Infectious disease Flashcards
MALARIA
i) what causes 75% of malaria in UK? how is it spread by which vector? what is injeted into the infected person?
ii) which organ does organism travel to first? what can it lay dormant as? what do they mature as? why do people with malaria have fever spikes every 48 hours?
iii) what is incubation period? name three non spec symptoms? name three signs
iv) how is a dx made? how many samples over how many days? why?
v) name four oral tx for uncomplicated malaria? name two IV options if complicated
i) plasmodium falciparum from female anopheles mosquito
suck blood > prod sporozites > inject into next person
ii) sporozites travel to the liver - can lay dormant as hypozoites (p vivax/ovale) or mature into merozoites
merozites infect FBC and reproduce 48 hours after RBC rupturre > rel more and cause haemolytic anaemia = fever spikes every 48 houts
iii) incunation is 1-4 weeks
non spec - fever, rigors, malaise, myalgia, headache, vomiting
signs - pallor (anaemia), hep splen megaly, jaundice (bili from RBC rupture)
iv) dx on malaria blood film (send in FBC bottle) > parasites, conc and type
3 samples sent over 3 consec days due to the 48 hours cycle
v) oral = riamet, malarone, quinine sulphate, doxy
IV if complicated = artesunate (effective but not licensed), quinine dihydrochloride
MALARIA COMPLICATIONS AND PROPHYLAXIS
i) name five complications
ii) name three ways it can be prevented?
iii) name two anti malarials that can be taken as prophylaxis? what has the best SE profile?
i) cerebral malaria, seixure, reduce conc, AKI pulm oedema, DIC
ii) mosquito spray with deet, nets, antimalarial
iii) malarone (best SE), mefloquine, doxycycline
TYPHOID
i) what bacterial group causes it? what are they aka? name three symptoms? what is incubation period
ii) how is it transmitted? what is the initial px symptom? name four other symptoms
iii) name three complications? what WCC, plats and LFTs are seen?
iv) how is it treated? for how long?
i) salmonella - gram negative rods
enteric fever = headache, fever, arthralgia
incubation 5-21 days
ii) transmitted by feco oraal route (contam food and water)
initial px with systemic upset
bradycardia, abdo paain, constipation, rose spots on trunk
iii) osteomyelitis, GI bleed, meningitis, cholecystitis
low WCC, low plats, deranged LFT
iv) tx with IV ceftriaxone for 14 days
TB
i) what is it caused by? what staining technique is used? how do they look? are they fast or flow dividing?
ii) how is it spread? what forms around the body? what is latent TB? what is it known as when it reactivates?
iii) name four RF? which vaccinee can be given? what type of vacc is it? what test is done before the vacc?
iv) name five common symptoms? what does the mantoux test involve? whaat does IFN gamma release assay involve?
v) name three things that can be cultured before tx is started? which test looks at DNA of TB?
i) mycobac TB - small rod shaped bacillus
zeihl neelsen stain > bright red against a blue background
slow dividing and use lots of oxygen
ii) spread via droplet spread then spreads through lymphatics and blood > granulomas form around the body
latent = imm sys encapsulates infection to stop progression
secondary is when latent TB reactivates
iii) RF - known contact, immigrant from endemic area, relatives, immsupp, homeless, IVDU
give BCG intradermally - live attenuated (protects against complicated TB)
do mantoux test before vaccine if negaative
iv) lethargy, fever, night sweats, weight loss, haemoptysis, LNs, erythema nodosum, spinal pain if spinal TB
mantoux - looks for prev imm response. (prev vacc, active or latent TB)
inject tuberculin into arm > induration of 5mm or more after 72 hours is positive
IFN assay - blood sample and mix with antigens
if TB antibodies > release IFN gamma (do after positive mantoux) - conforms latent TB
v) sputum, mycobac blood culture or LN aspiration
nuc acid amplific test
TB MANAGEMENT
i) do patients with latent TB need treated? what are two tx options of latent becomes reactivated?
ii) what four drugs are used to tx active TB? RIPE. what should be co prescribed?
iii) name three other diseases that need to be tested? how can patients be isolated when dx? what does tx for extrapulm disease include?
iv) name a size effecr if each RIPE drug? which three are assoc with hepatotox
i) no tx for latent
if reactivation - iso and rif for 3 months or iso for 6m
ii) rifampicin and isoniazid doe 6 months
pyrazinimide and ethambutol for 2 months
co prescribe vitamin B6 (pyridoxine) to help prevent periph neurop from iso
iii) test for HIV, hep B, hep C
isolate until estab on tx (2 weeks) in a negative pressure hosp room
tx for extra pulm disease with steroids
iv) rif - red/orange secretions, p450 inducer
iso - periph neurop (pyroxidine co prescribe)
pyrazin - hyperuric levels > gout
ehtam - colour blind and reduced vis acuity
rif iso pyrazin assoc with hepatotox
CELLULITIS
i) what is it? what are the two most common causative organisms? name three other organisms that can cause it?
ii) how is it characterised? (3) what is dx usually based on? when may a swab/aspiration cultures be done?
iii) name four investigations to be sent for patients that are acutely unwell? what should be taken if pt needs admission?
iv) what is first line tx if admin and severe? what severity classification can be used?
v) name five indications for admin
i) Cellulitis is an acute spreading infection of the skin with visually indistinct borders that principally involves the dermis and subcutaneous tissue
- most common causative bacteria are Streptococcus pyogenes and Staphylococcus aureus, but infection can be caused by Streptococcus pneumoniae, Haemophilus influenzae, gram-negative bacilli, and anaerobes
ii) it is characterised by redness, swelling, heat, and tenderness, and commonly occurs in an extremity
- based on history and examination only, although consider swab and aspiration cultures if cellulitis is associated with a break in the skin
iii) FBC, ESR (elevated), CRP (elevated), UE, blood culture (if pt needs admin)
iv) IV abx - start with fluclox or clarithromycin if allergic
- review after 48hrs and may be able to oral switch
- Eron classification (if class II or more > admit)
v) admin if > Signs of systemic illness, such as Confusion, Tachycardia, Tachypnoea, Hypotension, Suspected sepsis, Spreading cellulitis not responding to oral medication. Limb-threatening infection due to vascular compromise. Necrotising fasciitis, Orbital cellulitis
DENGUE FEVER
i) what can it progress to? what type of virus is it? how is it transmitted? what is the incubation period?
ii) name five presenting symptoms? where is a headache often seen? name three warning signs
iii) what is severe dengue aka? what is it?
iv) what is seen on bloods - WCC, plats and ALT? name three dx tests
v) how is it treated?
i) can progress to viral haemorrhagic fever
RNA virus transmitted by aedes mosquito
incubation of 7 days
ii) fever, retro-orbital headache, myalgia, bone pain, facial flushing, mac pap rash
warning signs - abdo pain, hepmeg, vomiting, fluid accum
iii) seveer = dengue haemorhagic fever - DIC
iv) low wcc, low plats, raised ALT
also do serology, NAAT for viral RNA and NS1 antigen test
v) mx is symptomatic control eg fluid, bloods
CAMPYLOBACTER
i) what is it the most common cause of? what type of bac is i? how is it spread? what is incubaation?
ii) what is seen in prodome? what type of diarrhoea? wher is pain?
iii) who should be treated? what is first line abx?
iv) name three complications
i) commonest cause of infectious intestinal disease in UK
gram neg bacillus campylobacter jejuni
faecal oral spread - incubation 1-6 days
ii) prodrome = headache and malaise
bloody diarhoea and abdo pain
iii) tx if immunocomp
first line is clarithro
iv) complicats = guilian barre, reactive arthritis, endocarditis
CMV
i) what viral family does it belong to? who does it usually cause disease in? how do infected cells look?
ii) name three things congential CMV can cause? what is CMV mono nucleosis?
iii) which are of the body may it affect in immcomp eg in HIV? what is the tx?
i) belongs to herpes viruses > disease im immunocompromised
infected cells = owls eye appearance
ii) congenital - growth retard, pinpoint petechial lesions, microceph, sensorineural deafness, eenceph, hepsplen megaly
iii) mononucleosis - maay dev in immunocompetent people
iv) CMV retinitis - tx with IV ganciclovir
CMV encephalitis
NECROTISING FASCITIS
i) what is type 1 and what is type 2? name five RF? what is the most common pre existing medical condition?
ii) what is the most common affected site? how does it present?
iii) what two things are done for mx? what is avg mortality?
i) type 1 - caused by mixed anerobes and aerobes (usually post op in diabetes)
type 2 - strep pyogenes
RF - recent traumaa, burns, soft tissue infec
DM is most common pre exisiting condition (espec SGLT2i) IVDU, immsupp
ii) most common affect perineum
acute onset with rapid worsening cellulitis out of keeping with physical features - very tender
skin necrosis and gas gangrene are late signs
iii) urgent surgical debride and Iv abx
mortality of 20%
YELLOW FEVER
i) what type of condition is it? how is it spread?
ii) what is incubation period? what type of symptoms does it initilly cause?
iii) what is the classic presentation? (3) what HR maay be seen?
iii) what may be seen in hepatocytes
i) type of viral haemmorhagic fver spread by aedes mosquito
ii) incubation 2-14 days
mild flu like illness initially
iii) sudden onset high fever, rigors, nausea and vom
bradycardia
brief remision then jaundice, haematemeisis
iii) councilman bodies in hepatocytes
ASCENDING CHOLANGITIS
i) what is it? what is it usually caused by?
ii) what is charcots triad? what is reynolds pentad?
iii) name four causes
iv) what is seen on US? what is seen on ERCP?
v) what immediate tx should be given? name three things done in definitive mx
i) inflam/infection of the bile duct
- usually caused by ascending bacteria from the duodenum
ii) CT - RUQ pain, jaundice, pyrexia
RP - RUQ, jaundice pyrexia, shock, confusion
iii) gallstones, strictures, malignancy, iatrogenic eg ERCP
iv) US - bile duct dilatation, ERCP - see obstruction
v) immediate - IV broad spec abx for 4-7 days > do cultures, IV access, analgesia
definitive - endoscopic biliary decompress (remove blockage by ERCP)
- perc transhepatic cholangioraphy if patient cant have ERCP
- may do lap chole if gallstones are the cause
HEPATITIS A C E
i) what type of virus is hep A? incubation? transmission? does it cause chronic disease? name four features? is there inc risk of hep cell carcinoma? is there a vacccine? name four groups of people that should be vacc?
ii) which two groups are most commonly affected by hep C? what type of virus is it? is breastfeeding contraindicated? is there a vaccine? what method has highest transmission rate? name three features that may be seen? what is the dx test of choice?
iii) do most people clear the virus after initial infection? what is chrnic hep C? name four complications? what is the aim of tx? what type of drugs are given?
iv) how is hep E spread? what is incubation? where areas is it common? (3) what other hep is it similar to? at what time does it carry significant mortality? is there as vaccine?
i) RNA virus, 2-4 weeks incubation - usually self limiting
feco oral spread and doesnt cause chronic disease
flu like prodome, abdo RUQ pain, hep meg, jaundice, deranged LFTs w no inc risk of HCC
vaccine - give to travellers to endemic areas, chronic liver disease, haemophilia, MSM, IVDU, lab/sewage/primate workers
ii) haemophiliacs that had blood transduse prior to 1991 and IVDU
RNA virus - breatfeeding is not contrainidicated
no vaccine - vertical has highest transmission (6%) needle stick is 2%
transient rise in ALT and jaundice, fever, arthralgia
dx test - hep C viral DNA - dx acute infection (antibodies will be positive even if cleared)
iii) majority will go on to develop chronic hep C >persistence in the blood for more than 6 months
complications - rheum (arthralgia), sjhogrens, cirrhosis, hep cell carcinoma, cryogloobulinaemia
mx with protease inhibitors - aim of tx is sustaineed virological response = undet viral RNA 6 months after the end of therapy
iv) RNA virus spread feco oral - incubation 3-8 weeks
common in central and SE asia, NW africa and mexico
sim to hep A but signif mort in pregnancy > no chronic disease of HCC and no vaccine
HEPATITIS B
i) what type of virus is it? how is it spread? what is incubation? name three common features
ii) name give complications of chronic infection?at what ages is vaccine given to children? name four other at risk groups that should be vacc? iii) what does the vaccine contain? name three RF for poor respinse to the vaccine? who should be checked for anti HBs levels? when a re they achecked? what is an adequate/subuptimal or non response to vaccine? what is done in each?
iv) what is the only tx available? how does it work? what else may also be given?
i) dsDNA spread through infected blood, body fluid and vertically
invubation is 6-20 weeks
fever, jaundice, elevated LFTs
ii) complications - chronic hep (ground glass hepatocytes), liver failure, hep cell carcinomaa, glomnephritis, polyarteritis nodosa, cryoglobulinaemia
vacc children at 2.3.4 months of age
at risk - healthcare, IVDU, sex workers, close contacts of indivi with hep B, CKD, prisoners
iii) vaccine containes Hb surface Ag adsorbed on aluminium - recombinant DNA technology
RF to poor repsonse to 3 doses = obesityu, smoking, ETOH, over 40
check in those at risk. of occupational exposure and patients with CKD = check 1-4m after primary imm
adequate = > 100 - no further testing but boost at 5 years
sub optimal = 10-100 - one extra dose given
non response = < 10 = test for current or past infection
iv) only tx is PEG interferom - reduces viral replication
also may given anti virals eg tenofivir
HEP B SEROLOGY
i) what is the first marker to appear and causes production of anti-HBs?
ii) what normally implies acute disease - 1-6m? what happens if this is present for more than 6m?
iii) what does presence of anti Hbs show? who does anti Hb-c show? what does IgM anti HBc show? which two types of antibody persist?
iv) what is HbeAg a marker of? why?
v) what antigen does will a person have if ongoing infection (either acute or chronic)? what will a person have if t hey have had hep B within 6 months but not if immunised?
i) first marker = Hb surface antigen > production of Hb surface antibody
ii) acute disese - HB surg antigen for 1-6m or chronic disease if over 6m
iii) anti Hbs (HBsAb) implies immunity (negative in chronic sease)
anti Hb C - previous or current infection and persists for about 6m
IgM - acute or recent infection
IgG and Anti HB-c persist
iv) Hb e Ag - marrker of infectivity and replication
v) Hb surface antigen if ongoing infection
anti HBc (caught) if actual infec but not if immunised
