Chapter 49: Urinary System Assessment

Welcome to Last Minute Lecture.

This free chapter overview is designed to help students review and understand key concepts.

These summaries supplement not replaced the original textbook and may not be redistributed or resold.

For complete coverage, always consult the official text.

Hey everyone and welcome back to the Deep Dive.

Hello.

Today we're embarking on a journey into one of the body's absolute unsung heroes.

I mean a system so vital life simply isn't possible without it.

We're talking about the urinary system.

It's true.

It's a system often taken for granted really until something goes awry.

Right.

Yet its functions are incredibly complex and essential for maintaining the body's delicate balance, you know, homeostasis.

And for you, our nursing students, our mission today is to take a deep dive into the dense material from Lewis's Medical Surgical Nursing.

That's the plan.

We're going to try and distill it into clear, structured, and maybe even engaging knowledge.

Hopefully.

Think of this as your shortcut to being well informed, ready for your studies, and ready to ace those NCLEX style questions.

We will guide you step by step through the structures, the functions, how to assess it, and the key diagnostic studies.

Yeah.

And we'll always be emphasizing the nursing process.

We'll even follow a real world clinical scenario with our patient AK.

He shows up in the ED in pretty acute distress.

Yeah.

And what's fascinating there is how seemingly small details in a patient's story, their history, can open up a whole cascade of diagnostic possibility.

Helps you connect the dots in a clinical setting.

Exactly.

The foundations, structures, and functions.

Okay.

Let's unpack this then.

Our sources, they break down the urinary system into two main parts.

You've got the upper system that you're two kidneys and two ureters.

Right.

And the lower system, the bladder and urethra.

Simple enough.

So put simply, kidneys form the urine, urinary transport it, bladder stores it, urethra takes it out.

At its core, yes.

But the kidneys are truly the principal organs.

Their main job is regulating the volume and composition of extracellular fluid and excreting waste.

But that's just scratching the surface, isn't it?

Oh, absolutely.

They also control blood pressure, produce erythropoietin.

For red blood cells.

Correct.

They activate vitamin D, regulate acid base balance.

So for you as nursing students, what's critical is understanding that kidney dysfunction, it won't just impact urine.

It hits the whole system.

Exactly.

It can destabilize everything, blood pressure, energy levels, makes early detection absolutely critical.

That's a lot for just a pair of bean -shaped organs.

Can you give us a quick visual?

Where are they actually located?

Sure.

They're kind of tucked away retroperitoneally.

Behind the peritoneum.

Right.

Cushioned by fat and connective tissue, protected by a fibrous capsule.

The hilus is their entry and exit point for vessels, nerves.

Gotcha.

Inside the kidney tissue, the parenchyma has an outer cortex and an inner medulla.

Okay.

And here's something important.

The renal pelvis, where urine first collects before the ureters.

It only holds about three to five milliliters.

Tiny.

Very small capacity.

It means backflow, say from an obstruction, can cause kidney damage pretty quickly.

A key point to remember.

So if that's the big picture view, where does the real work happen?

The microstructure.

Yeah.

I hear it's all about the nephron.

Exactly.

The nephron.

That's the kidney's functional unit.

The workhorse.

Absolutely the workhorse.

Each kidney has about a million of these tiny filtration factories.

A million.

Yeah.

And each nephron consists of the glomerulus.

That's the filter.

Sort of.

It's a capillary network.

Then there's the Bowman capsule surrounding it and a whole tubular system.

Okay, breakdown the tubular system.

You've got the proximal convoluted tubule, the loop of henlil, the distal convoluted tubule, and then the collecting tubules.

And these microscopic units, they must need a huge blood supply, right?

They absolutely do.

The kidneys get a full 20 % to 25 % of the cardiac output.

A quarter of the blood flow.

Every beat.

Yeah.

Blood enters via the renal artery, flows through tiny aphron arterioles to the glomerulus, then out through aphron arterioles into the paratubular capillaries, and finally back via the renal vein.

So what does this intricate setup actually mean for making urine?

How does that happen?

Well, it's a complex multi -step dance.

Filtration, reabsorption, secretion, and finally, excretion.

The glomerulus acts like a super efficient filter.

Hydrostatic pressure forces blood plasma, but not large proteins or blood cells, into Bowman capsule.

That fluid is the glomerular filtrate.

And that leads to the GFR.

Exactly.

The glomerular filtration rate, GFR, it's the amount filtered each minute, normally about 125 millibuels per minute.

125 a minute.

That's a lot.

It is.

Think about it.

It's like filtering a huge amount of fluid over a day, but then reclaiming almost all of it.

Reclaiming.

Yes, because most of that filtrate gets reabsorbed.

This incredible efficiency means even a small drop in GFR has a massive impact on waste removal.

So GFR is a critical number to watch.

A critical early warning sign for kidney issues, definitely.

Okay, so the glomerulus filters, and then the tubules.

Oh, you said they're like reclaimers, deciding what to keep.

Precisely.

The tubules in collecting ducts are responsible for reabsorbing essential materials, water, electrolytes, glucose, and secreting non -essential ones, like certain wastes or excess ions.

Can you give an example?

Sure.

The proximal convoluted tubule reabsorbs about 80 % of electrolytes, all the glucose and amino acids, small proteins.

Okay.

The loop of Henle is crucial for concentrating the filtrate, basically conserving water.

Makes sense.

And the distal tubule and collecting ducts handle the final adjustments for water balance and acid -base balance.

This part is regulated by hormones.

Hormones like ADH.

Exactly.

ADH, antidiuretic hormone, and also aldosterone.

They fine -tune how much water and sodium is reabsorbed right at the end.

So these kidneys are doing way more than just filtering.

They're regulating blood pressure, making red blood cells.

What are the critical implications for us as nurses if these core functions start to fail?

Great question.

This is where the nursing knowledge really hits home.

They produce erythropoietin.

Right, for red blood cells.

So a deficiency leads to anemia and kidney failure.

You will see this in your patients.

It explains why they might feel so fatigued.

Okay, that connection's important.

And they're using an aldosterone system, RAAS.

Ah yes, RAAS.

When blood flow to the kidneys drops, they release renin.

That starts a cascade, producing angiotensin II and aldosterone.

Which raises blood pressure.

Right, by constricting vessels and retaining sodium and water.

So, the takeaway for you.

Kidney issues and hypertension are often tightly linked.

You need to monitor BP closely in kidney patients.

But don't they also make something that lowers blood pressure?

They do.

Prostaglandins.

Produced right in the kidney, they actually cause vasodilation, increasing renal blood flow, and promoting sodium excretion.

They kind of counteract the RAAS system locally.

So losing those in renal failure would make hypertension worse?

Exactly.

It's another factor contributing to high blood pressure in kidney disease.

That makes perfect sense.

It's all interconnected.

Now speaking of flow, let's trace the journey of

That would be the ureters.

These are the tubes carrying urine from the renal pelvis down to the bladder.

How does it move?

Gravity?

Partially.

But mainly peristalsis.

Muscular waves push the urine along.

And what's clinically significant here are the narrow points.

The ureteropelvic junction, UPJ, right where it leaves the kidney.

And the ureterovesical junctions, UPJ, where they enter the bladder.

These are common spots for obstruction.

Like kidney stones.

Often kidney stones.

Yes.

Causing that sudden, severe pain we call renal colic.

Also, the way the UVJ angles into the bladder is crucial.

Why is that?

It acts like a one -way valve, preventing urine from refluxing back up into the ureters and kidneys, which could cause infections.

Smart design.

Yeah.

And the bladder itself, the storage tank.

Right, the bladder.

It's a flexible reservoir, sits just behind the symphysis pubis.

Its wall has the detrusor muscle.

That's the muscle that contracts to empty it.

Correct.

It can stretch quite a bit during filling and then contract powerfully for emptying.

You usually feel the urge to go around 200 to 250 mL.

It gets uncomfortable around 400 to 600 mL, though its total capacity can be up to 1 ,000 mL, sometimes more.

And the lining is special too, right?

Yes.

The urethelium.

It's a unique transitional cell epithelium that's resistant to urine absorption.

Keeps the waste products safely inside the system.

Finally, the exit route, the urethra.

The urethra is the small tube that controls voiding, takes urine out of the body.

And it's different in males and females.

Significantly.

Female urethras are shorter, just 1 -2 inches.

Which explains the higher UTI risk.

A major factor, yes.

Male urethras are longer, 8 -10 inches.

Now together, the bladder, urethra, and pelvic floor muscles form the urethravesical unit.

And that controls continence.

Yes.

Through a complex interplay of brain and spinal cord signals.

Any nerve damage, think diabetes, multiple sclerosis, spinal cord injury, even some medications can really mess with bladder function.

So as a nurse, you'll definitely see issues like incontinence or retention related to these nerve problems.

Very frequently.

It's a common challenge.

Gerontologic considerations.

What changes with age?

Okay, before we jump into assessment, it feels really crucial for you nursing students listening to understand how this system changes with age.

It absolutely is.

It will profoundly impact your assessment findings and how you interpret them.

So what happens?

Does it just slow down?

Pretty much.

Our sources highlighted gradual decline starting around age 30 actually.

30?

That early?

Yep.

Kidneys can decrease in size, weight, and blood flow roughly 10 % each decade.

Wow.

And the GFR, that key filtration rate.

It also tends to decline after age 40.

Things like atherosclerosis can speed this up.

So physiologically, what does that mean for an older adult?

It means decreased renal blood flow that reduced GFR changes in hormone levels like ADH and aldosterone responsiveness.

It all leads to a decreased ability to concentrate urine.

So they might need to pee more often.

Could be.

But the bigger picture is, while they often maintain basic homeostasis under normal conditions, their renal reserve is diminished.

Meaning they can't handle stress as well.

Exactly.

They're much more vulnerable to acute kidney injury, or AKI, during stresses like dehydration, fever, surgery, or serious illness.

So if an older patient comes in just feeling a bit off, maybe a little confused,

what should a nursing student's radar be for kidney issues even without classic urinary symptoms?

A radar should be high.

An older adult might not have typical UTI symptoms like burning or frequency.

What might you see instead?

Vague malaise.

Maybe some non -localized abdominal discomfort.

Critically, you might see confusion or disorientation, sometimes reported first by the family.

That's a huge nursing quaint confusion as a sign of UTI in the elderly.

Absolutely.

And for older women, loss of elasticity and muscle support in the pelvic floor makes them more prone to bladder infections and incontinence.

And for men?

Prostate enlargement, benign prostatic hyperplasia, or BPH, is very common.

That directly affects urinary patterns, causing hesitancy, retention, slow stream, dribbling.

And even constipation can play a role.

Yes.

Constipation is common in older adults, and a full rectum can actually press on the bladder outlet or urethra, causing urinary retention or frequency.

So you really have to look at the whole picture with older adults.

You do.

Multiple factors converge to alter urinary function as we age, and your assessment needs to account for that.

Nursing assessment, gathering the clues.

Okay.

Let's put on our nursing hats firmly now and talk assessment, gathering the clues.

We always start with subjective data, right?

What the patient tells us.

Correct.

A thorough health history is paramount.

You need to ask about any prior kidney disease, UTIs, BPH in men, kidney stones, but also other conditions that impact the kidneys, like hypertension,

diabetes, gout, even neurologic problems.

And medications are huge here, aren't they?

Absolutely vital.

Ask about everything, prescriptions, over -the -counter drugs, herbal therapies.

Many drugs are nephrotoxic.

Oh, armful to the kidneys.

Yes.

Lewis's text has a great table on this, but common culprits you see are NSI, certain antibiotics like amino glycosides, even some ACE inhibitors in certain situations.

So you really need to know your patient's med list inside out.

And ask about drugs that might just alter urine output, change its color, or affect bladder muscle function.

Patient safety depends on it.

What about past surgeries or procedures?

Definitely ask.

Pelvic surgery, for instance, can sometimes affect bladder function.

Any history of urinary tract instrumentation, like catheterization, increases infection risk.

Our Lewis chapter really emphasizes using functional health patterns for a holistic view.

It's a great framework.

So you'd ask about things like changes in energy levels.

Fatigue is common in kidney disease, vision changes, thirst, fluid retention, headaches.

These could all be subtle signals.

And under health perception, health management, you have to ask about smoking.

Why smoking?

Major risk factor for both bladder and kidney cancer.

Also, occupational exposure think chemicals used by machinists, painters, hairdressers increases bladder cancer risk.

Wow.

Even where someone lives.

Can be a clue.

The stone belt in the US Southeast has a higher incidence of urinary stones, likely due to climate dietary factors.

Fascinating.

What about nutritional metabolic patterns?

Fluid intake is obviously crucial.

Dehydration is a risk factor for UTIs, stones, even kidney failure.

High intake of certain things like dairy or protein can contribute to stone formation in susceptible people.

We'll come back to that with AK.

Okay.

And remind patients that some foods like asparagus or beets can change urine color or smell, so they don't panic unnecessarily.

But you need to differentiate that from something serious.

And then the big one, elimination.

What do we ask for?

You need the details.

Voiding frequency,

any urgency, nocturia, waking up at night to pee, any incontinence or retention.

What does the urine look like?

Color?

Clarity?

Is there blood?

Critically, when does the blood appear if they see it?

Start of stream.

End.

Throughout.

That detail matters.

It can help localize the problem.

Also, don't forget bowel function.

As we said, constipation or fecal impaction can actually obstruct the urethra or cause bladder irritability.

Okay.

Let's bring back AK.

He's our 28 -year -old who came in after a 10 -mile run.

Right.

Severe distress.

Sharp colicky abdominal pain, nausea and that dark smoky urine.

History of gout, high protein diet, admits he didn't hydrate well after his run.

Okay.

So based just on that subjective data, what are the immediate red flags for you as a nurse?

Well, the intense colicky pain screens obstruction, maybe a stone.

Good.

What else?

The dark smoky urine suggests blood hematuria.

Definitely.

And his history.

Gout, high protein, poor hydration.

That sounds like a perfect storm for kidney stones.

Maybe uric acid stones given the gout.

Excellent connections.

Those are precisely the concerns that emerge.

His subjective report points strongly towards nephrolithiasis or kidney stones and potential obstruction.

Okay.

So subjective data points us in a direction.

Now, for the objective data, our physical assessment, how do we start?

Always start with inspection.

Look at the skin, any power, a yellow -gray cast, that can be a late sign of kidney failure, excoriations from itching, changes in turgor indicating dehydration.

No.

Check the mouth for stomatitis, inflammation or that ammonia breath odor, uremic fetter, another sign of advanced kidney failure.

Look for edema generalized peripheral around the eyes.

Inspect the abdomen for contour, any asymmetry, visible masses, which could suggest bladder distension, or maybe a very enlarged kidney, though that's rare to see.

Also, just observe their overall state fatigue, lethargy.

And for palpation and percussion,

what are we feeling and tapping for?

For palpation, the kidneys themselves are usually not palpable because they're deep and posterior.

You might feel the lower pole of the right kidney in a thin person on deep inspiration, but usually not.

What can you palpate?

A distended bladder.

That is a key finding.

You'd feel it as a smooth, rounded, firm, and often sensitive organ rising above the symphysis pubis.

Okay.

And percussion?

Percussion is mainly for the kidneys and bladder.

For the kidneys, you perform fist percussion at the costo -vertebral angle, the CVA.

Where the ribs meet the spine, basically.

Exactly.

You place one hand flat there and gently thump it with your other fist.

Pain, elicited here, CVA tenderness is a significant sign.

Kidney infection, like pylonephritis, or sometimes polycystic kidney disease,

inflammation from a stone.

For the bladder, a distended bladder will percuss dull over an area above the symphysis pubis.

A very full bladder can reach the umbilicus.

So normal findings would be no CVA tenderness, non -palpable kidney and bladder.

Correct.

Oscultation isn't usually a major part of the urinary assessment itself, maybe just noting bowel sounds.

Let's check back with AK's physical assessment.

He's restless, knees drawn up, BP 15670, pulse 108, respirations 24, temp 37 .4 degrees C.

What stands out there?

Elevated BP and pulse, definitely.

The restlessness, positioning classic signs of severe pain, maybe renal colic.

Good.

What else did they find?

Positive left CVA tenderness.

And he's voiding small amounts of that dark smoky urine.

Right.

So his vital signs reflect pain and stress.

The CVA tenderness penpoints the left kidney area as the likely source of the problem.

And the urine appearance confirms the suspected hematuria.

So the objective data strongly supports the subjective picture.

Absolutely.

It all points towards an acute issue on the left side, highly suspicious for a kidney stone causing pain and bleeding.

This necessitates an immediate diagnostic workup.

Diagnostic studies confirming the suspicions.

Okay.

Time to confirm those suspicions with diagnostic studies.

For the urinary system, I'm guessing urinalysis is usually step one.

Almost always.

A urinalysis or UA provides crucial baseline information.

It's usually one of the first tests ordered.

Any tips for collection?

Ideally, get the first morning voided specimen.

It's generally more concentrated, making abnormalities easier to spot.

Okay.

And here's a critical nursing responsibility you absolutely need to remember.

The specimen needs to be examined within one hour of collection.

One hour?

Why so quick?

Because bacteria multiply rapidly at room temperature, red cells and white cells can break down.

Casts can disintegrate.

It changes the results.

If you can't get it to the lab within an hour, refrigerate it.

Good tip.

So what are we looking for in the UA?

Lewis's has a table, right?

Yes.

Table 49 .9 in the 12th edition is excellent.

Key things you'd look for that are abnormal include

bilirubin, castes, changes in color like AK's dark smoky or red brown, yellow brown.

Cloudiness.

Suggests UPI, glucose or ketones, think diabetes.

Starvation, unusual odor,

abnormal osmolality or pH.

Protein, a big indicator of kidney disease or even heart failure.

What about cells?

High RBCs points to stones, infection, cancer, trauma.

High WBCs usually mean UTI or inflammation.

Specific gravity tells you about the concentration ability.

So AK's dark smoky urine on the UA would likely show high RBCs?

Almost certainly.

That would confirm the hematuria.

Beyond a standard UA, what other urine studies are really key for kidney function?

Creatinine clearance.

This is generally considered the most accurate indicator of overall renal function because it closely approximates the GFR.

Why creatinine?

Creatinine is a waste product of muscle breakdown, produced at a fairly constant rate and almost entirely excreted by the kidneys.

So how well the kidneys clear it from the blood tells you a lot about their filtering efficiency.

How's that done?

Just a urine sample.

It requires a timed urine collection, usually over 24 hours, in a serum creatinine level measured during that same period.

Nursing role here involves carefully instructing the patient on the 24 -hour collection process.

It's easy to mess up.

Okay.

And urine culture?

Yes.

Urine culture and sensitivity identifies the specific bacteria causing a UTI and tells you which antibiotics will be effective, essential for treating infections properly.

What about blood studies?

What are we looking at there?

Key electrolytes are crucial.

Potassium is the big one.

Why potassium?

Because the kidneys are vital for excreting potassium.

In kidney disease, levels can rise dangerously high hyperkalemia.

Levels over 6 -banc and EQL can cause serious cardiac dysrhythmias.

You need to monitor this closely.

Okay.

Sodium.

Bi -R carbonate?

Also important, sodium balance is often disrupted.

Bicarbonate is typically low in renal failure because the kidneys can't excrete acids properly or regenerate bicarb, leading to metabolic acidosis.

And the classic kidney function blood tests?

Of course, BUN, blood urea nitrogen, and serum creatinine.

Which is more reliable?

Serum creatinine is generally more reliable specifically for kidney function because BUN can be affected by non -renal factors like hydration status, protein intake, or GI bleeding.

But you have to look at both.

Yes.

And the B and creatinine ratio can also give clues.

For example, a high ratio might suggest decreased blood flow to the kidneys, like in dehydration.

Got it.

Now for the imaging, the radiologic procedures.

Any special nursing considerations we need to know?

Big ones.

First, many of these studies require bowel preparation beforehand.

Why?

To clear stool and gas from the colon because that can obscure the view of the kidneys which sit retroperitoneally.

Makes sense.

What else?

The most critical point, many procedures like CT scans with contrast or IVPs use iodine -based contrast media.

And that can be nephrotoxic.

Exactly.

It can actually cause kidney damage,

especially in patients who already have some renal impairment or are dehydrated.

So what's the nursing role?

Hydration is key.

Before and after the procedure, ensure good fluid intake, sometimes with IV fluids.

A medication called N -acetylcysteine might be given beforehand to offer some protection.

And always, always assess for allergies to iodine or shellfish before contrast is given.

Crucial safety check.

Can you quickly mention some common imaging studies?

Sure.

CT scans are great for visualizing structures, identifying tumors, obstructions like stones.

IVP, intravenous pylogram, used to be common for visualizing the entire tract, but is used less now, especially if renal function is poor due to contrast risk.

What's often used instead?

Renal ultrasound.

It's excellent for detecting masses, cysts, hydronephrosis, kidney swelling from blockage, and stones.

Big advantage.

It's not invasive and doesn't use contrast, so it's safe for patients in renal failure.

Okay.

Any others?

Renal arteriograms look specifically at the blood vessels, maybe for stenosis or narrowing.

And what about actually getting a piece of the kidney, a renal biopsy?

That sounds pretty invasive.

It is.

It involves taking a small tissue sample for microscopic examination, usually to diagnose specific types of kidney disease.

What are the nursing responsibilities there?

They must be significant.

Absolutely critical.

Before and after, before.

Ensure informed consent is signed.

Check coagulation status.

Patients shouldn't be on aspirin or warfarin.

Type and cross -match blood, just in case.

And after the biopsy?

Apply a pressure dressing to the site.

Keep the patient lying on the affected side for 30 -60 minutes to help compress the site internally.

Strict bed rest is usually ordered for 24 hours.

Wow.

24 hours.

Yes.

And frequent vital signs monitoring, assessing for complications like flank pain, signs of bleeding like hypotension, or a dropping hematocrit or gross hematuria.

Teach the patient to avoid heavy lifting for several days afterwards.

Lots to manage there.

Finally, what are urodynamic studies?

These studies measure urinary tract function related to storage and flow.

Things like systemetrograms assess bladder capacity, pressure, and sensation.

Urine flow studies measure how quickly urine flows out, looking for obstruction.

Okay.

Let's quickly circle back to AK's diagnostic results.

His basic blood work, CBC, and metabolic panel were normal initially.

That's good news.

It means no major electrolyte shifts or signs of severe kidney damage yet.

But his urinalysis showed moderate hematuria.

Confirms the bleeding.

And the key finding.

Our renal ultrasound revealed several stones in his left ureter.

No hydronephrosis yet.

Okay.

So the ultrasound confirms the diagnosis left -sided ureteral stones.

No hydronephrosis yet is also important.

It means the blockage isn't complete or hasn't been there long enough to cause the kidney to swell, but it needs monitoring.

He's being admitted and prescribed IV opioids for pain.

Makes sense.

So the subjective story, the objective findings like CVA tenderness and the diagnostic results all align perfectly.

The UA confirmed blood.

The ultrasound found the stones.

Our immediate nursing focus is clear.

Pain management.

Top priority.

Renal colic is excruciating.

And vigilant monitoring for complications worsening obstruction, leading to hydronephrosis, signs of infection, ensuring adequate hydration.

Outrevous.

Wow.

Okay.

That was definitely a deep dive.

We've journeyed through the intricate structures of the urinary system,

explored its really multifaceted functions,

detailed the subjective and objective assessment piece by piece.

Gapping those clues.

And navigated the world of diagnostic studies all while kind of keeping AK's case woven through.

And hopefully for you listening, we've highlighted how crucial it is to understand the nephron as that functional unit, the importance of GFR, the role of hormones like ADH and aldosterone, how aging impacts the system, and those critical nursing responsibilities, especially around assessment medications and procedures like contrast studies or biopsies.

That holistic understanding, connecting the anatomy and physiology to the clinical picture in your nursing actions, that's essential.

Not just for practice, but for tackling those NCLEX questions too.

Absolutely.

So here's a thought for you to maybe mull over as you continue studying this.

How does the body's incredible ability to adapt to maintain homeostasis, even when things start to go slightly wrong?

That renal reserve concept.

How does that also contribute to the often silent progression of chronic kidney disease?

It makes early detection so hard, but so vital.

It's a paradox, isn't it?

What cues, maybe even subtle ones, could signal to you that a patient's kidneys are starting to lose that renal reserve before it becomes a major crisis?

Something to think about.

What are those early, maybe easily missed signs?

Keep that question in mind as you continue your learning journey.

Thank you so much for joining us on this Deep Dive.

Keep connecting those dots.

Keep asking those questions.

And keep learning.

We'll catch you next time.