endocrine and kidney diseases - ventimiglia

• Stone disease requires surgical treatment but is caused by underlying metabolic abnormality
• Addressing the primary cause prevents problem recurrence

Clinical Case & Risk Factors

• Stone disease can occur in pediatric and young patients
• A 24-year-old woman with a family history experienced stone disease
• The stone composition from her first episode was unassessed
• She then had two relapses
• Not all stone formers have the same risk
• High-risk stone formers often have:
  • Family history
  • Frequently recurring stones
  • Specific stone types
• Management involves treating the stones and the underlying causes

Lecture Concepts

• Lithogenesis is the formation of stones from a pathophysiological viewpoint
• Types of urinary stones represent different pathophysiological conditions
• Focus on metabolic alterations related to stone formation
• Also focus on therapeutic interventions

Epidemiology of Stone Disease

• Stone disease is prevalent worldwide, affecting over 10% of the population in specific countries
• A person with a prior stone episode has 50% risk of recurrence
• It is possible to prevent up to 80% of recurrent cases, by understanding the causes
• Though benign, it is the 3rd leading cause of end-stage renal disease in the US requiring dialysis

Stone Formation Factors

• Stone formation happens in urine due to an imbalance of components
• Crystal growth and aggregation leads to stones when urine reaches supersaturation
• Processes that drive stone formation:
  • Infectious diseases
  • Foreign bodies
  • Inductors of crystallogenesis
• Types of crystals are similar, suggesting therapeutic intervention possibilities
• Calcium oxalate is a typical species already in urine
• Risk is related to component concentration, not just presence

Super Saturation Crystallization Theory

• High concentrations increase the chances of crystal aggregation, leading to stone formation
• Crystal formation is concentration and pH dependent, especially uric acid
• Uric acid stones can be dissolved by alkalizing urine
• Crystal aggregation depends on size and location

Crystal Formation Inhibitors

• Early phase of crystal formation has inhibitors already in urine
• Crystal formation can arise from the lack of inhibitors
• Main inhibitors:
  • Citrate
  • Magnesium
  • pH regulation of urine
• Inhibitors of growth, aggregation, and retention of crystals
• Citrate is a powerful agent for prevention and reoccurrence

Promoters of Crystallization

• Promoters of crystallization include:
  • Already existing crystals
  • Randall plaques
  • Protein matrix
  • Necrotic epithelial cells
  • Foreign bodies
• Foreign bodies can facilitate crystallization

Randall's Plaques

• Randall's plaque is an anatomical component of the kidney
• It is in the renal papilla, the most distal part of the nephron
• They are nucleation centers for some stone types but are not sufficient to form stones alone
• 74% of stone formers have Randall's plaques, versus 43% in non-stone formers

Clinical Cases

• A 56-year-old male with spontaneous passage of monohydrate calcium oxalate stones and Randall plaques
• Tiny stones indicate Randall's plaques are the culprit
• Randall's plaques are not surgically treatable, recurrence is high

Foreign Bodies

• Foreign bodies contacting urine cause crystal aggregation
• Stitches after kidney surgery can lead to crystal growth

Crystals Balance

• Crystals in urine can aggregate:
  • Dependent on balance between crystals and inhibitors
  • Increased crystal concentration due to dehydration leads to stone formation

Surgical Stone Removal

• Surgically removed stones leave plaques behind
• Removal of plaques with lasers burns important kidney parts and has drawbacks

Types of Stones & Prevention

• Different stones require different preventive strategies
• Calcium oxalate monohydrate stones are common and easily prevented
• Struvite stones are infectious and can become very large

Lifestyle & Genetics

• Identical patients with identical lifestyles can still develop stone disease
• Genetics play a role
• For most patients, good health is not enough for prevention
• A good lifestyle includes hydration and avoiding high-risk foods

Morpho-constitutional Classification

• Morpho-constitutional classification is an easy method to classify stones
• Developed by Michel Daudon
• It is morphological classification, surface and section appearance matters
• It is constitutional, stone composition requires infrared spectroscopy

Stone Analysis

• Stone analysis is paramount:
  • Chemical species are not only what matters
  • Type of crystals is also important
• Best analysis method is through infrared spectroscopy
• Provides information on chemical and crystal species

Stone Classes & Formation

• Classification with 6 classes and 2 types of stones determines the cause
• Knowing the cause helps to fix the problem and prevent future stone formation
• Coexisting causes for stone formation can exist in a single person

Common Stones

• Most common stones consist of type I, type II, and type III
• Calcium oxalate monohydrate is the most frequent stone, accounting for 50% of encountered stones

Risk Factors for Calcium Oxalate Monohydrate

• Low diuresis
• High diet oxalate intake
• Low calcium intake, leading to high oxaluria
• Reduced calcium causes increased oxalate absorption

Typical Encounters

• Encounters often show young adults consuming high amounts of chocolate
• They also have low daily urine outputs, environement may play a factor
• They need to drink and pee a lot

Patient Recommendations

• Recommending to drink water is a great way to decrease concentration
• Increase of calcium increases calcium content

High Oxalate

• Chocolate contains a lot of oxalates
• Some fruits and vegetables have high content
• Patients will miss many nutrients to reduce intake
• Reduce by 200 grams per day instead of quitting completely

Less Frequent Causes of CaOx Monohydrate

• Bowel resection
• Chronic diseases
• Primary hyperoxaluria

Calcium Oxalate Dihydrate

• Calcium oxalate dihydrate is not hyperoxaluria dependent
• It arises from high calcium concentrate in the urine
• Hypercalciuria is due to high intake of:
  • Animal proteins
  • High salts
  • Metabolism related issues

Animal Proteins

• Excessive protein has impact on stone formation
• Can cause acidity needing to be balanced by bones using bone buffering
• The process causes calcium reabsorption and elimination
• Causes temporary, high intake

Key Intake Limit

• Limit of 0.8milligrams per kilogram of body weight
• Most should keep a relatively easy intake limit

High NaCl Intake

• High salt intake causes high urinary stones, as it inhibits resorption
• It enhances high calcium and goes hand in hand with it
• It is important to lower animal protein intake
• Diets with lower sodium levels are helpful

Primary Hyperparathyroidism

• Primary hyperparathyroidism is common in woman
• Usually arises after 50 years of age
• Often causes renal colic
• Most comes from bone remineralization

Bone Remineralization

• Bone remineralization causes bone diseases such as osteoporosis

Uric Acid

• Common stones are uric acid stones
• Tend to encounter patients with hypertension, high BMI and high uric acid levels in blood
• Also are reliant on pH
• Acidic levels cause greater risk

What to Eat

• Cut dietary intake of uric acid or purines
• Avoid organs, red meat, alcohol and sweetened beverages
• Also intake plenty of water

Low pH

• Low pH is poorly soluble with uric acid
• Try to increase it to about 6.5-7
• This causes an impaired benefit

Stones and Infections

• Stones often come with fever
• Most are from ureter blockage
• Pyelonephritis is a medical urgency

Bacterial Growth

• Some bacteria is involved by:
  • Calcium phosphate
  • Other combines
• The most important is struvite

No Sterile Environments

• Antibiotics can't treat bacteria from entering the urine stream
• If there is stone-fever and blockage- this is a medical urgency

Bacteria & Metabolized Urea

• Certain bacterias produce urease to metabolize urea
• This leads to struvite or ammonium
• Treating wont make the stones for free, needs life long treatment

Recessive Diseases

• Cystineuria is caused by an autosomal recessive disease
• Accounts for only 1% of encounters
• Reliant on pH
• High water intake is recommended

Dietary Recommendation

• Avoid methionine and animal products
• Try to force the intake of water per day

Kidney Disease

• Cystineuria is very hard to treat
• Most patients will deal with disease and dialysis over time

Basic Kidney Assessments

• Bloods will assess functions related to kidney
• Urinalysis is another assessment

Urinalysis Information

• Specific gravity
• pH

Key Consideration

• pH and density matter due to fluid and kidney actions

Volume

• Volume matter due to direct and indirect diet action

Primary Assessments

• Creatine and important
• Sodium and calcium
• Urea and uric acid
• Oxalate
• Citrate

Other Factors

• Patients will cheat tests and need a direct approach
• Volume often needs more than 2L of fluid
• Try to get to know them a little to encourage more drinking

Hypercalciuria

• Try to avoid too much high protein intake with high salt
• Pay close attention and be aware

General Goals

• Lower kidney stones and high urea value
• Change lifestyles and avoid future stones