Clinical aspects of nephrolithiasis Flashcards
Epidemiology of nephrolithiasis
•Incidence: –3-4/1000men/year –1-2/1000women/year •Lifetime risk –12% in men –6% in women •Age –30-60 in men –20-30 in women
Types of stones based on composition
•Calcium stones (80%) –Calcium oxalate –Calcium phosphate •Uric acid stones (5-10%) •Struvite(Mag/Ammonium/phosphate) stones (10-15%) •Cystinestones (less than 1%)
Types of stones based on location
- Kidneys
- Ureter
- Bladder
Etiology of nephrolithiasis
•Process of crystallization
–Too much solute
–Too little solvent (water)
–“Other” physical conditions (stasis, ph)
Risk Factors for Stone Formation
•Calcium stones
–Hypercalciuria •Higher salt in the diet •Higher non-dairy animal protein diet •High Sucrose content in the diet •Hyperparathyroidism •HypercalciuricHypocalcemia
–Hyperoxaluria •Increased intake in high oxalate-containing food •Decreased in oral calcium intake –Hypocitraturia –High urine pH •RTA type I –Low urine volume
Decreased in oral calcium intake
low calc in diet, bc it binds oxalate out of the absorption process, so it doesnt get absorbed, so dont have too much or too little calcium
major risk factors for calcium stone urinary
lower volume higher calcium higher oxalate lower citrate higher ph
major risk factors for calcium stone anatomic
medullary sponge kidney
horseshoe kidney
majore risk factors for calcium stone diet
lower fluid intake lower dietary calcium higher oxalate lower potassium higher animal protein higher sodium higher sucrose higher fructose lower phytate higher vitamin c
medical condition at risk for calcium stones
primary hyperparathyroidism
gout
obesity
diabetes mellitus
Risk Factors for Stone Formation
•Uric acid stones
–Hyperuricemia/hyperuricuria •Gout •Polycythemia Vera •Tumor lysissyndrome –Low urine pH •obesity, type 2 diabetes mellitus, and high non-dairy animal protein intake
metabolic syndrome - htn, obesity, cholesterol, uric acid, hyerglycemia
Risk factors for stone formation struvite stones
–Chronic UTI with ureaseproducing bacteria (Proteus or Klebsiella)
these bacteria produce ammonia by urease
risk factor for cysteine stones
cystinuria autosomal recessive disorder
Clinical Manifestation of stones
•Asymptomatic during formation •Renal colic when stone moves through and/or obstructs one of the ureters •Micro-or macro-hematuria •Sometimes associated with UTI –Fever/leukocytosis/pyuria/sepsis
paind from spasm in a hollow organ
pt cant get comfortable keep moving around trying to get comfortable
Renal colic
- Sudden
- Acute
- Severe
- Non-remitting with positional changes
- Abdominal or back pain
- Unilateral
Differential Diagnosis
- Acute cholecystitis
- Acute appendicitis
- Acute cystitis/pyelonephritis
- Acute diverticulitis
- Muscular or skeletal pain
- Herpes zoster
- Duodenal ulcer
- Abdominal aortic aneurysm
- Ureteralobstruction by materials other than a stone
- Pelvic Inflammatory Disease
Diagnosis
•Usually based on clinical presentation •Urine: RBC, WBC, crystals •Leukocytosis, ARF •Imaging –Plain film: May show Calcium stones –IVP—used less frequently now –CT-renal protocol—gold standard –US—may show intrarenalstones and/or hydronephrosis. Not sensitive for ureteralstones
Treatment
- Treatment of acute attack
- Treatment after acute attack
- Prevention of recurrences
Treatment of acute attacks
•Medical Therapy –Pain control –Nausea control –Propulsive therapy •Calcium channel blockers •Alfa-blockers - tamsulosin •Surgical Therapy –Ureteroscopywith stone removal and stent placement –Percutaneousnephrostomy
under 5 mm?
95% will pass
Treatment after acute attack
ECWL (lithotripsy) if large stones
nephrostomy
Prevention of Recurrences overview
•Analyze the stone
•Collect the information about dietary preferences and fluid intake
•Serum Ca, Phosphorus, uric acid
•If Ca is elevated, do hypercalcemiawork-up
–PTH, Vit D level, Protein electrophoresis
•24 urine collection for Ca, urate, oxalate, citrate
•Increase fluid Intake
•Dietary Modification
Prevention of Recurrence calcium stones
–Calcium Stones
•Adequate dietary Calcium intake
–From food, not from supplements
–Not too much, not too little
–Likely binds oxalate and prevents its absorption
•Restriction of nondairy animal protein (e.g., meat, chicken, seafood)
•Avoidance of spinach (the highest oxalate-containing food).
•Reducing sodium intake to less than 3g/day
–It will decrease concurrent urinary excretion of calcium
–Decreasing sucrose intake, which may increase urinary calcium excretion
•Increasing potassium-rich foods.
Prevention of Recurrences
•Uric Acid Stones
–Increasing urine pH by
•Reducing the intake of animal proteins
•Increasing the intake of alkali-rich foods (fruits and vegetables)
•Oral bicarbonate
Prevention of Recurrences
•Medications
–Thiazides
•Increase calcium reabsorption and decreases urine Calcium
–Allopurinol
•Decreases uric acid in the serum and urine
–Potassium Citrate
–Magnesium
•Forms
Gestational Age
number of weeks of pregnancy from last normal menstrual period
AGA (Appropriate for Gestational Age)
birth weight between the 10thand 90thpercentiles for a given gestational age
SGA (Small for Gestational Age)
birth weight
LGA (Large for Gestational Age)
> 90thpercentile for the given gestational age
LBW (Low Birth Weight Infant)-
an infant who weighs
VLBW (Very Low Birth Weight Infant
Infant)-
Preterm
term
Term-38-42 weeks gestation
postterm
Post-term->42 weeks gestation
infant death
a death occurring any time from birth to but not including 1 year of age
perinatal death
a death occurring between the 28thweek of gestation and 28thday of life
Fluid Considerations in the Newborn
•Total Body Water (TBW)
–In early fetal development TBW constitutes almost 95 % of total body weight
–At birth in the term infant TBW is approximately 75% of the total weight
–During the first week of life term infants will typically loss about 10% of their birth weight
–After decreased urinary output in the first 24-48 hours a diuresis occurs with loss of extracellular water
–In preterm infants the weight loss can be up to 15%
Sodium Balance in the Newborn
- Total sodium content determines the volume of ECF. So renal sodium handling is a critical component in maintaining proper volume
- Sodium is freely filtered by the glomerulus and almost completely reabsorbed in the tubular system
- In term infants, like adults fractional sodium excretion is
Parameters Associated with Fluid Management in the Newborn
- Urine output-1-3 ml/kg/hr
- Hypernatremia-Sodium > 150mmol/L
- Hyponatremia-Sodium
Signs of excessive water loss
–Excessive wtloss –Dry oral mucosa –Sunken anterior fontanelle –Capillary refill > 3seconds –Tachycardia –Decreased BP –Metabolic acidosis
Acute Renal Failure
- Definition of ARF in the newborn is based on a rapid elevation in the concentration in the blood of BUN, creatinine and other cellular waste products resulting from diminished GFR
- Cannot define a specific creatinine level to call ARF as measurements immediately after birth reflect the mother’s creatinine as well as the infant
- Normal creatinine levels depend on gestational age
- Urine output can be used as an indicator of ARF-usually less than 0.5 ml/kg/hour
Acute Renal Failure in the Newborn
•PrerenalCauses
–Sepsis –Hypovolemia –Hemorrhage –Hypoxia Ischemia –Cardiac Failure –Hypotension –Hyperviscosity
Renal (Intrinsic ) Causes
•ATN –Hypoxia-ischemia –Toxins •Drugs –Aminoglycosides –Contrast Agents •ACE inhibitors •Vascular –Renal vein or artery thrombosis •Congenital parenchymal disease •Maternal drugs •Transient acute renal failure of the newborn
Post Renal Causes (Obstructive)
•Congenital obstruction –Ureteral –Urethral –Bladder –Pelvic mass •Calculi
Fundamental Knowledge
- Hypernatremicdehydration in the neonatal period is well described arising from disproportionate deficit of body water relative to body sodium coupled with the extracellular water loss that occurs in this age range
- Most common cause is lactation failure
- Infants can loose water through the skin at a rapid rate, especially with non bullous ichthyosis
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