judith (L26) Flashcards

Question

Diagnosis of HBV infection

Answer 1

Clinical - History of exposure - Signs & symptoms Serology - Viral antigens (HBsAg, eAg) - Antibodies (anti-HBc, anti-Hbe, antiHBs) Genome detection - HBV DNA

Answer 2

- Interferon - Nucleoside analogues - use HBV DNA to monitor response - Liver transplant

Answer 3

25% spontaneous clearance 75% chronic infection 80% asymptomatic 20% cirrhosis 1-2% hepatocellular carcinoma Progression to cirrhosis or cancer takes decades

Answer 4

Relative few diagnosed in acute phase as symptoms often absent or minimal Detection of anti-HCV - marker of infection at some time Detection of HCV antigens - marker of current infection Detection of HCV RNA - marker of current infection What do we do? Test for antibodies to HCV If positive ‘reflex test’ for HCV RNA Result reporting ‘HCV RNA detected – evidence of current HCV infection; Please refer to a hepatologist.’

Answer 5

Interferon and ribavirin were mainstay of treatment for many years – but unpleasant drugs with limited efficacy. New direct-acting antivirals are now available - these are very much more effective and length of treatment is shorter – restrictions due to high costs are gradually being eased. So many drugs in the pipeline that drug companies regard HCV as ‘cured’ & are focusing on HBV. Liver transplantation

Answer 6

History (unsafe sex, sharing needles, travel etc) & examination (lymphadenopathy) may (or may not) suggest a specific viral aetiology but laboratory testing is required for confirmation. Epidemiology of viral infections has changed – sanitation, vaccination, infection control practices. This has necessitated review of the testing protocol. More testing for hepatitis E, less testing for hepatitis A.

Answer 7

Bacterial meningitis likely if: - CSF glucose level low cf blood glucose - CSF protein raised - Raised WBC, particularly if neutrophils Viral meningitis more likely if: - - Normal protein and glucose - Moderately raised WBC, particularly if lymphocytes

Answer 8

Very commom - Enteroviruses and Parechoviruses Fairly common - Herpes simplex virus (HSV) - Mumps Rare - Lymphocytic choriomeningitis virus - Varicellar zoster - Human herpesvirus type 6 - Influenza - West Nile

Answer 9

FAMILY: the Picornaviridae are a large and diverse family of non-enveloped RNA viruses has been reclassified into 9 genera based on acid lability, serum neutralization, and sequence homologies. GENUS: the Enterovirus genus contains human rhinoviruses A-C and human enteroviruses A-D (based on RNA sequence and their order of identification). Enteroviruses and rhinoviruses share an identical genomic organization and have high sequence homology but different phenotypic characteristics. GENUS: contains human parechoviruses 1-16.

Answer 10

Cytopathic viruses causing tissue-specific cell destruction. EV-A71: most neuropathogenic non-polio enterovirus in humans. EV-D68: spectrum of disease ranges from asymptomatic to acute respiratory infection including hospitalisation with severe respiratory disease and, sporadically, to neurological symptoms and death. HPeV 3 cause more severe illness in young infants, particularly neonates, including sepsis and CNS infections.

Answer 11

In summer and autumn 2014, the USA and Canada experienced an outbreak of EV-D68 associated with severe respiratory illness. There were 1 153 cases in the USA over a 5 month period of respiratory illness caused by EV-D68. There was a significant increase in acute flaccid myelitis cases in 2014 in the USA and Canada which coincided with this outbreak of severe respiratory illness caused by EV-D68. EV-D68 was not detected in CSF. Definitive causation between EV-D68 and AFM was not established but case controlled studies support the hypothesis.

Answer 12

diagnosis - virus isolation - pcr - new gold standard treatment - aciclovir when appropriate - supportive - stop antibiotics

Answer 13

Sexual Mother-to-baby - Antenatally: transplacental - Perinatally: in birth canal, exposure to maternal blood - Postnatally: in breast milk Blood or blood products - Sharing needles - Haemophiliacs - Blood transfusions

Answer 14

Detection of anti-HIV antibodies by immunoassay Detection of HIV antigens eg p24 by immunoassay Most laboratory screening tests are 4th generation ‘combo’ assays ie they detect antibody and p24 antigen Many POCT and self-test kits are antibody only Detection of viral genome by PCR

Answer 15

Acute infection – often associated with “seroconversion illness” 6-8 weeks after infection Asymptomatic phase Evidence of declining immune function eg oral candida,TB, shingles, generalised lymphadenopathy AIDS: AIDS is a very carefully defined disease.

Answer 16

``` acute HIV rash oral candidiasis TB crytococcal meningitis pneumocystis primary cerebral lymphoma ```