Nephrolithiasis

Overview

Definition

Nephrolithiasis (also known as kidney stones, urolithiasis, or urinary calculi) is the formation of stones anywhere along the urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy.

Classification

There are 5 main types of kidney stones:

• Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate stone:
  • Account for 75% of all kidney stones (most common type)
  • Envelope Envelope Bilayer lipid membrane acquired by viral particles during viral morphogenesis. Although the lipids of the viral envelope are host derived, various virus-encoded integral membrane proteins, i.e. Viral envelope proteins are incorporated there. Virology or dumbbell-shaped crystals
• Uric acid stone:
  • Account for 10% of all kidney stones
  • Rhomboid or rosette-shaped crystals
• Struvite (ammonium magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes) stone:
  • Account for 5%–10% of all kidney stones
  • “Coffin lid”-shaped crystals
• Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes stone:
  • Account for 5% of all kidney stones
  • Wedge-shaped prism
• Cystine stone:
  • Accounts for < 5% of kidney stones
  • Hexagonal crystals
  • Mnemonic: Pronounce cystine stones as “sixtine” stones (six-sided stones) to remember their shape.

Epidemiology

• More common in men than women
• Most common in White, non-Hispanic men
• Peak incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 45–70 years old, but can occur at any age
• Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency increases with age, with notable increase after the age 40.

Etiology

Normally soluble material supersaturates the urine and crystal formation begins.

Risk factors:

• Family history Family History Adult Health Maintenance
• Medical conditions:
  • Urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease (UTIs)
  • Cystinuria
  • Gout Gout Gout is a heterogeneous metabolic disease associated with elevated serum uric acid levels (> 6.8 mg/dL) and abnormal deposits of monosodium urate in tissues. The condition is often familial and is initially characterized by painful, recurring, and usually monoarticular acute arthritis, or “gout flare,” followed later by chronic deforming arthritis. Gout (high uric acid)
  • Hyperparathyroidism Hyperparathyroidism Hyperparathyroidism is a condition associated with elevated blood levels of parathyroid hormone (PTH). Depending on the pathogenesis of this condition, hyperparathyroidism can be defined as primary, secondary or tertiary. Hyperparathyroidism (high calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes levels)
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
  • Inflammatory bowel disease (IBD)
  • Short gut syndrome
• Diet:
  • High sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia: decreased sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia and calcium reabsorption Calcium reabsorption Tubular System in the proximal tubule Proximal tubule The renal tubule portion that extends from the bowman capsule in the kidney cortex into the kidney medulla. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the u-shaped loop of henle. Tubular System → hypercalciuria
  • High calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes
• Dehydration Dehydration The condition that results from excessive loss of water from a living organism. Volume Depletion and Dehydration: causes an excessive concentration of urine solutes → stone formation
• Medications:
  • Loop diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication: inhibits calcium reabsorption Calcium reabsorption Tubular System → hypercalciuria
  • Carbonic anhydrase Carbonic anhydrase A family of zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide. They play an important role in the transport of carbon dioxide from the tissues to the lung. Carbonic Anhydrase Inhibitors inhibitors → metabolic acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis which leads to increased urine pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance → calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes stone formation
    • Acetazolamide Acetazolamide One of the carbonic anhydrase inhibitors that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. Carbonic Anhydrase Inhibitors
    • Topiramate Topiramate A sulfamate-substituted fructose analog that was originally identified as a hypoglycemic agent. It is used for the treatment of epilepsy and migraine disorders, and may also promote weight loss. Second-Generation Anticonvulsant Drugs
  • Glucocorticoids Glucocorticoids Glucocorticoids are a class within the corticosteroid family. Glucocorticoids are chemically and functionally similar to endogenous cortisol. There are a wide array of indications, which primarily benefit from the antiinflammatory and immunosuppressive effects of this class of drugs. Glucocorticoids
  • Laxatives Laxatives Laxatives are medications used to promote defecation. Most often, laxatives are used to treat constipation or for bowel preparation for certain procedures. There are 4 main classes of laxatives: bulk-forming, stimulant, osmotic, and emollient. Laxatives
  • Antiviral Antiviral Antivirals for Hepatitis B agents:
    • Acyclovir Acyclovir A guanosine analog that acts as an antimetabolite. Viruses are especially susceptible. Used especially against herpes. Herpes Zoster (Shingles)
    • Atazanavir Atazanavir Anti-HIV Drugs
    • Indinavir Indinavir A potent and specific HIV protease inhibitor that appears to have good oral bioavailability. Anti-HIV Drugs
    • Ritonavir Ritonavir An HIV protease inhibitor that works by interfering with the reproductive cycle of HIV. It also inhibits cytochrome p-450 cyp3a. Anti-HIV Drugs
  • Antibiotics:
    • Ceftriaxone Ceftriaxone A broad-spectrum cephalosporin antibiotic and cefotaxime derivative with a very long half-life and high penetrability to meninges, eyes and inner ears. Cephalosporins
    • Ciprofloxacin Ciprofloxacin A broad-spectrum antimicrobial carboxyfluoroquinoline. Fluoroquinolones
    • Sulfa medications
  • Triamterene Triamterene A pteridinetriamine compound that inhibits sodium reabsorption through sodium channels in renal epithelial cells. Potassium-sparing Diuretics

Pathophysiology

Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate stones

• Idiopathic Idiopathic Dermatomyositis normocalcemic hypercalciuria (most common cause)
• Ethylene glycol (antifreeze) ingestion:
  • Ethylene glycol is metabolized to oxalate by alcohol dehydrogenase Alcohol dehydrogenase A zinc-containing enzyme which oxidizes primary and secondary alcohols or hemiacetals in the presence of nad. In alcoholic fermentation, it catalyzes the final step of reducing an aldehyde to an alcohol in the presence of nadh and hydrogen. Ethanol Metabolism and aldehyde dehydrogenase.
  • Oxalate filtered in the urine binds to urinary calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes producing calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate crystals.
• Decreased urine pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance:
  • Excessive H⁺ ions bind BIND Hyperbilirubinemia of the Newborn to citrate, resulting in hypocitraturia.
  • Urinary calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes can no longer bind BIND Hyperbilirubinemia of the Newborn to citrate and binds to oxalate instead, producing calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate crystals. 
• Excessive vitamin C Vitamin C A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant. Water-soluble Vitamins and their Deficiencies (ascorbic acid) ingestion: decreases urine pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance resulting in calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate crystals
• Crohn’s disease or small bowel Small bowel The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy resection:
  • Decreased absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption of fat due to damaged mucosa (Crohn’s disease) or small surface area ( small bowel Small bowel The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy resection)
  • Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes in the GI lumen binds to fat, resulting in increased free oxalate absorption Absorption Absorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation. Digestion and Absorption from the GI tract. 
  • Oxalate filtered across the glomeruli binds to urinary calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes, producing calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate crystals. 

Uric acid stones

• Decreased urine pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance:
  • Excessive H⁺ binds to urate and forms uric acid.
  • Uric acid moieties coalesce to form uric acid crystals.
• Arid climate:
  • Excessive sweating causes volume depletion Volume depletion Volume status is a balance between water and solutes, the majority of which is Na. Volume depletion refers to a loss of both water and Na, whereas dehydration refers only to a loss of water. Volume depletion can be caused by GI losses, renal losses, bleeding, poor oral Na intake, or third spacing of fluids. Volume Depletion and Dehydration.
  • Volume depletion Volume depletion Volume status is a balance between water and solutes, the majority of which is Na. Volume depletion refers to a loss of both water and Na, whereas dehydration refers only to a loss of water. Volume depletion can be caused by GI losses, renal losses, bleeding, poor oral Na intake, or third spacing of fluids. Volume Depletion and Dehydration concentrates urine, allowing uric acid moieties to coalesce and form crystals.
• Hyperuricemia Hyperuricemia Excessive uric acid or urate in blood as defined by its solubility in plasma at 37 degrees c; greater than 0. 42 mmol per liter (7. 0 mg/dl) in men or 0. 36 mmol per liter (6. 0 mg/dl) in women. Gout: Uric acid crystals are formed because of increased filtered uric acid.
• Increased cell turnover (e.g., lymphoma Lymphoma A general term for various neoplastic diseases of the lymphoid tissue. Imaging of the Mediastinum, leukemia):
  • Purine breakdown in the cell nucleus Nucleus Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. The Cell: Organelles produces uric acid.
  • Excessive uric acid is filtered across glomeruli and forms uric acid crystals.

Struvite stones

• UTI UTI Urinary tract infections (UTIs) represent a wide spectrum of diseases, from self-limiting simple cystitis to severe pyelonephritis that can result in sepsis and death. Urinary tract infections are most commonly caused by Escherichia coli, but may also be caused by other bacteria and fungi. Urinary Tract Infections (UTIs) with urease-positive Urease-positive Helicobacter bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology
• Urease Urease An enzyme that catalyzes the conversion of urea and water to carbon dioxide and ammonia. Nocardia/Nocardiosis breaks down urea Urea A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids. Urea Cycle into ammonia Ammonia A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as ammonium hydroxide. Acid-Base Balance and CO₂.
• Ammonia Ammonia A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as ammonium hydroxide. Acid-Base Balance binds to magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes and phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes forming struvite stones.
• Commonly implicated bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology:
  • Proteus mirabilis Proteus mirabilis A species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is frequently isolated from clinical specimens. Its most common site of infection is the urinary tract. Proteus (most common)
  • Ureaplasma urealyticum
  • Staphylococcus saprophyticus Staphylococcus saprophyticus A species of gram-positive bacteria in the family staphylococcaceae. It commonly causes urinary tract infections in humans. Staphylococcus
  • Klebsiella pneumoniae Klebsiella Pneumoniae Gram-negative, non-motile, capsulated, gas-producing rods found widely in nature and associated with urinary and respiratory infections in humans. Aminoglycosides

Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes stones

• Increased urine pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance results in high levels of monohydrogen phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes anions Anions Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis. Electrolytes.
• Monohydrogen phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes binds to calcium-forming calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes crystals.

Cystine stones

• Cystinuria: autosomal recessive Autosomal recessive Autosomal inheritance, both dominant and recessive, refers to the transmission of genes from the 22 autosomal chromosomes. Autosomal recessive diseases are only expressed when 2 copies of the recessive allele are inherited. Autosomal Recessive and Autosomal Dominant Inheritance defect in sodium-dibasic amino acid Amino acid Amino acids (AAs) are composed of a central carbon atom attached to a carboxyl group, an amino group, a hydrogen atom, and a side chain (R group). Basics of Amino Acids cotransporter
• Results in decreased tubular reabsorption of cystine, ornithine Ornithine An amino acid produced in the urea cycle by the splitting off of urea from arginine. Urea Cycle, arginine Arginine An essential amino acid that is physiologically active in the l-form. Urea Cycle, and lysine
• Cystine moieties are retained in the urine, coalesce, and form cystine stones.

Overview

Sites of obstruction and complications

• Kidney stones can lodge into any of the 3 natural narrowings along the ureter:
  • Ureteropelvic junction Ureteropelvic junction Urinary Tract: Anatomy (junction of the renal pelvis Renal pelvis Kidneys: Anatomy and ureter)
  • Ureter at the pelvic inlet Pelvic inlet Pelvis: Anatomy (site of ureteral crossing of the iliac vessels)
  • Ureterovesical junction (junction of the ureter and urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy) 
• A stone lodged at any of the 3 locations can cause obstruction and consequent proximal complications:
  • Acute pyelonephritis Acute pyelonephritis Inflammation of the kidney involving the renal parenchyma (the nephrons); kidney pelvis; and kidney calices. It is characterized by abdominal pain; fever; nausea; vomiting; and occasionally diarrhea. Imaging of the Urinary System:
    • Obstruction of the urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy, which allows for proximal overgrowth of bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology
    • Inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the renal pelvis Renal pelvis Kidneys: Anatomy (kidney parenchyma results)
    • Presents with fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, urinary frequency, urgency, dysuria Dysuria Painful urination. It is often associated with infections of the lower urinary tract. Urinary Tract Infections (UTIs), and costovertebral angle tenderness
  • Hydronephrosis Hydronephrosis Hydronephrosis is dilation of the renal collecting system as a result of the obstruction of urine outflow. Hydronephrosis can be unilateral or bilateral. Nephrolithiasis is the most common cause of hydronephrosis in young adults, while prostatic hyperplasia and neoplasm are seen in older patients. Hydronephrosis:
    • Obstruction causes proximal accumulation of urine.
    • Results in the dilation of the renal pelvis Renal pelvis Kidneys: Anatomy and calyces (visible on ultrasound)

Clinical Presentation and Diagnosis

Clinical presentation

• Depends on the size, number, and location of the stones
• Small stones may be asymptomatic.
• Stones within the renal pelvis Renal pelvis Kidneys: Anatomy and bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess are usually asymptomatic.
• Symptoms are usually associated with acute ureteral obstruction Ureteral obstruction Blockage in any part of the ureter causing obstruction of urine flow from the kidney to the urinary bladder. The obstruction may be congenital, acquired, unilateral, bilateral, complete, partial, acute, or chronic. Depending on the degree and duration of the obstruction, clinical features vary greatly such as hydronephrosis and obstructive nephropathy. Vesicoureteral Reflux:
  • Unilateral, colicky abdominal pain Abdominal Pain Acute Abdomen due to intermittent ureteral peristalsis Peristalsis A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction. Gastrointestinal Motility:
    • Colicky pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways radiates to the groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination, testes Testes Gonadal Hormones, or labia majora Labia majora Vagina, Vulva, and Pelvic Floor: Anatomy
    • Causes costovertebral angle tenderness
    • Usually associated with inability to lie still
  • Hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma due to trauma to the ureter (frank or microscopic)
  • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and/or vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
  • Fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever suggests associated infection or pyelonephritis Pyelonephritis Pyelonephritis is infection affecting the renal pelvis and the renal parenchyma. This condition arises mostly as a complication of bladder infection that ascends to the upper urinary tract. Pyelonephritis can be acute or chronic (which results from persistent or chronic infections). Typical acute symptoms are flank pain, fever, and nausea with vomiting. T Pyelonephritis and Perinephric Abscess.

Diagnosis

Imaging:

• Noncontrast CT of the abdomen and pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy:
  • Gold-standard of imaging for kidney stones
  • Can show location and size of the stone
  • Can detect hydronephrosis Hydronephrosis Hydronephrosis is dilation of the renal collecting system as a result of the obstruction of urine outflow. Hydronephrosis can be unilateral or bilateral. Nephrolithiasis is the most common cause of hydronephrosis in young adults, while prostatic hyperplasia and neoplasm are seen in older patients. Hydronephrosis
• Abdominal ultrasound: used in pregnant women and children to avoid radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma
• Abdominal X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests: can detect large stones

Laboratory studies:

• Urinalysis Urinalysis Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically. Urinary Tract Infections (UTIs) in Children and urine dipstick:
  • Useful for detecting microscopic hematuria Hematuria Presence of blood in the urine. Renal Cell Carcinoma
  • Determines urine pH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance and helps determine the type of stone
• Urine microscopy: evaluates the shape of the crystals

Management

Size-based approach

• ≤ 5 mm: observation only (spontaneous passage is likely)
• 6–10 mm: alpha-blockers Alpha-blockers Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma. Antiadrenergic Drugs or dihydropyridine Dihydropyridine Pyridine moieties which are partially saturated by the addition of two hydrogen atoms in any position. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers) calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers ( alpha-blockers Alpha-blockers Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma. Antiadrenergic Drugs are preferred)
• 10–20 mm: extracorporeal shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock wave lithotripsy (ESWL) or ureterorenoscopy/ureteroscopy (URS)
• > 20 mm: percutaneous nephrolithotomy

Medical management

General supportive care:

• Hydration with IV fluid
• Analgesic medications ( pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways can be severe)
• Alpha-blockers Alpha-blockers Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma. Antiadrenergic Drugs (e.g., terazosin Terazosin Antiadrenergic Drugs, tamsulosin Tamsulosin A sulfonamide derivative and adrenergic alpha-1 receptor antagonist that is used to relieve symptoms of urinary obstruction caused by benign prostatic hyperplasia. Antiadrenergic Drugs) or dihydropyridine Dihydropyridine Pyridine moieties which are partially saturated by the addition of two hydrogen atoms in any position. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers) calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes channel blockers (e.g., nifedipine Nifedipine A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure. Class 4 Antiarrhythmic Drugs (Calcium Channel Blockers)) to dilate and relax the ureters Ureters One of a pair of thick-walled tubes that transports urine from the kidney pelvis to the urinary bladder. Urinary Tract: Anatomy and allow for passage of stones < 10 mm

Stone-specific management:

• Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate and calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes phosphate Phosphate Inorganic salts of phosphoric acid. Electrolytes stones:
  • Low-sodium diet to increase concomitant sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia and calcium reabsorption Calcium reabsorption Tubular System in proximal tubules
  • Citrate to dissolve calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes oxalate crystals
  • Thiazide Thiazide Heterocyclic compounds with sulfur and nitrogen in the ring. This term commonly refers to the benzothiadiazines that inhibit sodium-potassium-chloride symporters and are used as diuretics. Hyponatremia diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication to increase calcium reabsorption Calcium reabsorption Tubular System in the distal tubule
• Struvite stones: antibiotic therapy to eliminate the causative microbe
• Uric acid stones:
  • Urine alkalinization with potassium Potassium An element in the alkali group of metals with an atomic symbol k, atomic number 19, and atomic weight 39. 10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the water-electrolyte balance. Hyperkalemia citrate to dissolve uric acid crystals
  • Allopurinol Allopurinol A xanthine oxidase inhibitor that decreases uric acid production. It also acts as an antimetabolite on some simpler organisms. Gout Drugs to decrease uric acid production
• Cystine stones: tiopronin or penicillamine Penicillamine 3-mercapto-d-valine. The most characteristic degradation product of the penicillin antibiotics. It is used as an antirheumatic and as a chelating agent in wilson’s disease. Wilson Disease to chelate cystine

Surgical management

• ESWL:
  • Stone fragmentation Fragmentation Chronic Apophyseal Injury with sound waves
  • Not routinely performed in obese patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship due to poor penetration Penetration X-rays of sound waves
• Ureterorenoscopy: a transurethral endoscopic procedure to visualize the entire urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy and retrieve the kidney stone
• Percutaneous nephrolithotomy: a surgical procedure with skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions incision to retrieve the kidney stone

Prevention

• Adequate hydration
• Low-sodium, low-protein diet

Differential Diagnosis

• Acute appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis: inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy caused by impaction of a fecalith Fecalith Imaging of the Intestines in adults, or by lymphoid hyperplasia Lymphoid hyperplasia Common Variable Immunodeficiency (CVID) in children. The initial presentation is diffuse periumbilical pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, which then localizes to the RLQ. In contrast, nephrolithiasis causes flank pain Flank pain Pain emanating from below the ribs and above the ilium. Renal Cell Carcinoma. The diagnosis of appendicitis Appendicitis Appendicitis is the acute inflammation of the vermiform appendix and the most common abdominal surgical emergency globally. The condition has a lifetime risk of 8%. Characteristic features include periumbilical abdominal pain that migrates to the right lower quadrant, fever, anorexia, nausea, and vomiting. Appendicitis is mostly clinical and treatment is an appendectomy Appendectomy Appendectomy is an invasive surgical procedure performed with the goal of resecting and extracting the vermiform appendix through either an open or a laparoscopic approach. The most common indication is acute appendicitis. Appendectomy. 
• Testicular torsion Testicular torsion Testicular torsion is the sudden rotation of the testicle, specifically the spermatic cord, around its axis in the inguinal canal or below. The acute rotation results in compromised blood flow to and from the testicle, which puts the testicle at risk for necrosis. Testicular Torsion: the twisting of the spermatic cord Spermatic Cord Either of a pair of tubular structures formed by ductus deferens; arteries; veins; lymphatic vessels; and nerves. The spermatic cord extends from the deep inguinal ring through the inguinal canal to the testis in the scrotum. Testicles: Anatomy caused by increased testicular mobility in the scrotal sac. Presentation includes erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion, swelling Swelling Inflammation, absent cremasteric reflex Cremasteric Reflex Male Genitourinary Examination, and sudden-onset, severe testicular pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. In contrast, nephrolithiasis-induced pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways originates in the flank and later radiates to the groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination. Diagnosis of testicular torsion Testicular torsion Testicular torsion is the sudden rotation of the testicle, specifically the spermatic cord, around its axis in the inguinal canal or below. The acute rotation results in compromised blood flow to and from the testicle, which puts the testicle at risk for necrosis. Testicular Torsion is via Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) ultrasound. Treatment is manual, or surgical detorsion with bilateral orchiopexy Orchiopexy A surgical procedure in which an undescended testicle is sutured inside the scrotum in male infants or children to correct cryptorchidism. Orchiopexy is also performed to treat testicular torsion in adults and adolescents. Cryptorchidism. 
• Biliary colic: a colicky, RUQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways caused by intermittent obstruction of the cystic Cystic Fibrocystic Change duct by the gallstone. Presentation is episodic pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, especially after ingestion of a fatty meal. In contrast, pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways due to nephrolithiasis is not related to eating. Diagnosis is based on the combination of clinical signs and RUQ ultrasound findings. Unless the patient develops acute cholecystitis Acute cholecystitis Acute inflammation of the gallbladder wall. It is characterized by the presence of abdominal pain; fever; and leukocytosis. Gallstone obstruction of the cystic duct is present in approximately 90% of the cases. Cholecystitis, treatment is observation.
• Diverticulitis Diverticulitis Inflammation of a diverticulum or diverticula. Diverticular Disease: an inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of diverticula caused by the impaction of a fecalith Fecalith Imaging of the Intestines. Presentation may include LLQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, moderate to high fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and bloody stools. In contrast, nephrolithiasis is not characterized by bloody stools. Diverticulitis Diverticulitis Inflammation of a diverticulum or diverticula. Diverticular Disease is diagnosed with a CT scan of the abdomen and most cases are treated with IV antibiotics.