1
Q
How are an individual’s maintenance fluid requirements calculated?
A
- 100 mL/kg/d for the first 10 kg of body weight
- 50 mL/kg/d for the second 10 kg of body weight
- 20 mL/kg/d for each additional kilogram
- more if they have excess insensible losses as in respiratory distress or if febrile
2
Q
What is the maintenance sodium and potassium requirement?
A
- sodium is 2-3 mEq/kg/d
- potassium is 1-2 mEq/kg/d
3
Q
In what two ways do we classify dehydration?
A
- based on severity or degree
- and based on serum sodium concentration as hypo-, iso-, or hypernatremic
4
Q
Rehydration of a hemodynamically unstable patient always begins with what?
A
a 20 mL/kg bolus of isotonic saline or LRs
5
Q
Over what time period do we typically correct dehydration? Why?
A
- over 24 hours for hyponatremic or isonatremic dehydration to prevent central pontine myelinolysis
- over 48 hours for hypernatremic dehydration to prevent cerebral edema
6
Q
What is the reasoning behind oral rehydration therapy?
A
- it is a combination of glucose and electrolytes
- intestinal absorption of sodium and other electrolytes is enhanced by the active absorption of glucose through co-transport
- this cotransport process continues to function normally even in cases of secretory diarrhea while other sodium absorption pathways are impaired
7
Q
For which patients is oral rehydration therapy insufficient?
A
- those with severe dehydration
- those with paralytic ileum or GI obstruction
- those with extremely rapid stool losses or repeated severe emesis losses
8
Q
How do we define microscopic hematuria?
A
as 6 or more RBCs per high-power field, detected on three or more consecutive samples
9
Q
Why is hematuria defined as 6 or more RBCs per high-power field, detected on three or more consecutive samples?
A
because, like proteinuria, many children have transient microscopic hematuria and a single positive test is not considered evidence of pathology
10
Q
RBC casts are indicative of what?
A
glomerulonephritis
11
Q
How does RBC morphology alter the interpretation of microscopic hematuria?
A
- if the RBCs originated in the glomerulus, they are usually dysmorphic with blebs in the RBC membrane
- those that appear normal more likely originated form the lower urinary tract
12
Q
What does it mean if a patient has a urinary dipstick positive for blood but no RBCs are found on microscopic urinary analysis?
A
since dipsticks pick up hemoglobin and myoglobin, it is suggestive of hemoglobinuria or myoglobinuria without hematuria
13
Q
How do we test for proteinuria?
A
- a 24 hour urinary protein collection is most accurate but difficult
- instead, we use a random spot uric total protein-to-creatinine ratio
- TP/CR should be less than 0.5 if 6-24 months old and less than 0.2 if older
14
Q
What is a normal TP/CR?
A
less than 0.5 if the individual is 6-24 months old and less than 0.2 if they are older
15
Q
What is benign transient proteinuria?
A
transiently increased urinary protein excretion associated with vigorous exercise, fever, dehydration, and congestive heart failure in children
16
Q
What is orthostatic proteinuria?
A
- a benign condition in which there is an increase in urinary protein excretion while upright but not supine
- diagnosed based on an elevated afternoon TP/CR but normal first-morning urine TP/CR
17
Q
What is the difference between glomerular proteinuria and tubular proteinuria?
A
- glomerular is caused by an increase in permeability of the glomerular capillaries to large molecular weight proteins
- tubular proteinuria is decreased reabsorption of low molecular weight proteins, especially B2-microglobulin, by tubular epithelial cells
18
Q
What does finding B2-microglobulin in the urine suggest?
A
it is a low molecular weight protein that filters but is usually entirely reabsorbed through the tubular epithelium; because of this, finding it in the urine is indicative of tubular proteinuria and suggests a pathology such as interstitial nephritis, ischemic renal injury, or tubular injury form a nephrotoxic drug
19
Q
What is a nephritic syndrome?
A
characterized by glomerular damage due immune complex deposition, activation of complement, C5a-mediated neutrophil chemotraction
- proteinuria is limited (< 3.5 g/day)
- oliguria and azotemia
- salt retention with periorbital edema and hypertension
- hematuria and RBC casts
20
Q
What are the signs and symptoms of nephrotic syndrome?
A
- a syndrome of hypoalbuminemia, hypogammaglobulinemia, a hyper coagulable state, and hyperlipidemia/hypercholesterolemia due to glomerular dysfunction
- protein loss contributes to pitting edema, loss of Ig increases the risk of infection, antithrombin III loss increases coagulability, and lipids may result in fatty casts in urine
21
Q
Poststreptococcal Glomerulonephritis
A
- also known as acute proliferative glomerulonephritis
- presents with it is a nephritic syndrome of hematuria, proteinuria, hypertension, and edema 2-3 weeks after a group A, beta-hemolytic strep infection
- diagnosis is based on clinical features, low serum complement, and detection of a prior strep infection with ASO or ADB titers
- renal biopsy is only indicated if the patient has significant renal impairment or nephritic syndrome
- glomeruli appear hyper cellular on light microscopy and granular, subepithelial deposits of IgG, IgM, and C3 are identified on EM
- treatment is supportive as children rarely progress to renal failure; this means fluid restriction, antihypertensive meds, and protein, sodium, potassium, and phosphorus restriction
22
Q
IgA Nephropathy
A
- the most common nephropathy worldwide
- it is due to IgA complex deposition in the mesangium
- presents during childhood with episodic hematuria with RBC casts present in urine, typically following mucosal infections
- diagnosed via renal biopsy which shows mesangial proliferation and increased mesangial matrix on light microscopy
- treatment is supportive
23
Q
Membranoproliferative Glomerulonephritis
A
- presents as a nephritic syndrome or as a nephrotic syndrome with hematuria as well as low serum complement
- type I is characterized by subendothelial deposits and an associated with HBV and HCV
- type II is characterized by intramembranous, “ribbon-like” deposits and C3 nephrotic factor (an antibody that stabilizes C3 convertase; see low levels of C3 in patient)
- light microscopy reveals a “tram-track” appearance
- IF reveals granular immune complex deposition
- there is no definitive treatment and most patients develop end-stage renal disease
24
Q
Describe the pathogenesis that leads to hypercholesterolemia as a part of nephrotic syndrome.
A
- reduced plasma oncotic pressure induces increased hepatic production of plasma proteins, including lipoproteins
- at the same time, plasma lipid clearance is reduced because of reduced activity of lipoprotein lipase in adipose tissue
25
Most mortality associated with nephrotic syndrome is caused by what?
- thrombosis following the loss of antithrombin III
| - S. pneumoniae infection following the loss of immunoglobulins
26
Describe four steps that should be taken in the management of nephrotic syndrome.
- IV infusion of 25% albumin
- implementation of a salt restriction
- corticosteroids for MCD; use cyclophosphamide or cyclosporine for steroid-resistant patients
- blood culture to evaluate for pneumococcal infection if the child is febrile
27
Minimal Change Disease
- the most common cause of nephrotic syndrome in children
- usually idiopathic, but may be associated with Hodgkin lymphoma
- glomeruli appear normal on light and electron microscopy, but effacement of foot processes can be seen on EM
- proteinuria is selective (only albumin)
- respond extremely well to steroids, suggesting damage is mediated by cytokines
28
Hemolytic Uremic Syndrome
- endothelial damage due to drugs or infection (primarily shiga toxin-producing bacteria like E. Coli, O157:H7), which results in the pathologic formation of platelet microthrombi, consuming platelets and shearing RBCs
- often presents with a diarrheal prodrome, if shiga toxin-mediated, followed by sudden onset hemolytic anemia, thrombocytopenia with mucocutaneous bleeding, and acute renal failure
- other findings include increased bleeding time, normal PT/PTT, elevated LDH, decreased haptoglobulin, and schistocytes present on blood smear
- treat with plasmapheresis and corticosteroids; transfusions as necessary; manage renal failure
- antibiotics are contraindicated in cases driven by shiga-like toxin
29
Alport's Syndrome
- an X-linked dominant type IV collagen defect
- results in thinning and splitting of the glomerular basement membrane, leading to progressive nephritis
- presents with hematuria, hypertension, sensory hearing loss, and ocular disturbances
- treated with ACE inhibitors to slow renal disease, management of hypertension, and eventually renal transplant
30
Medullary Cystic Kidney Disease
- an autosomal dominant defect leading to cysts in the medullary collecting ducts
- fibrosis of the parenchyma results in shrunken kidneys (as opposed to the enlarged, cystic kidneys of PKD)
31
Autosomal Recessive PKD
- an inherited defect leading to bilaterally enlarged kidneys with cysts in the renal cortex and medulla
- presents in infants as worsening renal failure with hypertension and possibly Potter sequence
- associated with congenital hepatic fibrosis, leading to portal hypertension and hepatic cysts
- requires transplantation
32
Autosomal Dominant PKD
- an inherited defect leading to bilaterally enlarged kidneys with cysts in the renal cortex and medulla
- due to an APKD1 or APKD2 mutation
- presents in young adults as abdominal pain, flank masses, hypertension, hematuria, and worsening renal failure with cysts developing over time
- associated with berry aneurysm, hepatic cysts, and mitral valve prolapse
33
What defines significant, severe, malignant, and essential hypertension?
- significant: greater than the 95th percentile
- severe: greater than the 99th percentile
- malignant: with evidence of end-organ damage
- essential: without a clear etiology
34
How should blood pressure be measured in infants and children?
- infants should be measured while supine
| - children and adolescents should be seated
35
What are the two most common causes of hypertension in children 1-10 and in adolescents 10-18?
- children: renal diseases and coarctation of the aorta
| - adolescents: renal diseases and essential hypertension
36
Renal Tubular Acidosis
- an inability of the kidney to maintain normal acid-base balance, either congenital or acquired
- symptoms vary based on the type of RTA but growth failure, vomiting, recurrent calculi, muscle weakness, bone pain, myalgia, and nephrocalcinosis are common
- presents as a hypercholremic, non-anion gap, metabolic acidosis
37
Type I Renal Tubular Acidosis
- an inability of the kidney to maintain normal acid-base balance
- due to an inability of the distal renal tubular alpha-intercalated cells to excrete acid
- secondary to amphotericin B toxicity, analgesic nephropathy, congenital anomalies of the urinary tract, or SLE
- presents with vomiting, growth failure, acidosis, and nephrocalcinosis
- labs find urine pH > 5.5 and serum potassium low
- treated with small doses of oral alkali
38
Type II Renal Tubular Acidosis
- an inability of the kidney to maintain normal acid-base balance
- due to impaired bicarbonate reabsorption by the proximal renal tubular cells
- secondary to fanconi syndrome, multiple myeloma, heavy metal ingestion, or carbonic anhydrase inhibitors
- presents with vomiting, growth failure, acidosis, and muscle weakness
- labs find urine pH < 5.5 as the kidneys try to compensate, and serum potassium is low
- treated with large doses of oral alkali
39
Type III Renal Tubular Acidosis
- an inability of the kidney to maintain normal acid-base balance
- it is a variant of type I due to an inability of the distal renal tubular alpha-intercalated cells to excrete acid but also complicated by proximal tubular bicarbonate wasting during infancy
- due to an inability of the distal renal tubular alpha-intercalated cells to excrete acid
- presents with vomiting, growth failure, acidosis, and nephrocalcinosis
- labs find urine pH > 5.5 and serum potassium low
- treated with large doses of oral alkali
40
Type IV Renal Tubular Acidosis
- an inability of the kidney to maintain normal acid-base balance
- presents as a transient acidosis in infants and children with hyperkalemia as the hallmark
- secondary to obstructive uropathy or aldosterone deficiency
- may be asymptomatic or present with failure to thrive
- labs find urine pH < 5.5 as the kidneys try to compensate, and serum potassium is high
- treated with furosemide to lower serum potassium as well as with oral alkali
41
How do we define oliguria?
as a urine output less than 1 mL/kg/hr
42
How should renal failure be managed?
- intravascular volume should be restored first and then total fluid intake should be restricted to the patient's insensible losses plus output only
- protein intake should be restricted
- patients should be monitored with daily weights, frequent BP measurements, calculation of Is and Os, and monitoring of electrolytes
- dialysis may be necessary if conservative management fails
43
What happens to BUN/Cr, FENa, and urine osmolality in someone with pre-renal azotemia?
- when RBF decreases, BUN reabsorption is enhanced and the BUN/Cr increases > 15
- since tubular function is intact, FENa is normal (<1%) and urine osmolarity is normal (>500 mOsm/kg)
44
What happens to BUN/Cr, FENa, and urine osmolality in someone with post-renal azotemia?
- in the early stage, increased tubular pressure enhances BUN reabsorption, and the BUN/Cr increases > 15
- in the early stage, tubular function is also normal with FENa < 1% and urine osmolarity > 500mOsm/kg
- with long-standing obstruction, tubular damage ensues and the BUN/Cr falls, FENa rises, and there is an inability to concentrate urine
45
Prerenal Acute Renal Failure
- caused by a reversible decrease in renal perfusion that leads to a reduction in GFR
- may be secondary to dehydration, hemorrhage, congestive heart failure, shock, or hypoproteinemic states
- BUN/Cr ratio increases, urine specific gravity increases, urine osmolarity increases, and FENa is normal
46
Intrarenal Acute Renal Failure
- may be due to damage to the glomerulus as in PSGN, lupus nephritis, or HUS; in these cases, it presents with hematuria and proteinuria
- may be due to damaged to the tubules (aka acute tubular necrosis) following ischemic injury with an increase in urinary B2-microglobulin and FENa above 1%
- may be due to damage to the interstitium (aka acute interstitial nephritis) following exposure to various drugs and presenting with eosinophilia, eosinophilia, and an increase in urinary B2-microglobulin
47
Acute Tubular Necrosis
- the most common cause of acute renal failure
- due to ischemia or nephrotoxicity in the form of aminoglycosides, heavy metals, myoglobinuria as in crush injury, ethylene glycol, radio contrast dye, or urate from tumor lysis syndrome
- injury results in necrosis of tubular epithelial cells, which form brown, granular casts and diminish GFR
- tubular dysfunction leads to elevated BUN and Cr, though the BUN/Cr is < 15, FENa > 1%, and Osm < 500
- clinical features include oliguria as well as hyperkalemia and acidosis due to the inability to secrete these cations
- reversible but requires supportive dialysis since electrolyte imbalances can be fatal
- recovery takes 2-3 weeks as tubular cells are stable and take time to re-enter the cell cycle
48
Acute Interstitial Nephritis
- an intra-renal azotemia (acute renal failure)
- characterized as a drug-induced hypersensitivity affecting the interstitium and tubules
- most commonly due to the 5 P's: Pee (diuretics), Pain-free (NSAIDS), Penicillins, Proton pump inhibitors, and rifamPin
- presents with oliguria, fever, and rash lasting days to weeks
- uniquely, eosinophils may be seen in urine
- biopsy will reveal an inflammatory infiltrate in the interstitium
- may progress to renal papillary necrosis
49
Postrenal Acute Renal Failure
- due to an obstruction of urine flow from either the kidney(s) or urethra
- secondary to stones, tumors, ureterocele, urethral trauma, neurogenic bladder, or posterior ureteral valves in males
- presents with dilation of the renal collecting system visible on ultrasound
- in the early stage, increased tubular pressure enhances BUN reabsorption, and the BUN/Cr increases > 15
- in the early stage, tubular function is also normal with FENa < 1% and urine osmolarity > 500mOsm/kg
- with long-standing obstruction, tubular damage ensues and the BUN/Cr falls, FENa rises, and there is an inability to concentrate urine
50
How do we manage end-stage renal disease?
- nutritional management with avoidance of high phosphorus, high sodium, or high potassium foods
- administration of oral phosphate binders and vitamin D analogs to prevent renal osteodystrophy
- protein restriction
- blood pressure monitoring and management
- anemia treated with iron and EPO
- growth hormone if growth fails to normalize
- dialysis once GFR is less than 5-10% of normal
- transplant once available
51
What is prune belly syndrome?
a syndrome of absent rectus muscles, bladder outlet obstruction, and cryptorchidism
52
Renal Agenesis
- unilateral or bilateral absent kidney formation secondary to failure of the mesonephric duct or metanephric blastema to develop
- unilateral leads to hypertrophy of the existing kidney and increases risk of renal failure later in life
- bilateral leads to Potter sequence
53
Dysplastic Kidney
- a non-inherited, congenital malformation of renal parenchyma with cysts and abnormal tissue
- may develop from any congenital obstruction and is more common than renal agenesis
- usually unilateral, but the bilateral form must be distinguished from inherited polycystic kidney disease
- bilateral leads to pulmonary hypoplasia and in either case, there is an association with concentrating defects, renal tubular acidosis, and varying degrees of renal insufficiency
- a multicycstic dysplastic kidney is the most common cause of abdominal mass discovered in newborns
54
What is the most common abdominal mass discovered in newborns?
multicystic dysplastic kidney
55
Horseshoe Kidney
- a most common congenital renal anomaly, in which the kidneys are conjoined, usually at the inferior pole
- ascent of the kidneys is stopped by the inferior mesenteric artery, and they end up located in the lower abdomen
56
Duplex Collecting System
- a congenital renal anomaly in which the ureteric bud bifurcates before interacting with the metanephric blastema, creating a bifid ureter
- can also arise if two ureteric buds interact with the same metanephric blastema
- strongly associated with vesicoureteral reflux and ureteral obstruction, increasing the risk of UTI
57
Vesicoureteral Reflux
- caused by abnormalities of the ureterovesical junction, most often a short submucosal tunnel in which the ureter inserts through the bladder wall
- has autosomal dominant inheritance
- low grades typically resolve spontaneously while more severe forms may predispose to pyelonephritis and eventual reflux nephropathy with end-stage renal disease and hypertension
- diagnosed with voiding cystourethrogram
- treated with low-dose prophylactic antibiotics and surgical reimplantation of the ureters if severe
58
Nephrolithiasis
- a precipitation of a urinary solute as a stone
- presents with colicky pain, hematuria, and unilateral flank tenderness
- high concentration of solute and low urine volume are risk factors
- usually passed within hours but may require surgical intervention
- typically calcium oxalate, calcium phosphate, ammonium magnesium phosphate, uric acid, or cystine in nature
- rare in children and providers should look for a predisposing metabolic disorder
- risk factors include hypercalciuria, hyperoxaluria secondary to enteric malabsorption, distal RTA, hyperuricosuria, cystinuria, UTI and P. mirabilis in particular, or hyperparathyroidism
59
Calcium Oxalate/Calcium Phosphate Nephrolithiasis
- the most common type of kidney stone
- the urine crystals have an envelope shape
- usually due to idiopathic hypercalciuria or hyperoxaluria, which can be inherited or secondary to enteric malabsorption
- treatment is HCTZ, a calcium-sparing diuretic that enhances calcium reabsorption
60
Cystine Nephrolithiasis
- a rare form of kidney stone that most commonly presents in children
- associated with cystinuria, an autosomal recessive tubule defect resulting in poor cysteine reabsorption as well as poor reabsorption of ornithine, lysine, and arginine
- the urine crystals are hexagonal
- may form a radiopaque staghorn calculi
- treatment involves hydration and alkalinization of urine
61
Urinary Tract Infection
- before 6 months of age, most common in uncircumcised males followed by circumcised, followed by females
- E. coli is the primary pathogen involved by Klebsiella, Pseudomonas, Staph saprophytic, Serratia, Proteus, and Enterococcus are all common
- in neonates, symptoms include lethargy, fever, irritability, and jaundice, but in older infants symptoms include fever, vomiting, and irritability
- young children who are toilet-trained may present with nocturnal enuresis or daytime wetting
- older children with cystitis may present with dysuria, urinary frequency, or urgency and a low grade fever
- urine culture is the gold standard: infants require suprapubic aspiration or sterile urethral catheterization but older children can obtain a clean catch urine sample
- urine culture is considered positive for any growth with suprapubic aspiration, more than 10K colonies by sterile cath, and more than 50K colonies by clean-catch
- UA is also likely to find leukocytes or a positive nitrite or leukocyte esterase test
- imaging is only indicated in children with pyelonephritis, recurrent UTI, males, and girls younger than 4 years old
- treat with empiric antibiotics (usually TMP-SMX or cephalexin) in most cases; but neonates should be admitted for IV ampicillin and gentamicin; toxic-appearing children should receive IV antibiotics and fluids until improving at which point oral antibiotics can be used
- 7-10 days of antibiotics are used for cystitis; 14 days for pyelonephritis in addition to 3 months of low-dose prophylactic antibiotics
62
Cystitis
- a infection fo the bladder
- most often due to E. coli; Staph saprophyticus is characteristically seen in young, sexually active women; K. pneumoniae is a common agent; Proteus mirabilis is likely if the urine is alkaline with an ammonia scent
- presents with dysuria, urinary frequency, urgency, and suprapubic pain, but systemic symptoms are absent
- urine is cloudy with WBC, dipstick is positive for leukocyte esterase and nitrites, culture grows greater than 100K colonies
- sterile pyuria (cystitis with a negative urine culture) suggests urethritis due to Chlamydia trachoma's or Neisseria gonorrhoeae
63
Acute Pyelonephritis
- an infection of the kidney
- usually due to ascending infection secondary to vesicoureteral reflux
- presents with fever, flank pain, WBC casts, and leukocytosis in addition to the symptoms of cystitis
- most commonly due to E. coli, Enterococcus faecalis, or Klebsiella
64
Chronic Pyelonephritis
- recurrent pyelonephritis, usually due to vesicoureteral reflux or obstruction
- leads to interstitial fibrosis and atrophy of the tubules
- atrophic tubules contain eosinophilic proteinaceous material and resemble thyroid follicles (referred to as thyroidization of the kidney)
- cortical scarring at the upper and lower poles with blunted calyces is indicative of vesicoureteral reflux
Pediatrics BRS
flashcards
Decks in class (20)
# Cards
-
Chapter 5 - Inborn Errors95
-
Chapter 1 - Health Supervision53
-
Chapter 2 - Development and Behavior85
-
Chapter 3 - Adolescent84
-
Chapter 4 - Neonatology77
-
Chapter 9 - Pulm39
-
Chapter 8 - Cardio45
-
Chapter 15 - Allergy & Immunology28
-
Chapter 14 - Oncology37
-
Chapter 20 - Emergency Med90
-
Chapter 12 - Neurology61
-
Chapter 18 - Ophtho35
-
Chapter 6 - Endocrine79
-
Chapter 7 - ID51
-
Chapter 10 - GI60
-
Chapter 11 - Renal64
-
Chapter 13 - Hematology64
-
Chapter 16 - Rheumatology19
-
Chapter 17 - Ortho51
-
Chapter 19 - Derm45
