Infectious disease Flashcards
TB meningitis CSF features
Cloudy
Lymphocytosis
Low glucose
High protein
TB meningitis treatment
IV rifampicn, isoniazid, pyrazinamide, dexamethasone
Avoid ethambutol due to optic complications
Rickettsial disease general features
Eschar, vasculitic rash, malaise, lymphadenopathy
Types of rickettsial disease
Americas - rocky mountain spotted fever
East asia - scrub typhus
Complications of rickettsial disease
Jaundice, meningoencephalitis, myocarditis, pneumonia and renal failure
Treatment of rickettsial disease
1) doxycycline
2) azithromycin
Fever frequency plasmodium vivax/ovale
48 hours
Fever frequency plasmodium malariae
72 hours
Fever frequency plasmodium falciparum
24 hours
Features of severe falciparum malaria (requires IV artesunate)
schizonts on a blood film parasitaemia > 2% hypoglycaemia acidosis temperature > 39 °C severe anaemia complications: cerebral malaria: seizures, coma; acute renal failure: blackwater fever, secondary to intravascular haemolysis, mechanism unknown; acute respiratory distress syndrome (ARDS); hypoglycaemia; disseminated intravascular coagulation (DIC)
Treatment of non-severe falciparum malaria
artemisin-based combination therapies
e.g. artemethur + lumefantrine / artesunate + amodiaquine
1) Treatment of plasmodium vivax / ovale
2) why?
1) chloroquine / ACT (if chloroquine resistant area) + primaquine
2) primaquine for hyponozoite stage in liver - risk of relapse if not treated
Treatment of malaria in pregnancy
chloroquine
Treatment options in legionella pneumonia
1) macrolides e.g. clarithromycin, erythromycin, azithromycin
2) fluoroquinolones e.g. ciprofloxacin, levofloxacin
Pregnant woman with no rash but exposed to chickenpox
1) check VZV serology
2) if no immunity, VZV Ig - effective 10 days PEP
Pregnant woman with chickenpox
1) PO aciclovir
2) IV aciclovir & foetal medicine if severe infection
Bone and joint TB mx
Initial: RIPE 2 months
Continuing: RI 4 months
Mycobacterium avium Mx
Rifampicin, ethambutol, clarithromycin - continue until sputum -ve for 12 months
Leprosy mx
Rifampicin, clofazimine, dapsone 6-12 months
Staph aureus bacteraemia mx
2 weeks IV fluclox
CPE treatment
Polymyxins (e.g. colistin), tigecycline, fosfomycin or aminoglycosides (e.g. gent)
Yersinia pestis
- buboes most common
- pneumonia (person-person - active in madagascar)
- septicaemia
Ix: blood cultre, serology
Mx: IV gent OR doxycycline
CMV colitis in HIV CD4 count
<50
African sleeping sickness parasites
West Africa - trypanosoma gambiense
East Africa - trypanosoma rhodesiense
African sleeping sickness mx
early: IV pentamidine
late (CNS): IV melarsoprol, suramin, eflornithine, nifurtimox
Chagas disease features
early: asymptomatic or chagoma
complications: myocarditis / dilated cardiomyopathy, megaoesophagus or megacolon
Chagas disease treatment
azoles e.g. benznidazole
heart failure management
Yellow fever features
- viral haemorrhagic fever
- aedes mosquito
- flu like illness
- period of brief remission
- jaundice, haematemesis, renal failure, thrombocytopenia
- hepatic inclusion bodies (councilman)
Strongyloides mx
Ivermectin OR bendazoles
Pinworm (pruritis ani, eggs on tape)
Bendazoles
Loa loa (loiasis)
- nematode cause of filiariasis
- Features: soft tissue swelling, eye worm, numbness in affected limb
- Mx: diethylcarbamazine
River blindness
- Onchocera volvulus
- hyperpigmentation
- blindness
- mx: ivermectin
Roundworm elephantitis
Wuchereria bancrofti from mosquito
Mx: diethylcarbamazine
Schistosomiasis types
- Intestinal -> pulmonary hypertension / liver cirrhosis: mansoni / intercalatum
- urinary: haematobium - risk squamous cell carcinoma and bladder neck fibrosis
Schistosomiasis mx
Praziquantel
+ steroids if acute disease -> prevents type 3 hypersensitivity reaction
ESBL
Carbapenems e.g. meropenem
OR nitrofurantoin / fosfomycin
Diet after giardiasis
Avoid lactose 2-6 weeks
mycobacterium marinum
- fish exposure
- break in skin -> cutaneous lesions
- lymphatic spread
- doxy / cipro / clari
Rabies mx already immunised
2x further vaccine doses
Rabies mx no immunisation
1) touching only - nil
2) no bleeding - full immunisation
3) transdermal bite / lick broken skin - rabies Ig & full immunisation
Typhoid Mx
1) Cefotaxime / ceftriaxone
2) Ciprofloxacin in certain sensitive cases
3) Azithromycin
CMV / HHV5 treatment
IV ganciclovir
Mycobacterium avium features
- fever, malaise, weight loss
- pulmonary symptoms
- abdominal: diarrhoea, abdo pain, deranged LFTs, hepatosplenomegaly
Mycobacterium avium treatment
Rifampicin/rifabutin + clarithromycin + ethambutol
- until 12 months -ve sputum
Complications of schistosomiasis
- Haematobium: urinary tract fibrosis +/- hydronephrosis, squamous cell carcinoma of the bladder
- portal hypertension and cirrhosis
- pulmonary hypertension
Cutaneous larva migrans features
Dog / cat hookworm
Passes in their faeces -> contact with human skin
Hypersensitivity reaction in the skin but cannot get passed basement membrane or replicate - no systemic disease
Cutaneous larva magrans mx
Ivermectin
OR
albendazole
Effect of P450 inhibition on steroid treatment
Possible iatrogenic cushing’s
HLA B 5701 allele positive in HIV?
Avoid abacavir (fatal hypersensitivity)
Hep B post exposure prophylaxis
No vaccine / non-responders: hep B Ig + vaccination
Known responders: hep B vaccine 2 x booster
Incomplete vaccine: hep B Ig + accelerated course
Hep C post exposure prophylaxis
NONE! 6 monthly hep C PCR +/- treatment
usually sofosbuvir combinations +/- ribavarin
HIV post exposure prophylaxis
- If undetectable viral load — very low risk, re test HIV at 8-12 weeks
- If high risk, offer combination ART e.g. tenofovir, emtricitabine, lopinavir and ritonavir for 4 weeks — re-test at 12 weeks
Cryptococcal meningitis features
Low CD4 count meningitic features sub acute raised ICP with false localising signs seizures CT: nil or meningeal enhancement CSF: pleocytosis, high protein, low glucose, india ink +ve
Cryptococcal meningitis mx
Amphotericin + fluconazole / flucytosine
TB mx in HIV on protease inhibitors
Rifabutin, isoniazid, pyrazinamide, ethambutol
rifampicin increases ART protease inhibitor metabolism
Leishmaniasis pathogenesis
Intracellular protozoan (leishmania) transmitted by sand flies can cause visceral, cutatneous and mucocutaneous patterns of disease
Cutaneous leishmaniasis features
- Leishmania tropica or Leishmania mexicana
- Crusted lesion at bite site -> ulceration
Cutaneous leishmaniasis mx
May self-resolve
Cryotherapy
Topical paromycin
PO ketoconazole
Mucocutaneous leishmaniasis features
- Leishmania braziliensis
- initial crusted skin lesions -> mucosa of nose, pharynx
- can occur years to decades after initial infection
Mucocutaneous leishmaniasis mx
- Amphotericin B
- Miltefosine
Visceral leishmaniasis features
- Leishmania donovani
- Mediterranean, Asia, South America, Africa
- initial crusted lesion at bite site
- general: fever, sweats, rigors, poor appetite, weight loss
- abdo: massive splenomegaly, hepatomegaly
- haem: pancytopenia secondary to hypersplenism
- grey skin ‘kala-azar’
Visceral leishmaniasis ix
DAT +ve
Bone marrow / splenic biopsy = gold standard
Can biopsy LNs
Visceral leishmaniasis mx
Amphotericin B / sodium stibogluconate / fluclonazole
Pneumocystis pneumonia prophylaxis
Reduced dose co-trimoxazole (septrin)
OR
Dapsone
VZV treatment in adults
1) immunocompromised
- IV aciclovir if they develop chickenpox
- IVIG if VZV IgG -ve and exposed to chicken pox
2) presenting with complications e.g. pneumonitis, encephalitis - IV aciclovir
Shingles
- Immunocompetent
< 72 hours - PO aciclovir
> 72 hours - nil if well
IV acyclovir if Ramsay Hunt / Herpes zoster opthalmicus if severe infection - Immunocompromised
PO aciclovir if well
IV acyclovir if disseminated / Ramsay Hunt / Herpes zoster opthalmicus
Toxoplasma gondii mx
pyrimethamine + sulfadiazine
West Nile virus
- similar to japanese encephalitis virus
- single stranded rna flavivirus
- mosquito vector
- most people asymptomatic
- others can have fever +/- maculopapular rash
- some can have CNS: meningitis, encephalitis, acute flaccid paralysis (assymetric, w/i 48 hours), axonal polyneuropathy
Tests for syphillis
VDRL & RPR
- false negatives e.g. HIV
- becomes negative after treatment
Antibody tests e.g. treponema pallidum haemagluttination assay
- more specific
- remains positive after treatment
Quickest active TB diagnostic test
nucleic acid amplification
Dengue fever
- aedes mosquito
- fever
- headache
- myalgia
- pleuritic pain
- petechial rash
- thrombocytopenia
- raised ALT
- may cause DIC -> viral haemorrhagic fever
Chikingunya
- ades mosquito
- high fever
- severe joint pain +/- joint pain
- flu-like illness
- transaminitis
- similar to dengue but ++ JOINT PAIN
Brucellosis
- brucella bacteria
- un-pasteurised milk
- fever, malaise
- sacroilitis, peripheral joint pain
- hyperhydrosis
- chronic: skin rash, hepatosplenomegaly
- Ix: serology, rose bengal plate test
- Mx: doxycycline + rifampicin
Q fever
- coxiella burnetii
- source: abattoir, cattle/sheep
- fever and malaise prodrome
- > PUO, atypical pneumonia, endocartidits (culture -ve)
- mx: doxycyline
Tetanus infection mx
- tetanus IVIG
- IV metronidazole
- wound debridement
Trypanosomiasis ix
- acute phase: peripheral blood smear
CNS features?
- CTH / MRI -> may show oedema / white matter enhancement late in disease
- LP: microscopy, elevated wcc, elevated IgM, elevated protein
American trypanosomiasis: serology
Babesiosis
- tick-borne protozoan infection
- fever, chills, rigors
- haemolytic anaemia
- haemoglobinuria
- reactive hypergammaglobulinaemia
- North east USA endemic
- less headache vs malaria, but otherwise similar
- ix: blood smear, PCR, serology
- mx: azithromycin + atovaquone; exchange transfusion if severe haemolytic anaemia
Typhoid features
- salmonella typhii
- fever, malaise, headache, arthrlagia
- abdo pain and CONSTIPATION
- deranged LFTs, hepatosplenomegaly
- relative bradycardia
- rose spots
- leukopenia
- complications: osteomyelitis, GI bleed, myo/endocarditis, meningitis, cholecystitis
Filiariasis
- parasitic worm with mosquito as vector
e. g. wuchereria bancrofti - common in rice paddy fields
- enter lymphatics -> lymphoedema, painful lymphadenopathy
- hypersensitivity reaction in the lungs -> tropical pulmonary eosinophilia - nocturnal wheeze, pulmonary oedema
- general: malaise, intermittent fevers
- Mx
1) diethylcarbamazine
2) ivermectin (esp if high parasitic load)
Cysticercosis
- larval stage of taenia solium (pork tapeworm)
- neurocysticercosis -> seizures, headache, vomiting
- extraneural SC nodules
Ix
- CT: cystic lesions
- fundoscopic visualisation of parasites
- serology
- LP is not necessary
Mx
- anticonvulsants
- antiparasitic: albendazole + praziquantel
- dexamethasone to reduce inflammation with degenerating cyst
MRSA pneumonia mx
Linezolid > vancomycin
Chlamydia infection
Ix: NAAT of urine and swab
Mx: 7 day doxy or single dose azithromycin
Gonorrhoea infection
- urethral swab NAAT
- IM ceftriaxone (specific to gonorrhoea) + azithromycin (chlamydia cover)
Severe malaria features
- GCS <11
- acidosis
- lactate >5
- hypoglycaemia
- parasitaemia >10%
- shock
- GI bleeding
- pulmonary oedema
- jaundice
- creat >265
- severe anaemia
Malaria prophylaxis
- chloroquine OR atovaquone + proguanil OR mefloquine OR doxycycline - take until 7 days after return - most resistance with falciparum
Cat scratch disease
- bartonella henselae (G-ve rod)
- fever, regional lymphadenopathy, malaise, headache
- preceding papular lesion
Complications
- neuroretinitis - visual loss
- abdo pain / hepatosplenomegaly
- encephalopathy / transverse myelitis
- MSK
Ix:
- serology
- MCS
- LN biopsy
- PCR
Mx: azithromycin
When to give steroids in addition to co-trimoxazole for PCP pneumonia
PaO2 <9.3
Leptospirosis
- leptospira interogans
- sewage workers, farmers, vets (must come into contact with rat urine)
- fever, flu-like, headache
- renal failure 50%
- jaundice w/ RUQ tenderness but NO hepatosplenomegaly
- meningitis may occur
Mx: benzylpenicillin / doxycycline / cephalopsorins
Parvovirus B19 related red cell aplasia: association, blood film, mx
- associated with HIV
- anaemia without reticulocytes
Mx: IVIG
Mx of meningiococcal meningitis if severe penicillin allergy
Chloramphenicol
Mx of S Aureus endocarditis if penicillin allergic
Vancomycin + rifampicin
Vaccines to avoid in HIV+ve patients
Live attenuated - BCG - intranasal influenza - typhoid - oral polio - cholera (- yellow fever -> consider if CD4 >200) (- varicella -> consider if CD4 >200) (- MMR -> consider if CD4 >200)
Decreased efficacy
- hep a/b combo
- hep a / typhoid combo
BD glucan
Found in fungi including p. jiroveci
Galactomannan
Found in aspergillus
