Metabolism Diseases
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Metabolism Diseases - Leaderboard
Metabolism Diseases - Details
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Addisons disease | Destruction of entire adrenal cortex • Deficiency of all hormones • Mineralocorticoids • Glucocorticoids • Sex steroids Clinical features • Weight loss • Anorexia • Malaiseh • Weakness • Fever • Depression , amenorrhoea, low libido, abdominal pain, myalgia, arthalgia, nausea. Specific clinical features: Pigmentation ACTH, Postural hypotension mineralocorticoid, 90% presentations. Biochemical features: Low sodium, hig |
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Ornithine transcarbmylase (OCT) defiency (problems with urea cycle | Severe defect in the urea cycle Severe urea cycle disorders → symptoms within 1 day of birth. If untreated child will die. • Mild urea cycle enzyme deficiencies may not show symptoms until early childhood Management: Low protein diet Replace amino acids in diet with keto acids Severity depends on: nature of defect and amount of protein eaten. |
Marasmus | Overall nutrient deficiency, no swollen abdomen, mainly in children. Due do decreases in carbs, proteins, minerals and vitamins. |
Kwashiorkor | Protein deficiency, resulting in oedema. Appearance shows swollen abdomen. Present with stunted growth, decreased fat muscle mass, enlarged liver, anaemia. |
Essential Fructosuria | Caused by a deficiency of the enzyme hepatic fructokinase is a clinically benign condition characterized by the incomplete metabolism of fructose in the liver, leading to its excretion in urine. |
Fructose intolerance | Deficiency of the enzyme fructose-1-phosphate aldolase, this enzyme is important in the breakdown of fructose by the body to be used as energy. Results in accumulation of fructose 1- phosphate in the liver. Increased unbroken down glucose, results in water to travel into the lumen, thus resulting in diarrhoea. symptom - poor feeding as a baby, vomiting, nausea and abdominal pain treatment- elimination of sucrose and fructose from diet |
Galactosaemia (Difference between the two causes) | Galactokinase deficiency non classical: Rare, deficiency of Galactokinase, Increased galactose in blood, urine (galactosuria), increased accumulation within cataracts. GALT (galactose-1-phosphate uridylyl transferase) deficiency: Less Rare, Deficiency in GALT, leading to Galactosuria, galactosaemia,galactose-1-p and galactitol accumulate causing cataracts, brain and liver damage . Galactitol formation depletes tissues of NADPH and raises osmotic pressure - structure damage Symptoms include- cirhossis, hepatomegaly, renal failure, voimiting, seizures, brain damage, hypoglycaemia. TREATMENT - dietary restriction (lactose and galactose) |
G6PDH deficiency | - reduced activity of G6PDH - x linked defect - decrease enzyme lowers levels of NADPH - RBC are most affected as pentose pathways is the only way to generate NADPH - - oxidative damage occurs - haemoglobin and other proteins become crosslinked via disulphide bonds forming oxidised SH groups - form insoluble aggregates called Heinz bodies - attach to RBC membrane - kill RBC causes haemolysis - asymptomatic unless chemicals i.e. antimalarials and foods, infections or stress.... |
PDH deficiency | Rare X-linked genetic defect in PDH, but the most common cause of congenital lactic acidosis No pyruvate conversion to Acetyl-CoA • Pyruvate cannot be processed and is reduced to lactate or converted to amino acids • Presents at birth with neurodegeneration, muscle abnormalities and may cause death in neonatal period • Management includes dietary restriction of carbohydrates and proteins, and vit. B supplement. This reduced the amount of lactic acids formed due to less pyruvates produced. |
Glycogen storage disease what are the two types | • Excess glycogen storage can lead to tissue damage: E.g. Von Gierke disease- liver glucose 6 phosphatase deficiency (hypoglycaemia, enlarged liver) • Insufficient glycogen degradation can lead to hypoglycaemia and poor exercise tolerance: E.g. McArdle disease- muscle glycogen phosphorylase deficiency (exercise-induced muscle pain and cramps) |
What are the main presentations of lyperlipoproteinaemia | - raised plasma level of one or more lipoprotein classes - cuased by over-production and under-removal - can be a defect in enzymes (LPL), receptors (LDLr), apoproteins (apoE") |
Hypercholestrolaemia | High levels of cholestrol in blood signs - xanthelasma - tendon xanthoma - corneal arcus treatments diet (increase fiber intake and decrease colestrol) lifestyle (decrease smoking increase excersise) DRUGS statins(inhibits HMG-CoA reducase) bile salts/acid sequestrants |
What are the 9 essential aa | Isoleucine lysine threonine histidine lucine methoinine phenylalanine trypotophan valine |
What aa 3 amino acids required in diet in pregnacy and in children | Argine, tyrosine and cystenine |
Name 2 glucogenic, ketogenic and both amino acids | Ketogenic - lysine, leucine glucogenic - glycine and arinine both tryptopham, tyrosine |
Cushings syndrome | Excessive breakdown of protein due to excess cortisol. weakens skin leads to straie formation |
Alwhat are the two important diagnosistic mnarkers in liver failure | Alanine aminotransferase (ALT) --> alanine to glutamate Asparate aminotransferase (AST) --> asparate to glutamate |
Refeeding syndrome | Can occur when nutritional support given to severely malnourished patients ammonia toxicty significant factor (urea ccyle down regulated) refeed at 5-10kcal/kg/day. raised gradually to full needs within a week. BMI <16 unintentional weight loss >15% in 3-6 months 10 days or more with limited or no nutritial intake |
Ornithine transcarbmylase (OCT) defiency (problems with urea cycle | Severe urea cycle disorders ---> symptoms within 1 day of birth. If untreated child will die Mild urea cycle enzyme deficiencies may not show symptoms until early childhood - managment low porteins diet symptoms vomiting letharygy irritability mental retardation seizures coma |
PKU | No phenylaline hydroxlase prevents phenylalanie convertion to trysine - affected pathways - noradrenaline - adrenaline - dopamine - melanin - thyroid hormone - portein synthesis symptoms - severe intelectual disability - developmental delay - microcephaly (small head) = seizures - hypopigmentation Autosomal recessive within chromosome 12, accumulation in phenylalanine in tissues, plasma and urine. Musty smell |
Homocystinuria | • Rare (incidence ~1 in 344,000) • Defect in cystathionine β-synthase (CBS) is the most common (defect in methionine synthase also possible) • Autosomal recessive disorders • Excess homocystine(oxidised form of homocysteine) excreted in urine • Accumulation of homocysteine and methionine causes disease symptoms |
Alcoholic liver disease | Liver toxicity due to acetaldehyde accumulation which leads to liver damage and dysfunction • Altered liver metabolism due to decrease in NAD+/NADH ratio and increased availability of acetyl CoA Consequences include: • Escape of liver enzymes (e.g. ALT, AST and gamma glutamyl transpeptidase) to blood • Reduced taking up and conjugation of bilirubin leading to hyperbilirubinaemia • Reduced production of urea leading to hyperammonaemia • Reduced synthesis of proteins (albumin, clotting factors and lipoproteins) |
Hypopituiatarism | Gonadal deficiencies: loss of libido and secondary sexual hair, amenorrhoea, erectile dysfunction, period irregularities GH deficiency: growth failure in children and impaired wellbeing in adults TSH deficiency: weight gain, dry skin and cold intolerance ACTH deficiency: mild hypotension, hyponatraemia |
Addisons disease | Destruction of entire adrenal cortex • Deficiency of all hormones • Mineralocorticoids • Glucocorticoids • Sex steroids Clinical features • Weight loss • Anorexia • Malaise • Weakness • Fever • Depression , amenorrhoea, low libido, abdominal pain, myalgia, arthalgia, nausea. Specific clinical features: Pigmentation ACTH, Postural hypotension mineralocorticoid, 90% presentations. Biochemical features: Low sodium, high potassium, high urea, low glucose. |
Hypoadrenal crisis | Hypotension, Hypoglycaemia, Hyponatraemia, Hyperkalaemia, Sever dehydration, Death if untreated Treatment: Acute presentation is a medical emergency, long term treatment necessary, Hydrocortisone 20-30mg daily (ammunocortisol replacement), Fludrocortisone 50-300ug daily Confirmatory tests: • 0900 cortisol (peak cortisol) should be 300 • Short synacthen test • ACTH • Plasma renin • Adrenal antibodies |
Hypothyroidism | See picture |
Heinz bodies | See picture |
Why Alcoholics May Have a Fatty Liver? | • Reduced levels of NAD + in liver for fatty acid oxidation • Increased levels of acetyl CoA will not be oxidised due to reduced levels of NAD+ • Increased fatty acid synthesis and ketone synthesis (may lead to ketoacidosis) from acetyl |
Why Alcoholics May Have Fasting Hypoglycaemia and Gout? | • Liver cells unable to use lactate and glycerol for de novo synthesis of glucose (+ poor diet - low glycogen levels) • Reduced levels of NAD+ in liver for conversion of lactate to pyruvate and for glycerol conversion to DHAP • Increased blood lactate leads to lactic acidosis and reduces the kidney’s ability to excrete uric acid; as uric acid levels increase, crystals of urate accumulate in tissues leading to gout |
Hypercalcaemia | Stones, moans (depression) and groans (abdominal pain) Treatment includes fluids as patients have lost excess fluid in urine and need circulating volume restoring. Hypercalcaemia, signs and symptoms CNS: altered behaviour: lethargy, depression, decreased alertness, confusion and coma GI: anorexia, constipation, nausea and vomiting Renal: diuresis, dehydration, risk for kidney stones. Skeletal: increased bone resorption, fracture risk, joint pain Cardiovascular: cause/exacerbate hypertension Largely explained by decreased nerve excitability or calcium precipitation |
Hypocalcaemia, clinical signs and symptoms | Neuromuscular: Tetany - involuntary muscle contraction Paresthesia – strange sensations eg numbness/tingling Twitching esp. face (cranial nerve) Muscle group contraction eg clawed hands Full blown convulsion, respiratory arrest and death CNS: irritability, seizures, personality changes, impaired cognition Cardiovascular: QT prolongation on ECG |