[08.02] Common Manifestations of Renal Disease V2.pdf

Azotemia

What condition is defined as the elevation of nitrogenous waste products, mainly Blood Urea Nitrogen (BUN) and serum creatinine, in the blood?

"Kidney is not clearing waste adequately"

What is the key conceptual idea to keep in mind regarding azotemia?

Normal physiology

In what state do kidneys filter urea and creatinine at the glomerulus, reabsorb some urea, and mostly excrete creatinine?

Glomerular filtration rate (GFR) falls

What physiological change leads to less filtration of waste and the development of azotemia?

Low flow states

In what condition do the tubules increase the reabsorption of urea?

Prerenal, intrinsic renal, and postrenal

What are the three classic classifications of azotemia based on the site of the lesion?

Prerenal

Which classification of azotemia is caused by low perfusion before the kidney?

Hypovolemia, heart failure, and sepsis

What are three common clinical causes of prerenal azotemia?

Intrinsic renal

Which classification of azotemia involves damage to the kidney parenchyma itself?

Acute tubular necrosis and glomerulonephritis

What are two examples of diseases that cause intrinsic renal azotemia?

Postrenal

Which classification of azotemia involves obstruction in the urinary tract excluding the kidneys?

Ureteral stones, prostate issues, and bladder masses

What are three examples of causes for postrenal azotemia?

Asymptomatic

How do many patients present during the early stages of azotemia?

"Para kang nilalason" (Like you are being poisoned)

How does Dr. Tang describe the feeling of symptoms in advanced uremia?

Fatigue, malaise, nausea, and anorexia

What are four common systemic symptoms that appear once azotemia becomes symptomatic?

Pruritus

Which skin symptom is associated with more advanced uremia?

Uremic encephalopathy

What condition causes confusion, a dementia-like state, and sleep disturbances in severe cases of azotemia?

Nocturia

What is a common early symptom of azotemia specifically in early Chronic Kidney Disease (CKD)?

Tachycardia, hypotension, and dry mucous membranes

What physical exam findings suggest prerenal azotemia with volume depletion?

Anasarca (edema), crackles, and elevated jugular venous pressure

What three physical exam findings suggest fluid overload in a renal patient?

Pericardial rub, asterixis, and neuropathy

What are three physical signs specifically indicative of advanced uremia?

Early marker of AKI or CKD

Clinically, what does the presence of azotemia serve as an early indicator for?

Drug dosing and avoidance of nephrotoxins

What clinical management decisions does the measurement of azotemia guide?

Bone-mineral disorders, anemia, and cardiovascular disease

What are three long-term complications associated with persistent azotemia?

Oliguria

What is the term for urine output less than 0.5 mL/kg/hour in adults?

≥ 6 hours

According to AKI criteria, over what minimum time frame is the oliguria cutoff typically applied?

< 400–500 mL/day

What is the rough approximation for oliguria in terms of daily volume for an average adult?

Anuria

What is the term for urine output less than 50–100 mL/day?

Runoff or remaining fluid from the bladder

In a patient with anuria, where is the minimal daily urine output likely originating from?

"No meaningful urine output"

What is the practical definition of anuria?

Laboratory exam

Unlike azotemia, what is not strictly required to diagnose oliguria or anuria?

Foley catheter

What tool is used in hospitalized patients to accurately monitor urine output for suspected oliguria?

Decreased effective GFR or flow of urine

What is the common underlying pathophysiological theme for both oliguria and anuria?

Severe bilateral obstruction, catastrophic loss of renal function, or complete vascular occlusion

What three conditions should be considered when a patient presents with anuria?

Renal artery thrombosis

What is an example of complete vascular occlusion that leads to anuria?

Prerenal hypoperfusion

What is the most common cause of oliguria?

Intense sodium and water reabsorption

How do the kidneys physiologically respond to decreased renal perfusion to maintain volume, resulting in oliguria?

Hypotension, heart failure, cirrhosis, or hemorrhagic shock

What are four common conditions where prerenal oliguria is frequently seen?

Glomerular damage and tubular injury

Within the classification of intrinsic renal disease, what two mechanisms lead to impaired urine formation?

Increased tubular pressure

In postrenal obstruction, what change leads to a decrease in GFR and subsequent oliguria?

Vomiting, diarrhea, bleeding, sepsis, and burns

What five history findings suggest a prerenal cause of oliguria?

Contrast, NSAIDs, and aminoglycosides

What are three common nephrotoxins that can lead to intrinsic renal injury?

Flank pain or renal colic

What pain-related symptoms suggest a postrenal/obstructive cause of decreased urine?

Complete vascular occlusion or bilateral obstruction

In what severe cases might a patient truly not pee at all in a day?

One kidney

According to the sources, how many kidneys are required for a person to survive?

Poor skin turgor and orthostatic hypotension

Besides dry mucous membranes, what are two signs of volume depletion?

Pitting edema and pulmonary crackles

What are two physical signs of volume expansion or overload?

The kidneys sense low effective circulating volume and conserve fluid

Why do patients with heart failure or cirrhosis present with oliguria despite having fluid overload?

Palpable bladder or distended lower abdomen

What physical finding indicates urinary retention?

Digital rectal examination (DRE)

What exam is performed in older males to identify a common cause of postrenal obstruction?

Hematuria

What is the term for red blood cells in the urine above normal levels?

Microscopic hematuria

What is defined as ≥ 3 RBCs per high power field (HPF) on microscopy from multiple specimens?

Two or three

How many properly collected specimens are typically required to confirm microscopic hematuria?

Macroscopic or gross hematuria

What is the term for visible red or cola-colored urine?

Myoglobin or hemoglobin

What two substances can cause a positive dipstick for blood in the absence of RBCs?

Glomerular hematuria

Which type of hematuria results from inflammation or structural damage to the glomerular capillaries?

Bowman space

Into what space do RBCs leak during glomerular hematuria?

RBC casts and dysmorphic RBCs

What are the two hallmark microscopic findings of glomerular hematuria?

Proteinuria, hypertension, and renal dysfunction

Besides blood, what three findings are often associated with glomerular hematuria?

IgA nephropathy, post-infectious GN, and lupus nephritis

What are three examples of diseases that cause glomerular hematuria?

Non-glomerular (urologic) hematuria

Which type of hematuria involves bleeding anywhere from the renal pelvis to the urethra?

Isomorphic RBCs

What is the morphology of RBCs in non-glomerular hematuria?

Clots

What finding may be present in the urine of patients with non-glomerular hematuria but is absent in glomerular sources?

Stones, infection, tumors, BPH, and trauma

What are five common causes of non-glomerular hematuria?

A single urinalysis with >100 RBCs

Besides gross blood or multiple tests, what single lab finding is considered clinically significant?

Isomorphic

What term describes RBCs that look normal and suggest a non-glomerular origin?

Dysmorphic

What term describes RBCs that appear deformed (like Mickey Mouse) and suggest a glomerular origin?

Isolated microscopic hematuria

What presentation is most commonly associated with glomerulonephritis when no other urine abnormalities are present?

IgA nephropathy, Alport Syndrome, and thin basement membrane disease

What are the three most common etiologies of glomerulonephritis causing isolated microscopic hematuria?

Hereditary nephritis

What is another name for Alport Syndrome?

Tamm-Horsfall protein

RBC casts form when RBCs are trapped in a cylindrical mold of what gelled protein?

Glomerulonephritis

What is virtually diagnosed by the presence of dysmorphic RBCs, RBC casts, and protein excretion >500 mg/d?

Hematuria, bacteriuria, and pyuria

What three findings together strongly suggest a UTI?

Symptoms

What should always be evaluated first when a UTI is suspected, even if lab results appear minimal?

Tea or cola-colored

How is the color of urine from a glomerular source of hematuria typically described?

Malignancy

What should be suspected until proven otherwise in an older patient with painless gross hematuria?

Flank colicky pain

What type of pain associated with hematuria suggests the presence of stones?

Post-streptococcal GN

A recent sore throat or skin infection followed by hematuria is suggestive of what condition?

Costovertebral angle (CVA) tenderness

What physical finding suggests pyelonephritis or renal stones?

Urinalysis, microscopy, imaging, and cystoscopy

What are four components of the clinical workup for hematuria?

Proteinuria

What is the term for an abnormal excess of protein excreted in the urine?

< 150 mg/day

What is the normal total daily urinary protein excretion?

< 30 mg/day

What is the normal daily excretion of albumin?

Albumin

What is the major protein found in the urine and used as a marker for glomerular damage?

Glomerular proteinuria

Which mechanism of proteinuria involves damage to the glomerular filtration barrier's charge or size selectivity?

Diabetic nephropathy, Minimal change disease, and FSGS

What are three examples of diseases that cause glomerular proteinuria?

Tubular proteinuria

Which mechanism involves impaired reabsorption of low-molecular-weight proteins due to tubular damage?

Non-albumin proteins

What type of proteins are typically secreted in cases of tubular proteinuria?

Acute tubular injury and interstitial nephritis

What are two examples of conditions causing tubular proteinuria?

Overflow proteinuria

Which mechanism occurs when overproduction of small proteins exceeds the kidney's reabsorptive capacity?

Multiple myeloma

In which disease are light chains found in the urine due to overflow proteinuria?

Rhabdomyolysis

Myoglobin is found in the urine in which condition?

Hemolysis

Hemoglobin is found in the urine in which condition?

≥ 3.5 g/day

What is the cutoff for nephrotic range proteinuria in a 24-hour collection?

Urine albumin-to-creatinine ratio (ACR)

What does ACR stand for?

30–300 mg/g

What ACR range is classified as "moderately increased"?

300 mg/g

What ACR value is classified as "severely increased"?

Urine Protein-to-creatinine ratio (PCR)

What does PCR stand for?

Trace

Which dipstick result corresponds to approximately 15–30 mg/dL of protein?

1+

Which dipstick result corresponds to approximately 30 mg/dL of protein?