Miscellaneous Flashcards
What does HIV stand for?
Human immunodeficiency virus
What is responsible for most human infections of HIV?
HIV1
Give 2 groups with the most prevalence for HIV in the UK
- ) Men who have sex with men
- ) IVDUs
What does IVDU stand for?
Intravenous drug user
Give the 7 steps of HIV pathogenesis
1) HIV binds to CD4 receptors
2) CD4 positive cells migrate where virus replicates and releases new virions
3) Infection progresses and decreases immunity
4) DNA copy of virus RNA genome made
5) Integrated into host DNA
6) Core viral proteins
7) Completed virus is released
What is the viral load of HIV?
Number of circulating viruses
What does the viral load of HIV predict?
Progression to AIDs
What does HIV bind via? (Step 1)
GP120 envelope protein
Where are the CD4 receptors that are bound to HIV? (Step 1)
Helper T cells, monocytes, macrophages, neural cells
Where do CD4 positive cells migrate to? (Step 2)
Lymphoid tissue
What do new virions do? (Step 2)
Infect new cells
Why does immunity decrease as infection progresses in HIV? (Step 3)
Depletion and impaired function of CD4 cells
What makes a DNA copy of the virus RNA genome? (Step 4)
Viral reverse transcriptase enzyme
What integrates the DNA copy of the virus RNA genome into host DNA? (Step 5)
Integrase
What are the core viral proteins initially synthesised as?
Large polypeptides that are cleaved by protease
What are the 3 stages of HIV?
- ) Seroconversion (primary infection)
- ) Asymptomatic period
- ) AIDs related complex
What may seroconversion by accompanied by?
Transient illness 2-6 weeks after exposure
What are the symptoms of seroconversion?
- ) Fever
- ) Malaise
- ) Myalgia
- ) Pharyngitis
- ) Maculopapular rash
What can occur instead of the asymptomatic period of HIV?
Persistent generalised lymphadenopathy
Give 3 later constitutional symptoms of HIV
- ) Night sweats
- ) Fever
- ) Diarrhoea
- ) Weight loss
- ) Possible opportunistic infections
Give 2 opportunistic infections of HIV
- ) Oral candida
- ) Herpes zoster
- ) Herpes simplex
What is the precursor to AIDS?
AIDS related complex
What is AIDS defined as?
- ) HIV plus an indicator disease
- ) CD4 usually <200x10^6
How long is the progression from HIV to AIDs usually?
8 years
How long is the progression from AIDS related complex to AIDS usually?
2 years
How long is the progression from AIDS to death without treatment?
2 years
Give 3 indications that HIV progression is more severe
- ) Fever
- ) Lymphadenopathy
- ) Cough
- ) Diarrhoea
- ) Oral thrush
- ) Weight loss
- ) TB
- ) Herpes zoster (shingles)
Which 2 HIV subtypes predominate in the UK?
A and B
What do we detect in tests for HIV?
Serum HIB antibody by ELISA
What do we do if the HIV test is negative? (3)
- ) Check again later
- ) Look for HIV RNA by PCR
- ) Look for core p24 antigen in plasma
What does ELISA stand for?
Enzyme linked immunosorbent assay
Give 3 ways to prevent HIV
- ) Good education
- ) Accessible tests and counselling
- ) Condoms
- ) Fewer sexual partners and only one at a time
- ) Decrease alcohol (risky behaviour)
- ) Circumcision
Give 3 complications/opportunistic infections of HIV
- ) TB
- ) Pneumocystis jiroveci pneumonia
- ) Candidiasis
- ) Toxoplasmosis
- ) Cryptococcal meningitis
- ) Cytomegalovirus retinitis
- ) Kaposi’s sarcoma
- ) Leishmaniasis
What 4 tests do we do routinely during treatment of HIV?
- ) CD4 T cell count
- ) HIV RNA
- ) Serum U&E, Cl, creatinine, bilirubin, LFT, FBC
- ) Lipid profile and glucose
When should we initiate therapy in HIV?
- ) AIDS defining illness
- ) CD4 <350
- ) Pregnancy
- ) Nephropathy
- ) HBV
What does highly active antiretroviral therapy aim to do?
Suppress plasma HIV RNA levels below limit of detection and restore immune function
Give 3 types of drug we give in HIV
- ) Nucleoside reverse transcriptase inhibitors
- ) Protease inhibitors
- ) Non-nucleoside reverse transcriptase inhibitors
- ) Integrase strand transfer inhibitors
Why do we use >3 drug combinations in HIV treatment?
To minimise replication and cross resistance
Give an example of a nucleoside reverse transcriptase inhibitor
- ) Tenofovir
- ) Lamivudine
- ) Abacavir
Give an example of a protease inhibitor
Lopanavir
Give an example of a non-nucleoside reverse transcriptase inhibitor
- ) Nevirapine
- ) Efavirenz
Give an example of an integrate strand transfer inhibitor
-) Ellvitegravir
What is the most severe type of malaria?
P. falciparum
Give the 4 main types of malaria
- ) P. falciparum
- ) P. ovale
- ) P. vivax
- ) P. malariae
How is malaria transmitted?
Plasmodium protozoa injected by bite of female anopheles mosquito
Give the 8 pathogenic steps of malaria transmission
1) Female mosquito takes blood meal containing gametocytes
2) Protozoa develop in mosquito
3) Sporozoites migrate to salivary glands
4) Inoculated into human host, taken up by liver
5) Multiply in hepatocytes to form merozoites
6) Hepatocytes rupture and merozoites released into blood
7) Merozoites multiply and form trophozoites, schizont and new merozoites inside erythrocytes
8) A few merozoites develop into gametocytes which are taken up by other mosquitos
Give 3 things protozoa multiplying in RBCs causes
- ) Haemolysis
- ) RBC sequestration
- ) Cytokine release
- ) Infect liver
What do fever paroxysms reflect in malaria?
Synchronous release of merozoites from mature schizonts, causes cold/hot fever and nausea/headache
Give 2 protective factors for malaria
- ) Glucose 6 phosphate dehydrogenase deficiency
- ) Sickle cell trait
Give 3 symptoms of malaria
- ) 90% present within 1 month
- ) Prodromal headache, malaise, myalgia, anorexia before 1st fever paroxysm
- ) Tertian fevers - recur every second day is classic
- ) Anaemia, jaundice, hepatosplenomegaly
What can decreased consciousness indicate in malaria?
Cerebral malaria
What is the mortality for falciparum malaria?
20%
Higher if very young/pregnant
Give 3 tests we do for malaria
- ) Serial thin and thick blood films to show level of parasiteaemia
- ) FBC may show anaemia (from haemolysis) and thrombocytopaenia
- ) Clotting, glucose, ABG/lactate, U&E, urinalysis
- ) Blood culture to check for septicaemia
How do we treat P. falciparum malaria? (5)
- ) Combination therapy containing artemisinin derivatives
- ) Possible atovaquone-proguanil (macaroni)
- ) Or quinine and doxycycline/clindamycin
- ) P. falciparum largely resistant to chloroquine
- ) IV with artesunate if severe (with above)
How do we treat uncomplicated P. ovale/vivax/malariae malaria?
- ) Chloroquine based
- ) Primaquine after in ovale and vivax to prevent relapse
- ) Malarone or quinine if resistant
What is the general treatment for malaria?
- ) Paracetamol
- ) Transfuse if severe anaemia
- ) Monitor bloods
How do we prevent malaria?
- ) Proguanil daily and chloroquine base weakly
- ) If chloroquine resistant - doxycycline or malarone
- ) Repellant, long sleeves, bed nets
What is malarone?
Atovaquine-proguanil
What is a lymphoedema?
Chronic non-pitting oedema due to lymphatic insufficiency
What part of the body does a lymphoedema normally affect?
Legs
What can chronic lymphoedema cause?
Secondary ‘cobblestone’ thickening of skin
Give a primary cause of lymphoedema
Milroy disease
Give a secondary cause of lymphoedema
Obstruction of lymphatic vessels
What is Milroy disease?
Lower leg swelling from birth, autosomal dominant
What are the mutations in Milroy disease?
VEGFR3 causing lymphatic malfunction
What is the treatment for Milroy disease?
Compression stockings/bandages, exercise
What is a filarial infection transmitted by?
5 genera of mosquito
What does a filarial infection cause?
Obstruction of the lymphatic vessels
Give 2 symptoms of an acute filarial infection
Fever
Lymphadenopathy
Chyluria
What can a filarial infection also cause?
Elephantiasis - massive lymphoedema in the legs and massive hydroceles
What can a sarcoma originate from?
Any mesenchymal tissue (fat/muscle/cartilage/bone)
What do soft tissue sarcomas present as?
Painless enlarging mass
Give a risk factor for a sarcoma
Neurofibromatosis, previous radiotherapy
Give 2 features that will lead a lump being considered malignant
- ) Lump bigger than 5cm
- ) Increasing in size
- ) Deep to deep fascia
- ) Painful
How do we diagnose a sarcoma?
MRI followed by needle biopsy
What is the most common sarcoma in children?
Rhabdo-myosarcoma
Give 2 types of sarcoma
Rhabdo-myosarcoma, liposarcoma, leiomyosarcoma, fibrosarcoma
How do we treat sarcomas?
Exision with wide margins followed by radiotherapy
What would we use chemotherapy in a sarcoma?
Osteosarcoma or mets
What is the general management for poisoning? (7)
- ) ABC, secure airway, shock
- ) Take blood, paracetamol and salicylate levels
- ) Possible empty stomach
- ) Consider specific antidote or oral activated charcoal
- ) Get more info, TOXBASE
- ) Monitor closely and give supportive care
- ) Psychiatry?
What does CO do?
Binds to Hb and decreases O2 delivery to tissues
Give 3 symptoms of CO poisoning
- ) Headache
- ) Vomiting
- ) High pulse
- ) Tachypnoea
- ) Fits, coma, cardiac arrest if severe
What does an ABG show in CO poisoning?
Low O2 saturation and high carboxyhaemoglobin
How do we treat CO poisoning?
Remove source and give O2 until carboxyhaemoglobin decreased
How do we treat cerebral oedema?
Mannitol
What does aspirin/salicylate poisoning do?
Uncoupling of oxidative phosphorylation leading to anaerobic metabolism and production of lactate and heat
Give 3 symptoms of salicylate poisoning
- ) Vomiting
- ) Dehydration
- ) Hyperventilation
- ) Tinnitus
- ) Vertigo
- ) Sweating
- ) Low GCS, low BP, seizures, hyperthermia, pulmonary oedema rarely
What sort of alkalosis is there in salicylate poisoning?
Initial respiratory alkalosis then metabolic acidosis
How do we treat salicylate poisoning?
- ) Correct dehydration
- ) Give activated charcoal within 1 hour
- ) Monitor bloods
- ) Correct acidosis
- ) Treat hypokalaemia if present
- ) Dialysis if severe and if complications
Give a complication of salicylate poisoning
AKI, HF, oedema, confusion, seizures
How do we correct acidosis?
IV sodium bicarbonate
Give 2 symptoms fo paracetamol poisoning
- ) Nothing initially
- ) Vomiting
- ) RUQ pain
- ) Jaundice and encephalopathy later
- ) Possible AKI
How do we treat paracetamol poisoning?
- ) Activated charcoal within 4 hours
- ) N-acetylcyseine within 10-12 hours and no vomiting
What do organophosphate insecticides cause?
Inactivate cholinesterase and thus increase acetylcholine
Give 4 symptoms of organophosphate insecticide poisoning
- ) SLUD - salivation, lacrimation, urination, diarrhoea
- ) Sweating
- ) Small pupils
- ) Muscle fasciculation
- ) Coma
How do we treat organophosphate insecticide poisoning? (3)
- ) Remove soiled clothes and wash skin
- ) Atropine IV until fully atropinates
- ) Pralidoxime and diazepam
What does atropinates mean?
Skin dry, pulse >70, pupils dilated
