Week 6 Flashcards

(182 cards)

1
Q

Describe the difference between gram positive and negative bacteria

A

positive have a thick peptidoglycan wall

negative have thin peptidoglycan wall and periplasm and outer membrane

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2
Q

Where can antibiotics target?

A

cell wall peptidoglycan
metabolism
DNA
ribosome

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3
Q

Describe the action of bactericidal antibiotics

A

achieve sterilisation of the infected site by directly killing bacteria
lysis of bacteria can lead to release of toxins and inflammatory material

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4
Q

Describe the action of bacteriostatic antibiotics

A

suppresses growth but do not directly sterilise infected site
requires additional factors to clear bacteria - immune mediated killing

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5
Q

What is meant by the antibiotic spectrum?

A

refers to the range of bacterial species effectively treated by the antibiotics

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6
Q

Describe the spectrum of meropenum

A

active against almost all gram positive and negative species. Resistance is rare except for MRSA

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7
Q

Describe the spectrum of benzyl-penicilin

A

highly active against streptococci. most other disease causing bacteria are resistant

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8
Q

Describe broad spectrum antibiotics

A

active against a wide range of bacteria

treat most causes of infection but also have a substantial effect on colonising bacteria

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9
Q

Describe narrow spectrum antibiotics

A

active against limited range of bacteria
useful where cause of infection is well defined
much more limited effect on colonising bacteria

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10
Q

What are the main gram positive bacteria?

A

clostridum
streptococcus
enterococcus
staphylococcus

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11
Q

What are the main gram negative bacteria?

A
bacteroides
psuedomonas
haemophilus 
neisseria
e.coli
other coliform
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12
Q

What is guided therapy?

A

depends on identifying cause of infection and selecting agent based on sensitivity testing

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13
Q

What is empirical therapy?

A

best guess therapy based on clinical/epidemiological acumen

used when therapy can’t wait for culture

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14
Q

What is prophylactic therapy?

A

preventing infection before it begins

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15
Q

What can the disruption of bacterial flora lead to?

A

overgrowth with yeasts - thrush
overgrowth of bowel - diarrhoea
development of C.dif colitis
future colonisation and infection with resistant organisms

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16
Q

What are the main classes of beta-lactam antibiotics?

A

penicillins
cephalosporins
carbapenems
monobactams

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17
Q

Describe the overall mechanism of action of b lactams

A

all share same structural feature
Beta-lactam motif analogue of branching structure of peptidoglycan
inhibits cross linking of cell wall peptidoglycan
causes lysis of bacteria - bacteriocidal

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18
Q

What are beta-lactamases?

A

enzymes that lyse and inactivate beta-lacta drugs
commonly secreted by gram negatives and S.aureas
confer high level resistance to antibiotic - high doses will not overcome it

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19
Q

Describe the pharmacology of beta-lactams

A

poorly absorbed in GI tract
usually excreted unchanged in urine, some also via bile
half life varies enormously
effectively distributed to infection sites

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20
Q

Which beta-lactams can be effective orally?

A

amoxicillin, flucloxacillin

vomiting limits dose

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21
Q

Describe the cross reactivity of penicillin allergy

A

patients allergic to a penicillin will usually be allergic to others
cross reactivity with other antibiotic classes is much lower

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22
Q

What are common penicillin?

A

benzyl-penicillin
amoxicillin
flucloxacillin

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23
Q

What is a common cephalosporins?

A

ceftriaxone

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24
Q

What is a common carbapenem?

A

meropenem

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25
WHat is a common monobactam?
aztreonam
26
What are common beta lacteal/beta lactase inhibitor combinations?
co-amoxiclav | piperacillin/tazobactam
27
Describe benzylpenicillin
chemically similar to original penicillin IV remains first choice antibiotic for serious strep infection narrow spectrum
28
Describe amoxicillin
semi-synthetic greatly increased activity against gram negative organisms much more orally bioavailable than natural peniclins widely used in the treatment of a wide range of infections non severe respiratory tract infections
29
Describe fluloxacillin
synthetic penicillin developed to be resistant to beta-lactase produced by staph highly active against staph.aureus and streptococci no activity at all against gram negative organism orally but nausea limits the dose
30
Describe beta-lactamase inhibitors
effectively inhibit some beta lactamases co-administered with penicillin antiobiotic greatly broadens spectrum of penicillins against gram negatives and S.aureus some uninhibited beta lactamases may still lead to antibiotic failure
31
Describe cepahlosporins
found to have good activity against gram negatives and positives less susceptible to beta-lactamases than penicillins
32
Describe the activity of cetriaxone
wide spectrum not enterococcus not pseudomonas not MRSA
33
Describe carbapenems
ultra broad spectrum beta-lactam antibiotics excellent spectrum of activity against gram positives and negatives no activity against MRSA new beta lactamases are emerging which lyse carbapenems
34
Describe the activity of meropenem
everything but MRSA
35
Describe monobactams
``` aztreonam only member of this class no cross reactivate to penicillins so can be given ti those with penicillin allergy (except anaphylaxis) only given IV ```
36
Describe the activity go aztreonam
all gram negative bacteria except bacterioides
37
Describe vancomycin
inhibits cell wall formation in gram positives no gram negative action not dependent on PBP so effective against resistant organisms always IV except for C.dif resistance is very uncpmmpn
38
What are the side effects associated with vancomycin?
nephrotoxicity red-man syndrome if injected too rapidly ototoxicity
39
Why is therapeutic drug monitoring carried out with vancomycin?
narrow therapeutic range | aim higher in severe illnesses
40
Give examples of protein synthesis inhibitors
``` 50s macrocodes clindamycin chloramphenicol 30S aminoglycosides tetracyclines ```
41
Give examples of macrolides
erythromycin clarithromycin azithromycin
42
Give an example of an aminoglycoside
gentamicin
43
Give an example of a tetracycline
doxycycline
44
Describe macrolides
good spectrum of activity against gram positives and respiratory gram negatives active against atypicals - legionella, mycoplasma, chlamydia excellent oral absorption - even on sever infection
45
What are the adverse effects associated with macrocodes?
diarrhoea and vomiting QT prolongation hearing loss with long term use
46
Describe the drug interactions with macrolides
clarihromycin - over 400 drug interactions simvastatin - avoid co-prescription atorvastatin warfarin
47
Describe clinamycin
``` similar to macrolides same mechanism of action excellent oral absorption principle actin against gram positives no action against aerobic gram negatives or atypicals excellent activity against anaerobes added to patients with gram positive toxin mediated disease - toxic shock syndrome, necrotising fascitis causes C.dif ```
48
Describe C.differgic antibiotics
antibiotics dramatically alter the colonic flora c.dif commonly colonises the human colon forms spores which can be difficult from hospitals has developed resistance to common antibiotics classe
49
What are the 4 Cs in C.differgic antibiotics?
clindamycin co-amoxiclav cephalosporins ciprofloxacilin
50
Describe chloramphenicol
inhibits 50S ribosome excellent spectrum of activity toxic - bone marrow, aplastic anaemia, pptic neuritis
51
What are the modern uses of chloramphenicol?
topical therapy to eyes | bacterial meningitis with beta-lactam allergy
52
Describe gentamicin
reversibly binds to the 30S ribosome - bacteriostatic actions poorly understood action on the cell membrane - bactericidal action
53
What are the side effects of gentamicin?
nephrotoxicity ototoxicity neuromuscular blockade
54
Describe tetracylcines
similar spectrum of activity of macrolides also active against atypical organisms relatively non toxic avoid in children and pregnant women
55
What are examples of quinolones?
cirprofloxacin | levofloxacilin
56
What type of antibiotics affect DNA repair and replication?
quinolones and rifampcin
57
Describe quinolones
broad spectrum, bactericidal antibiotics excellent oral biovavilabiliy active against many atypical pathogens including legionella
58
Describe the activity of ciprofloxacin
good against gram negatives, weaker against gram positives. Cmonly used in UTI/abdominal infection
59
Describe the activity of levofloxacin
sacrifices some gram negative activity for stronger gram positive activity - respiratory tract
60
What are the side effects of quinolones
``` GI toxicity QT prolongation Tendonitis Resistance emerging on therapy tendon damage C.diff infection ```
61
Describe rifampicin
principally used for two indications in UK - TB, in addition in serious gram positive infection (especially staph.a) drugs interactions are important
62
Describe the issues with TB
slow growing high bacterial burden limited access of drugs to granuloma
63
What is the solution to TB?
prolonged courses of therapy | combination therapy to prevent resistance and resting kill growing and resting organisms
64
What is the standard short course therapy of TB?
isoniazid rifampicin pyrazinamide ethambutamol
65
How to folate synthesis inhibits work?
inhibition of folate metabolism pathway leads to impaired nucleotide synthesis and therefore impaired DNA replication
66
Describe trimethoprim
orally administered good range of action against gram positives and negative resistance is Major problems limited to use in uncomplicated UTI
67
Describe the toxicity of trimethoprim
elevation of serum creatinine - does not reflect fall in GFR related to action on proximal tubules Elevation of serum K+ - problematic in patients with chronic renal impairment Rash and GI disturbance uncommon
68
Describe metronidazole
enters by passive diffusion and produces free radicals effective against most anaerobic bacteria often added to therapy in intra-abdominal infections, especially with abscess
69
What are the side effects of metronidazole?
causes unpleasant reaction with alcohol | peripheral neuropathy with long term use
70
Describe an uncomplicated UTI
Lower urinary tract symptoms absence of sepsis or evidence of upper tract involvement treatment only needs to sterilise the urine low risk infection so can wait for culture results
71
Describe the use of trimethoprim in lower UTI
currently fist line in most cases avoid in 1st trimester of pregnancy penetrates well into prostate so good choice for men
72
Describe the use of nitrofuratoin in UTI
excellent broad spectrum activity concentrated in urine so no effect on other tissues failure to concentrate in urine in renal failure relatively non-toxic in short courses- pulmonary fibrosis with long term use
73
Which antibiotics are thought to be safe in pregnancy?
most beta lactams broad spectrum agents may be associated with NEC in premature infants macrolides anti-tuberculants
74
What antibiotics are not considered safe during pregnancy ?
``` tetracyclines trimethoprim nitrofurantoin aminoglycosides quinolones ```
75
What is inherent antibiotic resistance?
lack a pathway or target which a drug interacts with, or the drug is unable to gain access to the target
76
What is acquired antibiotic resistance?
where a drug which was previously sensitive has gained some genetic material encoding for resistance
77
Describe vertical gene transfer
genetic information passed from parent cell to progeny
78
Describe horizontal gene transfer
genes transferred other than through traditional reprodocution
79
Describe spontaneous mutation
resistance mutations occur in bacteria exposed to drugs spontaneous mutations occur at a lower rate than acquisition of mobile pieces of DNA treatment of some infections with 2 drugs acting in different ways is based on the principle that if a mutation occurs in one drug target the other drug will still the organism
80
Describe conjugation
requires cell to cell contact between two bacteria small pieces of DNA called plasmids are transferred most important mechanism of horizontal gene transfer
81
Describe plasmids
plasmids are pieces of circular double stranded DNA Genetic information that can be carried on plasmidscan include resistance to antibiotics, heavy metals, UV light can carry genes which encode pili and mediate adherence and can encode toins
82
Describe transduction
this is where small pieces of DNA are transferred between bacteria by a virus bacteriophages are viruses which infect bacteria
83
Describe fitness cost and selection pressure
genetic material acquired may affect more than just drug susceptibilty this reduced growth is called a fitness cost in an environment without a selective pressure these slower growing mutants will be outgrown by their wild type colleagues and will slowly die awy the time this takes depends on the significance of the fitness cost sometimes other mutations may develop which compensate for the fitness cost allowing the mutated bacteria to compete with the wild type colleagues
84
Describe resistance in coliforms
gut commensals e.g E.coli and klebsiella cause of infections such as UTI, intra-abdominal sepsis and HAP antibiotics commonly used to treat these include amoxicillin, ciprofloxacin, cephalosporins and gentamicin
85
Describe beta-lactase inhibitors
clavlanate and tazobactam these are compounds which in themselves have only weak antibacterial activity but which mainly acts by bidding the beta-lactamase thus allowing the beta-lactam to continue to act
86
Describe extended spectrum beta-lactamases
ESBLs usaully plasmid encoded these are enzymes which are able to hydrolyse the beta-lactam ring of not only penicillins but also cephalosporins
87
what are the treatment options for ESBLs?
ciprofloxacin temocillin gentamicin meropenem
88
What are non-genetic mechanisms of resistance?
protected environment resting stage presence of a foreign body
89
How can the spread of resistance be prevented?
narrow spectrum where possible follow empirical prescribing guidance short courses - 3 days for UTI 5-7 days for LRTI
90
What are non-genetic mechanisms of resistance?
protected environment resting stage presence of a foreign body
91
WHat are the four main mechanisms of antibiotic resistance?
target change, inactivation, decreased entry and increased exit
92
What are conventional pathogens?
endogenous flora hospital acquired envionmental organisms
93
What are opportunistic pathogens in immunosuppressed patients?
CoNS (cannulas) | aspergillus (mould)
94
Describe primary immunodeficiencies
inherited exposure in utero to environmental factors rar
95
Describe secondary immunodeficiency
underlying disease state treatment for disease common
96
Why is there an increasing population of profoundly immunocompromised patients?
``` improved survival at extremes of life improved cancer treatment development in transplant techniques developments in intensive care management of chronic inflammatory conditions steroids ```
97
Describe neutropaenia
can be caused by chemotherapy or therapeutic irradiation | decreased proliferation of marriw
98
What is the definition of neutropenia?
<0.5X10 to the power of 9/ | <1.0 X10 the power of 9 and falling
99
Describe chronic granulomatous disease
inherited X linked disorder defect in gene coding for NADPH oxidase deficiency in production of oxygen radicals defective intracellular killing recurrent bacterial and fungal infections > abscesses lung, lymph nodes, skin inflammatory responses with widespread granuloma formation
100
What can suppress cellular immunity?
``` DiGeroge syndrome malignant lymphoma cytoxic chemotherapy extensive irradiation immunosupressive drugs allogeneic stem cell transplants infections - HIV, mycobacterial infections, measles, EBV, CMV ```
101
What can suppresses humoral immunity?
bruton agammaglobulinaemia Antibody production decreased in CLL< myeloma usually preserved in acute leukaemia intensive radio and chemotherapy
102
Describe splenic function
splenic macrophages eliminate non-opsonised microbes - encapsulated bacteria site of primary immunoglobulin response specific opsonising antibody required for phagocytosis of encapsulated bacteria impairs activity of all phagocytic cells
103
What infections are those with humeral deficiency, splenectomy or hypospenism predisposed to?
strep. pneumonia haemophilus influenza type B neisseria meningitidis
104
What are the important physical barrier in the immune system?
skin conjunctivae mucous membranes - gut, respiratory, GU
105
Why is the skin a good physical barrier to infection?
``` desquamates dry pH 5-6 temp is 5 degrees lower secretory IgA in sweat ```
106
Describe mucosal barrier injury and colonisation resistance
High mitotic inde - affected by chemo and radiation GI lymphoid tissue responds with inflammatory response mucositis pain, dysphasia etc impairment of GI function, altered nutrition status H2 antagonists, PPIS, antibiotics, diarrhoea can lead to an altered microbiome
107
wHat is the definition of severe nutritional deficiency?
<75% ideal body weight | or rapid weight loss and hypoalbuminaemia
108
What are the causes of impaired nutritional status?
anorexia nausea and vomiting mucositis metabolic derangements
109
What effect foes iron deficiency have on host defences?
reduces microbicidal capacity of neutrophils and T cell function
110
How can concurrent illness effect the immune system?
stress- reduced T cell function | diabetes mellitus - reduced opsonisation, chemotaxis
111
Why are premature babies so prone to infection?
``` no maternal immunoglobulin immature T cells lines ventilation urinary catheter prolonged time in hospital - resistant organisms ```
112
What are the non-infectious causes pf febrile neutropenia?
``` malignancy chemotherapy transfusion antibiotics colony stimulating factors allergies ```
113
What is the definition of a fever?
pyrexia or hypothermia (>38 or <36)
114
What is SIRS?
systemic inflammatory response sweats, chills, riggers, malaise, tachypnoea (>20) tachycardia (>90), hypotension (patients may seem well perfused despite hypotension)
115
What is sepsis?
Evidence of infection (including SIRS) and organ dysfunction (1 of hypotension, confusion or tachypnoea (RR>22)
116
What is septic shock?
sepsis induced hypotension requiring inotropic support or hypotension that is unresponsive (within 1hr) to adequate fluid resuscitation (<90 or >40 less from baseline)
117
What is neutropenic sepsis or febrile neutropenia?
neutrophil count <0.5 or <1 if recent chemotherapy | plus fever/hypothermia or SIRS or sepsis/septic shock
118
What should standard risk patients with febrile neutropenia receive?
piperacillin/tazobactam | or vancomycin or ciprofloxacin if penicillin allergic
119
What should high risk patients with febrile neutropenia receive?
piperacillin/tazobactam and gentamicin
120
How else should febrile neutropenia be managed?
``` if skin/soft tissue - vancomycin if atypical pneumonia- clarithromycin if previous ESBL= merepenem consider PCP refer to seniors ```
121
What is the key factor in selecting for resistance?
pressure or volume (duration of course X number of courses_
122
What is the individual effect in collateral damage due to antibiotics?
antibiotic resistance drug reaction/ toxicity/ interactions diarrhoea - cliff vascular site infection - S.aureas bacteraemia
123
What are the population effects of the unintended consequences of antibiotics?
antibiotic resistance | clostridium dificile
124
what is antimicrobial stewardship?
``` programme to ensure safe and appropriate use of ABx optimize outcomes minimise unintended consequences reduce AMR and c.dif patient at centre of Rx decision making ```
125
How is antimicrobial stewardship achieved?
``` monitoring/surveillance guidelines/protocols specific restrictions specific interventions MDT working ```
126
What is under surveillance in AMS?
``` volume of antibiotic prescribing quality of antibiotic prescribing antimicrobial resistance c.dif other adverse events related to prescribing /interventions ```
127
What is the role of the lab in AMS programme?
optimisation of lab diagnosis - sampling ,testing and minimisation of over diagnosis restricted reporting of organisms to prevent over treatment restricted reporting of sensitivities to reduce use of inappropriate agents Co-ordination of clinical advice with guidance data on resistance and CDI
128
When should antibiotics not be prescribed?
viral and self limiting bacterias infections (OM, sinusitis, LRTIs, COPD, URTIs) asymptomatic bacteruria, uncomplicated cystitis ingrown toe nails varicose ecxema systemic inflammatory response due to cancer, ischaemia, inflammation
129
What non-antibiotic measures can be used?
reassurance / explanation symptomatic measures - fluids, analgesia delayed script review date/opportunity - safety netting
130
What are symptoms and signs of bacterial infection?
``` fever sweats rigors shivers shakes ```
131
What are localising symptoms and signs of bacterial infection?
dysuria and freuency dyspnoea, cough and green/brown sputum, crepitations erythema, heat, swelling sore threat with exudate and adenopathy
132
What antibiotics should be used in non sever LRTI?
amoxicillin or doxycycline
133
Which antibiotics should be used in non severe UTIs?
trimethoprim or nitrofurantoin
134
Which antibiotics should be used in cellulitis?
flucloxacillin
135
Which antibiotics should be used in severe or life-threatening infection?
usually IV combination (beta lacteal and gentamicin) initlally use of protected Abx if risk of MDR
136
What are the human factors in knowledge and experience and prescribing antiobiotics?
perception of resistance misconception that spectrum of activity = efficacy lack of confidence in diagnosis fear of failure
137
What are the human factors in the prescribing culture of antibiotics?
peer practice speed of escalation of Rx brand familiarity fear of litigation
138
Describe scarlet fever
group A strep | strawberry tongue
139
What is the eagle effect?
in very severe strep mass of strep stop expressing PBP . Mitochondria produce endotoxins which cause low BP and rash. Clindamycin acts on mitochondria and prevents the production of endotoxins
140
What is the sepsis 6?
``` blood cultures antibiotic administration oxygen to achieve target saturation measure lactate and JHb IV fluids monitor urinary output hourly ```
141
What are the indications for IV antibiotic therapy?
sepsis, SIRS or rapidly progressing infection special conditions - endocarditis, CNS infection, bacteraemia, osteomyelitis mod-severe skin and soft tissue infection infection and oral route compromised no oral formulation of antibiotic available
142
What is cellulitis normally caused by?
beta haemolytic strep staph - wound infections gram negatives uncommon
143
What is the treatment of cellulitis
oral 5 days flucloxacillin if milf IV if modernly severe 7-10 days very severe IV clindamycin and gentamicin
144
What is necrotising fasciitis normally caused by?
beta haemolytic strep staph rarely gram negative
145
Describe necrotising fasciitis
pain out with appearance masked by NSAIDs rapidly progressive with multi organ faiilure EAGLE effect - static growth ophase with excess toxin production surgery, immunoglobulin
146
What needs to be done when there is S.aureus bacteraemia?
find and remove source of infection ECHO and other investigation for underlying source reread Bfs after 48-96 hours of effective IVABRx
147
What is the treatment of S.aureus bacteraemia?
flucloxacillin vans as per guidance if persistent fever or no improvement nor further positive blood culture then do TOE TOE also for negative TTE if PV or if endocarditis still suspected Rx all with IV therapy for >2 weeks
148
What history is important in a returning febrile traveller?
``` past medical history current medications pre travel advice vaccines / malarial tablets where travelled to (in world, rurual/urban) means of travel time- longer stay increased risk of some illnesses / decreased risk of others) activities - swimming, sex safari ```
149
What are the most common cases of traveller illnesses?
GI, febrile illness and dermatological diseases are the vast majority of cases
150
What is the management of travellers diarrhoea?
fluids!!!!! antibiotics (only in some cases) (quinolones, azithromycin) anti motility agents (use with caution) investigation for other cause if persistent
151
What type of travellers illness is the most concerning?
undifferentiated fever
152
What are the most common causes of undifferentiated fever?
malaria dengue - particularly southeast asia, carribean Typhoid - south central asia
153
Which mosquitos are most likely to bite at different parts of the day?
aedes - day biter. can live in most polluted cities | anopheline - night biter
154
What are the physical avoidance strategies to prevent mosquito bites?
indoors - AC, screens Impregnated netting clothing - cover up, spray/soak clothing
155
How is malaria diagnosed?
antigen testing and thin film | PCR is helpful for detect low levels of parasite
156
What are the clinical features of malaria?
fever, malaise, headache, myalgia, diarrhoea anaemia jaundice renal impariment
157
Describe severe malaria
``` parisitaemia >2% cerebral malaria severe anaemia renal failure shock DIC acidosis pulmonary oedema ```
158
What is the treatment of malaria?
traditionally quinine and doxycicline | artemehter compounds are more used now
159
What are the main chemoprophylaxis options against malaria?
mefloquine doxycicline malarone
160
Describe mefloquine
once weekly | psychiatric side effects (vivid dreams to psychosis)
161
Describe doxycicline
daily | photosensitisation
162
Describe malarone
minimal side effects | cost
163
What is enteric fever?
S.typhi and S.paratyphi
164
Describe enteric fever
human reservoir only | human to human spread and contaminated food / water
165
What is the incubation period of typhoid?
5-21 days
166
What does the incubation period for tyhpoid depend on?
age gastric acidity immune status infectious load
167
What are the clinical features of typhoid?
``` fever myalgia headache cough abdo pain constipation diarrhoea ```
168
What can typhoid lead to?
septic shock | death
169
What are the GI symptoms of thyphoid?
diarrhoea/constipation abdominal pain rectal bleeding bowel perforation
170
What are the neurological symptoms of thyphoid ?
headahce enteric encephalopathy - altered consciousness/ confusion increased mortality steroids
171
How is typhoid diagnosed?
travel history - area visited, food and drink, pre travel vaccination / advice blood culture (60-80% positive) stool culture and serology not very sensitive
172
What is the treatment of typhoid?
quinolones - resistance cephalosporins azithromycin
173
What type of mosquito is dengue fever spread by?
aedes
174
What are the clinical features of dengue fever?
``` headache fever retro-orbital pain arthralgia / myalgia rash cough sore throat nausea diarrhoea ```
175
What is likely to be seen in lab tests in dengue fever?
leucopenia thrombocytopenia transaminitis
176
What is the treatment of dengue fever?
symptomatic no specific anti-viral treatment horrible self limiting fever
177
What is dengue haemorrhagic fever?
increased vascular permeability thombocytopaenia fever bleeding
178
What types of viral haemorrhagic fevers are there?
``` lassa ebola / marburg CCHF SAVHFs RVF DHF yellow fever ```
179
What are the clinical features of viral haemorrhagic fever?
febrile, non specific, pharyngitis, conjunctival infection, chest pain, prostration haemorrhage - petichiae, mucosal surfaces oedema, effusions low WCC, low platelets, prolonged TT, prolonged APTT
180
What VHF is spread by rats?
lassa
181
What is ebola spread by?
bata
182
What is CCHF spread by?
ticks