General ID AB Flashcards by Anna Balabanski

What is the incubation period of P. falciparum?

7-28 days

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What are the features on blood film of P falciparum?

Multiple infected RBC
No enlargement of RBC
Crescent-shaped gametocytes
Ring-forms (chromatin)

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What are the features on blood film of P vivax?

Few infected RBC
Swollen infected RBC
Fine eosinophilic dots (Schuffner’s dotsS)
Round/oval gametocytes

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Give an example of the genetic basis of drug resistance in malaria.

Mefloquine & lumefantrine
- Pfmdr1 gene

Chloroquine

Pfmdr1 gene
Pfctr transporter
K76T

Antifolate drugs
- point mutations in DHFR and DHTS

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Give two common effects of malaria in pregnancy

Spontaneous abortions

IUGR

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What are the severe manifestations of malaria?

Unable to tolerate oral intake
Altered consciousness
>5% parasitaemia
Jaundice
Oligura
Hypoglycaemia
Severe anaemia
Acidosis 
ARDS

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How long from illness onset does severe disease manifest?

3-7 days after illness onset

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What is the mortality rate of severe malaria?

15-25%

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What findings may you see on CBE in malaria?

Haemolytic anaemia
WCC normal/low
- No eosinophilia
Thrombocytopaenia (95%)

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What is the management of severe P. falciparum?

IV Artesunate

IV quinine second line

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What are some adverse drug reactions of IV Artesunate?

Cerebellar ataxia
Abdominal pain
Diarrhoea
ALT elevation

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What comorbidity do you need to exclude prior to commencing quinine therapy?

G6PD deficiency (haemolysis)

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How do you treat uncomplicated P falciparum?

First line: Artemether-Lumefantrine (Riamet)
- >95% cure rate in P falciparum

Second line: atovaquone-proguanil (Malarone)
- Slower parasite clearance

Third line: quinine + doxy/clindamycin

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How do you treat P vivax/malariae/ovale?

Chloroquine

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What are the options for chemoprophylaxis in malaria?

Chloroquine
- 1 week prior to 4 weeks after

Atovaquone + proguanil (malarone)
- 1-2 days prior, 7 days after

Doxycycline

2 days prior to 4 weeks after
Can use in Mefloquine-resistant malaria (SEA)

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What are the contraindications for Mefloquine?

Neuropsychiatric disorders
Epilepsy
Cardiac conduction defects

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How do you treat Amoebiasis?

Metronidazole

Paromomycin or diloxanide fuorate (prevents continued luminal infection)

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What family of viruses does Ebola belong to?

Filovirus family

Zaire - current outbreak

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What is Ebola’s incubation period?

11 days (6-12)

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How to you test for Ebola?

Viral PCR

- positive 1 day prior to symptoms

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What is the pathophysiology of ebola?

Binds to surface receptors
Internalised by macropinocytosis
Moved to Endosomal compartments
Viral GP2 interacts with NPC1
Fusion of viral and endosomal membrane
Viral nucleocapsid released into cytoplasm
Genome is replicated

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What is the incubation period of Influenza?

1-3 days

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Antigenic shift - what does this cause in a population?

Pandemic

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Antigenic drift - what does this cause in a population?

Annual epidemic

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What are some extra-pulmonary sequelae of influenza?

``` Myositis GBS Encephalitis Reye syndrome - mostly influenza B + aspirin ```

Meningococcal meningitis - what is the treatment?

IV Benpen 1.8g 4 hourly (short course) Cipro if type 1 penicillin hypersensitivity

Meningococcal meningitis - what is the mortality?

7% (on treatment)

N meningitidis - what is the microbiology?

Gram negative diplococci | neiserria = negative

Meningococcal meningitis - what is the incubation period?

2-10 days

Pneumococcal meningitis - what is the treatment?

Empiric - Ceph + Vanc

L monocytogenes meningitis - what is the incubation?

Long - up to 6 weeks

L monocytogenes meningitis - what is the treatment?

Benpen (resistant to Ceph) | Resistant: TMP/SMX

Cryptococcal meningitis - what is the treatment?

Induction: Amphoterecin B + Flucytosine Consolidation: Fluconazole Minimum 10 weeks therapy

Hib meningitis - what is the treatment?

Ceftriaxone for 7 days | + Benpen for 7 days if susceptible

Steroids - what is the proven efficacy in meningitis?

Hib - hearing loss in children S pneumo - mortality benefit No benefit in meningococcal.

Diffuse erythematous rash - what are some infective causes?

``` Scarlet fever (strep) Toxic shock syndrome (staph or strep) Staph scalded skin syndrome Dengue Enterovirus ```

Purpuric rash - what are some infective causes?

``` Meningococcus Gonococcus Staph sepsis Dengue HBV Enterovirus Rickettsial infection ```

Cellulitis - what are the associated exposures with: - Dog/cat bite - Fresh water - Sea water - Immunocompromised - Shell fish - Other water exposure

- Dog/cat bite - pasturella - Fresh water - aeromonas (esp males with cirrosis/cancer) - Sea water - vibrio - Immunocompromised - clostridia - Shell fish - erisepelothrix - Other water exposure - mycobacterium marinum

Necrotising fasciitis - what is empiric therapy?

Meropenem Penicillin Clindamycin

Hyposplenism - name some causes

``` Haematologic disorders - CLL, sickle cell, lymphoma Splenic irradiation high dose steroids Coeliac disease Bone marrow transplant - Especially if GvHD ```

Name 4 encapsulated organisms

St pneumoniae N meningitidis H influenzae Capnocytophaga carimorus

Toxoplasmosis - what is the treatment?

Pyrimethamine/folinic acid and sulfadiazine or clindamycinc

Zygomycosis - what is the treatment?

Debridement and amphotericin (lipid formulations)

Varicella - what is the incubation period?

10-21 days

Schistosomiasis - which organism infects the urinary tract?

S haematobium

Schistosomiasis - which organisms infect the bowel?

S masonii, S japonicum, S intercalatum

Schistosomiasis - what is the typical clinical picture?

Days: pruritic rash Weeks later: febrile illness Months/years later: fibrotic response in urinary tract or gut Chronic infection: colitis, portal HT, urolithiasis, SCC bladder

Schistosomiasis - what is the management?

Praziquantel

Ascariasis - what sort of organism?

Helminthic (most common human)

Ascariasis - what is the management?

Mebendazole, pyrantel pamoate

Melioidosis - what is the organism?

Burkholderia pseudomallei

Melioidosis - what are the risk factors for infection?

DM | EtOH

Melioidosis - what are the clinical manifestations?

``` Pneumonia Abscesses (spleen, prostate) Osteomyelitis, septic arthritis Skin and soft tissue infection High mortality if sepsis ```

Melioidosis - what is the management?

Ceftazadime, Carbapenem | GCSF in sepsis

H pylori and gastric adenocarcinoma - which molecules/genes are involved?

``` CagA gene Vacuolating cytotoxin (vacA) ```

HPV - which strains are most likely to cause cervical cancer?

16 and 18

EBV and Burkitt's lymphoma - which chromosome is affected?

Chromosome 8 translocation - deregulation of c-MYC oncogene

EBV - what are the associated malignancies?

Burkitt's lymphoma Hodgkin's lymphoma NHL in immunocompromised Nasopharyngeal carcinoma

HHV-8 - what are the associated malignancies?

Kaposi sarcoma Primary effusion lymphoma Multi-centric Castleman's disease

Schistosomiasis - what is the associated malignancy?

SCC of the bladder

What is the Jarish-Herxheimer reaction?

Fever and transient exacerbation of constitutional symptoms from sudden release of bacterial products from injured or killed bacteria Seen with tertiary syphilis, brucellosis, enteric fever, schistosomiasis.

General ID AB Flashcards

(61 cards)