nephro Flashcards
enuresis
-Bedwetting is common
-~ 20% in first grade occasionally wet bed
-4% wet bed 2+ times/week
-Most are continent at night within 2 years of achieving daytime control
-Each year of age, frequency of bedwetting decreases -> by 15yo, 1-2%
-repeated urination into clothing during the day and into bed at night by a child > 5yo
-Pattern of urination must occur at least 2x a week x 3 months
enuresis: monosymptomatic
-ONLY AT NIGHT
-Uncomplicated, nighttime enuresis (NE)
-Must never have been dry at night x 6 mo, with no daytime accidents
-Reflection of maturational disorder (delay in maturation of urologic and neurologic systems) without underlying disorder
-Causes: Genetic factors, do not awake to sensation of full bladder, overproduction of urine (decreased desmopressin or ADH resistance – bladder empties before filled)
-Evaluation: H&P (anatomic abnormalities, pathology, or presence of constipation), UA (specific gravity), urine culture
-Tx:
-Education and avoidance of shaming
-Behavioral: Limiting fluids before sleep, awakening child at night/bedwetting alarms (66% cure rate) -> Continued x 3 months, every night
-bedwetting alarms = waking child to go pee regularly
-Desmopressin acetate or ADH analogue, imipramine (TCA)
-DDAVP decreases urine production
enuresis: non-monosymptomatic
-Involves NE and daytime incontinence, often reflecting underlying disorder
-Daytime continence achieved by 70% by 3yo and 90% by 6yo
-Consideration of underlying pathology: Cystitis, DI, DM, seizure disorders, neurogenic bladder, anatomical abnormalities
-Tx underlying cause
urinary tract infections
-Approx 8% of girls and 2% of boys
-Girls > 6mo have UTIs far MC than boys, whereas uncircumcised!! boys < 3mo have more UTIs than girls (circumcision reduces risk of UTI)
-Density of distal urethral and periurethral bacteria correlates with risk of UTI in children
-Most infections ascend
-MC pathogens are fecal flora: E. coli (> 85%), Klebsiella species, proteus species, other gram-negative bacteria; less frequently, Enterococcus or coagulase-negative staphylococci
urinary tract infections: pathogenesis
-Dysfunctional voiding (uncoordinated relaxation of urethral sphincter) -> incomplete emptying of bladder -> increased risk of bacterial colonization
-Anything that interferes with complete emptying of bladder: CONSTIPATION, vesicoureteral reflux (VUR), urinary tract obstruction, neurogenic bladder
-Poor perineal hygiene, structural abnormalities, catheterization, instrumentation of the urinary tract, sexual activity
-Pyelonephritis may produce renal parenchymal scars -> HTN, renal disease, and renal failure
urinary tract infections: VUR
-Congenital abnormality ~ 1% beyond infancy
-Graded using international scale (dont need to know):
I – Reflux into ureter
II – Reflux to kidneys
III – Reflux to kidneys with dilation of ureter only
IV – Reflux with dilation of ureter and mild blunting of renal calyces
V – Reflux with dilation of ureter and blunting of renal calyces
-30-50% presenting with UTI at 1yo and younger
-Reflux typically improves – 80% of grades I-III will resolve/improve in 3 years
-Debate on value of surgical intervention/prophylactic antibiotics
urinary tract infections: sx
-Newborns/infants: Fever, hypothermia, jaundice, poor feeding, irritability, vomiting, FTT, sepsis; strong, foul-smelling urine
-Preschool children: Abdominal/flank pain, vomiting, fever, urinary frequency, dysuria, urgency, enuresis
-School-aged children:
-Signs of cystitis: Frequency, dysuria, urgency
-Signs of pyelonephritis: Fever, vomiting, flank pain
-CVAT is unusual
-Physical: BP, abdominal, GU exam
UTI: labs
-Screening UA: Pyuria, leukocyte esterase, nitrites
-!!!Most have negative nitrites (70%) bc requires several hours for bacteria to convert ingested nitrates to nitrites in bladder
-Urine cx is gold standard (as long as properly collected)
-Toilet-trained: Midstream, clean-catch specimen
-Infants/younger children: Bladder catheterization or suprapubic collection
-Bagged specimens only for screening (if negative)
-!Positive results:
-SPT: Any growth
-Catheterization: > 50K cfu/mL
-Clean-catch: > 100K cfu/mL
UTI: imaging
-Type/timing of imaging studies in infants/children after first UTI remain controversial
-no longer recommend routine voiding cystourethrogram (VCUG) or Lasix renogram in infants between 2-24 months after first UTI
-Renal US should be performed in all infants following first febrile UTI (to screen for congenital urologic anomalies)
-Finding of significant hydronephrosis or another anomalies warrants further imaging
-Sensitivity for detection of VUR varies
UTI: Tx
-< 3mo and those with dehydration, toxicity, or sepsis: Hospital admission for parenteral antibiotics
-Older infants/children: Outpatient management
-Uncomplicated UTIs: First generation cephalosporin (cephalexin first-line), amoxicillin, trimethoprim-sulfamethoxazole x 7-10 days (longer end for suspected pyelonephritis)
-Highly concentrated in lower urinary tract > provides good coverage
-Sexually mature teenagers: Fluoroquinolones x 3 days
-Complicated UTIs: Parenteral, third-generation cephalosporin or aminoglycoside
-Initial antibiotic may be adjusted after C&S results are known
-Prophylactic antibiotics:
-Selected children with frequently occurring UTIs may benefit
-Those with high-grade VUR (V), dysfunctional voiding
-Trimethoprim-sulfamethoxazole and nitrofurantoin approved for prophylaxis
glomerulonephritis
-Various types with similar manifestations: Hematuria, urinary RBC casts, HTN, and edema
-Hematuria may be microscopic or gross (coffee- or tea-colored)
-Protein excretion may be normal (Pr/Cr ratio < 0.2) to nephrotic (Pr/Cr ratio > 2)
-Edema (periorbital, facial, extremities, ascites) occurs due to salt and water retention with impaired glomerular function > HTN (glomerular inflammation and renin production)
-Require evaluation of BP, renal function, serum albumin, urine protein excretion, C3 levels (to differentiate most likely cause), renal bx
acute post-infectious glomerulonephritis
-Dx of acute poststreptococcal GN is supported by recent infection within preceding 7-14 days (MC with GABHS)
-If positive culture is not available > infection may be supported by elevated titer of antistreptococcal antibodies (ASO)
-Associated with depressed serum C3 complement and normal C4
-Manifestations range from asymptomatic microhematuria to gross hematuria with nephrotic range proteinuria and AKI
-No specific treatment
-Antibiotic therapy if active infection documented
-BP monitoring
-Edema: Reduction in salt intake, diuretics, or CCBs
-Renal failure: HD or peritoneal dialysis
-In most cases, full recovery occurs and complement levels return to normal in 6-8 weeks, microscopic hematuria may persist for as long as a year
hemolytic uremic syndrome
-MC glomerular cause of acute renal failure in childhood
-Diarrhea-associated form (typical form) is usually the result of infection with Shiga toxin-producing strains of shigella or E. coli – MC pathogen is E. coli O157:H7
-Ingestion of undercooked ground beef/unpasteurized foods is a common source
-Bloody diarrhea is the usual presenting complaint, followed by hemolysis, thrombocytopenia, and renal failure
-Toxin > endothelial damage > platelet deposition/consumption > microvascular occlusion with subsequent hemolysis
-Clinical Manifestations
-Prodrome of abdominal pain, diarrhea, and vomiting > then, oliguria, pallor, and bleeding manifestations (GI)
-Anemia may be profound
-Shistocytes (RBC fragments) seen on blood smears
-High reticulocyte count, increased LDH, low haptoglobin (consistent with hemolysis)
-Severe thrombocytopenia
-Hematuria and proteinuria often present
hemolytic uremic syndrome: complications and tx
-Complications
-Acute kidney injury
-Seizures, PRES from hyponatremia, HTN, or CNS vascular disease
-Thrombosis from endothelial damage (despite thrombocytopenia)
-Treatment
-Attention to fluid and electrolyte status is critical
-No antimotility or antibiotic agents!
-May worsen release of Shiga toxin
-Timely dialysis improves prognosis
-RBC transfusions often necessary (EPO may reduce this need)
-Prognosis
-Most children recover from acute episode within 2-3 weeks
-Residual renal disease (HTN, proteinuria, CRI) in 30%
-End-stage renal failure in 15%
-Overall mortality (with CNS or cardiac complications) 3-5%
idiopathic nephrotic syndrome of childhood
-MCC is minimal change disease (MCD) in children
-MCD: Minimal changes noted with light microscopy, effacement of podocytes on electron microscopy
-Other causes: Focal segmental glomerulosclerosis (FSGS) and membranous nephropathy
-Clinical Manifestations
-Affected patients generally younger than 10 years at onset
-Typically, periorbital swelling and oliguria are noted > within several days, increasing edema (possibly anasarca) evident > dyspnea/massive ascites may occur
-Urine sediment usually normal
-Gross hematuria more common with FSGS than MCD
-Plasma albumin low > lipid levels increased (increased hepatic lipogenesis)
-Complications: Infections, hypercoagulability, HTN, renal insufficiency
-Treatment: Corticosteroids, QD x 6 weeks (tapered)
-May add calcineurin inhibitor (tacrolimus) or mycophenolate mofetil to achieve steroid discontinuance while maintaining remission
-Goal is disappearance of proteinuria
-No response > renal bx for further evaluation
ambiguous genitalia: normal sexual development
-Internal and external genitalia formed between 6 and 13 weeks gestation
-Fetal gonad and external genitalia are bipotential and have the capacity to support development of a normal male or female phenotype
-Presence of gene SRY (on Y chromosome) > fetal gonad differentiates into a testis > testosterone production > DHT production (via 5a-reductase)
-Enlargement, rugation, fusion of labioscrotal folds into a scrotum
-Fusion of ventral surface of penis to enclose urethra
-Enlargement of phallus with development of external male genitalia
-Mullerian-inhibitory substance > Regression of Mullerian ducts and derivatives (fallopian tubes/uterus)
-In presence of testosterone > Wolffian ducts develop into vas deferens, seminiferous tubules, and prostate
-Female phenotype develops unless specific male influences alter develop
ambiguous genitalia: abnormal sexual development: 46, XX Disorders of Sexual of Development
-Masculinization of the external genitalia of genotypic females is always caused by presence of excessive androgens during the critical period of development
-Mild clitoral enlargement to development of a male phallus with penile urethra and fused scrotum with raphe
-MCC of female ambiguous genitalia is congenital virilizing adrenal hyperplasia (ACTH hypersecretion > hyperplasia of adrenal cortex > excessive adrenal production of androgens)
Ambiguous Genitalia: Abnormal Sexual Development: 46, XY Disorders of Sexual of Development
-Underdevelopment of male external genitalia occurs because of a relative deficiency of testosterone production or action
-Small penis, varying degrees of hypospadias (associated chordee, ventral binding of phallus)
-B/L cryptorchidism may be present
-Androgen Resistance/Androgen Insensitivity Syndrome
-46, XY karyotype
-Normal formed testes (usually in inguinal canal/labia majora)
-Female external genitalia with short vagina and no internal Mullerian structures
-At puberty: Breast development without growth of pubic, facial, or axillary hair or the occurrence of menstruation (estrogen unopposed by androgen)
-5a-reductase deficiency
-Presents at birth with predominantly female phenotype or with ambiguous genitalia
-At puberty: Secondary male sexual development occurs
ambiguous genitalia: approach to infants
-Goal is rapid identification of any life-threatening disorders
-Classic approach to sex assignment has been based on feasibility of genital reconstruction and potential fertility, but effects of prenatal androgen must be considered
-Recommended to wait until child can be part of the dialogue regarding gender identity and reconstruction when appropriate
-Treatment should be individualized and managed by a team
ambiguous genitalia: dx and tx
-Dx:
-First step: Determine whether findings represent virilization of genetic female (androgen excess) or underdevelopment of genetic male (androgen deficiency)
-Virilized females:
-Most have CAH; 90% of these females with 21-hydroxylase deficiency
-Diagnosis made by measuring plasma concentration of 17-hydroxyprogesterone and androstenedione (typically 100 x normal)
-Underdeveloped males:
-Adrenal hyperplasia with defects in androgen production of testes, excessive ACTH secretion > elevated levels of adrenal steroid precursors
-Limited to testosterone biosynthesis: Measurement of testosterone and precursors in basal state + after stimulation by HCG
-Normal levels of testosterone: Androgen resistance or interruption of normal morphogenesis of genitalia
-Treatment
-Hormone replacement: Cortisol (adrenal hyperplasia), testosterone
-Surgical restoration
-Psychologic support of family
phimosis/paraphimosis
-90% of uncircumcised males -> foreskin retractable by adolescence
-Prior to adolescence -> prepuce may be tight and doesnt require tx
-Following this age:
-Inability to retract -> phimosis
-May be congenital or result of inflammation
-Rarely symptomatic
-Tx:
-Reassurance (loosening of prepuce by puberty)
-Topical steroid if needed
-If narrowing is severe > gentle stretching
-Circumcision reserved for most severe cases
-Paraphimosis: Prepuce retracted behind coronal sulcus, cannot resume normal position > causes swelling of the glans/pain (venous stasis)
-Tx:
-When discovered early: Retraction of foreskin may be possible with lubrication
-In some cases, circumcision may be needed
circumcision
-Elective (religious/social) procedure performed only in healthy, stable infants
-Medical benefits: Prevention of UTIs, decreased incidence of penile cancer, decreased incidence of STDs
-Risks: Local infection, bleeding, removal of too much skin, urethral injury (< 1 % incidence of complications overall)
-Contraindication: Genital abnormalities
-Coagulation screen prior to procedure in those with family history of serious bleeding disorders
balanoposthitis
-Combination of inflammation of glans penis (balanitis) and inflammation of the foreskin (posthitis)
-MC in uncircumcised males as a result of poor hygiene, local/recurrent irritation, or infection (Candida, Gardnerella, or Streptococcus pyogenes)
-May be sole presenting symptom of DM
-History: Thorough PMHx and FHx; associated systemic symptoms
-Physical: Retract foreskin and inspect underlying glans, looking for erythema, warmth, discharge
-Dx: Glucose test, cultures
-Tx:
-Regular cleansing of the glans with soap/water with foreskin retracted
-Topical antifungal cream (nystatin, clotrimazole)
-PO abx if bacterial infection suspected
hypospadias
-Occurs in ~1 in 500 newborn infants
-Urethral folds fail to fuse completely over urethral groove, leaving urethral meatus ventral and proximal to normal position; ventral foreskin also lacking
-Often occurs alone, but may be associated with a chordee – fixed, ventral curvature of penile shaft
-Causes: Genetic and environmental factors that interfere with androgenic stimulation
-Clinical Manifestations/Treatment
-Meatal opening may be anterior (glans, coronal, or distal third of shaft), on middle third of shaft, or posteriorly (near scrotum)
-Should not be circumcised if meatus is proximal to glans (foreskin may be necessary for later repair)
-Most pediatric urologists repair hypospadias before 18 months of age
