Miscellaneous Flashcards
HIV/AIDS
What group is HIV part of and what does this mean?
- Lentivirus group (retrovirus) meaning it encodes reverse transcriptase, allowing DNA copies to be produced from viral RNA – error prone, meaning a significant mutation rate contributing to treatment resistance.
HIV/AIDS
What is the initial response to HIV virus and how does it spread?
- Local inflammation with a mucosal macrophage/dendritic cell established before spreading to other cells.
- As these are antigen presenting cells, some migrate to local lymph nodes to present antigen to T cells where infection of T helper cells occurs.
HIV/AIDS
How does HIV bind to cells?
- Via its GP120 envelope glycoprotein to CD4 receptors on T helper cells, monocytes + macrophages.
HIV/AIDS
What happens once HIV has bound to CD4 receptors?
- CD4 cells migrate to lymphoid tissue where virus replicates with production of billions of new virions which are released + infect new CD4 cells.
HIV/AIDS
How does HIV replicate?
- Viral capsid enters, enzymes + nucleic acid uncoated + released.
- Reverse transcriptase makes single stranded RNA into double stranded DNA + viral DNA is integrated to host cell’s DNA via integrase.
HIV/AIDS
How does HIV lead to decreased immune function?
- Depletion/impaired function due to viraemia causes uncontrolled activation of CD4 T cells + so apoptosis of CD4 cells.
HIV/AIDS
Why is HIV not stopped?
- Able to avoid antibodies + CD8 cytotoxic T lymphocytes due to viral envelope glycoprotein being poorly immunogenic + mutations.
HIV/AIDS
What is the epidemiology of HIV?
- Mostly HIV-1, less HIV-2.
- Men > women as HIV spreads well by anal intercourse, very prevalent in male-male sexual activity.
- Majority of new infections worldwide are 15–24y/o.
HIV/AIDS
What are high risk groups for HIV?
- Homosexual men + heterosexual women.
- IV drug users.
- Commercial sex workers, truck drivers.
- Uncircumcised men.
HIV/AIDS
What are the routes of acquisition of HIV?
- Sexual intercourse (vaginal + anal), STIs enhance transmission.
- Mother-to-child in utero.
- Contaminated blood + organ donation (minimal in developed countries).
- Contaminated needles.
HIV/AIDS
What is the first stage in the clinical presentation of HIV?
Acute primary infection (seroconversion, 2–6 weeks)…
- Transient immunosuppression + fall in CD4 count followed by gradual rise.
- Acute rise in viral load then fall to set point.
- Transient, non-specific symptoms (fever, malaise, myalgia, rash).
HIV/AIDS
What is the second stage in the clinical presentation of HIV?
Asymptomatic phase (years)... - Clinical latency with progressive loss of CD4 T cells resulting in poor immunity but asymptomatic (spreads infection further).
HIV/AIDS
What is the third stage in the clinical presentation of HIV?
Early symptomatic HIV…
- Associated with rise in viral load + fall in CD4 count.
- Symptoms like fever, night sweats, diarrhoea.
- Opportunistic infections (herpes zoster, recurrent herpes simplex).
- Collection of symptoms is AIDS-related complex (ARC).
HIV/AIDS
What is the final stage in clinical presentation of HIV.
AIDS…
- Symptoms of immune deficiency with a CD4 <200uL.
HIV/AIDS
What is the natural time frame for HIV to AIDs development?
HIV>[8 years]>ARC>[2 years]>AIDS>[2 years]>death.
HIV/AIDS
What are AIDS defining conditions?
- Oesophageal candidiasis.
- Mycobacterium TB.
- Persistent herpes simplex.
- Kaposi’s carcinoma.
- Non-Hodgkin’s lymphoma.
- HIV dementia.
HIV/AIDS
What are the investigations for HIV?
Enzyme-linked immunosorbent assay (ELISA)…
- Can take up to 3 months for HIV antibody/antigen detection.
- Confirmatory assay diagnostic.
Rapid point of care testing…
- Immunoassay kit provides rapid result from finger-prick/mouth swab, needs serological confirmation.
Nucleic acid testing/viral PCR…
- Qualitative test for presence of viral RNA, used to aid diagnosis of HIV in babies.
HIV/AIDS
What methods are used to monitor HIV infection?
Viral load…
- Quantification of HIV RNA.
CD4 count…
- Monitors immune system function.
HIV/AIDS
What are the treatment for HIV?
High active antiretroviral therapy (HAART)…
- Before CD4<200uL is ideal.
Nucleoside reverse transcriptase inhibitors (NRTI)…
- Inhibit synthesis of DNA by reverse transcription + also act as DNA chain terminators.
Non-nucleoside reverse transcriptase inhibitors (NNRTI).
- Bind directly to + inhibits reverse transcriptase.
Protease inhibitors…
- Act competitively on HIV enzyme involved in production of functional viral proteins + enzymes.
Integrase inhibitors…
- Inhibits insertion of HIV DNA into human genome.
HIV/AIDS
What is the prevention of HIV?
- Education on transmission, contraception.
- Give IV drug users clean needles.
- Pre/post-exposure prophylaxis in high-risk individuals (antiretroviral therapy).
- Male circumcision.
BREAST CANCER
What is the pathophysiology of breast cancer?
- Can arise from epithelial lining of ducts (ductal) or epithelium of terminal ducts of lobules (lobular).
BREAST CANCER
What are the 4 types of breast cancer?
Invasive ductal carcinoma... - MOST common. Lobular carcinoma... - Accounts for 10–15% Medullary cancers... - Often younger patients. Colloid/mucoid cancers... - Often elderly patients.
BREAST CANCER
What is the epidemiology of breast cancer?
- 1/8 women (most common cancer in women, second most common cause of death in UK).
- Rare in men (1% of all breast cancers).
BREAST CANCER
What are the risk factors for breast cancer?
- BRCA1/BRCA2 mutations.
- Early menarche/late menopause.
- Continuous combined HRT.
- Increasing age, never having borne a child/first child after 30y/o.
- Not breastfeeding.
BREAST CANCER
What are BRCA1/BRCA2 genes?
- Tumour suppression genes that act as inhibitors of cellular growth.
BREAST CANCER
What is the difference between BRCA1/BRCA2?
BRCA1 (5–10% breast cancers)... - Mutation of long arm of c17. - 65% lifetime risk, stronger incidence. BRCA2... - Mutation of long arm of c13. - 45% lifetime risk.
BREAST CANCER
What is the clinical presentation of breast cancer?
- Nipple discharge/retraction.
- Dimpling of skin (peau d’orange) = sinister as caused by lymphatic invasion.
- Oedema/erythema.
- PAINLESS lump.
BREAST CANCER
What are lumps of concern in breast cancer?
- Hardness/irregularity/focal nodularity.
- Asymmetry with other breast.
- FIxation to skin/muscle.
BREAST CANCER
What are the complications of breast cancer?
- Spread to liver, lungs, bones, brain + nearby lymph nodes (axilla).
- Lymphoedema after axillary surgery.
BREAST CANCER
Name 4 differentials of breast cancer which are benign lesions.
- Fibroadenoma (most common).
- Breast cysts.
- Breast abscess.
- Intraductal papilloma.
BREAST CANCER
What is a fibroadenoma? How does it present and develop?
- Benign overgrowth of collagenous mesenchyme of one breast lobule.
- Usually <30y/o, firm, non-tender, highly mobile lump.
- 1/3 regress, stay same + grow.
BREAST CANCER
What is the investigation + treatment of fibroadenoma?
- Observation + reassurance, ultrasound ± fine needle aspiration.
- Surgical excision if large.
BREAST CANCER
What is a breast cyst? How does it present? What are the investigations?
- Palpable, fluid-filled rounded lump, not fixed to surrounding tissue, occasionally painful.
- Common >35y/o, especially around menopause.
- Diagnosis via aspiration.
BREAST CANCER
What is a breast abscess? How does it present and what is the treatment?
- Infection of mammary duct.
- Warm, painful swelling.
- Abx + drainage.
BREAST CANCER
What is an intraductal papilloma? How does it present?
- Benign, warty lesion usually located just behind areola.
- Presents as small lump, sticky, possibly blood-stained discharge possible.
- Women in 40s more likely to have one, younger = multiple.
BREAST CANCER
What is the investigation of intraductal papilloma?
Triple assessment required in specialist breast clinic…
- Examination.
- Radiology.
- Biopsy.
BREAST CANCER
What is the prevention of breast cancer?
- Promote awareness by public health campaigns.
- Breast cancer screening programme involving biplanar digital mammography every 3 years in women aged 50–70y/o.
BREAST CANCER
What are the investigations for breast cancer?
Triple assessment…
- Clinical examination.
- Radiology (USS<35/yo, + mammography if >35y/o).
- Fine needle aspiration/core biospy for histology/cytology.
Check oestrogen receptor (ER), progresterone receptor (PR) + human epidermal growth factor 2 (HER2) status.
BREAST CANCER
What is the surgical treatment for breast cancer?
- Removal of tumour by wide local excision (WLE)/lumpectomy.
- Mastectomy ± breast reconstruction.
- Axillary node sampling/surgical clearance.
BREAST CANCER
What is the medical treatment for breast cancer?
Radiotherapy…
- Recommended for all patients with invasive cancer after WLE.
- Given to bone metastases (give bisphoshonates).
- Side effects = pericarditis, rib fracture.
Chemotherapy.
BREAST CANCER
What is the aim of endocrine therapy in breast cancer? What does expression of HER2 indicate?
- Reduce oestrogen activity to reduce tumour growth, used in ER + PR +ve disease.
- Adverse factor as tumour more likely to grow + divide.
BREAST CANCER What is the endocrine therapy in... i) post-menopausal women? ii) pre-menopausal women? iii) HER2+ve women?
i) Oestrogen receptor block (tamoxifen), aromatase inhibitors (anastrozole).
ii) Ovarian ablation via surgery/radiotherapy, GnRH analogues (goserelin).
iii) Trastuzumab.
OVERDOSE
What is the effect of excessive opioid drug exposure? What is the clinical presentation? What is the treatment?
- Diamorphine/codeine produce physical dependence such that acute withdrawal syndrome develops w/ profuse sweating, tachycardia, vomiting, diarrhoea.
- Pinpoint pupils, reduced RR, coma, convulsions.
- IV naloxone 400mg/2min until breathing adequate.
AMYLOIDOSIS
What is amyloidosis?
- Group of disorders characterised by extracellular deposits of protein in abnormal fibrillar form, resistant to degradation?
AMYLOIDOSIS
What are the three types of amyloidosis?
- AL amyloid (primary).
- AA amyloid (secondary).
- Familial amyloidosis.
AMYLOIDOSIS
What is the pathophysiology of AL amyloid?
Proliferation of plasma cell clone leads to amyoidogenic monoclonal immunoglobulins which cause fibrillar light chain protein deposition, organ failure + death.
AMYLOIDOSIS
What is the pathophysiology of AA amyloid?
Amyloid derived from serum amyloid A, acute phase protein, reflecting chronic inflammation in RA, Crohn’s etc.
AMYLOIDOSIS
What is the pathophysiology of familial amyloidosis?
- AD inheritance, results from mutations in transthyretin (transport protein produced by liver).
AMYLOIDOSIS
What is the clinical presentation of AL amyloid?
- Kidneys = glomerular lesions = proteinuria + nephrotic syndrome.
- Heart = restrictive cardiomyopathy, arrhythmias.
- Nerves = peripheral neuropathy, carpal tunnel.
- GI = macroglossia, malabsorption.
- Vascular = purpura.
AMYLOIDOSIS
What is the clinical presentation of AA amyloid?
- Proteinuria, nephrotic syndrome or hepatosplenomegaly.
AMYLOIDOSIS
What is the clinical presentation of familial amyloidosis?
- Sensory/autonomic neuropathy ± renal/cardiac involvement.
AMYLOIDOSIS
What are the investigations for familial amyloidosis?
- Rectum/subcutaneous fat used for biopsy.
- Biopsy +ve if congo red staining with apple-green birefringence under polarised microscopy.
AMYLOIDOSIS
What is the treatment of amyloidosis?
AL = optimise nutrition, prednisolone. AA = treat underlying cause. FA = liver transplant can cure.
LYMPHOEDEMA
What is the pathophysiology of lymphoedema?
- Chronic, non-pitting oedema caused by lymphatic insufficiency (like failure of lymphatic drainage).
LYMPHOEDEMA
What is the aetiology of lymphoedema?
- Primary = presents in early life due to inherited deficiency of lymphatics.
Secondary = due to obstruction of lymphatic vessels from trauma, radiotherapy, surgery, malignant disease.
LYMPHOEDEMA
What is the clinical presentation of lymphoedema?
- Most commonly affects legs + tends to progress w/ age.
- Legs can become enormous + prevent normal shoes.
- Chronic disease may cause secondary ‘cobblestone’ thickening of skin.
LYMPHOEDEMA
What is the treatment of lymphoedema?
- Compression stocking.
- Physical massage.
- If recurrent cellulitis then prophylaxis with low-dose phenoxymethylpenicillin.
SARCOMA
What is the pathophysiology of sarcoma?
- Group of rare solid tumours of connective tissues.
- Soft tissue sarcomas (80%) are more common than bone sarcomas.
SARCOMA
Give an example of some soft tissue sarcomas.
Liposarcoma = malignant neoplasm of adipose tissue. Leiomyosarcoma = malignant neoplasm of smooth muscle Rhabdomyosarcoma = malignant neoplasm of skeletal muscle.
SARCOMA
What is the clinical presentation of sarcoma?
- Lump that’s painless at first.
- Pain + soreness as lump grows + presses against nerves + muscles.
- Metastases to lung initially giving respiratory symptoms.
SARCOMA
What are the investigations + treatment of sarcoma?
- MRI + core needle biopsy, CT chest for lung metastases.
- Surgical resection (if possible) + chemotherapy ± radiotherapy.