infectious disease Flashcards
how long does HIV seroconversion take?
It typically occurs 3-12 weeks after infection
what are the features of acute schistosomiasis syndrome (katayama fever)?
fever
urticaria/angioedema
arthralgia/myalgia
cough
diarrhoea
eosinophilia
what is the treatment for acute schistosomiasis
praziquantel
what are the factors which reduce vertical transmission of HIV?
- maternal antiretroviral therapy
- mode of delivery (caesarean section)
- neonatal antiretroviral therapy
- infant feeding (bottle feeding)
what is the monod sign?
a mass within a cavity with a ‘Monod sign’ (the crescent of the surrounding air
Angola is an area with a high prevalence of TB and the chest x-ray findings are typical of aspergilloma
what is the CNS lymphoma associated with?
EBV - epstein barr virus
what is the treatment for CNS lymphoma?
steroids ( may significantly reduce tumour size)
chemotherapy (methotrexate)
what is the pathology behind progressive multifocal leukoencephalothy?
due to infection of oligodenrocytes by JC virus ( a polyoma DNA virus)
-widespread demyelination
what is the differene on thallium SPECT scan for toxoplasmosis and lymphoma?
Thallium SPECT negative - toxoplasmosis
Thallium SPECT positive - Lymphoma
what is lemierre syndrome?
Infectious thrombophlebitis of the internal jugular vein.
what is the cause of peritonsillar abscess?
Secondary to a bacterial sore throat caused by Fusobacterium necrophorum leading to a peritonsillar abscess
combination of spread of the infection laterally from the abscess and compression lead to thrombosis of IJV
what are the features of lemierre’s syndrome?
Patients will present with a history of bacterial sore throat followed by neck pain, stiffness and tenderness (may be mistaken for meningitis) and systemic involvement (fevers, rigors, etc)
Septic pulmonary emboli may also occur
What are the features of Disseminated gonococcal infection ?
- tenosynovitis
- migratory polyarthritis
- dermatitis (lesions can be maculopapular or vesicular)
what are the features of congenital CMV infection?
- growth retardation,
- pinpoint petechial ‘blueberry muffin’ skin lesions
- microcephaly
- sensorineural deafness,
- encephalitiis (seizures)
- hepatosplenomegaly
what is the typical pattern of presentation of yellow fever?
Yellow fever typically presents with flu like illness → brief remission→ followed by jaundice and haematemesis
The first stage classically causes a non-specific illness which is often described as ‘flu-like’ with fever, malaise, nausea, myalgia and headache. This stage is due to the circulating virus in the bloodstream (viraemic stage).
There is then a recovery stage when the viraemia clears
Around 15% of patients progress after about 3-7 days after the onset of symptoms which presents with fever, nausea and vomiting, acute kidney injury, hepatitis with jaundice, and haemorrhage.
what is the cause of spread of yellow fever?
zoonotic infection: spread by Aedes mosquitos
incubation period = 2 - 14 days
what vaccines are contrindicated in patients with HIV?
Cholera CVD103-HgR
Influenza-intranasal
Poliomyelitis-oral (OPV)
Tuberculosis (BCG)
what is seen under the microscope in a diagnosis of BV?
gram positive coccobacilli
what are the malignancies associated with EBV infection?
- Burkitt’s lymphoma*
- Hodgkin’s lymphoma
- nasopharyngeal carcinoma
- HIV-associated central nervous system lymphomas
how is lassa fever contracted?
Lassa fever is contracted by contact with the excreta of infected African rats (Mastomys rodent) or by person-to-person spread
what is the cause of leprosy?
Granulomatous disease primarily affecting the peripheral nerves and skin. It is caused by Mycobacterium leprae.
what are the features of leprosy?
- patches of hypopigmented skin typically affecting the buttocks, face, and extensor surfaces of limbs
- sensory loss
what is the treatment for leprosy?
rifampicin, dapsone and clofazimine
what UTI causes present with nitrate negative, leucocyte positive urine dip?
Gram negative organisms test positive on the nitrite test as they convert nitrates to nitrites for energy. Gram positive organisms are unable to reduce nitrate to nitrite and therefore, test negative
what UTI causes present with nitrate negative, leucocyte positive urine dip?
Gram negative organisms test positive on the nitrite test as they convert nitrates to nitrites for energy. Gram positive organisms are unable to reduce nitrate to nitrite and therefore, test negative
what is the treatment of pneumocystis jiroveci?
- co-trimoxazole
- In severe cases - IV pentamidine
- Steroids if hypoxic (if pO2 < 9.3kPa - they reduce the risk of respiratory failure)
what are the false positive causes of non-treponemal tests?
pregnancy
SLE, anti-phospholipid syndrome
tuberculosis
leprosy
malaria
HIV
what are the different tests you can do for testing for syphilis?
Treponemal specific testing - Tp-EIA trep.pallidum enzyme immunoassay
Non-treponemal tests - VDRL, RPR - rapid plasma reagin