ID Flashcards
What cancers are associated with EBV?
Hodgkins, Burkits and gastric
What are the complications of a congenital CMV infection?
Prematurity, low birth weight, jaundice, enlarged liver, microcephaly, rash, pneumonia and seizures
Hep B serology:
What are the 3 antigens that Hep B has?
HBsAG (hep B surface antigen)
HBcAG (hep B core antigen)
HBeAG (hep B e antigen - a secreted protein with unknown function)
Hep B serology:
What Hep B serology marker would be +ve if they have an infection?
HBsAg would be positive if they have a an active infection
Surface antigen is the first thing seen in the serum 4w–>12wks and then is replaced by anti-HBs
Hep B serology:
Which Hep B serum marker tests if they have some immunity (regardless if it is from vaccine or from past infection)?
HB surface antibody
Tests for immunity +ve for vaccination or if they have had a past infection
Anti-HBc determines if they have got their immunity from a past infection or if it has just been from the vaccine. What would the following results mean?
Anti-HBc: IgG +ve and IgM -ve
They have got their immunity from the vaccine
Anti-HBc determines if they have got their immunity from a past infection or if it has just been from the vaccine. What would the following results mean?
Anti-HBc: IgG +ve and IgM +ve
They have had a past infection and cleared it
When do you vaccinate against Hep B?
- HBsAG given at 0, 1 & 6/12 with boosters every 5 years
- Anti HBV immunoglobulins
What are the symptoms of Hep B?
Fever, Jaundice and elevated liver transaminases
What are the complications of Hep B infection?
Chronic hepatitis
Fulminant liver failure
HCC
Glomerular nephritis
How would you diagnose Hep C?
Serum test for: HCV RNA
Do the majority of people with Hep C go onto clear the virus or to have chronic disease?
15-45% clear
55-85% go onto have chronic hepatitis
What defines chronic hep c?
When they have had HCV RNA in the blood for >6m
What are the potential complications for Hep C?
HCC
Cirrhosis
Rhuem: arthralgia and arthritis
Eye: Sjogrens
What does the management of Hep C depend on?
Their viral genotype which should be tested for before starting treatment
How would you treat a chronic hep C infection?
1) Protease inhibitors (telaprivir, daclatasvir)
2) Antiviral - nucleoside inhibitor (Ribavirin)
3) Peg INF alpha
Protease inhibitors are a class of drug used to treat Hep C. How do they work? Give 2 examples
Protease inhibitors are anti-virals that prevent viral replication by selectively binding to proteases + blocking proteolytic cleavage of proteins
E.g Telaprevir + Beceprevir
How does PEG INF alpha work to treat Hep C?
PEG INF alpha acts as a multifunctional immuno-regulatory cytokine which stimulates B cells
What are the SE of PEG INF alpha?
Headache, fatigue, N + hairless
Flu-like symptoms, leukopenia and thrombocytopenia
Depression and fatigue
How does Ribavirin work?
It is an anti-viral that reduces the viral load as it is a nucleoside inhibitor
What are the SE of the specialist treatment of Hep C infection?
SE of the specialist Hep C treatment:
- Flu-like symptoms
- Haemolytic anaemia and other blood dyscrasias
- Depression
- Dry skin, eczema and itch
- Hypo/hyperthyroidism
- Sleep disturbances
What are the 4 types of malaria parasite?
Plasmodium falciparum
Plasmodium viva
Plasmodium malaria
Plasmodium ovale
Briefly explain the life-cycle of malaria
When an infected mosquito bits a human the sporozoites travel to the human liver where they mature. Mature organisms (merozoites) can rupture to release more organisms into the blood. Merozoites invade RBC and reproduce to make more sporozoites which can be transmitted/picked up by more mosquitos when they have a blood meal.
Infection of RBC –> haemolysis
A 26yr old has just returned from Africa. He is unwell with SOB, fits, hypoglycaemia and AKI and is bleeding. You suspect that he has a severe malaria infection - but what would your differentials be?
Typhoid Hepatits Dengue fever Influenza HIV Viral haemorrhage fevers
What is the gold standard test to dx malaria?
Thick and thin blood smears stained with giemsa
How can you dx malaria?
1) Thick and thin blood smears stained with giemsa
2) Rapid diagnostic tests (RDTS) - dipstick based investigations
How do you treat non-fallciparum malaria?
1) Chloroquine
Or if resistant:
- Malarone (atovaquone-proguanil)
//
- Riamet (artemether w. lumefantrine)
How do you treat non-complicated Fallciparum malaria?
Qunine + doxycyline or// Malarone or// Riamet
How do you treat complicated Fallciparum malaria?
Iv Quinine dihydrochloride with doxycycline
What are the possible complications of malaria?
LOC/siezures Renal impairment Acidosis Hypoglycaemia Anaemia Splenic rupture DIC Multiple organ failure Death
What cells are most affected by HIV?
Helper T lymphocytes
other CD4 cells: monocytes+ macrophages
What is HIV seroconversion?
HIV seroconversion is the time during which the HIV abs become detectable.
It is symptomatic in 60% of patients and they experience a glandular fever type illness
What are some of the symptoms that someone experiencing the HIV seroconversion illness may experience?
Sore throat Lymphadenopathy Malaise, myalgia and arthralgia Diarrhoea Maculopapular rash
The window period of HIV is 1-3 weeks
How can you dx HIV during this time?
1) HIV RNA PCR
2) Core p24 antigen (detectable <4wks when there is very high viral replication)
How do you diagnose HIV?
2 ab test:
1) ELISA
2) Western blot
+ serum CD4 count and HIV RNA PCR (for viral load)
What are the stages of HIV?
1 = Seroconversion (2-6 weeks) 2 = asymptomatic/clinical latency 3 = AIDs related complex (constitutional symptoms - fever, night sweats, D, weight loss + minor opportunistic infections) 4 = AIDS (HIV + indicator disease)
How do you treat HIV?
HAART = highly active anti retroviral therapy
> 3 different drugs are used to reduce the cross resistance
2x NRTI + 1x NNRTI
2x NRTI + 1x PI
Give examples of the types of drugs used to treat HIV
- Nucleoside reverse transcriptase inhibitors
- Nucleotide reverse transcriptase inhibitors
- Non-nucleoside reverse trancriptase inhibitors
- Protease inhibitors
- Fusion inhibitors
- Integrase inhibitors
What is PEP?
Post exposure prophylaxis
Start immediately if there has been significant exposure
- 4 week course usually of Truvada (NRTI) + Raltegravir (Integrase inhibitor)
What is AIDs related complex?
It is a prodromal infection in a person with HIV which they can have before they develop AIDS
Pyrexia, fever, night sweats, D and weight loss
It is differentiated between AIDS with serology markers (b lymphocytes levels ect…)
Not used as much now
Define AIDS
Acquired immune deficiency syndrome
It is defined by the occurrence of any of more than 20 opportunistic infections or HIV-related cancers in a person who is HIV +ve
Give examples of the AIDS defining illnesses
CMV - cytomegalovirus PCP - pneumocystis jirovecii TB Cancers - Karposi's sarcoma + lymphoma Candidiasis HSV VZV - at multiple dermatomes
What abx are used to treat MRSA?
1st line = vancomycin
2nd line = linezolid
How would you treat a HIV patient who was also suffering with PCP chest infection?
co-trimoxazole
What can cause headaches in a person with HIV who is not being treated?
Toxoplasmosis
Crytococcal meningitis
What should you do if you get a needle stick injury?
Encourage it to bleed and run it under water and soap
How would you treat a CMV infection in a person with HIV?
Ganciclovir
What class of anti-retrovirals does Lamivudine belong to?
Nucleoside reverse transcriptase inhibitors
What are the SE of the Nucleoside reverse transcriptase inhibitors
Haemolytic anaemia and hypersensitivity reactions
What class of anti-retrovirals does raltegravir belong to?
Integrase inhibitors
What class of anti-retrovirals does efavirenz belong to?
Non-nucleoside reverse transcriptase inhibitors
What are the SE of Non-nucleoside reverse transcriptase inhibitors?
Rash, liver toxicity, drug interactions and sleep disturbance
Which out of HIV, Hep B or Hep C is the most infectious?
Hep B
There is no indication for treatment of acute Hep B infection however it can rarely go into fulminant hepatic failure which may need a liver transplant.
What blood test is used as a marker for this?
Increasing INR
Hep C is the 3rd most common cause of liver failure in the UK.
What are the most common causes?
Alcohol and non-alcoholic fatty liver disease
How do patients with Hep C get assessed for the severity of their liver disease?
They undergo a baseline liver fibrosis scan - Firboscan looking at the liver transient elastography (liver stiffness)
How are patients with Hep C and evidence of cirrhosis screened for HCC?
6mly AFP and liver USS
[if there is evidence of portal HTN they are screened for gastric and oesophageal varies with an OGD]
What factors reduce the efficacy of Hep C treatment?
Male sex High HCV RNA Age >40 Obesity HIV + Hep B co-infection Degree of liver damage Black ethnicity
