogues
- Lamivudine
- Emtricitabine
- Abacavir
Nucleotide analogues
- Tenofovir (disoproxil fumarate or alefenamide)
84
Examples of INSTIs
Raltegravir
Dolutegravir
Bictegravir
85
Examples of entry inhbitors
Fusion inhibitors - enfuvirtide
CCR5 inhibitors - maraviroc
Attachment inhibitor - ibalizumab, fostemsavir
86
Examples of protease inhibitors
Darunavir
Atazanavir
87
Examples of NNRTIs
Nevirapine
Efavirenz
Etravirine
Rilpivirine
88
Recommendation for treatment naive HIV
Doltegravir (INSTIs) + Lamivudine (3TC)
Suggested if starting HIV viral load < 500,000
89
Definition of treatment success
Virological suppression
Confirmed HIV RNA below limit of assay detection
Low level viraemia
90
Definition of virologic failure
Incomplete virologic response - HIV RNA > 200 after 24 weeks ART
Viral rebound - repeated detection of HIV RNA > 200 after viral suppression
91
Management of treatment experienced HIV pt
Drug resistance testing should be obtained whilst pt taking failing regimen
Genotype testing
- usually need HIV VL > 1000 for test
Phenotype testing
- though very expensive
92
Complications of ART
Drug resistance
Toxicities
Drug interactions
Cost
93
Tenofovir drug toxicity
Renal toxicity
Decline bone mineral density
94
Abacavir drug toxicity
Allergic reaction --> GIT symptoms, myalgia +/- rash, cough, leukopenia
Doubles risk of AMI
95
Tenofovir alefenamide vs donepexil
Less renal dysfunction and bone effects with TAF compared to TDF
Weight gain with TAF
96
Protease inhibitor toxicities
Dolutegravir, bictegravir
Insomnia, headache, dizziness, fatigue, nausea, diarrhoea
Weight gain
97
Efavirenz toxicities
NNRTIs
CNS side effects - vivid dreams, sleep change, headache
Rash
Teratogenic
98
PI and NNRTI metabolism
By hepatic cytochrome P4503A4 enzymes
99
Opportunistic infection and malignancy with HIV infected patients
CD4 cell count 200-500: Herpes zoster, pneumococcal pneumonia, oral candidiasis, tuberculosis
50-200: PJP, CNS toxoplasmosis, cryptococcus, Kaposi's sarcoma, NHL, PCNS, lymhpoma
<50: Disseminated MAC, CMV retinitis, cryptosporidiosis
100
Features of IRIS
Inflammatory syndrome that can occur after initiation of ART and consists of either the appearance of a new condition or worsening of a preexisting condition (infection, malignancy or autoimmune)
Develops within 4–8 weeks of initiation of ART
Presentation varies depending on the underlying illness, however, patients often have clinical deterioration and localized tissue inflammation.
101
Risk factors for IRIS
CD4+ cells < 50
Older age
Genetic suscepitbility
Most commonly seen with mycobacteria Tb, cryptococcus meningitis, PJP and PML
102
Kaposi sarcoma virus association
HHV-8 disease
103
Disseminated mycobacterium avium complex (MAC) epidemiology
M avium causative agent in majority of AIDS patients with disseminated MAC
Transmission via inhalation, ingestion, inoculation, person-person transmission unlikely
104
Clinical manifestations of MAC
Fever
Night sweats
Abdominal pain
Diarrhoea
Wt loss
Cough
Lymphadenopathy
Lymphadenitis, pnumonitis, pericarditis, OM, skin or soft tissue abscesses, genital ulcers, CNS infections
105
Diagnosis of toxoplasma gondii encephalitis
Serum IgG
Imaging - oedematous enhancing lesions
PET scan can help distinguish TE from lymphoma
Brain biopsy - however presumptive diagnosis if clinical picture and above investigations positive
106
Treatment of toxoplasma gondii
Pyrimethamine 200mg first > 50mg-75mg daily + sulfadiazine + leucovorin
Corticosteroids if indicated for mass effect treatment
Anticonvulsants for seizures
107
Malaria life cycle
Infected anopheline mosquito injects sporozoites
Sporozoite passes to liver and multiplies
Infected cells burst and release merozoites into circulation to invade RBC
Asexual division into schizonts
Daughter merozoites released when RBC bursts
Invade other RBC
108
Features of P. falciparum on blood film
Multiple infected RBC but no enlargement of RBC
Crescent shaped gametocytes
109
Features of P. vivax on blood film
Fewer infected RBC
Swollen RBCs
Fine eosinophilic dots
110
Malaria bacteria with hypnozoites
P. vivax and P. ovale
Treat with primaquine
111
Diagnosis of malaria
Rapid diagnostic testing
Thick and thin films
- determines species and parasite count
- repeat if clinical suspicion high
112
Causes of false positive and false negative of T&T films
False negative - partial treatment, fluoroquinolones, tetracycles
False positive - artefacts, debris (Howell-Jolly, platelets)
113
Drug resistant genes in malarial treatments
Mefloquin and lumefantrine
- Pfmdr1
Chloroquine
- Pfmdr1, plasmodium falciparum chloroquine resistant transporter, K76T
Antifolate drugs (sulfadoxine-pyrimethamine)
- Point mutations in dihydrofolate reductase (DHFR) and hydropteroate synthase (DHTS) genes
114
Treatment of malaria
P. vivax, malariae, ovale and uncomplicated P. falciparum
- artemether + lumefantrine
- atovaquone + proguanil
- quinine sulfate + doxycycline
- primaquine for vivax and ovale
Severe malaria (chloroquine-resistant P. falciparum)
- IV artesunate or quinine
115
Features of severe malaria
Reduced consciousness
Jaundice
Oliguria
Severe anaemia
Hypoglycaemia
Pulmonary oedema
116
Features of typhoid fever
Faecal-oral spread
Fever, abdominal pain, constipation
LFT derangement
"Rose spots" - maculopapular, truncal distribution
Complications in 3rd-4th week
Leukopenia
Blood culture, stool culture
117
Complications of typhoid fever
Occur in 3rd-4th weeks
Intestinal perforation
Bone and joint
Endocarditis
Pericarditis
Splenic or liver abscess
Endovascular - grafts, atherosclerotic plaques, aneurysms
118
Treatment of typhoid fever
Azithromycin
Ciprofloxxacin
Ceftriaxone
119
Features of dengue
Fever
Headache and retro-orbital pain
MSK pain
Rash
"Break bone fever"
120
Typhoid fever bacteria
S. typhi, parathyroid
121
Dengue vector
Aedes aegyptii
Breeds around human dwellings
122
Diagnostic features of typhoid fever
Leukopenia
Neutropenia
Thrombocytopenia
LFT derangement
Arbovirus IgM serology
123
Amoebiasis bacteria
Entamoeba histolyica
124
Cycle of amoebiasis
Ingestion > excystation (small intestine) > trophozoite infection (colon)
Cysts remain viable for weeks-months in moist environments outside body
125
Diagnosis of amoebiasis
3 fresh stool specimen
Serology - antibodies detectable in 99% of pts with liver abscess
126
Management of amoebiasis
Metronidazole
Paromomycin or diloxanide furoate
127
Hepatitis A features
Acute, self limiting virus
Faecal-oral transmission - contaminated water, milk, food (seafood), institutionalised, travel to endemic areas
Highly contagious
128
Hepatitis A diagnosis
IgM anti-HAV
129
Pathogens in Traveller's diarrhoea
E. coli (ETEC, EIEC)
Shigella sp
Salmonella sp
Campylobacter jejuni
Vibrio parahaemolyticus
Aeromonas hydrophila
Giardia lamblia
Entamoeba histolytica
Cryptosporidium sp,
Rotavirus, norwalk virus
130
Ebola virus
Filovirus family
Zaire ebolavirus
IP 11 days
- Fever
- Weakness
- Diarrhoea
131
Zika virus features
Flavivirus
Mosquito borne transmission (Aedes aegypti), mother-infant, sexual
- Acute febrile illness (rash, fever, arthralgia, conjunctivitis, myalgia, headache)
- Neurological
- Adverse foetal outcomes (microcephaly)
Symptomatic management
132
Influenza features
Droplet spread and direct contact
- Fever
- Headache
- Tiredness
- Respiratory tract symptoms
- Myalgia
133
Causes of aseptic meningitis
Enteroviral: echovirus, coxsackie
Mumps
EBV
CMV
HIV
HSV
TB
Cryptococcus
Leptospirosis
Syphilis
Non infectious - sarcoid, vasculitis, CNS lymphoma
134
Use of steroids in meningitis
Should have dexamethasone 10mg IV, before or with first dose of antibiotics then 6/24 for 4 days
135
Treatment of pneumococcal meningitis
Benzylpenicillin
If gram positive diplococci --> add on vancomycin
136
Infectious causes for diffuse erythematous rash
Scarlet fever
Toxic shock syndrome
Staph scalded skin syndrome
Dengue
Enteroviral infection
137
Infectious causes of purpuric rash
Meningococcaemia
Staphylococcal sepsis
Gonococcaemia
Rickettsial infection
Dengue
Enteroviral infection
Hepatitis B
138
Strep pyogenes bacteria
Beta haemolytic streptococcus
139
Features of impetigo
Erythematous papule > vesicle > pustule > yellow crust and purulent discharge
Spread to close contacts, schools
Associated scabies
140
Clinical syndromes of cellulitis
Beta haemolytic streptococci (group A, B, C, G)
Staph aureus
Pasteurella - dog/cat bite, with puncture wound
Aeromonas spp.
Vibrio spp.
Clostridia spp. - gram negative, immunocompromised
Mycobacteria marinum
Erisepelothrix
141
Features of necrotising myofasciitis
Acutely swollen and painful lower limb or abdominal wall
Severe pain
High fevers
142
Risk factors for necrotising myofasciitis
Diabetes
IVDU
Alcoholism
Local trauma
Surgery
Bowel pathology
143
Management of necrotising myofasciitis
Surgery
Broad spectrum antibiotics (meropenem, penicillin, clindamycin)
IVIg - improved mortality in group A strep
144
Causes of asplenia
Splenectomy
Functional asplenia/hyposplenism
- haematological - hereditary spherocytosis, sickle cell anaemia, thalassaemia major, Hodgkin's disease, NHL, CLL, Sezary's syndrome
- Splenic irradiation
- High dose steroid therapy
- Coeliac disease
- Bone marrow transplant
145
Risk of infections in splenectomy
Strep pneumoniae
Neisseria meningitidis
Haemophilus influenzae
Capnocytophaga canimorsus
Malaria
146
Infection risk with solid organ transplantation
Cardiac transplant
- pneumonia, mediastinitis
- CMV
- toxoplasmosis
- Nocardia
Liver
- Candida
- Hepatobiliary sepsis
- CMV hepatitis
Renal
- UTI
- CMV
- PJP
- Fungal e.g. cryptococcus
- BK nephropathy
147
Features of pneumocytis jiroveci
Ubiquitous fungus, reactivated in impaired cellular immunity
Diffuse bilateral interstitial infiltrates
Respiratory tract sampling
IF, PCR
Management with Bactrim, pentamidine, clindamycin or primaquine
Corticosteroids
148
Nocardia features
Gram positive
N. asteroides, N. farcinica, N. brasileinsis
Environmental, soil, organic matter, water
Clinical features
- Cutaneous/lymphocutaneous
- Pulmonary
- systemic/CNS
Management
- surgical drainage/debridement
- Bactrim --> for pulmonary disease (resistant for N. farcinica, N. otitidiscaviarum)
- imipenem, ceftriaxone
149
Toxoplasmosis features
T. gondii, parasite
Increased risk with T cell mediated defects
CNS, myocardial, pulmonary, chorioretinitis
Management with pyrimethamine/folinic acid, sulfadiazine or clindamycin
150
Toxoplasmosis lifecycle
Cats shed oocyst > sporulation occurs outside cat 1-5 days later (required to be infectious) > tachyzoite (human intestine) > cyst (tissue)
151
Features of candidiasis
C. albicans - commensal on skin, GIT, female genital tract
Active in ICU or immunosuppressed patients
152
Syndromes of candidiasis
Syndromes
- Disseminated candidiasis --> fever after neutrophil recovery, abdominal pain, increase ALP
- Candidaemia --> fever +/- sepsis, use with broad spectrum abx, CVC, urinary catheters, TPN, renal imapriment, GIT surgery, mucositis, neutropenia
153
Management of candidiasis
Immunocompetent
- Systemic antifungal treatment for 14 days
- Removal of device, drain any collection
Immunocompromised
- Systemic antifungal therapy, 10-14 days
Triazole
Echinocandins
Amphotericin
154
Features of aspergillus
Ubiquitous, environmental spores
A. flavus, A. fumigatus
Primary infection in lung, later dissemination
Syndromes
- Pulmonary aspergillosis
- Cerebral --> severe immunocompromised, sinusitis with bone erosion
- ABPA
- Aspergilloma
155
Management of aspergillus
Antifungal therapy - voriconazole, posaconazole, amphotericin B, caspofungin
Surgery if isolated lesions
156
Features of zygomycosis
Absidia spp., Mucor, rhizopus
Risk with acute leukaemia, solid organ transplantation, DKA, iron overload, burns
Involvement of paranasal sinuses with dissemination. tobrain and orbit
157
Features of cryptococcus
Budding yeast
C. neoformans var gattii (immunocompetent hosts), vars neoformans (immunodeficient hosts)
Elevated CSF opening pressure, protein and lymphocytes. Decreased glucose.
Management with amphotericin B and flucytosine
158
Multidrug resistant candida
Candida auris
Echinocandin therapy as first line
159
Schistosomiasis features
Penetration of intact skin by cercarial lavae in fresh water
Pruritic rash within days, febrile illness, fibrotic response in urinary tract or gut, chronic infection (colitis, portal HTN, urolithiasis, SCC bladder)
Diagnosis via serology, eosinophilia, urine/stool microscopy
Management of praziquantel
160
Features of ascariasis
A. lumbricoides
Most common human helminthic infection, usually asymptomatic
Adult worms in small intestine shed ova > ingested eggs hatch > migrate into intestinal wall and via portal veins to lungs + small intestine
Pulmonary (laval migration)
Nutritional
Mechanical i.e. SBO
Treatment with stool microscopy
Management with mebendazole, pyrantel pamoate
161
Rabies features
Infection by contact with respiratory secretions from animal hosts
Fever, headache, malaise in prodrome (4-10 days), encephalitic-hydrophobia, deliriu, agitation, arrhythmias, autonomic dysfunction, paralysis
162
Leptospirosis features
Spirochete zoonosis from contaminated water
Mild, self-limiting
Hyperbilirubiaemia, AKI, pulmonary haemorrhage
Biphasic illness
Supportive therapy with antibiotics (penicillin and doxycycline)
163
Melioidosis features
Burkholderia pseudomallei (gram negative rod, soil saprophyte)
SEA,Northern Australia
Diabetes, EtOH use are risk factors
Pneumonia, abscesses (spleen, prostate), OM, septic arthritis, skin. andsoft tissue infection, high mortality in sepsis
Treatment with ceftazidime, carbapenem
164
Common manifestations fo strongyloidiasis
GI symptoms
Hepatomegaly, hepatic abscess, abnormal LFTs
Respiratory symptoms - dyspnoea, bronchospasm, haemoptysis, bronchopneumonia, interlobular septal fibrosis
Eosinophilia
Bacterial meningiits
Erythematous serpinginous lesions
Gram negative septivaemia or sepsis
MOF
165
