Flashcards in ESA1 Deck (41)
Define Type 1 diabetes
-An absolute lack of insulin caused by autoimmune destruction of the beta islet cells of the pancreas which results in an inability to utilise glucose and therefore a high blood glucose concentration which can lead to cardiovascular damage
Define type 2 diabetes and the associated risk factors for developing it
-A relative lack of insulin caused by increased insulin resistance and pancreatic exhaustion. Leads to an elevated blood glucose which predisposes to cardiovascular damage
-Obesity, physical inactivity, high sugar intake, genetics
Describe the typical symptoms of diabetes
-Polyuria, polydipsia, tiredness, blurred vision, thrush, weight loss (type 1)
Describe the micro and macrovascular complications of diabetes
-Micro -> neuropathy, retinopathy, nephropathy
-Macro -> MI, Stroke, gangrene, peripheral vascular disease
-Acute -> DKA/HONK, hypoglycaemia, hyperglycaemia
What is sickle cell disease? What is a sickle crisis?
-An autosomal recessive condition where there is a point mutation from A->T producing the amino acid valine instead of glutamate in the haemoglobin chain. This produces a hydrophobic sticky pocket due to alteration in the folding of the globin chain. These hydrophobic pockets attract one another, when in deoxy Hb state, leading to polymerisation of Hb and temporary distorting of the cell. After repeated sickling the RBC remains distorted. This leads to increased destruction of RBCs and also possibly damage to small vasculature as the sickled cells can occlude the vessel due to increased membrane rigidity
-Sickle crisis is when there is a high number of RBCs which sickle at the same time and occlude vasculature and can be precipitated by cold, stress etc
Describe both a and b thalassaemias
-A-> decreased or absent a-chains resulting in Hb chains made from B-tetramers -> stable tetramer. Symptoms appear before birth as foetal Hb is 2a and 2g chains
-B-Thalassaemia -> decreased or absent b chains but a-chains cannot form stable tetramer. Symptoms appear after birth as a chains become replaced by b chains
What is scurvy?
-Vitamin C deficiency which results in an inability for the enzyme propyl hydroxylase leading to weak tropocollagen helices. This produces weak collagen bundles and results in swollen and bleeding gums and joint pain
What is down syndrome?
-Genetic alteration whereby there is an extra complete or partial copy of chromosomal 21. This leads to characteristic facial features and mild to moderate intellectual disability.
What is turner syndrome?
-Caused by an genetic alteration caused by a sex linked aneuloidy whereby the karyotype is 45,X
-Produces females with short stature, webbed neck, low-set ears, infertility and renal problems
What is klinefelters syndrome?
-Genetic alteration caused by a sex linked aneuploidy whereby the karyotype is 47, XXY
-Produces males with gynaecomastia and language and reading impairment
What is Marfan's syndrome?
-Genetic abnormality in fibrillin gene producing an abnormal fibrillin-1-protein which normally coats the outside of elastin. This produces abnormal elastin and leads to tall stature, arachnodactyly and increased susceptibility to aortic dissection
What is Elhers-Danlos?
-Deficiency in Type 3 collagen (reticular collagen) leading to weaker collagen structures. Presents with unstable joints, easy bruising, flat feet and stretchy skin
What is Vitiligo?
-Autoimmune destruction of melanocytes which leads to skin depigmentation. Can have major psychological effects depending on ethnicity and area affected
What is alopecia?
-Autoimmune condition which leads to hair loss in varying locations
What is psoriasis? Name the layers of the skin
-Disorder of epidermal growth and differentiation of unknown cause. Suspected to have a genetic association. Produces excessive proliferation of all layers of the skin and results in scaling
-Stratum basale, stratum spinosum, stratum granulosum and stratum corneum
What is osteogenesis imperfecta and why is it of medicolegal importance?
-Autosomal dominant defect in the production of type 1 collagen which produces a spectrum depending on the severity of the defect
-Can range from being incompatible with life to having fragile long bones and bone deformities
-Can often be confused for non-accidental injury
What is osteoporosis. Give its major risk factors
-Decrease in bone density increasing chance of fractures either due to a increased osteoclast activity or an attenuated osteoblast activity
-Menopause (decrease in oestrogen decreases inhibition of osteoclasts)
-Age (decreased osteoblast activity)
-Long term corticosteroids use
What is osteomalacia? What is rickets?
-Softening of the bones due to calcium deficiency in adults, most commonly secondary to vitamin D deficiency due to lack in diet or sun exposure leading to fragility and fractures
-Softening of bones due to calcium deficiency in children leading to poor bone matrix and distorted epiphyseal growth plates leading to slow growth and deformed bones
What is achondroplasia?
-Genetic abnormality in FGFR3 gene which results in abnormal epiphyseal growth plates producing short limed dwarfism
What is pituitary dwarfism?
-Deficiency of GH due to a problem with the pituitary producing dwarfism with normal proportions
What is acromegaly?
-Excessive GH in an adult producing widening of bones by periosteal growth
What is cretinism and how can it be treated?
-Hypothyroidism in the neonate which has not been detected and produced mental retardation
-If caught early enough can be treated with thyroxine to prevent mental retardation and promote normal growth
What is myasthenia gravis?
-Autoimmune destruction of NMJ end plates which results in widening of the synaptic cleft and Ach receptor loss
-Symptoms include ptosis, fatigue and double vision. Can be come fatal if affects resp muscles.
-Treated with pyridostgmine (AchE inhibitor)
What is botulism?
-Toxin which blocks release of Ach from pre-synaptic bulb. Prevents muscle contraction
What is organophosphate poisoning?
-Irevesible inhibition of Ach-esterase resulting in a prolonged state of muscle contraction (tetani)
What is muscular dystrophy?
-Recessive x-linked disease resulting in decreased or absent production of the dytropin protein. Spectrum from beckers to duchennes. Duchennes is a total loss leading to muscle fibres tearing them selves apart upon contraction leading to necrosis of cells due to excessive Ca entry and fibrous scar tissue formation
What is malignant hyperthermia? How is it treated?
-Autosomal dominant condition which becomes apparent during exposure to genral anaesthesia. Leads to a drastic and uncontrolled increase in oxidative metabolism in skeletal muscle which overwhelms the bodys capacity to supply o2/remove co2 and regulate body temp. Quickly leads to circulatory collapse
-Treated with dantrolene (muscle relaxant)
What is marasmus and kwashiokor?
-Marasmus is protein-energy malnutrition resulting in muscle wasting, loss of body fat, no oedema
-Kwashiorkor is protein deficiency producing oedema, ascites, fatty liver and anorexia
What is lactose intolerance?
-Intrinsic low activity of lactase enzyme
-Bacteria break down lactose in the gut producing flatulence, diarrhoea and stomach cramps