MISC Flashcards
What is AIDS?
Acquired Immunodeficiency syndrome–> Late stage HIV
What is HIV
Human immunodeficiency virus: An RNA retrovirus
What is the most common type of HIV?
HIV-1
HIV-2 confined to West Africa
What does the HIV virus do?
Enters and destroys CD4 T helper cells.
How does HIV enter cells?
Via the GP120 envelope glycoprotein on its surface.
What happens to the infected CD4 cells?
They migrate to lymphoid tissue where the virus replicates, producing billions of new virions which are released and go on to infect new CD4 cells
What is a virion?
An entire virus particle, consisting of a capsid (outer protein shell) and inner core of DNA or RNA/
What is the structure of HIV?
Spherical RNA lentivirus. Envelope covered in glycoproteins gp120 and gp41 contains matrix with nucleus held inside the capsid.
What does HIV’s capsid contain?
Two enzymes essential for replication (reverse transcriptase and integrase) and two strands of RNA.
What cells does HIV infect?
Cells with CD4 receptors on their surface: T cells, monocytes, macrophages and dendritic cells.
How does HIV attach and enter immune cells?
The gp120 spikes lock onto the CD4 receptor and another co-receptor (CCR5 or CXCR4). The gp41 protein is then used to fuse the HIV envelope to the cell wall, allowing the capsid to enter.
What happens when HIV RNA enters the immune cell?
It must be reverse transcribed into proviral DNA before it can be integrated into the hosts DNA. This is done using reverse transcriptase
What happens after HIV RNA has been converted into DNA?
HIV’s integrase enzyme attaches itself to the end of the proviral DNA strands and it passes through the wall of the cell nucleus and binds to the host cells DNA
What is a latently infected cell?
When the proviral DNA has integrated into the host cells DNA, HIV remains dormant for a period.
When do infected CD4 cells become activated?
If they encounter an infectious agent
What happens when the infected cell becomes active?
HIV uses the hosts RNA polymerase to make new HIV RNA which are split into pieces using HIV’s protease enzyme
What happens to the newly formed HIV RNA after being produced?
They begin to assemble into new viruses at the cell wall and becomes enclosed in a capsid. It then takes lipids from the cell wall to make surface glycoproteins and buds from the cell wall.
How does HIV enter the body?
By infecting CD4 cells in the mucous membranes of the vagina or rectum, or by direct infection of CD4 T-cells in the bloodstream
What is PrEP?
Pre-exposure prophylaxis that people at risk of HIV can take consistently to prevent it.
How soon after exposure does HIV arrive at the lymph nodes?
24 to 28 hours
Where does HIV begin to replicate and how long does this stage last?
the lymph nodes for 7-21 days. Not detectable at this period
How soon after exposure is HIV detectable in the blood by viral load testing?
Several weeks after infection
What are the common symptoms of acute HIV infection and how long do they last?
Symptoms can last for up to 2 weeks: Fever Rash Swollen glands Myalgia Significant weight loss May be asymptomatic
What is the asymptomatic phase of HIV and how long does it last?
After acute infection, HIV will not cause further illness for some years and the number of infected CD4 cells falls. (usually lasts around 10 years)
What does the length of the asymptomatic phase depend on?
How quickly the CD4 count declines–> Once it is below 200 the patient is at far greater risk of AIDS.
What are the two largest groups of people living with HIV
Sub-Saharan Africans and homosexuals.
Who is most at risk of AIDS
Homosexuals Those who have unprotected sex IV drug users Sex workers Truck drivers and migrant workers Uncircumcised men
How is HIV transmitted?
Unprotected anal, vaginal or oral sex
Mother to child in pregnancy, birth or breastfeeding (vertical transmission)
Mucous membrane, blood or open wound exposure to infected blood or bodily fluids (e.g. sharing needles)
What is Late-Stage HIV?
When AIDs occurs, patients are highly susceptible to opportunistic infections due to low CD4 count
What are the most common AIDS-defining illnesses?
Infections–> Pneumonia, Ctyomegalovirus infection
Candidiasis, Tuberculosis, herpes simplex e.t.c.
Neoplams–> Kaposi’s sarcoma, Lymphomas
Who should be screened for HIV?
Anybody admitted to hospital with an infectious disease regardless of risk factors and patients with any risk factors.
How is HIV tested for?
Antibody blood test
p24 antigen test
PCR testing with HIV RNA levels indicates viral load
How can HIV be monitored?
CD4 count
Viral load
What are the symptoms of early symptomatic HIV? (AIDS-related complex ARC)
Fever Night sweat Diarrhoea Weight loss Minor opportunistic infection (oral candida, herpes zoster- shingles, herpes simplex)
How is HIV treated?
HAART:
Use more than 3 drugs–> 2NRTIs + 1 NNRTI or 2 NRTI and 1 PI.
ART (Antiretroviral therapy)--> Offered to everyone diagnosed despite viral load or CD4 count. Single combination tablet once a day. 2 NRTIs (Nucleoside reverse transcriptase inhibitors)
What is HAART and what are the different medication classes?
Highly active Anti-retrovirus therapy:
Protease inhibitors (PIs)
Integrase inhibitors (IIs)
Nucleoside reverse transcriptase inhibitors (NRTIs)
non-nucleoside reverse transcriptase inhibitors (NNRTIs)
Entry inhibitors. (EIs)
What additional management is given to HIV patients to reduce risk of complications?
Prophylactiv Septrin given to patients with CD4< 200 to protect against pneumonia
Close monitoring of CV risk factors and appropriate treatment (e.g. statins)
Yearly cervical smears
Vaccinations up to date (avoid live vaccines)
What measures should be taken for a HIV positive pregnancy?
Can use sperm washing and IVF
C-section should be used unless mother has undetectable viral load
Newborns should receive ART for 4 weeks after birth.
What is post-exposure prophylaxis?
Combination of ART therapy (Truvada and Raltegravir) given within 72 hours of exposure to prevent infection.
What is amyloidosis?
A rare group of conditions caused by an abnormal buildup or a protein called amyloid in the organs, interfering with their normal function.
What are the symptoms of AL amyloidosis?
Depends on the tissues/ organs affects:
Kidney failure–> Oedema, tiredness, weakness, loss of appetite
Heart failure–> S.O.B., oedema, arrhythmia
Lightheadedness
GI problems
Carpal tunnel
Easy bruising
What causes AL amyloidosis?
Abnormal plasma cells produce abnormal forms of light chain proteins which clump together (amyloid fibrils) and build up in tissues and organs as amyloid deposits
How is amyloidosis treated?
No cure but treatments can prevent more abnormal proteins being produced:
Chemotherapy (damages abnormal bone marrow cells to stop them producing abnormal proteins)
Steroids (boost chemo)
Stem cell transplant
Treatment of complications (e.g. dialysis, kidney tranplant)
How can amyloidosis be diagnosed?
Biopsy from affected part of the body See how it has affected the body: -Bone marrow sample -Echocardiogram - Blood tests -CT/ MRI
What is the most common cancer in women?
Breast cancer
Where do the majority of breast cancers arise from?
Epithelial lining of ducts (ductal) or epithelium of terminal ducts of the lobules (lobular)
How many women are diagnosed with breast cancer in their life?
1 in 8
What are the main breast cancer symptoms?
Lump or area of thickened breast tissue Change in size/ shape of breast Discharge from either nipple Lump/ Swelling in either armpit Dimpling of skin Rash Change in nipple appearance (e.g. sunken)
What are the main risk factors with breast cancer?
Age Family history BRXA1 or BRCA2 mutation Previous diagnosis Previous benign breast lump Being tall, overweight or obese Drinking alcohol
How is breast cancer diagnosed?
Breast examination Mammography Ultrasound scan Biopsy Fine-needle aspiration
What are the two main types of breast cancer?
Non-invasive–> Found in ducts but not spread to surrounding tissue
Invasive–> Cancer cells have spread to surrounding breast tissue
What is the breast cancer screening programme?
All women age 50-70 invited for mammogram every 3 years.
How is breast cancer treated?
Surgery
Chemotherapy
Radiotherapy
What gene is associated with breast cancers?
BRCA1/2
What is the most common type of breast cancer?
Infiltrating ductal carcinoma
What are the different stages of breast cancer?
Stage 0= ductal carcinoma in situ
Stage 1= Tumuor < 2cm and isolated to breast
Stage 2= Tumour measures 2-5cm, armpit lymph nodes affected but nowhere else
Stage 3= Tumour is 2-5cm and may be attached to structures in the breast such as skin and surrounding tissues, lymph nodes are affected
Stage 4= Tumour of anzy size has metastasised.
What is the TNM staging system?
T= size of tumour N= Whether the cancer has spread to the lymph nodes M= Where the cancer has spread to other parts of the body.
What are the different grades of breast cancer?
Low grade (G1)= Abnormal cells appear to be growing slowly Medium grade (G2)= Cells look more abnormal than G1 High grade (G3)= Cells look more abnormal and grow more quickly.
What is lymphoedema?
A chronic condition that causes swelling of the tissues due to lymphatic insufficiency.
What causes lymphoedema?
When the lymphatic system fails to drain.
What are the 2 main types of lympheodema?
Primary lymphoedema- caused by fenetic mutations that affect the development of the lymphatic system
Secondary lymphoedema- caused by damage to the lymphatic systemor problems with the movement and drainage of fluid (e.g. cancer treatment, infection, inflammation e.t.c.)
What are the symptoms of lymphoedema?
Swelling in a limb (may come and go but eventually gets more persistent) Aching, heavy feeling Difficulty moving Skin infections Hard, tight skin, Skin folds
How is lymphoedema managed?
No cure- just treat symptoms: Compression garments Skin care Regular movement/ exercise Healthy diet/ lifestyle
What is the most common complication of lymphoedema?
Cellulitis- bacterial infection of dermis
What causes carbon monoxide poisining?
Inhalation of smoke, car exhaust fumes or improperly maintained/ ventilated heating systems
Why does carbon monoxide reduce the oxygen-carrying capacity of Hb?
It has 200 X greater affinity for the oxygen-binding sites on haemoglobin than oxygen.
In what direction does CO shift the oxygen-haemoglobin dissociation curve?
Left
What are the main symptoms of CO poisoning?
Hypoxaemia Vomiting Tachypnoea Headache, mental impairment Convulsions/ coma/ cardiac arrest et.c.
How is CO poisoning diagnosed?
ABG that looks for oxygen haemoglobin satruration, haemoglobin and COHb/
How is Co poisoning treated?
Remove CO source
Give 100% O2 until COHb <10%
How can opioid withdrawal symptoms be reduced?
Using methadone (pharmaceutical preperation of an opioid)
What are the main presentations of an insecticide overdose? /
SLUD: Salivation Lacrimation (tears) Urination Diarrhoea
What are sarcomas?
Rare tumours that form in the connective tissues.
Where can sarcomas develop?
Muscle, bone, nerves, cartilage, tendons, blood vessels, fatty and fibrous tissues
What are the two main types of sarcoma?
Soft tissue sarcoma (80%) Bone sarcoma (20%)
What are the red flags that indicate a soft tissue sarcoma?
Lump that is : - Big (>5cm) or getting bigger -Deep in body tissues Painful Occurs in older patient
What are the key presentations of STS?
Lump that is painless at first
Pain and soreness as lump grows and presses against nerves and muscles
How is STS diagnosed?
MRI and cor needle biopsy
CT for metastases
How is STS treated?
Surgical resection + Chemo/ radiotherapy
What are the red flags for.a bone sarcoma?
Non-mechanical bone pain
Night pain
Palpable bony ass
For > 3months
How does bone tumour present?
Non mechanical bone pain that is still present when lying still Swelling Fatigue Pyrexia Weight loss
How is bone sarcoma diagnosed?
X-ray
CT/ MRI
Bone scans/ biopsy
How are bone sarcomas treated?
Wide surgical resection/ reconstruction
Chemo/ Radiotherapy
