Problems for the week

Crosswords

General Chemical Pathology crossword #1 General Chemical Pathology crossword #3  Liver Anaemia crossword Interactive Liver Anaemia crossword with answers  Designed by Professor Pillay of Division of Chemical Pathology, UCT

Problem discussions

From Dr G. vd Watt A mother is known to be a carrier for classical PKU and Pyruvate kinase deficiency. What are the chances that her unborn child will have either of these disorders given that she has married a guy from the same population group with an incidence of PKU of 1 in 10 000 and PK deficiency of 1 in 10 000. From Dr Berman Three substances, X, Y and Z, when injected intravenously, equilibrate differently within the various fluid compartments in the body. Compound X remains in the vascular compartment, compound Y equilibrates with the interstitial space but is excluded from the intracellular space, whereas compound Z equilibrates with total body water. Assuming all three compounds are cleared by glomerular filtration (i.e. are neither absorbed nor secreted by the tubules), estimate their ½ life in the plasma of an individual with normal renal function following IV injection and equilibration in the compartment(s) to which each compound has access. Which compound most closely resembles creatinine in its behaviour? From Dr Berman At an ambient temperature of 37°C, no heat can be lost to the environment by conduction or convection, and the body becomes totally dependant on heat loss by evaporation (sweating, insensible loss). A sedentary individual consumes energy at a rate of 2400 kcal/day. Estimate his/her rate of water loss per hour required to maintain a normal body temperature. At this rate of water loss, estimate how rapidly serum [Na] will change (assume a negligible [Na] of sweat).

Case discussions

From Dr Berman 27yr old male with necrotising fasciitis. Urea creatinine K+ urate Ca (corr) Pi CRP CK 77 1588 6.1 1.28 1.24 4.3 137 468 000U/l Comment on the findings, including possible cause of the renal failure, and suggest how this could be confirmed. A second sample on the same patient taken 10h later showed some major changes. Postulate possible cause(s) for such sudden changes, and indicate how inspection of haematological investigations done on both samples can confirm your suspicion.   Na K urea creat Mg Pi total prot alb Sample1 131 6.1 77 1588 1.33 4.3 55 28 Sample2 137 4.1 39 871 0.96 2.5 20 11 From Dr van der Watt A 4kg infant was accidentally, rapidly transfused with 50ml of a 8% solution of NaHCO3 (instead of 5ml). Calculate the effect that this would have on the total body water, sodium and pH of the baby, both before and after equilibriation with the intracellular fluid. From Dr Berman (1)   A 62 yr old woman with CA thyroid had a total thyroidectomy, and is now about to have a whole body I123 uptake scan to screen for metastasis. You note her TSH is 78 mU/ml (normal 0.4 to 4) and fT4 is 0.4 pmol/l (normal 11 to 24). Comment on these results To what site does follicular CA thyroid frequently metastasise? What biochemical test serves a similar function to an uptake scan (for detecting recurrence of CA thyroid)? (2)  While signing out, you notice a patient with a serum creatinine of 5615μmol/l. Comment.