Approach to Oliguria and/or Proteinuria Flashcards
Anuria is described as a urine output of ___ mL/day
< 50-100 mL/day
Oliguria is described as a urine output of ___ mL/day
< 400-500 mL/day
Polyuria is described as a urine output of ___ mL/day
> 3,000 mL/day
What is Azotemia?
Elevated blood urea nitrogen (BUN) WITHOUT symptoms
What is Uremia?
Elevated BUN with symptoms
What symptoms are associated with Uremia?
- Nausea/vomiting
- Confusion
- Pruritus (uncomfortable irritating sensation that creates an urge to itch)
- Metallic taste in mouth
- Fatigue
- Anorexia
Differential diagnosis of Cardiorenal Syndrome in the setting of a pt that presents with oliguria and proteinuria implies what?
Cardiorenal Syndrome implies Heart failure
Either Systolic Heart Failure (reduced Ejection Fraction)
OR
Diastolic Heart Failure (preserved Ejection Fraction)
What is Cor pulmonale?
Pulmonary HTN causing Right Sided Heart Failure
Can cause kidney damage, resulting in oliguria/proteinuria
What valvular abnormalities can lead to oliguria/proteinuria?
Aortic Regurgitation Aortic Stenosis Mitral Regurgitation Tricuspid Regurgitation Tricuspid Stenosis
What issues of the pericardium can cause oliguria/proteinuria?
Constrictive pericarditis
Pericardial effusion/Cardiac Tamponade
What pulmonary issues can cause oliguria/proteinuria?
ANCA-vasculitis
Goodpasture Syndrome (anti-GBM disease)
What ANCA-vascultiis diseases cause pulmonary pathologies that can cause oliguria/proteinuria?
p-ANCA (MPO - Myeloperoxidase)
c-ANCA (PR3 - Proteinase 3)
Churg-Strauss
What liver pathology can result in oliguria/proteinuria?
Hepatorenal Syndrome
- Cirrhosis
What is Pre-renal Azotemia?
Effective Circulating Volume is decreased
- Shock
What causes decreased Effective Circulating Volume?
Hypovolemic shock
- Dehydration
- GI Bleed
Cardiogenic Shock
Neurogenic Shock
Septic Shock
What are the 3 general causes of AKI?
Pre-renal Azotemia
Intrinsic Kidney Dysfunction
Post-renal Obstruction
What are the tree examples of Intrinsic Kidney Dysfunctions that cause AKIs?
Acute Tubular Necrosis (ATN)
Interstitial Nephritis
Glomerulonephritis
- Nephrotic Syndrome
- Nephritic Syndrome
What can cause Chronic Kidney Disease?
Diabetes
HTN
Acute Kidney Injury
What are you trying to learn from a patient when asking “Have you been drinking enough fluids?”
How much water, coffee, tea, soda is the pt drinking each day
Normal total fluid intake is around 1.5-2.0 L/day (50-60oz/day)
What are you trying to learn from a patient when asking “Are you lightheaded or dizzy with position changes (laying -> sitting; sitting -> standing)?”
Pts that get dizzy with position changes have orthostatic hypotension
What are you trying to learn from a patient when asking “Do you have a history of hypertension and if so for how long?” What follow up question can you ask?
Hypertension is one of the major causes of kidney disease.
Follow up with “what is your typical home blood pressure?” if they measure their BP at home.
What are you trying to learn from a patient when asking “Do you have a history of diabetes and if so how long?” What follow up questions can you ask if Pt does have DM?
Diabetes is a leading cause of kidney disease.
Follow up with “how well is it controlled?” and “what was your last HgbA1C?”
What are you trying to learn from a patient when asking “Do you use certain medications?” What follow up questions can you ask?
Some medications can be nephrotoxic
- NSAIDs
- Antibiotics
- Proton Pump Inhibitors
Follow up with “Which ones?” “How often do you take them?” “How long have you been taking them?”
What are you trying to learn from a patient when asking “Have you had any recent IV iodine contrast dye?”
IV contrast dye is a nephrotoxin
- It is used in cardiac catheterizations and CT scans
NOTE:
- Oral iodine contrast does not result in contrast induced nephropathy, only IV contrast
What are you trying to learn from a patient when asking “Do you empty your bladder completely or feel like you are retaining urine?”
Urinary retention can be caused by
- Benign Prostatic Hyperplasia (BPH)
- Neurogenic Bladder
What are you trying to learn from a patient when asking “Any family history of kidney disease?”
Many kidney pathologies can be inheritable
You want to make sure to ask Pt about family history with
- Hematuria
- Proteinuria
- Kidney Cysts (PKD)
- Chronic Kidney Disease/ End Stage Renal Disease
- Family members requiring dialysis
What are some important findings to look for when examining volume status in a Pt presenting with Oliguria/Proteinuria?
- JVD
- Oral Mucosa (dry, tongue fissuring, moist)
- Capillary Refill (normal < 3 seconds)
- Skin tenting (best to use forehead in elderly)
- S3 (heart failure)
- Crackles (non-specific, pulmonary edema)
- Ascites
- LE pitting edema
- Sacral edema (elderly, non-mobile, hospitalized Pts)
What are some important findings to look for when examining HEENT in a Pt presenting with Oliguria/Proteinuria?
- Tonsillar exudates (Post-infectious GN)
- Oral Ulcers (autoimmune conditions, SLE, etc)
- Retinopathy (HTN or diabetic)
- Nasal ulcers or crusting (ANCA vasculitis)
What are some important findings to look for when examining the heart in a Pt presenting with Oliguria/Proteinuria?
- S3 (heart failure)
- Heart rhythm (i.e., atrial fibrillation may cause hypotension, intracardiac thombus, or indicate electrolyte abnormality)
What are some important findings to look for when examining the lungs in a Pt presenting with Oliguria/Proteinuria?
- Crackles
- Pleural effusions (systemic disease, CHF, infection)
What are some important findings to look for when conducting an abdominal exam in a Pt presenting with Oliguria/Proteinuria?
- Abdominal bruits (Renal Artery Stenosis, Abdominal Aortic Aneurysm, Iliac Arteries)
- Palpable kidneys (ADPKD or Kidney transplant—Usually RLQ)
- Tense abdomen (abdominal compartment syndrome)
- Ascites
What are some important findings to look for when examining the skin of a Pt presenting with Oliguria/Proteinuria?
- Malar rash (SLE)
- Palpable purpura (vasculitis)
- Non-blanching purpura (Thrombocytopenia)
- Buttock and Leg purpura (Henoch-Schonlein Purpura; aka IgA Vasculitis)
- Livedo reticularis (SLE, cryoglobulinemia, hypercoagulable states, vasculitis)
- Emboli (septic or thrombotic)
- Drug Rash
What are some important findings to look for when conducting a musculoskeletal exam in a Pt presenting with Oliguria/Proteinuria?
- Synovitis
- Myalgia
- CVA (Costovertebral Angle) tenderness - Urinary infection; Kidney stone
How do you diagnose CKD?
You need 1 of the 2 criteria for more than 3 months
- Markers of Kidney damage
- Decreased GFR (<60 mL/min)
What are markers of kidney damage?
- Albuminuria (proteinuria)
- Urine sediment abnormalities (casts in urine)
- Electrolyte and other abnormalities due to tubular disorders (i.e., Renal tubular acidosis)
- Abnormalities detected by Histology
- Structural Abnormalities detected by imaging
- History of kidney transplantation (even if transplanted kidney is functioning normally, it is still considered a kidney damage marker)
What happens if you have 1 of the 2 criteria for CKD but for less than 3 months?
Acute Kidney Injury (AKI)
At what value is a GFR considered reduced?
< 60 mL/min
What are the 6 stages of CKD?
Stage 1
- GFR >90 mL/min
- Normal or High
Stage 2
- GFR 60-89 mL/min
- Mild decrease
Stage 3a
- GFR 45-59 mL/min
- Mild to moderate decrease
Stage 3b
- GFR 30-44 mL/min
- Moderate to severe decrease
Stage 4
- GFR 15-29 mL/min
- Severe decrease
Stage 5
- GFR <15 mL/min
- Kidney Failure/ End Stage Renal Disease (ESRD)
Do the GFR categories Stage 1 and Stage 2 meet the criteria for CKD?
In the absence of evidence of kidney damage, Stages 1 and 2 do not meet the criteria for CKD
Recall that the GFR criteria for CKD requires that GFR be less than 60 mL/min for 3 months
Stage 1 describes GFR at > 90 mL/min
Stage 2 describes GFR at 60-89 mL/min
The three most common causes of CKD are ____
Diabetes, HTN, Glomerulonephritis
The vast majority of CKD cases are caused by____
Diabetes and HTN
The most common cause of CKD is____
Diabetes
Many patients with CKD are _____
Asymptomatic
Many patients discover they have CKD from ____
Routine laboratory testing, as many are asymptomatic
The signs and symptoms of CKD include:
- Edema
- HTN
- Decreased Urinary Output (UOP)
- Foamy urine (proteinuria)
- Uremia (Nausea/Vomiting, confusion, pruritis, metallic taste in mouth, fatigue, anorexia
- Pericardial friction rub (pericarditis/pericardial effusion due to uremia)
- Asterixis (flapping wrist, due to uremia)
- Uremic Frost
What are the 3 simple necessary tests required to identify most CKD patients?
- Estimated GFR (eGFR)
- Urine Albumin:Creatinine ratio or Urine Protein:Creatinine ratio
- Urinalysis (with microscopy)
What is a major limitation of eGFR?
eGFR is not accurate in settings of rapidly changing creatinine (i.e. AKI)
What is the common error when using Creatinine Clearance to estimate GFR?
Creatinine Clearance tends to overestimate GFR
This is because creatinine is freely filtered at the glomerulus but is also secreted by tubules making urine creatinine concentration higher than expected
What is wrong with having a patient do a 24 hour urine collection?
It is very cumbersome and patients struggle to accurately collect their urine
How is the Albumin:Creatinine/Protein:Creatinine ratio measured?
Random Spot Urine Sample
- easy to collect
What is the most commonly used imaging technique for analyzing the kidneys?
Renal Ultrasound
What are the signs seen on ultrasound that indicate CKD?
- Atrophic or small kidneys
- Cortical thinning
- Increased echogenicity (brighter)
- Elevated resistive indices (High resistive indices indicates resistance to arterial flow within the kidney)
What is doppler renal ultrasound used for?
To evaluate:
- Renal Artery Stenosis (RAS)
- Renal Vein Thrombosis
- Resistive Index
What is resistive index?
High Resistive Indices (>0.7-0.8) indicates resistance to arterial blood within the kidney
What values indicate a High Resistive Index?
> 0.7-0.8
What is Abdominal CT used for?
Abdominal CT is better at detecting masses and kidney stones
Can also evaluate for the same things as renal ultrasound
What is Abdominal MRI used for?
Evaluates:
- Renal Artery Stenosis (RAS)
- Renal Vein Thrombosis
- Really good at evaluating Renal Masses**
What are the complications of CKD?
- Proetinuria
- HTN
- Hyperlipidemia
- Anemia
- Metabolic Acidosis
- Hyperkalemia
- CKD-BMD (Bone and Mineral Disorder)
- Volume Overload
How do you treat Proteinuria secondary to CKD?
- Low salt diet
- BP control
- RAAS Blockers (ACEi, ARB, aldosterone antagonist, renin inhibitor, non-dihydropyridine CCB)
How do you treat HTN secondary to CKD?
Reduce blood pressure, different goals depending on proteinuria
No Proteinuria: Goal BP < 140/90
Proteinuria: Goal BP < 130/80
How do you treat Hyperlipidemia secondary to CKD?
Statin therapy
How does CKD cause anemia?
Healthy kidney makes Erythropoietin (EPO), promoting RBC generation
Unhealthy kidney does not produce enough EPO -> anemia
How do you treat anemia secondary to CKD?
Oral or IV iron
Erythropoietin Stimulating Agents (ESA)
How do you treat metabolic acidosis secondary to CKD?
Bicarbonate supplementation if HCO3- is <22 mEq/L
How do you treat Hyperkalemia secondary to CKD?
- Renal Failure diet (low salt, potassium, and phosphorus)
- Diuretics
- Sodium Polystyrene sulfonate (Kayexalate) or Patiromer (Veltassa)
How does CKD cause Bone and Mineral Disorder (CKD-BMD)?
Decreased GFR causes Phosphorus retention and Reduced Calcium
Increased serum Phosphorus/Decreased Serum Calcium promotes Parathyroid Hormone secretion –> Secondary Hyperparathyroidism
Hyperparathyroidism promotes Bone mineralization (decreasing bone density)
How do you treat Bone and Mineral Disorder secondary to CKD (CKD-BMD)?
- Low Phosphorus diet
- Phosphorus Binder (lowers phosphorus absorption in the gut)
- Vitamin D supplementation (lowers PTH)
- Calcimimetics (lowers PTH)
- Dialysis (extreme move just to control phosphorus)
How do you treat volume overload secondary to CKD?
- Diuretics
- Fluid Restriction
- Dialysis
How do you treat CKD?
Renal Replacement Therapy
- Hemodialysis
- Peritoneal Dialysis
- Renal Transplantation (living or deceased donor)
What are the indications for Dialysis?
A, E, I, O, U
Acidosis (severe)
Electrolyte Disturbance (usually hyperkalemia)
Ingestion (of dialyzable materials: ethylene gloycols, methanol, etc)
Overload (volume)
Uremia
What are the three categories of AKI?
Pre-renal
Intrinsic
Post-renal
What causes Pre-renal AKI?
- Hypotension
- Hypovolemia
- Reduces Cardiac output (heart failure, tamponade, massive PE)
- Systemic Vasodilation (sepsis, systemic inflammatory response syndrome [SIRS], hepatorenal syndrome)
What are the three categories of Intrinsic AKI?
Tubular Necrosis
Interstitial Nephritis
Glomerulonephritis
What are the two categories of Tubular Necrosis?
Ischemia
Toxins (nephrotoxic)
Which of the three categories of Intrinsic AKI is the most common?
Tubular Necrosis
- Ischemia (50%)
- Toxic (35%)
What causes Post-renal AKI?
Bladder Outler obstruction
- BPH, Cancer, Strictures, blood clots
Ureteral Obstruction
- Bilateral obstruction
- Unilateral Obstruction (in the case of a single functioning kidney)
- Stones, malignancy, retroperitoneal fibrosis
Renal Pelvis
- Papillary Necrosis (NSAIDs), stones
What is the clinical presentation of AKI?
MANY SYMPTOMS IDENTICAL TO CKD:
- Edema
- HTN
- Decreased Urinary Output (UOP)
- Foamy urine (proteinuria)
- Uremia (Nausea/Vomiting, confusion, pruritis, metallic taste in mouth, fatigue, anorexia
- Pericardial friction rub (pericarditis/pericardial effusion due to uremia)
- Asterixis (flapping wrist, due to uremia)
- Uremic Frost
SYMPTOMS NOT SEEN IN CKD:
- Hematuria
- Shortness of Breath (if pulmonary edema is present)
What are the common diagnostic tests for AKI?
Urinalysis with Microscopy
Urine Albumine:Creatinine ratio; Protein:Creatinine ratio
Renal Ultrasound
(urinalysis and protein/albumin:cr ratio also used for CKD diagnosis)
What are the complications with AKI?
- Hypervolemia
- Electrolyte Abnormalities
- Hyperuricemia
- Uremia
- Pericarditis
- Metabolic Acidosis
- Bleeding (platelet dysfunction, BUN > 100 mg/dL
- Need for Dialysis
How do you treat AKI?
Depends on the etiology, correct the underlying disease if possible
- mostly supportive
What findings are seen in Nephrotic Syndrome?
Proteinuria (> 3.5 g/day)
Hypoalbuminemia
Peripheral edema
Hyperlipidemia
Lipiduria
What are the complications associated with Nephrotic Syndrome?
Edema
Hyperlipidemia
Infection
Thrombosis
How does Nephrotic syndrome cause edema?
Two theories:
- Low serum albumin causes reduced vascular oncotic pressure, thus reducing water taken up by the vessel
- Low renal perfusion from low effective circulating volume causes RAAS activation –> Increased sodium reabsorption (increased Total Body Water and Na+)
How does Nephrotic Syndrome cause hyperlipidemia?
Etiology not well understood
Low oncotic pressure (from proteinuria) stimulates liver lipoprotein syntehsis –> Hypercholesterolemia
How does Nephrotic Syndrome cause infections?
Proteinuria includes urinary loss of IgG
Requires occasional IVIg supplementation
How does Nephrotic Syndrome cause thrombosis?
Etiology not well understood
High Risk Thrombosis factors associated with Nephrotic syndrome:
- Serum Albumin < 20g/L
- Clinical hypovolemia
- Bed rest/intercurrent illness
- Membranous Nephropathy
Higher risk when Albumin < 2.0-2.5 g/dL
Urinary loss of Antithrombin III, plasminogen, protein S, and other anticoagulant proteins
Increased levels of procoagulant factors
- Fibrinogen, Coagulation Factors (II, V, VII, VIII, X, XIII), etc
How does Nephrotic Syndrome cause Vitamin D Deficiency?
Urinary loss of Vitamin D binding protein (necessary for proper metabolism of Vit D)
How does Nephrotic Syndrome cause Anemia?
Urinary loss of Transferrin and Erythropoietin
What is the number one cause of Nephrotic Syndrome?
Diabetic Nephropathy
What Nephrotic Syndrome is seen commonly in children?
Minimal Change Disease
What subtype of FSGS is seen in individuals with HIV infection?
Collapsing FSGS
Which Nephrotic Syndrome (specifically) is commonly associated with underlying malignancy and/or renal vein thrombosis?
SECONDARY Membranous Nephropathy
What is monoclonal disease?
Abnormal proteins called Monoclonal Proteins (M Protein) accumulate in the system.
In response, light chain and heavy chain immunoglobulins are produced
Deposition of these Igs in the kidney can cause problems
What is the most definitive test you can do to diagnose Nephrotic syndromes?
Renal Biopsy
- You specifically want to biopsy the cortex, where the glomeruli are located
How do you manage Nephrotic syndrome?
Treat the underlying etiology of the nephrotic syndrome
- may require immunosuppression
How do you treat edema secondary to Nephrotic syndrome?
Dietary sodium restriction
Diuretics
How do you treat Proteinuria secondary to nephrotic syndrome?
LOWER BLOOD PRESSURE
ACEi or ARB
Alternative antiproteinuric medications (non-dihydropyridine CCV, aldosterone antagonist, renin inhibitor)
How do you treat hyperlipidemia secondary to nephrotic syndrome?
Statin therapy
How do you treat thrombosis secondary to nephrotic syndrome?
Heparin or Warfarin
Consider prophylactic anticoagualtion therapy for Pts with serum Albumin <2.5 g/dL
(high risk of thrombosis at serum albumin levels <2.0-2.5 g/dL)
How do you treat infection secondary to nephrotic syndrome?
IVIg supplementation
How do you treat vitamin D deficiency secondary to nephrotic syndrome?
Vitamin D supplementation
What are the findings seen in Nephritic Syndrome?
Proteinuria (< 3.5 g/day)
Hematuria*
HTN*
Renal failure is common
(Hematuria and HTN are the required diagnostic criteria for nephritic syndrome)
What is commonly found in urine in the case of nephritic syndromes?
Nephritic syndromes usually have Active Urinary Sediment
i.e., hematuria, dysmorphic RBCs, RBC casts, WBCs, WBC casts, granular casts, etc
How is the uniary sediment described in nephrotic syndrome?
Bland urinary sediment
What is the classic clinical presentation for nephritic syndrome?
New onset HTN
New onset Hematuria (microscopic or gross)
Acute Kidney Injury (severe cases may have RPGN over days to weeks)
Proteinuria (foamy urine, typically < 3.5 g/day)
Edema (less severe than nephrotic syndrome)
Is edema typically more severe in nephritic or nephrotic syndrome?
Nephrotic syndrome typically has more severe edema
In severe cases of AKI due to nephritic syndrome, you may also see what?
In severe cases of AKI due to Nephritic syndrome, you may have a Rapidly Progressive Glomerulonephritis (RPGN) over days to weeks
What is the most definitive test you can do to diagnose Nephritic syndromes?
Renal Biopsy
- You specifically want to biopsy the cortex, where the glomeruli are located