Integrative Urinary Case Study

While working as a general practitioner, your patient Lamarcomes to your office for a standard checkup. Because Lamar is 60years old and has type II diabetes, you frequently subject him tolab tests to evaluate kidney function, as you know that kidneyfunction can be compromised in diabetics.

Urinary Case Study.01

One type of damage that you are worried about detecting isdamage to the endothelial cells of the kidney glomeruli and thepodocytes that make up the Bowman’s capsule epithelium. This damagecan cause the openings in these tissue layers (e.g., intercellularclefts and other fenestrations) to widen in diabetic patients.Based on analysis of a urine sample from Lamar(urinalysis), which of the following would be thebest evidence that such damage has occurred?

A Higher than normal protein levels in the urine.

B Higher than normal Na levels in the urine.

C Lower than normal protein levels in the urine.

D Lower than normal Na levels in the urine.

Urinary Case Study.02

Unfortunately, you detect the evidence of kidney damage that youidentified in question #1 from Lamar’s urinalysis results. Whateffect, if any, do you predict this will have on the osmoticpressure (osmolarity) of his blood plasma?

A It should be higher than normal.

B It should be normal.

C It should be lower than normal.

Urinary Case Study.03

Given the answer to question #2, what should happen to Lamar’sinterstitial fluid volume?

A It should be higher than normal.

B It should be normal.

C It should be lower than normal.

Urinary Case Study.04

Why does the answer to question #2 cause the answer to question#3?

A Because Lamar’s TPR is higher than that of a healthyindividual.

B Since the osmotic pressure of Lamar’s blood plasma should bethe same as that of a healthy individual, it makes sense that hisinterstitial fluid volume should be normal.

C Because Lamar’s GFR is higher than that of a healthyindividual.

D Because the balance of Starling’s forces in Lamar’s systemiccapillaries is altered relative to that of a healthyindividual.

Urinary Case Study.05

You also detect significant amounts of glucose in Lamar’s urinesample, which is typical in diabetics. What does this tell youabout his kidney function?

A His glucose reabsorption rate must exceed his glucoseexcretion rate.

B His glucose reabsorption rate must exceed his glucosesecretion rate.

C His glucose filtration rate must exceed his glucose secretionrate.

D His glucose filtration rate must exceed his glucosereabsorption rate.

Urinary Case Study.06

Since Lamar’s diabetes is very poorly controlled, you decidethat you want to prescribe him another anti-diabetic drug inaddition to the ones he is already on: a glifozin,which is a class of drugs that inhibit SGLTs (sodium-dependentglucose transporters). These drugs reduce blood sugar through theiractions on the urinary system. Why would inhibiting SGLTs reduceblood sugar?

A Inhibiting SGLTs will increase the rate that glucose isreabsorbed by secondary active transport.

B Inhibiting SGLTs will reduce the rate that glucose isreabsorbed by secondary active transport.

C Inhibiting SGLTs will increase the rate that glucose isreabsorbed by primary active transport.

D Inhibiting SGLTs will decrease the rate that glucose isreabsorbed by primary active transport.

Urinary Case Study.07

Before he leaves, you measure Lamar’s blood pressure and findthat it is elevated, as it has been over the past few visits. Toattempt to get his hypertension under control you decide toprescribe him an ACE inhibitor. How will this druglower his blood pressure?

A It will cause vasoconstriction of the afferent arteriolesfeeding the kidney glomeruli.

B It will enhance the activity of Na-K-ATPases in thebasolateral membranes of proximal convoluted tubule epithelialcells (causing reabsorption of more Na per unit time).

C It will cause vasodilation of the efferent arterioles exitingthe kidney glomeruli.

D It will increase rates of Na and HO excretion via theurine.