Nephrology Flashcards
What is the most common renal stone?
Calcium Oxalate
Teenager Found to have struvite stone…what is the next step?
Urine Culture
Struvite calculi
UTIs caused by urea-splitting organisms result in urinary alkalinisation and excessive production of ammonia -> precipitation of magnesium ammonium phosphate (struvite) and calcium phosphate
In the kidney, the calculi often have a staghorn configuration, filling the calyces
Often are seen in children with neuropathic bladder, particularly those who have undergone a urinary tract reconstructive procedure
Bacteria result in alkaline urine -> tx it by acidifying the urine! e. Urologic removal of struvite calculi is generally required to eradicate the underlying infection. Persistent infection, usually due to a urease-producing bacteria (eg, Proteus or Klebsiella), is a risk factor for recurrent stone formation.
A boy with family history of renal stones, presents with 24-48h right flank pain. Passed a 5 mm stone determined to be calcium oxalate.
Name 4 dietary interventions you would recommend to decrease the risk of further stones
- Increase fluids
- Increase citrate in diet (eg add lime/lemon/orange to water)
- Normal calcium intake (do not restrict calcium)
- Low sodium intake (urinary calcium is excreted with urinary sodium)
- Minimize use of furosemide/steroids/excess vit D
- Consider thiazide diuretic to decrease calciuria or potassium citrate to augment stone inhibition
A 12-year-old girl who has had cola-colored urine for 3 days is brought to your office.
Temp 37.7°C, RR 26 breaths/min, HR 110 beats/min, BP 140/90 mm Hg. P/E significant for mild edema. Normal growth parameters.
U/A: >100 RBC, 10-20 WBC, and 2-3 granular casts per HPF.
What diagnosis do you suspect?
Post Infectious GN
PIGN has what complement variations?
low C3 level and normal C4 level
What are the clinical features of glomerularnephritis?
cola-colored urine microscopic hematuria hypertension edema proteinuria
SLE has what complement profile
Low C3…BUT SYSTEMIC ILLNESS
IgA Nephropathy has what complement profile
Normal C3…renal limited disease
HSP has what complement profile
Normal C3…but systemic illness
Alport has what complement profile?
Normal C3 but systemic illness
In PIGN how long does it take for resolution of the following?
How long does it take for resolution of the following?
Gross hematuria
Proteinuria
Low C3
Microscopic hematuria
Gross hematuria: 1-2 weeks
Proteinuria: shortly after gross hematuria
Low C3: 6-8 weeks
Microscopic hematuria: up to 1 year
What type of RTA is this? has HYPERCALCIURIA → renal stones Urine pH = alkalotic >5.5 (can’t excrete H+ so urine alkalotic) Hypokalemia Hypocitraturia
Type 1 = distal
What type of RTA is this?
Hypokalemia
No stones
Urine pH = alkalotic, then acidotic
Can be isolated acidosis
Can be associated with other tubular defects: Fanconi
- Hypophosphatemia
Rickets/osteomalacia
- Aminoaciduria
- Glucosuria
- FTT or short stature
Type 2 = proximal
What type of RTA is this? Urine Acidic pH (<5) Hyperkalemia Congenital – hypoaldo/pseudohypoaldosterone Medications – ACE inhibitors
Type 4
14 month male, FTT, vx, met acidosis, pH 7.31, bicarb 14, K 3.5, Na 140, Cl 118, urine pH 7.3. Dx?
Distal RTA (can’t excrete H ions so urine alkalotic)
What’s the most common condition associated with type II (proximal) RTA?
Cystinosis
What is Fanconi Syndrome?
Excess amounts of things in the urine Amino aciduria Glucosuria (no hyperglycemia) Phosphaturia --> hypophosphatemia Uric aciduria FTT (from acidosis) Hypokalemia
Think genetic disorders Cystinosis Galactosemia Fructose intolerance Tyrosinemia Wilson's Lowe's (oculocerebrorenal syndrome)
CPS UTI mangement
CPS statement first febrile UTI > 2mos of age No known renal/urological pathology Urinary symptoms or unexplained fever Urine culture and analysis Catheter or mid stream Unlikely UTI if analysis has no pyuria Treat 7-10 days oral if can tolerate po
What imaging needs to be done if first febrile UTI 2months- 2 years of age
Ultrasound
During or within 2 weeks of presentation
Less invasive, available, less expensive
VCUG Pursue if renal abnormalities, obstruction, signs of VUR on RUS or second UTI Hydronephrosis, hydroureter Small kidneys Thick walled bladder Renal parenchyma abnormal – scars, cysts
What is cystinosis?
AR Lysosomal storage disease Accumulation of cysteine in various organs Cysteine dimers accumulate in lysosomes 1 in 100,000 children No increased risk of stones
How do you confirm diagnosis of cystinosis?
Leukocyte cysteine
What is the pathophysiology of Type 4 RTA?
Either impaired aldosterone production or impaired renal responsiveness to aldosterone
Can present with growth failure in the first few years of life
Polyuria and dehydration = common
Hyperkalemic non-anion gap MA
What does aldosterone do?
Aldosterone functions (at kidney level):
Secretes H+, secretes K+
Reabsorbs Na
No aldosterone = high potassium
What is the main cause of Type 1 RTA?
Idiopathic
What is the main defect in Type 1 RTA?
Inability of the distal tubule to secrete Hydrogen Ion
What is the main defect in Type 2 RTA?
Decreased Ability of proximal tubule to reabsorb bicarb.
List some medications that can cause Hypertension
Corticosteroids Decongestants Nonsteroidal anti-inflammatory medications Herbal supplements β-adrenergic agonists Erythropoietin Cyclosporine Tacrolimus Stimulants *Recent discontinuation of antihypertensive medications
What is needed to determine normal range of blood pressure?
Age
Gender
Height
What are the BP Stages for children 1-13 y
Normal BP: <90th percentile
Elevated BP: ≥90th percentile to <95th percentile or 120/80 mm Hg to <95th percentile (whichever is lower)
Stage 1 HTN: ≥95th percentile to <95th percentile + 12 mm Hg or 130/80–139/89 mm Hg (whichever is lower)
Stage 2 HTN: ≥95th percentile + 12 mm Hg or ≥140/90 mm Hg (whichever is lower)
What are the BP Stages for Children > 13
Normal BP: <120/<80 mm Hg
Elevated BP: 120/<80–129/<80 mm Hg
Stage 1 HTN: 130/80–139/89 mm Hg
Stage 2 HTN: ≥140/90 mm Hg
What do you do after you identify their BP based on their stage?
Normal/Elevated BP: Repeat q 6 months. Lifestyle counselling.
Stage 1 HTN
A. Repeat 1-2 weeks. up to 3 months. Lifestyle counselling. Treat if persistent at 3 months.
Stage 2 HTN: Repeat in office. Treat. Refer to subspecialist
A 14-year-old boy presents for a health supervision visit. The boy is doing well at school, and his parents have no concerns. His vital signs include a temperature of 37.7°C, heart rate of 65 beats/min, respiratory rate of 14 breaths/min, and blood pressure of 120/74 mm Hg. His growth parameters and physical examination findings are normal. The boy’s mother, age 38 years, was recently diagnosed with autosomal dominant polycystic kidney disease (ADPKD). His 55-year-old maternal grandfather has end-stage renal disease secondary to ADPKD, and is currently receiving dialysis.
Of the following, the extrarenal manifestation MOST likely to be seen with this disease is: Biliary dysgenesis Cerebral aneurysm Lenticonus Portal fibrosis
Cerebral Aneurysm
AR Polycystic Kidney Disease Presentation
Autosomal recessive
Manifests in infancy
Large flank masses
Potter syndrome
Resp distress from pulmonary hypoplasia
Potter faces (flattened ears/nose, micrognathia from oligohydramnios)
U/S
Large echogenic kidneys w decreased “corticomedullary differentiation”
macrocysts are NOT typically seen- Unlike ADPKD
Extrarenal manifestations
Liver fibrosis
Congenital
Extrahepatic portal HTN
AD Polycystic Kidney Disease Presentation
Autosomal dominant
usually asymptomatic in childhood
Dx when renal cysts detected incidentally
Can present with: Persistent microscopic hematuria HTN Flank pain UTI (serum Cr = normal!) Renal function is normal until 4th decade of life
Extrarenal manifestations Cerebral aneurysms (most common) hepatic/pancreatic/seminal vesicle cysts Cardiac valve diseases Abdo wall hernia Colonic diverticula
What is Prune Belly Syndrome
Partial or complete absence of the abdominal wall muscles -> wrinkled abdominal wall
Cryptorchidism
Urinary tract abnormalities
B/L hydroureteronephrosis
Enlarged bladder with thick walls (collagen deposits) and abnormal bladder pressures
Varying degrees of renal dysplasia
~30% develop ESRD requiring renal replacement therapy with dialysis or renal transplant
Hypoplastic or dysplastic prostate
Anomalies of the musculoskeletal, gastrointestinal, and cardiopulmonary systems
NO GENE IDENTIFIED
7 year old with microscopic hematuria most likely dx?
Hypercalciuria. Usually idiopathic 30%
What is this:
An inherited disorder of basement membrane collagen characterized by involvement of the kidneys (always), ears (often), and eyes (occasionally)
Persistent hematuria (microscopic, macroscopic) = earliest symptom and universal symptom
Proteinuria and hypertension can accompany
Can have SNHL and Anterior lenticonus lens
Alport Syndrome
What is the inheritance of Alport Syndrome?
Most common inheritance: X-linked (*Maternal Uncle)
Males affected
Female carriers
What is Alport Syndrome
An inherited disorder of basement membrane collagen characterized by involvement of the kidneys (always), ears (often), and eyes (occasionally)
Persistent hematuria (microscopic, macroscopic) = earliest symptom and universal symptom
Proteinuria and hypertension can accompany
Can have SNHL and Anterior lenticonus lens
What makes the prognosis in a kid with hematuria worse?
Associated Proteinuria
What are some benign causes of proteinuria?
Orthostatic proteinuria
Transient proteinuria: fever, stress, exercise, cold, abdominal surgery
How do you diagnose orthostatic proteinuria?
Benign
Occurs when children are active and disappears when they are supine/asleep for at least 2 hours
Diagnosed with absence of proteinuria in three consecutive first morning U/A
A urine protein-creatinine ratio greater than 0.2 in a first-morning sample is abnormal
Bright red blood in urine usually indicates what?
Bright red hematuria is usually indicative of lower urinary tract bleeding
Cola/tea coloured urine usually indicates what?
glomerular hematuria (as in nephritis) is commonly described as cola, tea, or brown colored.
A 10 year old child has type 1 diabetes which was diagnosed at age 3 years old. When should they start screening for diabetic nephropathy and how?
YEARLY screening starting at age 12 years in those with T1DM for > 5 years
First morning or random ACR
Most likely origin for abdominal mass in newborn?
Renal (55%)
Most likely cause of abdominal mass in newborn?
- Hydronephrosis (#1)
2. Multicystic dysplastic kidney
Most common cause of MIDLINE mass in newborn?
Mesenteric Cyst
First line imaging of abdominal mass?
Abdo Ultrasound
Ultrasound has many advantages over CT or MRI in this situation. They are:
A. generally harmless
B. less expense
C. no sedation
D. ability to perform at the bedside
How much Na, Cl and osm is in a bag of NS?
154 meq/L Na
154 meq/L Cl
Osm= 154+ 154= 308
What is the equation for insensible losses?
400mL/m2
How do you calculate BSA?
square root of height x weight /3600
How much glucose do you need in a day?
4-6mg/kg/min
What is a normal Anion Gap?
<12
How do you calculate Anion Gap?
Na-Cl-HCO3
What are two conditions that present with a non anion gap metabolic acidosis?
A. Renal tubular acidosis
B. Gastroenteritis
What are the characteristics of proximal RTA?
Proximal RTA • Urine pH<7 • Acidosis – HCO3 15 • Often hypoNa • Can have hypoPhos • Glucosuria • Mild tubular proteinuria or generalized aminoaciduria • Fanconi’s syndrome
What are the characteristics of distal RTA?
- Urine pH>7
- Acidosis – HCO3 can go below 10
- Sodium usually normal
- Nephrocalcinosis may be present
Most common cause of Type 1 RTA (distal)
Idiopathic
Familial Secondary • Ifofamide • Valporate • Amphotericin • Lupus • Obstructive uropathy • Renal dysplasia • Lithium Carbonate
Most common cause of Type 2 RTA (proximal)
– Metabolic • Cystinosis = most common • Glycogen storage diseases • Wilson’s • Tyrosinemia • Galactosemia
Idiopathic
Acquired • Ifosfamide • Carbonic anhydrase inhibitors • Lead • Paroxysmal nocturnal hemoglobinuria
Type 4 RTA causes
Aldosterone Deficiency – CAH – Acute GN – ACEI – NSAIDs
Aldosterone Resistance – Spironolactone – Dysplasia – CKD – Pseudohypoaldosteroni sm
How to treat distal RTA?
Potassium Citrate
Checking for hearing loss
Genetic testing
What is the single most important risk factor for future loss of kidney function
Proteinuria
What is the most common cause of proteinuria in pediatrics?
Transient proteinuria
• Exercise
• Fever
• Infection
Prevalence: 5 -15%
Definition of persistent Proteinuria
Defined as proteinuria on 2 or 3 separate samples take 1-2 weeks apart
How can falsely negative and positive dipsticks happen for protein?
Does not measure the actual amount…just the concentration
Concentrated sample - protein may look much higher than it actually is
dilute sample - may look higher than actual
How do we normally assess proteinuria in peds?
Protein/creatinine ratio
What are the normal protein/creatinine rations in children?
Normal:
Infants (< 2 years of age) – Upc < 50 mg/mmol
Children (> 2 years of age) – Upc < 20 mg/mmol
Most common cause of proteinuria in adolescents?
Orthostatic Proteinuria
How do you assess orthostatic proteinuria?
Assess with two separate night and daytime sample
If AM sample Upc < 20, diagnosis can be made
