Nephrology Flashcards
What is the most common cause of severe obstructive uropathy in Prune-Belly Syndrome?
Posterior urethral valves
What are the electrolyte changes seen in cystinosis?
Pure proximal tubular disorder
- Losses of sodium, potassium, citrate, bicarb, phosphate, vitamin D, copper and carnitine
What clinical features are seen in cystinosis?
- Presents usually in first 6 months of life
- Renal findings first
- Eye findings (cysteine crystal deposition)
- Bones become infiltrated with cysteine crystal laden granulomas - fractures, rickets, bony pain, genu valgus
- Chiari 1 malformation
- Premature skin aging
What is the gold standard for confirming cystinosis?
HPLC mass spec forleucocyte cystine content
Can also do genetic screen for mutations in CTNS gene
What treatment is available for children with cystinosis?
Supportive measures:
○ Substitution of urinary lost compounds
○ Nutritional support - prevention of rickets and improvement of growth
§ Free access to water, Na, K, citrate or bicarb, P, vitamin D, Cu, Carnitine
§ goal: 130% of recommended daily intake
○ Hormonal replacement therapy
§ Growth hormone
§ Levothyroxine for hypothyroidism
§ Insulin
○ ACE-i for proteinuria
Treatment: Cystine-depleting therapy by use of cysteamine (PO or topical)
What is the most common manifestation of end-organ damage as a result of hypertension?
LVH
Will also likely see increased carotid intima-media thickness, hypertensive retinopathy, microalbuminuria
What are some common renovascular causes of hypertension in children?
- Fibromuscular dysplasia
- Syndromic → NFI, TS, Williams syndrome, Marfan syndrome
- Vasculitis → Takayasu disease, Polyarteritis nodosa, Kawasaki disease
- Other → radiation therapy, UAC, trauma, congenital rubella syndrome, transplant renal artery stenosis
How do you ensure an accurate BP measurement?
- Appropriate size cuff has bladder that take up 40% of arm circumference and should cover ⅔ of upper arm length and 80-100% of its circumference
- Child should be seated, quiet and in no distress
What is the diagnostic criteria for hypertension in a child?
SBP and / or DBP ≥ 95th percentile for age, sex, and height on ≥ 3 occasions
For children aged 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 or 130/80 to 139/89 mm Hg (whichever is lower)
- Stage 2 HTN: ≥95th percentile +12 or 140/90 (whichever is lower)
For children aged ≥13 y
- Normal BP: <120/<80 mm Hg
- Elevated BP: 120/<80 to 129/<80 mm Hg
- Stage 1 HTN: 130/80 to 139/89 mm Hg
- Stage 2 HTN: ≥140/90 mm Hg
How often should BP be checked in children?
• At least once a year in all children 3 or older
• At every health visit if the child has known or suspected diabetes, renovascular disease, CKD, or a predisposing condition linked to HTN
- in some cases, this may also involve checking for ketones and/or proteinuria
Can children with hypertension take part in competitive sports?
Children and adolescents with HTN may participate in competitive sports once hypertensive target organ effects and cardiovascular risk have been assessed
Children and adolescents with HTN should receive treatment to lower BP below stage 2 thresholds before participation in competitive sports
What tests should be done to assess renal function in the case of hypertension?
- For all children with hypertension:
• Blood chemistry (sodium, potassium, chloride, total CO2, and creatinine)
• Urinalysis
• Renal ultrasound - For children with HTN who need evaluation of cardiovascular risk:
• Fasting blood glucose
• Serum total cholesterol and high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides - For children with HTN who need assessment for target organ damage:
• Echocardiogram
• Retinal examination
• Albumin/creatinine ratio (first morning)
What are the clinical features of Denys-Drash syndrome?
- Risk of developing Wilm’s tumours
- Early-onset nephrotic syndrome
- Progressive renal insufficiency
- Ambiguous genitalia
In what conditions would you expect a decreased C3 level?
“MAPLES”
Membranoproliferative glomerularnephritis
Atypical HUS
Post-infectious glomerulonephritis (No. 1 most common)
Lupus
Endocarditis
Shunt nephritis
What are the 4 hallmark clinical findings of Henoch Schonlein Purpura?
Small vessel vasculitis, characterized by IgA deposition and leukocytoclastic vasculitis
1) Palpable purpuric rash
2) Joint pain
3) Renal disease (proteinuria/hematuria)
4) GI involvement
How long should you be monitoring a child with HSP for renal complications?
Throughout illness and up to 1-2 months afterwards: BP and urinalysis q weekly
Up to 6-12 months post recovery: q monthly
What treatment do you offer for children with HSP?
Mostly supportive management - may consider prednisone (short course, 1-2 mg/kg/day) in those with severe GI disease
What are some potential surgical complications of HSP?
- Intussusception
- Mesenteric ischemia
- Intestinal perforation
- Orchitis
- Testicular torsion
- Pulmonary hemorrhage
What is the definition of nephrotic range proteinuria?
• Proteinuria
○ > 40 mg protein/m2/hr or >1000mg/m2/day
○ >3+ protein on dipstick
○ >3-3.5 g in a 24 hr urine sample
○ >2.5-3 urine protein to creatinine ratio in a random sample
Nephrotic syndrome patients will also have:
• Hyperlipidemia cholesterol >200 mg/dL
• Edema
• Hypoalbuminemia ≤2.5 g/dL
What is orthostatic proteinuria?
- Increased urinary protein excretion during the day in tall, active, slender adolescents, which usually resolves when first morning sample is collected (disappears with supine position after at least 2 hours)
- Accounts for 60% of proteinuria in adolescents
- Benign condition
- Should be tested for proteinuria on a yearly basis
• If protein-creatinine ratio is >0.2 in a first morning urine, it is abnormal and indicates renal pathology
What are some benign causes for proteinuria?
- Febrile illness
- Seizures
- Extreme cold
- Stress
- Epinephrine administration
- CHF
- Abdominal surgery
- Strenuous exercise
In nephrotic syndrome, patients are at greatest risk of infection from which organisms?
Encapsulated organisms - mostly pneumococcus • S. Pneumoniae • N. Meningitidis • K. Pneumonia • H. Influenzae • Cryptococcus • Pseudomonas
Loss of complement factors (C3 and C5)
Why are children with nephrotic syndrome at greater risk of thromobotic events?
Loss of anticoagulant factors over pro-coagulant factors
§ Decreased antithrombin III
§ Decreased protein C and S
What are some causes of falsely elevated protein on urine dipstick?
- Alkaline or concentrated urine
- Pyuria
- Bacteuria
- Acidic urine
- High ammonia
What is the most common cause of chronic glomerular disease?
IgA Nephropathy
With respect to hydronephrosis, what are the grades of severity?
- Stage 0: no findings
- Stage 1: dilation of renal pelvis only. If >15 mm, associated with increased risk of disease
- Stage 2: dilation of pelvis with some calyceal dilation
- Stage 3: uniform dilation of renal calyces
- Stage 4: dilation of pelvis and calyces with thinning of renal parenchyma
How do you determine the grade of hydronephrosis?
- 2nd TM: Normal <=4mm (mild 4-<7mm, moderate 7-10, severe >10mm)
- 3rd TM: Normal <=7mm (mild 7-9, moderate 9-15mm, severe >15mm)
- Postnatal: Normal <=5mm (mild HN 6-9mm, moderate HN 10-15mm, severe HN >15mm)
How do you manage a child with known hydronephrosis post-natally?
- All children should get a follow up ultrasound at 2 weeks of life to reassess degree of hydronephrosis
- All children with SFU grade 3 hydronephrosis should receive prophylactic TMP until studies complete (US and VCUG)
- Prophylaxis should also be given to all children with bilateral hydronephrosis (suggestible for additional pathology i.e. PUV)
What is the difference between IgA nephropathy and PSGN?
- In IgA nephropathy, the renal changes occur during the acute illness, rather than a few weeks afterwards
- IgA nephropathy has normal C3 and C4 levels, C3 will be decreased in PSGN
What is the classic triad in Eagle-Barrett Syndrome?
- Abdominal wall laxity
- Bilateral cryptorchidism in males
- Urinary tract dysmorphisms (long, tortuous ureters due to replacement of smooth muscle with fibrous tissue, thick but disrupted smooth muscle of the bladder due to irregular collagen deposition etc.)
What anticipatory guidance is required for children with Prune Belly Syndrome?
Annual evaluation with • Renal US • Physical exam and assessment of somatic growth • Regular blood pressure checks • Urinalysis • Serum electrolytes
How to determine what type of RTA is occuring?
- Assess for normal anion gap (true RTA vs ingestion)
- Is K+ high or low? High suggests aldosterone mediated problem, resulting in RTA type 4
- If urinary pH >5.5 or <5.5?
- Type 1 and Type 2 respectively
What are the main differences between the different types of RTA?
- Type 1 - distal collecting duct issue; cannot secrete H+ ion, hypercalciuria
- Type 2 - proximal collecting duct issue; cannot reabsorb HCO3-, low serum phosphate
- Type 4 - decreased aldosterone secretion or resistant action to aldosterone, hyperK+
What is the most common type of renal stone in children?
Calcium oxalate (45-65%)
- Calcium phosphate (15-30%)
- Struvite (13%) - infection
- Cystine (5%)
- Uric acid (4%) - radiolucent
- Mixed/miscellaneous/Indinavir (4%)
Why are kidney stones more likely in children with Crohn’s disease or other intestinal malabsorption diseases?
- Inability to absorb fat leave it free to bind with calcium, leaving oxalate free to form oxalate stones
- These children also tend lose a great deal of water; persistent state of dehydration increases risk of kidney stones
What are the acute interventions that can be done to treat renal stones?
• Pain management: NSAIDS, opioids
• Hydration: IV
• Medications
○ Glucocorticoids (instilled into bladder) - reduce edema
○ Alpha blockers (Tamsulosin 0.4 mg PO od) - dilates lower ureter
○ CCB (Nifedipine 0.5 mg/kg or long acting once daily) - inhibit stone-induced ureteral spasm :. maintain peristalsis
• Surgical intervention (urology)
○ ESW Lithotripsy: Break into smaller chunks (ESWL, percutaneous ultrasonic, electrohydraulic, laser)
○ PCN lithotomy (#1 - IR): nephrolithotomy (kidney), pyelolithotomy (renal pelvis), ureterolithotomy (ureter)
○ Ureteroscopy w/ basket extraction
What long term strategies are required to help prevent renal stones?
- Do no decrease calcium intake
- Increase fluid intake
- Increase K+ intake
- Decrease Na intake
- Reduce animal protein intake
What are the features of drug rash with eosinophilia and systemic symptoms (DRESS) syndrome?
○ Cutaneous eruption - severe exanthematous rash (edematous, pustular, purpuric), exfoliative dermatitis ○ Fever ○ Eosinophilia ○ Hepatic dysfunction ○ Lymphadenopathy ○ Nephritis ○ Carditis ○ Atypical lymphocytes
List interventional treatments for hyperkalemia
- Insulin + glucose
- Ventolin
- Lasix
- Kayexalate
- Dialysis
• must always include cardioprotection: continuous monitoring and calcium gluconate
VCUG Quick facts
- Injection of contrast into bladder via urethral catheter. Flouroscopy during bladder filling & voiding
- Indications: Assess for VUR (M & F) & PUV (M)
- Advantages: Provides anatomical detail of refluxing collecting systems, bladder & urethra. Allows for IRS grading (VUR grade I-V) (unlike a NC)
- Disadvantages: Invasive (catheter). Radiation.
Nuclear Cystogram Quick facts
- Injection of radionuclide into bladder via urethral catheter. Gamma camera imaging during bladder filling & voiding.
- Indications: Initial assessment for VUR in F only. Follow-up of VUR in both M & F
- Advantage: Potentially less radiation than VCUG (can take multiple pictures, not radiation with each picture the way you do in a VCUG, although the latter is improving)
- Disadvantages: Invasive (catheter). Radiation. Does NOT assess for PUV. Therefore, should NOT be 1st line cystogram for a M w/ congenital hydronephosis or UTI
Renal Scan Quick facts
- IV injection of radionuclide. Gamma camera imaging of kidney uptake +/-excretion
- Indications: Different radionuclides for different indications; All provide differential renal function (DRF)
- A diuretic is only used for assessing obstruction
- Only DMSA detects renal scarring
- Advantages: Provides “functional” information re: filtering urine and drainage
- Disadvantages: Invasive (IV +/-urethral catheter). Radiation. Child must be held still for clear pictures
Note: Use of catheters & IV sedation varies among centres
MEG3 Renal Scan Quick Facts
- Dynamic renal scan → shows function and differential renal function (tubular)
- Will tell you about obstruction (produces a clearance picture) (<10 secs is normal, >15 sec is obstruction)
- Very small risk of UPJ obstruction in contralateral kidney
DMSA Scan Quick Facts
• Does not give you any information on function
• Any area that isn’t working will not take up tracer
○ Will generally be a picture of scarring but cystic kidneys and pyelonephritis may also appear as ‘‘low tracer without volume loss’’
• Should be done 6 months after last infection
What is the classic clinical features of hemolytic uremic syndrome? (3)
- Microangiopathic hemolytic anemia
- Thrombocytopenia
- Renal insufficiency
Common causative agents of HUS?
- Infectious: E. coli (O157:H7), strep pneumoniae
- Drugs: quinine, clopidogrel, OCPs, calcineurin inhibitors
- Genetic: deficiencies of vWF–cleaving protease (ADAMTS13) or complement factor H, I, or B, and defects in vitamin B12 metabolism
When treating HUS, what considerations re: blood products, must be taken?
- Do not give platelets - rapidly consumed and may worsen thrombotic events in blood vessels
- RBCs given to treat anemia should be washed in the case of pneumococci-associated HUS
What is the inheritance pattern of Alport Syndrome?
• X-linked
What are the clinical features of Alport Syndrome?
- Bilateral sensorineural hearing loss (not congenital)
- Asymptomatic hematuria
- Ocular abnormalities (anterior lenticonus)
- Leiomyomatosis
What are the clinical manifestations of Bartter Syndrome?
- Hypokalemia, metabolic alkalosis with hypercalciuria and salt-wasting
- Present as babies
- Dysmorphic features: triangular facies, protruding ears, large eyes with strabismus, drooping mouth
- Older children may have hx of recurrent episodes of polyuria w/ dehydration
What is the most common cause of an abdominal mass in a newborn?
Multicystic dysplastic kidney disease
- Unilateral (as bilateral is incompatible with life)
- Not inherited
- Parenchyma is not functional
What are the potential side effects of Furosemide?
• Electrolyte abnormalities: HypoK, metabolic alkalosis
• Over-diuresis
• Hypersensitivity (furosemide is a sulfonamide)
○ Rash, interstitial nephritis (if present, can use ethacrynic acid instead – non sulfonamide)
• Ototoxicity: +/- permanent deafness
○ High dose IV, renal failure OR concurrent aminoglycoside
• Nephrotoxicity
• Photosensitivity
• Nephrocalcinosis
What are the findings in minimal change disease?
- proteinuria 3+ with no or microscopic hematuria
- presents between 1-6 years of age
- normal C3 and C4
- hypercholesterolemia
- hypercoagulable
What is Nutcracker Syndrome?
Unilateral bleeding of varicose veins of the left ureter resulting from compression of the left renal vein between the aorta and superior mesenteric artery (mesoaortic compression)
• Persistent microscopic hematuria +/- proteinuria
• Recurrent gross hematuria
• L flank pain or LLQ pain particularly with exercise
○ Increased blood flow during exercise –> increased renal flow –> varicose veins may rupture leading to hematuria
Test of choice: U/S with dopplers and looking at the blood flow post SMA
