BOARD REVIEW
NEPHROLOGY
Karen Estrella-Ramadan
Question 1


You are seeing a 10-year-old girl who has SLE for a
WCC. You diagnosed SLE when she was 8y/o, based
on an initial presentation of idiopathic
thrombocytopenic purpura and a positive ANA test and
the subsequent development of arthritis and a positive
anti-double-stranded DNA test. She is currently doing
well in school and has no concerns about her memory or
problem-solving skills. The only finding of note on her
physical examination is a slight erythematous rash in a
malar distribution.
Of the following, the MOST useful screening test for
other organ involvement in this girl is:
Of the following, the MOST useful screening test for
other organ involvement in this girl is:
1.
2.
3.
4.
5.
Coombs test
erythrocyte sedimentation rate
magnetic resonance imaging of
the brain
Urinalysis
Venereal Disease Research
Laboratory (VDRL) testing
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0%
0%
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0%
0%
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SLE patients have high mortality from Renal and
CNS disease:




Renal disease occurs in 75% to 80% of children who have SLE, usually within 2 years
of diagnosis. Renal manifestations are not typically apparent at diagnosis; most
patients present with fever, rash, arthritis, and mucositis

Typical screening besides U/A, include: urine protein-to-creatinine ratio, and serum
creatinine and albumin.

Renal manifestations can range from asymptomatic hematuria and proteinuria to overt
nephritis (gross hematuria, azotemia, and hypertension), nephrotic syndrome, or
hypertension.

Patients in whom proteinuria (>1+ on a dipstick or urine protein-to-creatinine ratio
>0.2 [mg/mg]) is discovered need Renal referral for assessment and possible renal
biopsy.
CNS: MRI if pt develops: seizures, psychosis, headaches, difficulty with
concentration, or memory problems.
Other organs:


Renal: do a U/A to screen , initially may be subclinical
Hem: hemolytic anemia pallor, do Coombs +
ESR: non specific ; VDRL: false positive
Question 2


An 8-year-old boy presents with cola-colored urine without blood clots. He
was well until 2 days ago, when he developed a sore throat with upper
respiratory tract infection symptoms. He denies any dysuria, frequency,
urgency, flank pain, or trauma. On physical examination, his temperature is
37.8°C, heart rate is 84 beats/min, respiratory rate is 18 breaths/min, and
blood pressure is 118/78 mm Hg. He has no costovertebral tenderness,
abdominal tenderness, or edema.
Labs show:

Urine: Specific gravity, 1.025, pH, 6.0, 3+ blood, 3+ protein, 1+ leukocyte
esterase, Nitrite, negative






Microscopy shows more than 100 RBC/hpf and 5-10 WBC-hpf
BUN 24 mg/dL (8.6 mmol/L)
Creatinine, 0.9 mg/dL (79.6 mcmol/L)
C3: 140 mg/dL (normal, 80 to 200 mg/dL)
C4: 30 mg/dL (normal, 16 to 40 mg/dL)
ANA: negative
Of the following, the most likely
diagnosis is:
1.
2.
3.
4.
5.
acute pyelonephritis
immunoglobulin A
glomerulonephritis
postinfectious
glomerulonephritis
Urolithiasis
viral cystitis
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Dx: acute glomerulonephritiscola-colored urine,
hematuria/proteinuria, and mild azotemia

Things to differentiate:
 Urine color:
 bright red: Lower tract bleeding viral hemorrhagic
cystitis or stones often accompanied by clots.
 Cola-colored urine without clots glomerular hematuria.
 Yellow but on UA dipstick + RBC, do a UA and likely +
for myoglobin,

Time:
 Very recent URI: of but not specific for immunoglobulin A
(IgA) glomerulonephritis.
 7-21 days later: PSGN
Remember



Piuria: > 10WBC/hpf
Hematuria: >3 RBC/hpf in2 centrifugated samples
of fresh urine
Proteinuria: >3.5 gr/day
Evaluation of a child with suspected
AGN

Follow up Blood pressure and creatinine levels


If HTN, or rising creatinine levels  renal bx
Follow serologic markers: C3 and C4, ANA and antiDNAds

The combination of a normocomplementemic GN and a
synpharyngitic pattern =IgA nephropathy



Can also present with asymptomatic hematuria or hematuria/proteinuria.
Patients who have gross hematuria have a better prognosis.
Treatment usually consists of steroids, ACE
Alternative diagnostic include:




Alport :renal, sensorineural hearing loss, ocular defects
Membranoproliferative glomerulonephritis: low C3 + low C4
PIAGN: strep infection, low C3, normal C4
Focal glomerulonephritis (HIV): normal complement
Question 3

A 17-year-old sexually active girl presents for a
follow-up evaluation after her third episode of a
urinary tract infection. She is currently
asymptomatic. The results of renal ultrasonography
and voiding cystourethrography are negative. She
asks you how to prevent further episodes.
Of the following, you are MOST likely
to advise her to
1.
2.
3.
4.
5.
drink cranberry juice frequently
increase her daily water intake
make sure to void after
intercourse
self-medicate with antibiotics
for 3 days when symptomatic
use single-dose postcoital
antibiotic prophylaxis
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She has…acute cystitis


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> common in girls, > 3 UTI in a yr
Best preventive measure ( even after 5y of use):
 symptoms with sexual intercourse postcoital antibiotic prophylaxis (taken within 2 hours
of intercourse).
 nitrofurantoin 50 mg, TMP-SMX] 40/200 mg, or cephalexin 500 mg
 Those who fail, UTI not associated with a modifiable cause or at risk of complicated UTI
give: continuous
 TMP-SMX (40/200 mg daily at bedtime or 3 times per week)
 nitrofurantoin (50 to 100 mg daily at bedtime or 3 times per week),
 norfloxacin (200 mg daily at bedtime or 3 times per week)
 and cephalexin (250 mg daily).
 Stop meds after 6-12 months: trial, if fails, restart abx
Self-medication when symptomatic with a 3-day regimen is another option
 Women with one to two UTI per year).
IF UTI after sexually active: no imaging
~Behavior changes: “proper wiping,” avoid tight pants, avoid urge-initiated voiding,
+postcoital voiding, increased fluid intake, and the daily consumption of cranberry juice
Question 4

You are examining a newborn who has wrinkling of
the abdominal wall skin. His mother recalls her
obstetrician mentioning that her “fluid was low.” The
infant was born at 37 weeks’ gestation, and his
birthweight was appropriate for gestational age.
Of the following, the MOST likely additional findings
expected in this infant are cryptorchidism and
1.
2.
3.
4.
5.
bilateral
hydronephrosis
Hypospadias
Nephrocalcinosis
polycystic kidney
disease
unilateral renal
agenesis
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BL hydroureteral nephrosis + absence of abdominal wall
musculature +undescended testicle= prune-belly syndrome




PBS  obstructive
uropathy
Associated with renal
dysplasia BUT NOT: renal
agenesis, nephrocalcinosis,
cystic renal disease,
hypospadias.
almost exclusively in males
30% of affected patients
eventually develop endstage renal disease
PRUNE-BELLY SYNDROME
CRIPTORCHIDISM
ABSCENSE OF ABDOMINAL WALL
MUSCLE-WRINKLY
Question 5
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

A 6y/o girl presents for a WCC that was scheduled as a follow-up
appointment after she had an elevated blood pressure at an urgent care
facility during an evaluation for abdominal pain. Her abdominal pain has
resolved. Her mother recalls the blood pressure in the urgent care center as
135/90 mm Hg. The girl has had 2 UTI with fever in the past, and her
father had hypertension diagnosed at age 45 years.
On physical examination, the girl’s temperature is 37.3°C, heart rate is 90
beats/min, respiratory rate is 20 breaths/min, and blood pressure is
146/86 mm Hg. A repeat blood pressure reading is 142/88 mm Hg. The
four limb blood pressures are: 142/88 mm Hg in the right arm, 144/84
mm Hg in the left arm, 156/100 mm Hg in the right leg, and 160/96 mm
Hg in the left leg. You find no cardiac murmurs, abdominal bruits, or
edema. Femoral pulses are 2+ and symmetrical bilaterally.
Renal ultrasonography shows the left kidney to be 8.5 cm with normal
corticomedullary differentiation and the right kidney to be 5.5 cm with
increased echogenicity.
Of the following, the MOST likely cause for this
patient’s elevated blood pressure is
1.
2.
3.
4.
5.
coarctation of the aorta
essential hypertension
renal artery stenosis
renal
hypoplasia/dysplasia
renal scarring from prior
pyelonephritis
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
HTN, + hx of UTIs and US findings (increased
ecogenicity) renal scaring from pyelonephritis
(+)VUR: HTN in 20% of pts



Up to 8 yrs to develop
(+)HTN: 30-40% had scarring Hypertension can occur
in up to 20% of patients who have (+)VUR
Patients usually respond well to ACEIs
caution in female patients of childbearing age due to risks
of teratogenicity.
 If BL stenosis or on monorenal pt—DON’T USE ACEIs will

worsen renal failure due to inhibition contraction of efferent arteriole
that will maintain glomerular filtration
Why not?




Coartation of the aorta: femoral pulses are present
and blood pressures are higher in the legs than in the
arms
Essential HTN: is a diagnosis of exclusion mild
hypertension in adolescent patients who are overweight
and have a positive family history of hypertension.
Renal artery stenosis is rare, associated with abdominal
bruits on examination and a small kidney on
ultrasonography.
Renal hypoplasia/dysplasia can be associated with an
isolated small kidney, BUT hypertension is uncommon in
this setting.
Question 6

You are called to attend the delivery of a newborn
male who had been monitored carefully prenatally
for moderate oligohydramnios. Prenatal
ultrasonography suggested bilateral cystic
dysplastic kidneys, with no other congenital
anomalies identified.
Of the following, the MOST likely immediate lifethreatening problem in this infant is
1.
2.
3.
4.
5.
bladder outlet
obstruction
cardiac arrhythmias
liver failure
renal failure
respiratory failure
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0%
0%
2
3
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4
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
The most immediate
possibility of respiratory
failure from pulmonary
hypoplasia.


due to decreased amniotic
fluid volume, which may lead
to reduced fetal respiratory
excursion which impedes
pulmonary development.
“Potter sequence”
(oligohydramnios with
pulmonary hypoplasia,
clubfeet, and flattened facies)
Question 7

A 1-year-old girl presents for a health supervision
visit. Her father underwent kidney transplantation
for end-stage renal disease due to autosomal
dominant polycystic kidney disease. The parents
request assessment of the child's kidney function.
Her serum creatinine measurement is normal for
age.
Of the following, the MOST correct statement about
serum creatinine measurements in the pediatric patient
is that
1.
2.
3.
4.
5.
serum creatinine value of 0.6 mg/dL (53.1 mcmol/L)
is considered normal for a 1-year-old child
healthy preterm infants (<36 weeks' gestation)
typically have lower serum creatinine values than
term infants
males and females have similar serum creatinine
values up to 17 years of age
newborns in the first few days after birth have lower
serum creatinine concentrations than those seen in 2month-old infants
serum creatinine values are related more closely to
patient height than to patient age in children
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Kidney function is assessed best by measurement of the
glomerular filtration rate (GFR
The serum creatinine is the most frequently used agent to
assess GFR clinically.
 Skeletal muscle metabolism, high values during growth
The GFR in the pediatric patient increases throughout the
first postnatal year before reaching adult values by
approximately 18 months of age.
 Newborn: high values-represent maternal value, declines
after 10 days
 Preterms have higher values
 1y/o: <0.4 mg/dl

Question 8

A parent requests referral to a urologist for her 7year-old son because of his bedwetting problem.
He has no urinary incontinence during the day and
is otherwise healthy. Physical examination reveals
normal growth parameters and normal genitalia
with a circumcised phallus. Dipstick urinalysis results
are normal, with a specific gravity of 1.025.
Of the following, the MOST appropriate
next step is
1.
2.
3.
4.
5.
a complete blood count
psychological evaluation
reassurance and a follow-up
visit in 6 months
referral to a urologist
renal/bladder
ultrasonography
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Nocturnal enuresis


Involuntary passage of urine during sleep in children >5 y/o and occurs in
approximately 15% of children at age 5 and 1% of teens at age 15.
There is a male predominance and often a positive family history.
Child with NO daytime wetting, NO dysuria and normal UA: renal very
unlikely


reassurance and a follow-up visit in 6 months
Child with BOTH daytime and nighttime wetting, older than 6y/o, enuresis
+ encopresis, or urinary symptoms further eval



assess genitourinary anatomy, exclude trauma from sexual abuse, detect
lumbosacral spine anomalies, and exclude bladder dilatation or abdominal
mass.
Older children and children for whom nocturnal enuresis is related to social
dysfunction, family stress, or poor self-esteem may benefit from therapy to
target those effects.
The use of a bedwetting alarm has the highest rate of success in young children.
Question 9

You are examining an
asymptomatic adolescent
male for his annual health
supervision visit. Genital
examination reveals
genitalia at Sexual
Maturity Rating 5 and a
nontender mass in his left
scrotum that extends from
the inguinal canal to the
upper pole of the testis
The mass decreases in size
when he lies down.
Of the following, the MOST likely
diagnosis is
1.
2.
3.
4.
5.
direct inguinal hernia
Hydrocele
Spermatocele
testicular tumor
varicocele
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Varicocele








Develops slowly
usually asymptomatic
>15-25y/o
> left side (drain to renal vein)
vary in size, can extend from the
testis to the inguinal canal, and feel
like a "bag of worms"
INCREASE in size with standing or
valsalva
REDUCE when lying down
If a varicocele develops suddenly,
does not reduce in the supine
position, or is on the right side, a
cause for obstruction of the
spermatic vein should be sought.
Pampiniform plexus
Why not?

Inguinal hernias: painless, intermittent groin masses that
appear with straining and usually reduce spontaneously.


Hydrocele: fluid within the tunica vaginalis that surrounds the
testis rather than being distinct from it.



They may increase in size and become obstructed, resulting in a
painful scrotal mass.
Transilluminates
Spermatoceles are cystic lesions within the spermatic cord
that are above and distinct from the testis and
transilluminate.
Testicular tumors are painless solid masses within the testicle
that do not transilluminate.
Question 10

The attending neonatologist notifies
you that she is caring for a newborn
boy in your practice who has
multiple congenital anomalies. The
baby was transferred from the
newborn nursery to the intensive care
unit due to cyanosis.
Echocardiography reveals findings
consistent with tetralogy of Fallot.
The infant has a cleft palate. Chest
radiographs show multiple thoracic
hemivertebrae. Renal
ultrasonography documents
unilateral renal agenesis. On
physical examination, the infant has
hypoplastic thumbs. The baby is
normally grown and vigorous.
Of the following, the MOST likely
diagnosis for this infant is
1.
2.
3.
4.
5.
CHARGE syndrome
Fanconi anemia
trisomy 18
22q11 deletion syndrome
VACTERL association
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CHARGE syndrome






C: coloboma
H: heart
A: atresia choanae
R: retardation of growth
and/or development
G: genital anomalies
E: ear anomalies
Fanconi anemia


AR
thumb hypoplasia, short
stature, microcephaly,
abnormal ears, epicanthal
folds, site of ureteral
reimplantation, congenital
dislocated hips


bone marrow failure
more common among persons
of Ashkenazi Jewish heritage
VACTERL






V: vertebral anomalies
A: anal atresia
TE: tracheoesophageal
fistula
R: renal anomalies
C: cardiac defects
L: (radial)limb anomalies

The combination of tetralogy of
Fallot, hypoplastic thumbs, cleft
palate, and a renal abnormality
22q11 deletion syndrome
Recent studies have shown that tetralogy of Fallot with pulmonary atresia belongs to
a spectrum of conotruncal cardiac malformations that are often associated with
monosomy 22q11. The clinical presentation of monosomy 22q11 includes patients
with conotruncal anomaly face syndrome, velo-cardio-facial syndrome, and
DiGeorge syndrome. More recently these syndromes have been incorporated as a
group under the acronym catch 22 (cardiac defect, abnormal face, thymic
hypoplasia, cleft palate, hypocalcaemia, and microdeletion 22q11)
Question 11
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
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
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
You are evaluating a newborn in whom intrauterine renal US results are abnormal.
The child appears very edematous, but requires resuscitation with fluids for initial
respiratory distress and hypotension. One day later, the child appears more
edematous.
He has an excellent urine output. Measurements of his serum electrolytes reveal:
Na: 127mEq/L
K: 4.6mEq/L
Cl: 92mEq/L
HCO3: 27 mEq/L
BUN: 10mg/dL
Creatinine: 0.7 mg/dl
Albumin: 0.9g/dl
UA: no blood, but (4+) protein with a random urine protein to creatinine ratio of
43.5.
Of the following, the MOST likely cause of this
child’s clinical status is:
1.
2.
3.
4.
5.
Acute glomerulonephritis
Congenital nephrotic
syndrome
Diffuse mesangial
sclerosis
Focal segmental
glomerulosclerosis
Membranous nephropathy
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0%
0%
2
3
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0%
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Congenital nephrotic syndrome

Cystic formation sec to mutation in: nephrin (BM)
leakage
 Massive
proteinuria decrease oncotic pressure
edema
 By
2 months: kidneys enlarged with loss of
coticomedullary differentiation
 By 12 mo: decrease in size with hyperechogenicity
fibrosis/ glomerular sclerosis failure

Rarely in newborn period:
 Acute
glomerulonephritis
 Membranous nephropathy
 Focal segmental glomerulosclerosis
Question 12




A 3 mo old boy is admitted to the hospital for
evaluation of FFT. His bwt was at %50 and length at
%75. Currently, his wt is below the %5 and length is at
%25, His VS and PE are otherwise normal.
He appears well hydrated.
Measurement of serum electrolytes reveals; Na:139, K:
4.7, Cl: 114, bicarbonate : 12, BUN: 8, creatinine: 0.3.
A consulting nephrologist recommends measurement of
urine pH (which is 7.5) and urine ammonium (which is
12000 mcm/L—normal is > 60000)
Of the following the MOST likely cause of
child’s acidosis is?
1.
2.
3.
4.
5.
Inborn error of
metabolism
Lactic acidosis
Type I (distal renal
tubular) acidosis
Type II (proximal renal
tubular) acidosis
Type IV (renal tubular
acidosis)
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Step 1



Calculate anion gap help you narrow your differential
HIGH:
 severe CRF
 Ketoacidosis: diabetic, alcoholic, starvation
 Lactic acidosis
 Poisonings: salycilates, methanol, ethylene glycol
NORMAL:
 Renal tubular acidosis
 Diarrhea
 Carbonic anhydrase inhibitors
 Hyperalimentation with TPN
RTA

3 types
 Type
1: distal
 Type 2: proximal
 Type 4: distal
 NO TYPE 3
Type 2-proximal

Inability to reabsorb HCO3 Very very alkaline urine
If distal is normal, will compensate a little by excreting H+
and the urine is ~6
 K: is low or normal

CAUSES
• Fanconi sd
• Acetazolamide, 6 mercaptopurine
• Heavy metals: lead, copper, mercury, cadmium
• Disorders in protein, CHO, AA
• Multiple myeloma
Type2
Type 1-distal


Inability to excrete hydrogen, as well as ammonium secretion
 Urine very very alkalotic~>7.5 with a low urine ammonium
 hypokalemic
CAUSES:

RENAL STONES-obstruction / hypercalciuria

Amphotericin

Toluene (glue sniffing)

Lithium

SLE

Sjogren

Chronic active hepatitis
Type 1
Type 4-distal

Affects Na/K/H exchange
 Hyperkalemic
 Hyperchloremic
CAUSES:
 Obstructive uropathy
 Interstitial renal disease
 Multicystic renal disease
 Type 1 pseudohypoaldosteronism
 Diabetic nephropathy
 21-OH deficiency
 Renal transplant
Type 4
Type 1
Don’t forget….

Anion gap: Na+(Cl-HCO3)
 In RTA
 lost of bicarbonate will actually increase absorption of
chloride—therefore, there is a balance in the equation
ALL RTA HAVE:
HYPERCHLOREMIA
NORMAL ANION GAP
TYPE 1: HYPO-K
TYPE 2: NORMAL K
TYPE 4: HYPER K
Question 13



A 6y/o F had been noted by her gral pediatrician to
have symptomatic, persistent hematuria for 2 yrs. Her
initial UA and microscopic analysis in your office show
moderate blood, with 25-50 RBC/hpf. Results of her
renal US were normal, as was her urine calcium-tocreatinine ratio. Serum electrolytes were normal in 2
occasions.
Over the next 2 yrs, you ordered 4 concurrent UA, all
of which showed moderate blood with 25-50 RBC/hpf,
without proteinuria.
She comes to clinic after being lost to follow up for 3
yrs.
Of the following, the clinical symptom or laboratory
result MOST consistent with progression of renal disease
in this child will be?
1.
2.
3.
4.
5.
Abdominal pain
Leukocyturia
Proteinuria
Recurrent gross
hematuria
Urinary RBC casts
0%
1
0%
0%
2
3
0%
0%
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
Hematuria + proteinuria= renal disease
Proteinuria-important facts

False positives: highly concentrated, alkaline urine

Fixed proteinuria (day/night) requires further eval




Transient hematuria: in fever, strenuous exercise and CHF
Benign orthostatic proteinuria: higher during growth spurt



Random urine protein/creatinine ratio > 0.5
24 hrs urine protein excretion > 3.5 gr/day
Females
When lying down: none, when up: positive
Microalbuminuria: DM

> 300: nephropathy
Question 14
You are evaluating a 10y/o boy who has intermittent
urinary incontinence. Voiding cystourethrography detects a
urethral stricture.
Of the following, the most likely cause of this body’s urethral
stricture is?
1.
2.
3.
4.
5.
Carcinoma
Chronic narrowing
Congenital narrowing
Intermittent urolithiasis
Trauma
0%
1
0%
0%
2
3
0%
4
0%
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Urethral strictures
•Mostly secondary to trauma: pelvic fx
•> rare: instrumentation,
infection(gonorrhea), congenital,
complication of balanitis, cancer
•SYMPTOMS: Straining to urinate, decrease in size and force of urine stream, persistent
sense of bladder fullness, urine dribbling, and freq and urgency of urination
•<2cm: endoscopic dilatation
Question 15


A 10y/o F presents to the ER with a 1 day hx of
brown urine. She reports no dysuria, urgency or
abdominal or flank pain. Her VS: T 98.8, BP:
165/97, HR: 84, RR: 20. On PE, moderate
periobital edema is evident, but here are no other
abnormalities. UA reveals: moderate blood, and 4+
protein.
The serum C3 concentration is low and the C4
concentration is normal.
Of the following, the most likely cause of
this girl’s hematuria is?
1.
2.
3.
4.
5.
Focal segmental
glomerulosclerosis
Immunoglobulin A nephropathy
Lupus nephritis
Membranous proliferative
glomerulonephritis
Postinfectious acute
glomerulosclerosis
0%
1
0%
0%
2
3
0%
4
0%
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Countdown

Gross hematuria + hypertension+ periorbital
edema+ decreased C3 and normal C4
PIAGN



Self-limited
C3 will be back to normal in 8wks
HTN sec to Na + water retention up to 3 months
Now…lets go for a case
Case


A 4mo M infant presents with a hx of poor wt gain and
irritability. FT, NSVD, Bwt:3.5kg. He was BF for 3 months
and appeared to have satisfactory wt gain initially. He
was then switched to formula feeds, which he has been
taking well. Mom says his diapers are always soaking
wet. His development has been normal and his vaccines
are UTD.
On PE, you find an infant that is thin with wt <5% and
ht <25%. He appears to be irritable, with midly sunken
anterior fontanel, an umbilical hernia and mild bilateral
tibial curvature.
Lab studies

Serum
Hb: 10.8; hct: 32.9%
 BUN 17, creat: 0.5
 Na: 148
 K: 3.7
 Cl: 114
 Bicarb: 20
 Calcium: 9.8
 Phosphorus: 5.5
 Alk Phos: 360
 Mg: 1.9
 Glucose: 72


Urine
S. gravity: 1.005
 Urine pH: 6.8
 Urine osm: 198

The serum osm on this pt is?
1.
2.
3.
4.
5.
296
302
306
300
None of the above
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Serum osmolarity

= 2Na + [(BUN/3) + (glucose/18)]
Normal: 285-295
The most likely cause for this infant’s failure
to thrive is?
1.
2.
3.
4.
5.
Metabolic acidosis because of renal
tubular acidosis an urinary concentration
defect
Nephrogenic diabetes insipidus
Bartter syndrome with polyuria
Gittelman syndrome
Liddle disease
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
Calculate anion gap
Diabetes insipidus:
Serum: HIGH Na + HIGH osmolarity
Urine: LOW Na+ LOW osmolarity
In this case, baby developed early because initially on breast milk
which has less sodium, less protein and less osmolar load, compared to
formula which has higher solutes.
While baby on breast milk  less water loss

Bartter syndrome: defect in
Na-K-2Cl cotransporter on
the loop of Henle

Loss of Na, K, Cl


Gitelman syndrome: older
children, defect in Na-CL
cotransport in the distal
convulated tubule

Loss of Na, K, Cl, Mg


Hypokalemic, hypochloremic
metabolic alkalosis
Hypokalemic, hypochloremic
metabolic alkalosis
Liddle syndrome: adolescents
and adults, upregulation of
Na channel in principal cell of
cortical convulated tubule


Excessive Na absorption with
hypoK due to exchange and
loss in urine
HTN/ deafness/ blindness
Other laboratory investigations that
may be helpful include:
1.
2.
3.
4.
5.
Spot urine calcium-to
creatinine ratio
Serum vasopressin
levels
Nasal vasopressin
(DDAVP) test
1 and 3
All of the above
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
Diabetes insipidus = ADH problem
 Nephrogenic:
insensibility to ADH
 Central: no production of ADH
 Do
a vasopressin test:
 Give
1 dose of DDAVP intranasal and collect urine over the
next 5hrs


Nephrogenic: unable to concentrate urine= persists low urine osm
(<200)
Central: + response with concentrated urine
The disease is most commonly inherited as?
1.
2.
3.
4.
5.
AR
AD
X-linked recessive
X-linked dominant
None of the above
* Remember the case
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
Congenital Nephrogenic DI
 90%
X-linked recessive
 Common


 10%
symptoms:
Hypernatremia
FTT on a baby switched from Breast Milk to formula
sec to mutation in aquaporin 2
This condition is most appropriately
treated with?
1.
2.
3.
4.
5.
Low-solute diet
Thiazide diuretics +
amiloride +
indomethacin
Thiazide diuretics +
indomethacin
All of the above
1 and 3
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Treatment GOAL avoid dehydration
1.
2.
Decrease solute load Free water replacement,
change to breast milk
ADD diuretics: Thiazides
 Add
K-sparing diuretic: amiloride
 Add prostaglandin synthesis inhibitors: indomethacin

acts on mesangial cells in the glomerulus increasing GFR