infection 1 Flashcards
notifiable diseases
Acute encephalitis
Acute infectious hepatitis
Acute meningitis
Acute poliomyelitis
Anthrax
Botulism
Brucellosis
Cholera
COVID-19
Diphtheria
Enteric fever (typhoid or paratyphoid fever)
Food poisoning
Haemolytic uraemic syndrome (HUS)
Infectious bloody diarrhoea
Invasive group A streptococcal disease
Legionnaires’ disease
Leprosy
Malaria
Measles
Meningococcal septicaemia
Monkeypox
Mumps
Plague
Rabies
Rubella
Severe Acute Respiratory Syndrome (SARS)
Scarlet fever
Smallpox
Tetanus
Tuberculosis
Typhus
Viral haemorrhagic fever (VHF)
Whooping cough
Yellow fever
discuss covid 19 + risk factors.
a SARS disease (SARS-cov-2), single strand rna.
presents as a respiratory infection - severity from mild cold type illness to a severe pneumonia.
Risk factors for significant disease:
older age, sex, ethnicity, obesity, prev disease. pregnancy etc.
management and investigations of covid -19
PCR test for genetic typing
manage symtpmatically
Cxr- gound glass opacity, bilateral peripheral, basal.
not much use of CT.
Rx:
oxygen
dex 6mg.
monoclonal antibodies
emco
remdesivir- antiviral
what goes on with the cytokine storm
earl ydisease damage is caused purely by virus replication.
in late phase- T cells recruited, monocites, and naeutrophils also.
TNF-A, CM-CSF, Il1, 6, ifn-y are realeased.
overactivation of these causes overwhelming immune response.
discuss influenza + gold standard diagnostic test.
communicable viral disease affecting the upper and lower respiratory tract.
7-10 day course, self limiting in most cases.
4 types of influenza (ABCD)
A+B cause human infection annually
A is the neuraminidase and hemagglutinin typed one (H1N1)
wide spectrum of viruses.
Gold standard for Dx is PCR or viral culture of throat secretions.
vaccine is mainstay of preventative treatment.
oseltamivir - neuraminidase inhibitor.
discuss URTI
defined: self limiting irritation and welling of the upper airways with associated cough and no signs of pneumonia. In a patient with no other condition that would account for their symptoms.
caused by rhinovirus (85% is viral) , strep A pyogenes.
22 billion annual cost in the US.
usually droplet or contact spread, can be areosolised.
7-10 day syptoms, can transmit one day before symptomatic.
Honey is as good as Abx for relef of disease.
discuss herpes viruses
more than 100 different types
8 infect humans.
simplex 1(cold sore), 2 (genital), VZV, CMV, EBV, human herpes virus 6, 7, kaposis sarcoma (number 8)
4 layerd structure- double stranded dna.
what are the 4 underlying principles of herpes infections
code for unique enzymmes involved in the biosynthesis of ciral nucleiuc acids
synthesis and assembly of viral DNA is initiated in the nucleus + capsid is also assembled in nucleus
release of progeny virus from infected cell is accompanied by cell death.
all viruses establish latent infection within tissues that are characteristic for each virus.
discuss classification of herpes viruses by replication cycles
simplex 1-2 + VZV have short replication cycle and broad host range
B herpes viruses - CMV, 6,7 have long replicative cycles and restircted host range
y- EBV and 8 very restricted host range + long cycle.
discuss viral hepatitis as a whole
common caused by the 5 unrelated hepatitis viruses (ABCDE)
Food + water (faeco-oral) A+E- mostly self limiting acute illness with full resolution
blood and bodily fluids B+C- acute+ chronic disease
discuss Hep A
abrupt-onset fever, abdominal pain, malaise, jaundice, dark urine or light-coloured stools, or diarrhoea.
Ix: clinical jaundice with marked elevation of serum transaminases (usually >1000 units/L), check bilirubin, AKI screen, IgM anti-hepatitis A (gold)
RF: living/ visiting endemic regions. known contact, men who have sex with men, illicit drug use.
liver injucy caused by cytotoxic T cells lyseing infected hepatocells.
Rx: if contact within 2 weeks- give 1 dose vaccine.
- supportive care otherwise.
liver transplant if faliure.
non infectious 1 week after jaundice.
Hep B summary
the most common liver infection globally 15-20% go on to develop chronic disease (chirrosis)- a small % of them get hepatocellular cancer
transmitted via sexual contact, sharing needles,
RF: perinatal exposure, high risk sex, IVDU, being in an endemic region, incarceration.
S+S: 70% are asymptomatic.
jaundice, hepatomegaly, ascites, fever/chills,malaise.
generally last for 1-3 months.
investigations for Hep B + Rx.
Ix: hepatitis B surface antigen- presence of viral envilope- suggests pt is infectious- chornic infection is inducated by this being present for more than 6 months.
LFT (elevated aminotransferases, low albu), microcytic anaemia,
Rx: 95% of people will be fine- supportive care. - tenofovir or entecavir antiviral therapy.
Chronic: antiviral- entecavir or tenofovir
if immunosupressed or preg/ breast feeding- more aggressive antiviral rx
work up for liver transplant if failing.
discuss hep C
becomes chronic in about 75% of people who get it. - liver disease and chirrosis - 25% of all HCC is caused by hep C.
acute infection is generally asymptomatic (80%)
can get jaundice, dark urine, fever, abdo pain,
needles, sex, vertically (not through milk).
Ix: antibody test (to see if chronic) and HCV RNA test- to see if acute.
Rx:
same day refferal if considered acute, urgent if chroinc.
FBC,U+E, LFT, Clotting, hba1c.
antiviral: Glecaprevir, pibrentasvir
discuss hepatitis D
a defective virus that cannot replicate without the protein of hepatitis B
chronic HDV infection is the most serious type- commonly leads to cirrhosis, faliure + carcinoma.
S+S: fever, jaundice, ascited, scleral icterus
RF: hepatits B infection, sex, drug use. endemic region visit, habitation.
Ix:
liver biochem. serum antibody to HDV.
Rx:
hep B vaccine to prevent disease
no antiviral drugs are approved for hep D.
