December Board Review
Renal: Part Deux
Test Question
• In the epic Christmas classic “National
Lampoon’s Christmas Vacation,” what was the
name of cousin Eddie’s dog?
– A. Buff
– B. Barf
– C. Snot
– D. Chewie
HYPERTENSION
Question #1
• A 12-year-old boy has the following vitals at his routine
health supervision visit: HR 75 beats/min and BP
128/85 mmHg using the appropriate-sized cuff (>95%
for height). His weight is above the 95th percentile and
height is at the 50th percentile. The remainder of the
physical exam is normal.
• Of the following, the MOST appropriate next step is:
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–
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–
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A. BUN, Cr, electrolytes
B. Echocardiogrpahy
C. Repeat BP over 3 visits
D. Advise therapeutic lifestyle change
E. Repeat BP in 6 months
Diagnostic Evaluation
• COST
•
•
•
•
Confirm the diagnosis
Organize a diagnostic approach
Determine the Severity of the HTN
Treat the HTN effectively
Confirm Diagnosis
Ensure proper BP cuff size ( know that may be a cause
of false readings)
-Bladder should encircle the arm by at least 80%
Question #2
• A 15-year-old girl comes in for health supervision
visit. She has no complaints and is doing well in
school. She is on the cross-country running team.
She is not receiving any prescription medication.
On PE she appears thin, but is otherwise normal.
Her height and weight are at the 25%. Her HR is
100 beats/min and her BP is 145/95 mmHg.
• The MOST appropriate next step is:
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–
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–
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A. BUN, Cr, electrolytes
B. Echocardiography
C. Recommend therapeutic lifestyle change
D. Review the list of OTC medications she has used
E. Screen for the use of anabolic steroids
Organize a Diagnostic Approach
• MONSTER
– Medications
– Obesity
– Neonatal history
– Symptoms or signs
– Trends in the family
– Endocrine or renal
•BMI > 95%
•3 to 5 times more likely to have hypertension
•Can have obstructive sleep apnea syndrome (OSAS)
•Causes significantly higher diastolic BPs
Question #3
• A 11-year-old female comes in for a health supervision
visit. She has no complaints. Her BP is 121/82 mmHg.
Her height is at the 10% and weight is at the 95%. On
physical exam she is obese with abdominal striae and
has a rash on her face. Family history is negative.
• Of the following, the MOST likely cause of her HTN is:
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–
–
–
–
A. Essential HTN
B. Cushing’s syndrome
C. Neurofibromatosis
D. Systemic lupus erythematous
E. Renal disease
Renal artery stenosis is assoc.
with Williams syndrome
Suggested Eval for Children with HTN
Question #4
• A 17-year-old athlete well-known to your practice
comes in complaining of headaches for the past 2
weeks. He has a history of asthma which is wellcontrolled. He denies using any illicit or prescription
drugs. His BP is 180/120 mmHg. You repeat the
measurement using a leg cuff of proper size and obtain
the same result.
• The BEST management plan is:
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–
–
–
–
A. ACE inhibitor as an outpatient
B. Beta blocker as an outpatient
C. Diuretic therapy as an inpatient
D. Repeat blood pressure in 1 to 2 weeks
E. Vasodilator therapy as an inpatient
Determine the Severity
• Severe HTN or hypertensive emergencies with
significant symptoms of headache, epistaxis,
diplopia, seizures, encephalopathy,
hemiplegia, lethargy, or somnolence require
hospitalization
Treatment
• Nonpharmacologic treatment
– Lifestyle modifications or environmental changes
must be implemented or at least attempted!
– Reducing sodium intake
– Physical activity
• If significant essential or severe HTN, avoid weight
lifting, body building, and strength training
• Restriction based on the possibility of catastrophic
event
Question #5
• You have confirmed HTN in an 11-year-old girl. She has
no complaints and feels fine. She is anxious to return to
ballet class once a week. Her height and weight are at
the 50%. Her BP is 125/83 mmHg (>95%), but
otherwise her exam is normal. You have already
performed BUN/Cr, CBC, UA and renal U/S, all of which
were normal.
• Of the following, the next MOST appropriate step is:
– A. Initiate captopril therapy and re-examine the girl in 1
week
– B. Reassure the parents and re-examine the girl in 1 week
– C. Hydralazine intravenous as an inpatient
– D. Beta blocker as an outpatient
– E. Restrict her from ballet class
Treatment
• First-line
– ACE inhibitors (ex: Captopril, Enalpril)
• Mechanism of action
– Blocks the conversion of angiotensin I to angiotensin II and
inhibits kinase II
• SE = renal impairment, hyperkalemia, neutropenia,
anemia, dry cough, angioedema, contraindicated in
pregnancy
– Angiotensin receptor blockers
• Mechanism of action
– Directly block the action of angiotensin II on their cell
membrane receptors
• SE = renal impairment, hyperkalemia, neutropenia,
anemia
Treatment (cont’d)
– Calcium channel blockers (ex: Nifedipine,
Isradipine)
• Mechanism of action
– Direct vasodilators by inhibiting calcium transport into
vascular smooth muscle and other contractile cells
• SE = peripheral edema, dizziness, nausea, headache,
flushing, weakness, postural hypotension
Treatment (cont’d)
• Second-line therapy
– Beta-blockers (ex: atenolol, labetalol, metoprolol)
• Mechanism of action
– Decreased cardiac output, decreased peripheral vascular
resistance, inhibition of renin secretion, decreased circulating
plasma volume, and inhibition of CNS sympathetic activity
• SE = CV changes, CNS effects, GI changes, hematologic
effects, impotence
• Contraindicated = asthma, Raynaud, CF, BPD,
uncompensated congestive heart failure, bradycardia,
cardiogenic shock, athletes
Treatment (cont’d)
– Central alpha agonists (ex: Clonidine)
• Mechanism of action
– Modulation of CNS centers for cardiovascular control and
alpha-adrenoreceptor agonist
• SE = sedation, dry mouth, fatigue, hallucinations,
rebound HTN
– Vasodilators (ex: Hydralazine, Minoxidil)
• Mechanism of action
– Dilate the arteriolar resistance vessels, with a less pronounced
effect on the venous capacitance vessels
• SE = headache, palpitations, tachycardia, flushing, fluid
and sodium retention, lupus-like syndrome
Treatment (cont’d)
– Diuretics
• Mechanism of action
– Inhibit the absorption of solute, resulting in decreased
reabsorption of water and enhanced urine flow
• SE = fluid and electrolyte disturbance (hypokalemia,
hypomagnesemia, hypercalcemia), metabolic
disturbances, GI effects, ototoxicity
• Potassium-sparing diuretics (spironolactone,
triamterene, amiloride)
– Competative antagonist of aldosterone
RENAL STONE DISEASE
Definitions and Epidemiology
• Definitions
– Urolithiasis= renal stones at any location
– Nephrolithiasis= stones formed exclusively in the
kidney
– Nephrocalcinosis= calcium salts in the renal
parenchyma
• Epidemiology
– Uncommon disease in children, but increasing
incidence
– Males> females
– Caucasians> African Americans
Some Basics to Start
• Crystalluria ≠ stone formation
– Uric acid, calcium phosphate and calcium oxalate
crystals in the urine do not distinguish stone
formers from non-stone formers
– Cystine and triple phosphate crystals indicative if
underlying disease
• Cystinuria, struvite stones
Some Basics to Start
• Formation of stones influenced by
– Urine concentrations of stone forming substances
• Calcium
• Oxylate
• Uric acid
– Urine concentrations of inhibitors
• Citrate
• Magnesium
– *Urine volume
– Urine pH
Calcium Oxylate
Crystals
Stones
Calcium Phosphate
Crystals
Stones
Struvite
Crystals
Stones
Cystine
Crystals
Stones
Uric Acid
Crystals
Stones
Causes of Renal Stone Disease
•
•
•
•
•
Hypercalciuria
Hyperoxaluria
Hypocitraturia
Hyperuricosuira
Low urine volume
Question #6
• A 2-year-old boy who has a history of poorly controlled seizures that are
managed with a ketogenic diet presents with increased fussiness and side
pain. A urinalysis reveals:
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Specific gravity, 1.020
pH, 6
3+ ketones
2+ blood
Negative for protein, glucose, nitrite, and leukocyte esterase
5 to 10 red blood cells/high-power field (hpf)
Fewer than 5 white blood cells/hpf
• Of the following, the MOST likely associated urinary finding in this patient
is:
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–
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–
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A. bacteruria
B. cystinuria
C. hemoglobinuria
D. hypercalciuria
E. hyperoxaluria
*Hypercalciuria
• Most common
abnormality found in stone
formers (30-50%)
– Idiopathic
• Encountered commonly
in a child with nonglomerular hematuria
– Risk of stone formation 4-17% over the next 111yrs
*Hypercalciuria
• Ca excretion> 4mg/kg/d or Ca/Cr> 0.2
– Child>2yo (younger children can have higher
values)
• Sodium intake enhances calcium excretion
• Calcium intake itself does not alter urinary
calcium concentration significantly
– Low Ca diet not recommended
Hyperoxaluria
• Increased biosynthesis
– Primary hyperoxaluria
• Rare AR d/o; 2 types
• Causes early and severe calcium oxalate stone
formation, nephrocalcinosis and ?renal failure
• Increased GI absorption
– Associated with chronic diarrheal d/o
• IBD, Celiac dz, CF
Hypocitrauria
• Citrate is a natural inhibitor of calcium
phosphate and calcium phosphate crystal
growth
Hyperuricosuria
• Uric acid stones are associated with
– Excessive purine loads (high protein diet)
– Low urinary pH
• Most important factor in determining the
solubility of uric acid is pH
• Associated as much with calcium oxalate
stone formation as uric acid stone formation
Cystinuria
• Rare AR defect
– 2 different genetic defects types I-III
• Cystine stones characterized by their ability to
form very large calculi that fill the collecting
system (staghorn calculi)
• Screening test: cyanide-nitroprusside test
Question #7
• A 9 yo F with h/o spina bifida and frequent UTIs
presents to the ED with worsening right-sided flank
pain for the past week. Mom has also noticed some
blood in her urine. On CT scan, she is found to have a
large staghorn calculus in her right renal collecting
system. Of the following, infection with which of the
following bacteria most likely lead to stone formation?
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–
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A. E. coli
B. S. aureus
C. Proteus
D. Enterococcus
E. S. saprophyticus
*Struvite Stones
• Develop following change in urinary composition
caused by urease-producing bacteria (alkaline
urine with a high ammonium concentration)
– Proteus
– Pseudomonas
– Klebsiella
• Can grow quickly and form staghorn calculi with
bacteria being trapped in the stone
– Associated with significant morbidity and mortality
• Children with neurogenic bladders, urinary
diversions, and recurrent UTIs are at greatest risk
Question #8
• A 2 yo M presents to ED with a two week h/o of
LLQ abdominal pain. CT of the abdomen shows a
small stone in the left renal collecting duct and
one in the ureter. Are you:
– A. Surprised at the diagnosis; younger children with
renal stones usually present with flank pain that
radiates to the groin.
– B. Not surprised at the diagnosis; younger children
with renal stones typically present with non-specific
pain localized to the abdomen, flank or pelvis.
*Clinical Presentation
• Adolescents present similarly to adults
– Severe flank pain that radiates to the groin
– Dysuria or frequency
– Passage of blood or stones
• Younger children
– Non-specific pain localized to the abdomen, flank, or
pelvis
• Infants
– Pain that mimics colic
– UTI
*Evaluation
Lab Findings
• UA
– Sterile pyuria
– Gross or microscopic hematuria
• 30-90% of children with stones
– Crystalluria
– High specific gravity
• Low urine output
– Abnormal urine pH
• <6: uric acids stones
• >7: calcium phosphate stones
• >8: struvite stones
Lab Findings
• Electrolytes
– RTA
– Overall renal fxn
– Ca and Phos abnormalities
Question #9
• A 10 yo M with h/o renal stones was found to have
idiopathic hypercalciuria 6 months ago. Upon
diagnosis, he was told to increase his fluid intake and
eat a “no added salt” diet. Despite these changes, he
was admitted to the hospital 1 mo ago due to another
renal stone. Of the following, the most likely next step
in this patient’s management would be the addition of:
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–
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A. HCTZ
B. Furosemide
C. Mannitol
D. Morphine
E. Potassium citrate
*Medical Management
Medical Management
• Struvite stones
– Pose a serious therapeutic challenge due to their
large size and propensity to recur with incomplete
removal
– Combination of medical and surgical management
• Appropriate antibiotic therapy
Surgery
• Most stones <5mm pass spontaneously
• Stones >5mm may require:
– Percutaneous nephrolithotomy
– Extracorporal shockwave lithotripsy
– Retrograde endoscopic lithotripsy
HEMOLYTIC-UREMIC SYNDROME
Hemolytic-Uremic Syndrome (HUS)
• Triad
– 1) Microangiopathic hemolytic anemia
– 2) Thrombocytopenia
– 3) Renal insufficiency
• 2 categories:
– 1) typical HUS with diarrhea (D+)
• 90% of cases in US
• Caused by shiga-toxin-producing strain of E. coli (STEC)
– O157:H7
– 2) atypical HUS without diarrhea (D-)
Shiga-toxin-producing E. Coli
• Also called
enterohemorrhagic E.
coli (EHEC)
• Infects children age 9
months to 4 years
• Summer and Fall
• Primary reservoir is
cattle
Pathogenesis
• Thrombotic microangiopathy
• Enterocyte death and disruption of
microvasculature  hemorrhagic colitis
• Cell injury leads to intravascular creation of
fibrin meshwork  damages platelets and
RBCs
Clinical Diagnosis
• Diarrheal prodrome
– Abdominal pain
– 35 to 90% with bloody diarrhea (self-limited)
– Low grade fever
•
•
•
•
Pale and icterus (from hemolysis)
HTN (volume overload and RAAS)
Petechiae (thrombocytopenia)
CNS involvement (15 to 20%; mostly seizure or
coma)
Question #10
• A mother brings in her 4-year-old daughter because of
decreased energy following a 3-day history of diarrhea
without vomiting. On PE, the girl's temp is 100.2°F,
heart rate is 130 beats/min, RR is 18 breaths/min, and
BP is 122/84 mm Hg. She has pale conjunctivae, a
hyperdynamic precordium, and mild pretibial edema.
Laboratory evaluation reveals BUN 40, Cr 1.4, Hgb 6,
and Plts 90.
• The most likely additional lab abnormality is:
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A. Low reticulocyte count
B. High LDH
C. Elevated PTH
D. Postitive Coombs
E. Prolonged PTT
Laboratory Findings
• Microangiopathic hemolytic anemia
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•
•
•
•
•
Hgb < 10
Negative Coombs
Schistocytes and helmet cells
Increased indirect bilirubin
Decreased haptoglobin
Increased LDH
Thrombocytopenia
PT and PTT are normal
Hematuria and proteinuria
Elevated BUN/Cr
Low albumin
Question #11
• You are seeing a 4-year-old male in the ER with 3 days
of diarrhea, fatigue, low grade fever, pallor, and
petichiae. Mom is worried because she noticed blood
in his stool this morning and now his urine output has
decreased.
• Of the following, the BEST way to manage this patient
is:
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–
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–
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A. Start Loperamide po
B. Order platelet transfusion
C. Start Bactrim po
D. Volume expansion with isotonic fluids
E. Await results of stool culture before proceeding
Treatment
• Supportive
– Volume expansion and maintenance fluids
(isotonic fluids)
– Dialysis for BUN >80 to 100, fluid overload not
responsive to diuretics, electrolyte abnormalities
– PRBCs for hematocrit below 15 to 18%
– Avoid platelet transfusion unless active bleeding
– Avoid antibiotics and antimotility agents during
diarrheal prodrome may worsen disease
ACUTE RENAL FAILURE
An Introduction…
• Definition:
– Acute decline in renal function characterized by
increase in BUN and creatinine values, often
accompanied by hyperkalemia, metabolic acidosis,
and hypertension
• Three general forms:
– Prerenal failure
– Intrinsic renal failure
– Postrenal failure
Question #12
• A 4 yo F presents to the ED with a one week h/o
vomiting and diarrhea. For the past 1-2 days, Mom has
noticed that her urine output has been decreasing. A
BMP shows a creatinine of 1.3. Urine specific gravity is
1.030 with urine osmolarity of 600 mOsm. The FENa in
this patient would likely be:
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A. 6%
B. 4%
C. 3%
D. 2%
E. 0.5%
*Causes of
Prerenal Failure
**Think kidney
hypoperfusion!!**
Pathophysiology- Prerenal
• Decreased intravascular volume decreased
renal perfusion ischemic/ toxic injury to the
renal cells decreased GFR relaxation of
afferent arterioles, catecholamine/
vasopressin release, +RAA system, and
prostacyclin release
Clinical Symptoms and Lab Findings
• Clinical Symptoms
– Clinical Hx should reveal a cause of volume
depletion
– Decreased urine output
• *Lab Findings
Prerenal
UOP
Sediments
↓
Normal
UNa
>400mOsm <10mEq/L
FENa
BUN/Cr
<1%
↑
~Renal US and renal scan should be nml
Question #13
• A 3 yo F presents with a 4- to 5-day history of diarrhea, increased
fussiness, and decreased urine output over the previous day. On physical
examination, her temperature is 37.5°C, heart rate is 120 beats/min,
respiratory rate is 24 breaths/min, and blood pressure is 126/84 mm Hg.
In addition, she has slightly pale, moist mucous membranes and a II/VI
flow murmur, but no gallop or edema. Laboratory evaluation shows:
•
•
•
•
•
Hemoglobin, 6.1 g/dL (61 g/L)
Hematocrit, 18.5% (0.185)
Platelet count, 68x103/mcL (68x109/L)
Blood urea nitrogen, 60 mg/dL (21.4 mmol/L)
Creatinine, 2.9 mg/dL (256.4 mcmol/L)
• Of the following, her FENa is most likely:
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–
–
–
–
A. 0.5%
B. 4%
C. 1.5%
D. 1%
E. 0%
Intrinsic Renal Failure
• Pathophysiology
– Ischemic/toxic insult
cellular dysfunction with
breakdown and necrosis
decreased GFR
Clinical Symptoms and Lab Findings
• Clinical Symptoms
– Clinical Hx should reveal a cause of injury
– Decreased urine output
• Oliguria (<0.5-1 mL/kg/h)
• Anuria (no urine)
• *Lab Findings
UOP
Sediments
Prerenal
↓
Renal
↓
Uosm
UNa
FENa
BUN/Cr
Normal
<10mEq/L
<1%
↑
RBC casts,
granular
casts, RBC
<350mOsm >40mEq/L
>2-3%
↔
Other Diagnostic Studies
• Renal scans
– Ex: MAG3
– Demonstrate extent of
kidney function
• Renal biopsy
– Rapidly increasing SCr
– Establishing acute vs. chronic GN
– Positive serology for systemic diseases
Question #14
• All of the following are possible causes of
postrenal failure except:
– A. Posterior urethral valves
– B. UPJ obstruction
– C. Urolithiasis
– D. Nephrotic syndrome
– E. Tumor
Postrenal Failure
• *Causes
• Pathophysiology
– Obstruction of the ureter, bladder or urethra
increase in pressure proximal to the obstruction
renal damage decreased GFR
Clinical Symptoms and Lab Findings
• History
– Colicky abdominal pain
– Gross hematuria
– UOP variable
• PE
– Palpable flank mass
• Labs
– Urine sediment variable
– Other parameters usually normal
Imaging
• Renal US
– Dilated renal pelvis
• Radioisotope scan
– Collection within the kidney (ureter, bladder) with
delayed or absent excretion of the isotope
Principles of Management
•
•
•
•
•
•
•
Maintaining renal perfusion
Fluid/ electrolyte balance
Controlling BP
Treating anemia
Adequate nutrition
Adjusting meds for degree of renal impairment
Initiating renal replacement therapy when
indicated
Management
• Vasoactive agents
– Given to improve BP and ensure adequate renal
perfusion
– ?Efficacy of “renal dosing” of dopamine (0.5-3
mcg/kg/min)
– ANP
• Dilates afferent and constricts efferent arterioles
increase in GFR
• More studies needed in children
Management
• *Fluids
– Depend on patient’s hemodynamic status and
UOP
• Oliguria + HD instability20mg/kg bolus isotonic fluids;
repeat PRN
– Once IV volume replaced:
• Fluid restrict to 400mL/m2/d+ UOP+ extrarenal losses
– Furosemide or mannitol to promote urination
• Use of these alone does not change the need for renal
replacement therapies
Question #15
• A 5 yo M presents to the ED with a 2 week h/o
increasing lethargy, weakness and pallor. A BMP
shows a BUN of 65, creatinine of 3.2, and a K of
6.5. EKG shows peaked T waves. Of the
following, which is part of the treatment regimen
of hyperkalemia?
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–
–
–
–
A. Calcium gluconate
B. Insulin and glucose
C. Sodium bicarbonate
D. Beta agonists
E. All of the above
Management
• *Electrolytes
Management
• Anemia
– Transfusion indicated
• Active bleeding
• HD instability
• Hct<25%
• HTN
– Usually secondary to volume overload or changes in
vascular tone
• HTN crisis: IV labetolol, nicardipine, enalaprilat, diazoxide
• Less severe HTN: short-acting nifedipine
Management
• *Nutrition
– Patients in a catabolic state
– Diet with following own
• 70% calories from carbs
• <20% lipids
• Biologic value proteins 0.5-2g/kg/d
• *Medications
– Dosage or interval should be adjusted for degree
of renal impairment
Management
• Renal replacement therapy
– Indications
•
•
•
•
•
•
CHF
Anemia
Hyperkalemia
Severe acidosis
Pericarditis
Inadequate nutrition
– CVVH, CAVH, hemodialysis, peritoneal dialysis
Prognosis
• Recovery: days weeks
• Prognosis depends on:
– Need for dialysis
– Time between onset and presentation to medical
care
– Underlying disease
• Multisystem organ failure and young age at
presentation= poor prognostic factors
HAPPY HOLIDAYS!!!