Clinical Conditions - ESA 1 Flashcards
What is Amyloidosis?
Misfolding of proteins that leads to insoluble aggregates
What causes Sickle Cell anaemia?
Hydrophilic Glutamate -> Hydrophobic Valine, causes Hydrophobic pocket when cell is in T-state. Hb can then polymerise causing the cell to adopt sickle shape
What causes Cystic Fibrosis?
Mutation of the CFTR gene, leads to impaired Cl-
What causes α + β Thalassaemia? Which is more serious and why?
Decreased or absent α or β chains.
α-chains unable to form stable tetramers by themselves, after Foetal Hb goes they suffer growth problems
What causes Haemophillia A?
Reduced or Absent Factor VIII production meaning blood doesnt clot as well
What causes Scurvy and what does it lead to?
Vit. C deficiency, Causes reduced H-bonds and cross links in Collagen so its not as strong as usual
What is an Ectopic Pregnancy?
Implantation of the embryo in the Fallopian tube
What is Placenta Praevia?
Implantation of the embryo in the lower segment of the uterine wall blocking the cervix
What is Ethlers-Danlos Disease?
Deficiency of type III collagen leading to loss of reticulin, presents as stretchy skin, unstable joints + easy bruising
What is Vitiligo?
Autoimmune destruction of melanocytes leading to depigmentation
What is Alopecia Areata/Universalis?
Autoimmune destruction of hair follicles
What is Osteogenesis Imperfecta?
Disease resulting in type I collagen deformity/deficiency, most cases repeated fractures cause bowed long bones, blue sclera
What is Rickets?
Deficiency of vitamin D in children, leads to bowed bones as they are still growing
What is Osteomalacia?
Vitamin D deficiency in adults, leads to bone/back arch. Can be cause by damage to kidneys or liver. More common in people with dark skin as they don’t synthesis Vit. D so well
What is Osteoporosis?
Type I - (Menopausal) due to oestrogen no longer mediating Osteoblasts
Type II - (Old age) due to loss of Osteoblast function
What causes Acromegaly?
Too much GH leads to increase in bone width from intramembranous growth
What is Cretinism caused by?
Neonatal Hypothyroidism leads to retardation + short stature. Corrected with thyroxine before 3 weeks
What is Myasthenia Gravis?
Autoimmune destruction of the end plate ACh receptors. Causes droopy eyelids, fatigue, sudden collapse. Treated by immunosuppressants + AChesterase inhibitors
What is Muscular Dystrophy?
Absence of dystrophin means the muscle fibres tear on contraction, this leads to calcium induced necrosis. Fat + connective tissue layer down (pseudohypertrophy), presents with Gowers sign (brace thighs with arms)
What is Malignant Hyperthermia?
Reaction to Succinylcholine leads to release of Ca2+ from Sarcoplasmic reticulum -> spike in oxidative phosphorylation of skeletal muscle -> temperature spike overwhelms control mechanisms -> death.
Treated with Dantrolene which prevents Ca release
What is Glucose-6-Phosphate Dehydrogenase deficiency?
Rate limiting enzyme in PPP, leads to reduction in NADPH -> Heinz bodies -> Haemolytic anaemia,
Primaquine (anti-malarial) produces ROS so makes symptoms worse
What is Marasmus?
Total malnutrition, body breaks down fat + muscle so emaciated appearance. Diahorrea + anaemia. Treat with nutritional diet
What is Kwashiorkor?
No protein intake, fatty liver as there is no LDL to remove fats from liver. Oedema due to low serum albumin. Don’t give to much protein as leads to ammonia build up (refeeding syndrome)
What is Lactate Dehydrogenase Deficiency?
Lack of enzyme means no reconversion to pyruvate. Builds up -> lactic acidosis
What is Cyanide poisoning?
It non competitively inhibits Cytochrome C oxidase, this stops oxidative phosphorylation causing death
What is Phynylketonuria?
Lack of Phenylalanine Hydroxylase leads to build up of Phenylalanine as it can’t be converted to tyrosine. Converted to phenyl pyruvate instead, this interferes with brain metabolism (prevents pyruvate entering mitochondria). Phenyl ketones detected in blood as they overcome the renal threshold
What is Homocystinuria?
Deficiency of cystathione B synthase, causes Homocysteine build up as it can’t be converted to Cysteine. Affects connective tissue, can be confused with Marfans.
Second pathway converts to methionine which can be found in the urine
What is Hyperlipidaemia?
Deficiency of Lipoprotein lipase means chylomicrons aren’t broken down so cholesterol in the blood is high, can block pancreas and cause pancreatitis
What is Hypercholesterolaemia?
Caused by diet -> increased LDL production. Statins block HMG CoA reductase to block cholesterol release from Acetyl CoA
What happens in Paracetamol Overdose?
Overdose saturated primary pathway leading to secondary metabolism generating NAPQI, this is toxic to hepatocytes. Glutathione depleted trying to breakdown NAPQI -> no defence against ROS. Treat with B-acetyl cysteine or activated charcoal if
What is Diabetic Ketoacidosis?
Lack of insulin activates HMG CoA lyase, Acetyl CoA -> Ketones, this leads to acidosis
What is Addison’s Disease (Hypoadrenalism)?
Autoimmune destruction of adrenal cortex, secondary to reduced ACTH due to problems with ant. Pituitary.
Weakness, fatigue, decreased BP, abdominal pain
What is an Addisonian Crisis?
Total lack of Cortisol leads to Nausea, vomiting, shock -> coma -> death
What is Cushing’s Disease + Syndrome?
Disease - Pituitary adenoma produces ACTH -> increased Cortisol
Syndrome - Adrenal Adenoma produces Cortisol
Leads to moon face, big belly, purple striae
What is Hypothyroidism (Hashimoto’s)?
Autoimmune disease produces antibodies that block TSH or destroys Follicular cells.
Cold intolerance, weight gain, lethargy, apathy, constipation, Goitre.
Treated with oral Thyroxine
What us Hyperthyroidism (Grave’s)?
Autoimmune disease that produces antibodies that stimulate TSH receptors.
Weight loss, heat intolerance, hyperactivity,
