UTI & Pyelonephritis PDF

# UTI & Pyelonephritis Carisa O. Jiménez Chaparro ## Urinary Tract Infections (UTIs) - **Definition:** Infection of the urinary tract, classified into lower UTIs (cystitis) and upper UTIs (pyelonephritis). - **Common Pathogens:** - *E. coli:* Causes 75-90% of UTIs. - *Staphylococcus sapro...

# UTI & Pyelonephritis Carisa O. Jiménez Chaparro ## Urinary Tract Infections (UTIs) - **Definition:** Infection of the urinary tract, classified into lower UTIs (cystitis) and upper UTIs (pyelonephritis). - **Common Pathogens:** - *E. coli:* Causes 75-90% of UTIs. - *Staphylococcus saprophyticus:* 2nd most common, especially in sexually active young women. - *Klebsiella:* Associated with UTIs in catheterized patients and those with diabetes. - *Proteus mirabilis:* Urease-producing, associated with alkaline urine and struvite stones. - *Enterococcus:* Common in hospital-acquired infections. - **Etiology:** - **Prevalent in:** Women, particularly those who are sexually active or pregnant. - **Risk factors:** Catheter use, diabetes, urinary tract abnormalities, menopause. ## Pyelonephritis - **Definition:** Infection of the kidney, often ascending from the bladder. - **Common Pathogens:** - *E. coli:* Most common pathogen, responsible for the majority of cases. - *Proteus mirabilis:* Associated with alkaline urine and kidney stones. - *Klebsiella pneumoniae:* Often seen in complicated cases. - *Enterococcus:* Common in nosocomial infections. - **Signs & Symptoms:** High fever, chills, flank pain, nausea, vomiting, and dysuria. - **Diagnostic Methods:** - **Urinalysis:** Positive for WBCs and bacteria; may show casts. - **Urine Culture:** ≥10^5 CFU/mL confirms infection. - **Imaging:** Consider ultrasound or CT for complications (e.g., abscess). ## Emphysematous Pyelonephritis - **Definition:** Emphysematous pyelonephritis is a severe, necrotizing kidney infection characterized by the presence of gas-forming organisms, leading to gas production within the renal parenchyma. This condition is often associated with diabetes mellitus and is considered a surgical emergency. - **Etiology:** - **Common Pathogens:** - *Escherichia coli* (most common). - Other gram-negative bacteria such as *Klebsiella pneumoniae* and *Proteus mirabilis*. - **Risk Factors:** - **Diabetes mellitus:** Impaired immunity and vascular supply. - **Urinary tract obstruction:** Increases infection risk. - **Signs & Symptoms:** High fever, flank pain, abdominal pain, nausea and vomiting, signs of sepsis in severe cases. - **Diagnostic Methods:** - **Imaging:** - CT scan: Shows renal enlargement, abscess formation, and gas within the renal parenchyma. - Ultrasound: May also demonstrate gas formation. - **Treatment:** - **Antibiotics:** Broad-spectrum IV antibiotics. - **Surgical intervention:** Drainage of abscesses or nephrectomy may be necessary in severe cases. ## Xanthogranulomatous Pyelonephritis - **Definition:** Xanthogranulomatous pyelonephritis is a chronic kidney infection characterized by the destruction of renal parenchyma and the presence of lipid-laden macrophages (foam cells) within the kidney. It is often confused with renal tumors due to its appearance. - **Etiology:** - **Common Pathogens:** - *Proteus mirabilis* is frequently associated. - Other organisms can also be involved. - **Risk Factors:** - Chronic urinary tract obstruction (e.g., from stones or tumors). - Diabetes mellitus. - **Signs & Symptoms:** Flank pain, fever, weight loss, hematuria (blood in urine), fluctuating renal function. - **Diagnostic Methods:** - **Imaging:** - CT scan: Shows a non-functioning kidney with renal enlargement, heterogeneous mass, and possible obstruction. - Ultrasound: May show a hydronephrotic kidney with changes suggestive of chronic infection. - **Treatment:** Surgical intervention: Nephrectomy is typically necessary due to significant renal destruction and the risk of complications. ## Renal Failure: Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD) Carisa O. Jiménez Chaparro ## Renal Failure Overview - **Definition of Renal Failure:** - Renal failure is a condition characterized by a decline in renal filtration, leading to the retention of nitrogenous waste products and disturbances in electrolyte balance. - **Consequences of Renal Failure:** - Accumulation of waste products such as urea and creatinine. - Electrolyte imbalances, including hyperkalemia and metabolic acidosis. ## Acute Kidney Injury AKI - **Definition:** Sudden decline in kidney function over hours to 7 days; characterized by elevated creatinine and decreased urine output. - **Signs & Symptoms:** Oliguria (<400 mL/day) or anuria, fluid overload (edema, hypertension), electrolyte imbalances (hyperkalemia, metabolic acidosis). - **Causes:** - **Pre-Renal:** - Hypovolemia (dehydration, blood loss, diuretics). - Decreased cardiac output (heart failure, cardiogenic shock). - Vasodilation (sepsis, anaphylaxis). - Renal artery stenosis. - Systemic hypotension. - **Renal (Intrinsic):** - Acute tubular necrosis (ischemia, nephrotoxins). - Acute interstitial nephritis (allergic reactions, infections). - Glomerulonephritis (post-streptococcal, lupus nephritis). - Vascular causes (renal artery occlusion). - **Post-Renal:** - Ureteral obstruction (kidney stones, tumors). - Bladder outlet obstruction (BPH, prostate cancer). - Neurogenic bladder (nerve damage). - **Diagnostic Methods:** - Creatinine and BUN: Elevated levels. - GFR: Rapid decline. - Urinalysis: May show granular casts in intrinsic AKI. - **Urinary Sodium (UNa):** Varies based on Na and H2O intake. - Low (<20 mEq/L) when kidneys retain salt/water. - **FeNa:** - Pre-Renal: <1% - Renal: >2% - **Urine Osmolality:** - Pre-Renal: >500 mOsm/kg - Renal: <350 mOsm/kg - **Treatment:** - Address underlying cause (e.g., hydration for pre-renal, cessation of nephrotoxins). - Supportive care (e.g., diuretics, electrolyte management). ## Acute Kidney Disease AKD - **Definition:** Kidney dysfunction lasting 7 days to <3 months, often following AKI. - **Signs & Symptoms:** Variable; may include continued elevated creatinine and BUN. - **Diagnostic Methods:** - Persistent elevated creatinine and BUN. - Urinalysis: May show proteinuria and hematuria. - Assess underlying conditions (e.g., imaging studies if indicated). - **Treatment:** - Monitor and manage underlying conditions. - Supportive care as in AKI. - Consider referral to nephrology if persistent dysfunction. ## Chronic Kidney Disease CKD - **Definition:** Chronic kidney dysfunction lasting >3 months, characterized by a progressive decline in kidney function. - **Most Common Causes:** - Diabetes Mellitus: Leading cause of CKD. - Hypertension: Second leading cause. - **Laboratory Findings:** - **Blood Tests:** - BUN: Elevated (>20 mg/dL is suggestive of kidney dysfunction). - Creatinine: Elevated (>1.2 mg/dL in women, >1.4 mg/dL in men, indicative of kidney impairment). - **Stages Based on GFR:** - **Stage 1:** GFR >90 mL/min (normal kidney function). - **Stage 2:** GFR 60-89 mL/min (mild reduction). - **Stage 3:** GFR 30-59 mL/min (moderate reduction). - **Stage 4:** GFR 15-29 mL/min (severe reduction, approaching dialysis). - **Stage 5:** GFR <15 mL/min (end-stage renal disease). ## Complications of CKD - **Anemia:** Loss of EPO leading to normocytic anemia. - **Dyslipidemia:** Increased triglycerides due to loss of protein in urine and impaired clearance of chylomicrons and VLDL. - **Renal Osteodystrophy:** - **Pathways:** - Phosphate retention decreases calcium levels in plasma, causing hypocalcemia. - Lack of active Vitamin D reduces calcium absorption from the gut, also causing hypocalcemia. - **Consequences:** Both pathways stimulate parathyroid hormone (PTH) secretion, leading to secondary and tertiary hyperparathyroidism. - **Symptoms/Manifestations:** - Bone pain and fractures. - Osteitis fibrosa cystica (bone disease due to high PTH). - Brown tumors (osteoclasts with fibrous tissue). ## Diagnostic Methods - **Blood Tests:** - Serum creatinine and BUN levels to assess kidney function. - Complete blood count (CBC) to evaluate for anemia. - Electrolyte panel to check for hyperkalemia and metabolic acidosis. - **Urinalysis:** May show proteinuria and hematuria. - **Imaging Studies:** Ultrasound or CT scan to assess kidney size and structure and to rule out obstruction. - **GFR Calculation:** Estimated using serum creatinine, age, gender, and race. ## Treatment of CKD - **Manage Underlying Causes:** - Tight control of blood sugar in diabetes. - Control of blood pressure using ACE inhibitors or ARBs. - **Supportive Care:** - Dietary modifications (low protein, low potassium, low phosphorus). - Management of complications (e.g., erythropoietin-stimulating agents for anemia). - **Dialysis:** - Initiated when GFR falls below 15 mL/min or when symptomatic (e.g., fluid overload, severe electrolyte imbalance). - **Kidney Transplant:** Considered for eligible patients with end-stage renal disease. ## Dialysis - **Definition:** Dialysis is a medical procedure used to remove waste products and excess fluid from the blood when the kidneys are unable to function adequately. - **Indications for Dialysis (ΑΕΙΟU):** - A: Acidemia: Metabolic acidosis that cannot be managed medically. - E: Electrolytes: Severe hyperkalemia (high potassium) that poses a risk to cardiac function. - I: Intoxication: Poisoning or overdose from dialyzable substances. - O: Overload of fluid: Fluid overload leading to congestive heart failure (CHF) or pulmonary edema. - U: Uremic Symptoms: Symptoms of uremia, including nausea, vomiting, confusion, and pericarditis. - **Dialyzable Substances:** - Salicylates (e.g., aspirin): Commonly used pain reliever. - Lithium: Medication used for bipolar disorder. - Isopropyl alcohol: Common household product. - Magnesium laxatives: Used for constipation. - Ethylene Glycol: Found in antifreeze; toxic when ingested. - **Dialysis Methods:** - **Hemodialysis:** - Vascular Access: Ideally through a fistula (surgical connection of an artery and vein). - Blood is pumped out of the body to a dialysis machine where it is filtered and then returned to the body. - Typically performed in sessions lasting a few hours, several times a week. - **Peritoneal Dialysis:** - A sterile fluid is cycled through the peritoneal cavity. - The peritoneum serves as the dialysis membrane/filter, allowing waste and excess fluid to be removed. - Can be done manually (Continuous Ambulatory Peritoneal Dialysis, CAPD) or with a machine (Automated Peritoneal Dialysis, APD).