10 - Renal Case Study Flashcards
Describe the patient presentation
- 32 y/o African-American female seen for bilateral ankle and leg swelling of one month duration
- Concerned about a 10 lb weight gain
Describe what you find in the review of systems
- Nocturia (urinating at night)
- “Foamy” urine (bubbly)
- Denies cold intolerance
- Normal menstrual cycle w/o edema
- 2 uneventful full-term pregnancies
Describe the medical history of this patient
- Excellent health
- No medications
- No allergies
- Family history non-contributory
Describe the social history of this patient
- Denies tobacco, alcohol, illicit drugs
- Normal appetite with no change in diet
- Regular exercise without fatigue or dyspnea
Describe the vitals of this patient
- BP: 110/70
- Pulse: 80
- Respirations: 12
- Temp: 36.6°C
Normal
Describe the physical exam
- Cardiopulmonary exam: normal
- Abdominal exam: normal
- Neurovascular exam: normal
- Musculoskeletal exam: normal
Describe the dermatological exam
- No jaundice or pallor
- 2+ pitting edema of anterior tibial crest
- Whitish lines on toenails and fingernails parallel to the lunula
What does pitting edema suggest to you?
Pitting edema
- No excess of pitting in the soft tissue
Non-pitting
- Excess of protein in the soft tissue
What does the H&P suggest?
You are evaluating swelling… So, thinking of the system you are now in, what could cause this?
- CHF (backup of fluid, increased pressure driving fluid out of vessels)
- Kidney failure (glomeruli failure)
- Liver failure (Nothing palpable on abdomen and no jaundice, but if it had liver failure possible - cirrhosis leading to edema from decreased protein production)
- NO pallor (whitish) indicates that the patient probably does NOT have anemia
- Anemia would be due to kidney failure (produces erythropoetin)
What are the three major etiologies of peripheral edema?
Three major
- CHF
- Cirrhosis of liver
- Nephrotic syndreme
Others
- Hypothyroidism
- Idiopathic cyclic edema (edema during menstruation)
- Pregnancy
Together, these are the main 6 systemic, metabolic causes of peripheral edema
The MOST common cause of peripheral edema is venous insufficiency, but that is localized, not systemic
How do the main 3 cause edema?
Mechanism of edema
- All three lead to DECREASED RENAL PERFUSION, leading to activation of renin-angiotensin-aldosterone system
- This leads to increased sodium and water retention to maintain effective blood volume
Direct
- Renal = direct damage to glomeruli
- Liver = cirrhosis leads to increased production of vasodilators which increase splanchnic circulation and “steals” blood flow from the kidney
- Cardiac = increased cardiac output
In CHF, what would you see?
FINISH
In CHF, edema also caused by increased capillovenous pressure
In cirrhosis, what would you see?
FINISH
- In cirrhosis, edema caused by **hypoalbuminemia, **portal hypertension, intrahepatic lymphatic obstruction, and inability to destroy antidiuretic hormone and aldosterone contribute to ascites
So, do you think it is CHF?
No…
- Cardio exam is normal
- No history of heart disease
- Able to exercise with no impairment
- No family history
Is it cirrhosis?
No…
- No jaundice
- No abdominal mass
- No liver enlargement
- Denies alcohol and other drug use
- Not on any medications that cause liver problems
Is it kidney disease?
Yes…
- Nocturia and “foamy urine” which suggests proteinuria ***
- Paired white lines “Muehrcke’s lines” are seen in hypoalbuminemia ***
These suggest that we are spilling protein or are not making enough protein… or both
Hypoalbuminemia could be caused by spillage into urine
Is it hypothyroidism?
No…
- No cold tolerance
- Normal bowel habits
Is it cyclic edema?
No…
- No edema during menstruation
Is it pregnancy?
No…
- Husband had his “tubes tied” after birth of second child
What do you do next?
- Creatinine (kidney function test)
- Urinalysis
- Urine culture
- AST, ALT, total protein (liver function tests - total protein is albumin and globulin)
- Cholesterol (low lipoprotein lipase so high cholsesterol in liver problem)
- BMP (basic metabolic panel)
- TSH (for thyroid function)
- CBC (hemoglobin for anemia)
- 2 hour PP glucose, ANA, serum complement *** (not the ones you aren’t expected to know, but they will be relevant for this patient)
List the results
- CBC normal
- No advanced renal insufficiency
- This is because erythropoetin is not elevated (look at slide)
- NOTE - liver disease can cause iron deficiency anemia due to decreased production of transferrin
Describe the urinalysis
- pH 6.0
- Trace of glucose* (170+ BS?)
- Urobilinogen and bilirubin-negative
- Protein 4+*
- Microscopic
If you are getting a lot of protein loss, it can bring glucose with it without being diabetic
Describe the microscopic urinalysis
- One WBC and RBC/hpf (high power field)
- Two to four hyaline casts with fatty inclusions and one oval fat body/hpf* (“fat in urine”)
- Urine culture negative
All is normal except fat in urine
Describe the proteinuriea
- Protein of 4+ suggests nephrotic syndrome
- Proteinuria of renal-based disorders is PRIMARILY composed of albumin
- This is because it is the smallest of the major proteins and, therefore, is the first to “leak out”
What does the microscopic urinalysis mean?
Few WBC and RBC suggest we are not dealing with a typical glomerulonephropathy
Casts with fatty inclusions and fat bodies point towards nephrotic syndrome
- In the syndrome, hepatic synthesis of lipoproteins is increased
- Secondary to hypoalbuminemia and decreased amounts of lipoprotein lipase
What does serum protein electrophoresis show?
- Serum protein electrophoresis shows decreased albumin
- Total proteins are 5.1g/dL (albumin 2.1 g and globulin 3.0 g)
- Serum cholesterol is 390 mg/dL
What is the serum creatinine?
Serum creatinine is 0.9 mg/dL
This is normal because she has not been experiencing symptoms for long
Describe the lab work for nephrotic syndrome
- 2 hPPG is 98mg/dL (for diabetes - normal)
- ANA is absent (for lupus - normal)
- Serum complement is normal (distinguish between the types of nephrotic syndromes)
These three tests were ordered to seek a cause for the nephrotic syndrome
Describe complement levels in nephrotic syndrome
Disorders in which C3 is decreased but C4 is not include MPGN and post-infectious glomerulonephritis; disorders in which BOTH C3 and C4 are decreased include lupus nephritis and cryoglobulinemia.
What is the sequence of events seen in nephrotic syndrome
- Glomerular defect
- Massive proteinuria
- Hypoalbuminemia
- Edema
- Decreased renal blood flow
- Renal retention of salt and water
- More edema
What do we know now?
- Complement is normal
- No matter what is the cause of the nephrotic syndrome, glomerular injury is the common denominator
- List of causes is massive
What do we do now?
Renal biopsy
What does histological diagnosis include?
- Mesangial proliferative glomerulonephritis
- Focal and segmental glomerulosclerosis
- Membranous glomerulopathy
- Membranoproliferative glomerulonephritis
Don’t need to know this for exam
What is the final diagnosis for this patient?
Final diagnosis is membranous glomerulopathy, an immune complex form of glomerulonephritis
What is the list of differentials that are systemic causes of peripheral edema
KNOW THIS
C CHIP N’ DALE
- CHF
- Cirrhosis
- Hypothyroidism
- Intermittent cyclical edema
- Pregnancy
- Nephrotic syndrome
- Decreased renal perfusion
- Alcohol
- Liver
- Edema
