MedGems Chempath Flashcards
(43 cards)
What condition describes inadequate function of the proximal renal tubules of the kidney and is associated with glucosuria, hypophosphatemia and hyperuricosuria?
Fanconi Syndrome
A 9 year old boy presents to the GP with enlarged orange coloured tonsils.
Examination elicits a peripheral neuropathy and blood tests show very low plasma HDL levels.
What is the most likely diagnosis?
Tangier disease
In the liver which cytochrome P450 enzyme catalyses the first step in the formation of bile acids via the classical pathway?
Cholesterol 7 alpha hydroxylase
A 14 month old boy presents showing signs of delayed motor development and self-mutilation of the lips and fingers. He is found to have hyperuricaemia.
What enzyme is deficient in this condition?
Lesch Nyhan syndrome - HGPRT enzyme is deficient
A patient with Bipolar Affective Disorder complains of excessive thirst and says they have been drinking more than usual and passing urine more frequently for some time now.
Urine osmolality is low. Blood glucose is 5.1 mmol/L.
You decide to do a water deprivation test.
At the start of the test urine osmolality is 196 mOsmol/kg and after 4 hours urine osmolality remains low.
After a subcutaneous injection of Desmopressin is given urine osmolality is 204 mOsmol/kg.
What is the most likely underlying diagnosis?
Arginine vasopressin resistance
A 3 year old child is seen in the paediatric clinic after concerns about failure to thrive.
He has already been diagnosed with rickets and is on appropriate calcium and vitamin D replacement.
Blood tests show him to be hypokalaemic.
Urine dip shows the presence of protein and glucose. The pH of the urine is 8.6 (alkaline). There are no ketones in his blood.
What is the probable explanation for his failure to thrive, blood test result and urine dip findings?
Fanconi syndrome
Where in the nephron is the majority of bicarbonate reabsorbed?
Proximal convoluted tubule
Their ECG shows a very broad complex tachycardia. The team are unable to record a blood pressure. The medical student comments the ECG trace “almost looks like a sine wave”.
Electrolyte abnormality?
Hyperkalaemia
A patient’s blood tests have returned and show they have a low serum sodium level. What investigation should be done to determine if this is a true hyponatraemia?
serum osmolality
A urine dipstick positive for blood but negative for erythrocytes on direct microscopy suggests the presence of what molecule?
Myoglobin
Rhabdomyolysis describes necrosis of muscle and release of intracellular components. It may be caused by traumatic crush injuries. A serum creatine kinase measurement greater than 5 times the upper limit of normal is considered diagnostic. Myoglobin is a protein normally present in urine in small amounts. The muscle breakdown in rhabdomyolysis causes raised serum myoglobin which leads to myoglobinuria. The high levels of myoglobin in the urine are responsible for the dark brown colour. It may occur after vigorous exercise. A urine dipstick test measures the peroxidase activity of erythrocytes and therefore will be positive for blood if myoglobin is present.
In which organ does the enzyme 25 hydroxylase convert cholecalciferol to 25-hydroxycholecalciferol?
Liver
What family of enzymes in the gut does Orlistat inhibit?
Lipases
In uric acid metabolism, what does FEUA stand for?
fractional extretion of uric acid
ApoE4 classically gives an increased risk of developing which neurodegenerative condition?
Alzheimer’s disease
Where in the gut are bile acids reabsorbed?
Terminal ileum
A young man is brought to the emergency department confused. He is mumbling nonsensical phrases and hyperventilating. The paramedics state he was found next to a number of white, circular pills however they were unable to determine what these were.
A panel of bloods reveals normal kidney function, but a low bicarbonate (17, NR 22-28) .
A head CT was unremarkable. Urine Drug Screen negative. Blood Alcohol levels negative.
An ABG reveals a pH of 7.5 (NR 7.35-7.45)
What drug is the patient likely to have overdosed on?
Salicylates
What class of drug must not be co-administered with azathioprine in individuals with TPMT deficiency, else a potentially fatal buildup of toxic metabolites may occur?
Xanthine oxidase inhibitors
Which enzyme forms the rate limiting step in de novo purine synthesis?
PAT
Phosphoribosyl pyrophosphate amidotransferase (PAT)
A 24 year old lady is referred to a cardiologist.
She has irregular yellow growths on her hands and one on her achilles tendon.
The cardiologist informs her she has premature atherosclerosis.
Blood tests show grossly raised levels of plant sterol in her blood.
Which autosomal recessive disorder does she most likely have?
Phytosterolaemia
A 36 year old man with Wilson’s disease is noted to be hypokalaemic on routine bloods performed at his GP.
He denies any nausea, vomiting or diarrhoea. His oral intake is normal for him and he doesn’t feel he is losing weight. He does not drink any alcohol. He is on no regular medications.
A urine dip is normal.
What condition is associated with Wilson’s disease which may cause hypokalaemia?
Renal tubular Acidosis
What score, derived from a DEXA scan, describes how a patient’s bone mass varies compared to an age matched control?
Z-score
Under polarised light, what colour would you expect needle shaped crystals to appear when parallel to a red filter?
Orange
Under polarised light, what colour would you expect needle shaped crystals to appear when perpendicular to a red filter?
blue
A patient with chronic kidney disease (CKD) has low calcium and raised phosphate. PTH levels are found to be high. What kind of hyperparathyroidism does this patient have?
Secondary
