Clinical Conditions Flashcards
What are the clinical consequences and symptoms of G6PD deficiency? When do symptoms appear?
Low NADPH levels, disulphide bridges form between Hb cysteine residues, Heinz bodies form, increased destruction of rbcs leads to anaemia, jaundice and fatigue. Disulphide bridges in eye lens cause cataracts. Symptoms appear at times of oxidative stress, infection etc
What is the cause of G6PD deficiency?
X linked genetic condition
What are symptoms of both types of galactosaemia? Which is more severe?
Kinase- cataracts caused by low NADPH levels in eye
Transferase- same as kinase but more severe as also damage to liver, kidney and brain due to build up of glucose-1-phosphate
Symptoms present in newborns and must be treated quickly
What is galactitol and explain its significance in galactosaemia?
When galactose builds up (e.g. in galactosaemia) it is converted to galactitol, converting NADPH to NADP.
How can deficiency in galactose 1 P uridyl transferase cause jaundice?
Leads to build up of glucose 1 phosphate, this damages liver, reducing its ability to conjugate haemoglobin, causing Hb build up = jaundice
What are the two causes of galactosaemia and which is most common?
Deficiency of Galactokinase enzyme or deficiency of galactose (1 phosphate uridyl)transferase, transferase is most common.
What is the cause and possible effects of a glycogen storage disease?
Genetic cause, deficiency/dysfunction of an enzyme
Excess storage- tissue damage
Diminished storage- hypoglycaemia, low exercise tolerance (Von Gierkes)
What is the cause of phenylketonuria?
Deficiency of phenylalanine hydroxylase, can’t metabolise phenylalanine so it accumulates and is converted to phenyl ketones
How, when and why is PKU diagnosed?
Heel prick test in newborns, must be detected early as if left untreated brain development is stunted
How is PKU managed?
Special diet, low in phenylalanine
What causes homocysteinuria?
Deficiency of CBS enzyme, leads to increased level of homocysteine and methionine
What are the effects to the body of homocysteinuria?
Damage to connective tissue, muscle, CNS, cardiovascular system
What can homocysteinuria often be mistaken for?
Marfan’s syndrome
Describe the cause, symptoms and treatment of marasmus…
Cause- general malnutrition, under fed, usually children <5
Symptoms- muscle wasting, loss of body fat, hair dry and thin, may have diarrhoea, anaemia
Treatment- gradually build up diet
Describe the cause, symptoms and treatment for Kwashiorkor…
Cause- low protein diet
Symptoms- lethargy, loss of appetite, oedema, hepatomegaly, low serum albumin, often anaemia
Treatment- gradual reintroduction of protein into diet
What is the treatment for galactosaemia?
No dairy!!
Describe hyperlipoprotainaemia, it’s causes and symptoms…
High levels of one or more classes of lipoprotein
Cause- under removal/over storage/defective enzyme, receptor or apoprotein
Symptoms- xanthelasma, corneal arcus, can lead to atherosclerosis/CHD
Describe the process of atheroma formation…
Oxidised LDLs taken up by macrophages, macrophages become foam cells, foam cells accumulate in wall of blood vessel (fatty streak), fatty streak expands and swells = atheroma
What is the treatment of hyperlipoprotainaemia?
Diet- lower cholesterol and saturated fat
Lifestyle- more exercise, stop smoking,
Statins- inhibit HMG CoA reductase, lower production of cholesterol by body,
How is paracetamol metabolised during an overdose and why is this harmful?
Normal phase II pathway is saturated, goes through phase I, converted to NAPQI, NAPQI conjugated with glutathione, glutathione antioxidant used up leaving liver cells open to to attack by ROS which damages/kills them
What is the treatment for paracetamol overdose and what is the time frame for effectiveness?
<8 hours after exposure, give N-acetylcysteine, any longer then damage has already been done so a liver transplant is needed
What is the pathway for alcohol metabolism?
Alcohol converted to acetaldehyde by alcohol dehydrogenase, then to acetic acid using aldehyde dehydrogenase. Acetic acid can then be converted to acetyl CoA and enters the Krebs cycle.
What causes the adverse effects of alcohol?
The intermediate, acetaldehyde
What are the consequences of prolonged binge drinking?
Fatty liver, alcoholic hepatitis, alcoholic cirrhosis
What causes fatty liver in alcoholics?
Excess NADH from the metabolism of alcohol increases fat deposition
What can alcoholics be given to stop their addiction and how does it work?
Disulfiram- inhibits aldehyde dehydrogenase so acetaldehyde builds up causing a very very bad hangover, lasting days, hopefully this is bad enough to put them off for good
What are the symptoms of hypoglycaemia?
Slurred speech, staggering, confusion, loss of consciousness, eventually death
What are the consequences of a leptin deficiency?
Appetite isn’t adequately suppressed, keep eating, get very, very fat like ob/ob mouse