Renal failure: Pathology review


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Renal failure: Pathology review

Renal system

Renal and ureteral disorders

Renal agenesis

Horseshoe kidney

Potter sequence











Renal tubular acidosis

Minimal change disease

Diabetic nephropathy

Focal segmental glomerulosclerosis (NORD)


Membranous nephropathy

Lupus nephritis

Membranoproliferative glomerulonephritis

Poststreptococcal glomerulonephritis

Goodpasture syndrome

Rapidly progressive glomerulonephritis

IgA nephropathy (NORD)

Lupus nephritis

Alport syndrome

Kidney stones


Acute pyelonephritis

Chronic pyelonephritis

Prerenal azotemia

Renal azotemia

Acute tubular necrosis

Postrenal azotemia

Renal papillary necrosis

Renal cortical necrosis

Chronic kidney disease

Polycystic kidney disease

Multicystic dysplastic kidney

Medullary cystic kidney disease

Medullary sponge kidney

Renal artery stenosis

Renal cell carcinoma


Nephroblastoma (Wilms tumor)

WAGR syndrome

Beckwith-Wiedemann syndrome

Bladder and urethral disorders

Posterior urethral valves

Hypospadias and epispadias

Vesicoureteral reflux

Bladder exstrophy

Urinary incontinence

Neurogenic bladder

Lower urinary tract infection

Transitional cell carcinoma

Non-urothelial bladder cancers

Renal system pathology review

Congenital renal disorders: Pathology review

Renal tubular defects: Pathology review

Renal tubular acidosis: Pathology review

Acid-base disturbances: Pathology review

Electrolyte disturbances: Pathology review

Renal failure: Pathology review

Nephrotic syndromes: Pathology review

Nephritic syndromes: Pathology review

Urinary incontinence: Pathology review

Urinary tract infections: Pathology review

Kidney stones: Pathology review

Renal and urinary tract masses: Pathology review


Renal failure: Pathology review

USMLE® Step 1 questions

0 / 11 complete


USMLE® Step 1 style questions USMLE

of complete

A 50-year-old man comes to his primary care physician’s office for routine follow-up. He was recently diagnosed with osteoarthritis of the knees four weeks ago and was initiated on analgesic medications. Past medical history is significant for diabetes mellitus. Current medications include metformin, naproxen and acetaminophen. His vitals and physical exam are within normal limits. Laboratory results are as follows.  

 Laboratory value  Results 
  4 weeks ago  Today 
 Serum chemistry 
 Sodium  138 mEq/L  137 mEq/L 
 Potassium  4 mEq/L  4.1 mEq/L 
 Bicarbonate  24 mEq/L  25 mEq/L 
 Chloride  96 mEq/L  94 mEq/L 
 Creatinine  1.1 mg/dL  1.6 mg/dL 
 Protein  100 mg/day  102 mg/day 
 Cast  None  None 
 Blood  negative  negative 
Changes to which of the following anatomic regions is most likely accountable for this patient’s rise in creatinine?  


Content Reviewers

Yifan Xiao, MD

Filip Vasiljević, MD


Ursula Florjanczyk, MScBMC

Anca-Elena Stefan, MD

Sam Gillespie, BSc

Tanner Marshall, MS

On the Nephrology ward, two people came in. The first one is 55 year old Matilda, who came in with oliguria, fever and a rash on her arm. Matilda also has a history of taking NSAIDs for her knee-pain. The second one is 34 year old George, which came in with oliguria, hypotension, tachycardia and cold extremities. George says that he’s also been having diarrhea for a few days now. BUN and creatinine levels were high for both of them.

Both Matilda and George have renal failure. Now, renal failure is when the kidneys aren’t functioning properly. Before talking specifics, let’s remember some basic renal physiology. Now the kidney’s job is to regulate what’s in the blood, so they might remove waste, or make sure electrolyte levels are steady, or regulate the overall amount of water, and even make hormones, such as erythropoietin, which stimulates red blood cell production. Okay, so blood gets into the kidney through the renal artery, into tiny clumps of arterioles called glomeruli where filtration happens. After filtration, the stuff that’s filtered out, called the filtrate, moves into the renal tubules, where reabsorption and secretion of fluid and electrolytes happens. Along with fluid and electrolytes, though, waste-containing compounds are also filtered, like urea and creatinine, although some urea is actually reabsorbed back into the blood, whereas only a little bit of creatinine is reabsorbed. In fact, in the blood, the normal ratio of blood urea nitrogen, or BUN, to creatinine is between 5 and 20 to 1—meaning the blood carries 5 to 20 molecules of urea for every one molecule of creatinine, and this is a pretty good way to assess kidney function! So, when we want to check renal function, we look at BUN and creatinine levels and if there’s something wrong, then levels of both BUN and creatinine will be high.

Now, back to renal failure. There are two types of renal failure: acute and chronic. Now, acute renal failure is now called acute kidney injury. This is when the kidney isn’t functioning at 100% and that decrease in function develops relatively quickly, typically over a few days. In this case, the individual typically presents with oliguria, even anuria and levels of BUN and creatinine will be high. Then there’s chronic kidney failure, which is now called chronic kidney disease. This is when the kidney function gradually decreases over a minimum of three months. This is usually caused by hypertension, diabetes mellitus, or congenital renal conditions.


Renal failure is a condition in which the kidneys are no longer able to function properly. There are two main types of renal failure: acute renal failure and chronic renal failure. Acute renal failure, also known as acute kidney injury (AKI), is when the kidney isn't functioning at 100% and that decrease in function develops relatively quickly, typically over a few days. AKI is commonly caused by anything that causes acute damage to the kidneys, such as infection, injury, toxins, and certain medications. The symptoms include swelling, decreased urine output, and changes in the color and smell of urine.

In chronic kidney failure, which is now called chronic kidney disease (CKD), kidney function gradually decreases over a minimum of three months. CKD is most commonly caused by chronic disorders like diabetes mellitus and hypertension. Other causes of CRF include glomerulonephritis, polycystic kidney disease, and chronic obstructive uropathy. The symptoms of CRF can include fatigue, anemia, and signs of fluid retention.


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  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Current Medical Diagnosis & Treatment 2009" McGraw-Hill Prof Med/Tech (2008)
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  5. "Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury" Critical Care (2007)
  6. "The future for diagnostic tests of acute kidney injury in critical care: evidence synthesis, care pathway analysis and research prioritisation" Health Technology Assessment (2018)
  7. "Ultrasonography of the Kidney: A Pictorial Review" Diagnostics (2015)
  8. "ANCA Glomerulonephritis and Vasculitis" Clinical Journal of the American Society of Nephrology (2017)

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