Nephrology Quiz for Medical Students

Nephrology - Glomerular Disorders

• Glomerular disorders are inflammatory disorders impacting the glomeruli. They mostly arise from immunologic factors.
• Immune complex reactions are a primary cause. Antibodies bind to antigens, forming complexes that deposit in glomeruli, causing inflammatory injury. This accounts for 95% of cases.
• Autoimmune reactions also occur, wherein antibodies target the body's own tissues (endogenous antigens). These antibodies also deposit in glomeruli, initiating inflammation.
• Inflammatory changes in glomeruli can manifest in various forms, including proliferative glomerulonephritis, membranous glomerulonephritis, membranoproliferative glomerulonephritis, focal glomerulosclerosis, and diffuse mesangial proliferation.
• Clinical syndromes resulting from these glomerular changes include nephrotic syndrome, nephritic syndrome, and nephrotic-nephritic syndrome. Nephrotic syndrome is characterized by massive proteinuria, hypoproteinemia, hyperlipidemia, and generalized edema. Nephritic syndrome is associated with hematuria, oliguria, and hypertension.

Nephrotic Syndrome

• Minimal change nephrotic syndrome is the most common cause of nephrotic syndrome in children, accounting for approximately 90% of cases.
• The etiology of minimal change nephrotic syndrome isn't fully understood, but it is thought to involve T-cell dysfunction, leading to increased glomerular permeability to proteins, resulting in protein loss in the urine.
• Pathologically, minimal change nephrotic syndrome shows no identifiable abnormalities by light microscopy, but electron microscopy reveals fusion of the foot processes of podocytes.
• Causes of nephrotic syndrome also include Kidney involvement(most common), infections (bilharzia, hepatitis B, malaria), collagen diseases (systemic lupus), blood disorders (sickle cell anemia, lymphoma, leukemia), metabolic disorders (diabetes), and medications (gold, mercury).

Pathogenesis of Nephrotic Syndrome

• Proteinuria is due to heightened glomerular permeability to proteins, leading to protein loss in the urine. Primarily albumin is lost.
• Hypoproteinemia results from proteinuria.
• Hyperlipidemia is triggered by the liver increasing lipoprotein production to compensate for the lack of proteins
• Edema arises from decreased osmotic pressure in the blood, causing fluid to shift from the blood vessels to the interstitial tissues. Hypovolemia, renin-angiotensin-aldosterone, and antidiuretic responses lead to water and sodium retention.
• T cells are abnormally releasing lymphokines, which leads to increased glomerular permeability to proteins.

Clinical Picture of Nephrotic Syndrome

• Generalized edema is a common presenting symptom.
• Periorbital edema, edema in lower limbs, sacral edema, and anterior abdominal wall edema may occur.
• Ascites can occur in severe cases.
• Respiratory distress can also be noted.
• Gastrointestinal manifestations such as anorexia, abdominal pain, and diarrhea are possible due to fluid shifts in the intestines

Complications of Nephrotic Syndrome

• Infections are common due to loss of immunoglobulins and complement factors in the urine.
• Hypertension can occur due to fluid shifts and hormonal changes.
• Thrombosis due to an increase in platelet aggregation and loss of antithrombin III in the urine can be a significant risk.
• Renal failure is a danger that can occur, either due to pre-renal mechanisms or acute glomerulonephritis, or acute kidney injury.

Investigations and Treatment of Nephrotic Syndrome

• Urine tests are crucial, including checking for proteinuria, hematuria, casts and urine culture.
• Blood tests examine serum albumin, cholesterol, and other relevant markers.
• Renal biopsy can help pinpoint the specific cause.
• Management includes salt restriction, high protein diet, and immunosuppressive medications (like corticosteroids), and sometimes, cytotoxic drugs.

Nephritic Syndrome

• It is a clinical syndrome characterized by hematuria, oliguria, and hypertension.
• Post-streptococcal glomerulonephritis (APSGN) is the most common type of nephritic syndrome in children.
• It is a non-suppurative complication of group A beta-hemolytic streptococcal infections.

Pathogenesis of Nephritic Syndrome

• Immune complexes form in the body after infection, depositing in the glomeruli.
• These complexes activate the complement system, leading to glomerular inflammatory reactions.
• This process causes inflammation and damage within the glomeruli, which manifest as hematuria, oliguria, and hypertension.

Clinical Picture of Nephritic Syndrome

• Hematuria is often a noticeable symptom, resulting from damage to glomeruli.
• Oliguria, decreased urine output, is a common sign.
• Hypertension (high blood pressure) is usually present.
• Mild generalized edema may be noted.
• Complications such as acute kidney failure, heart failure, and hypertensive encephalopathy can also potentially develop.

Investigations and Treatment of Nephritic Syndrome

• Urine tests check for hematuria, proteinuria, and other abnormalities.
• Blood tests examine serum complement levels (C3), and other pertinent markers.
• Renal biopsy may be needed to confirm a diagnosis.
• Treatment primarily targets the underlying cause, such as a streptococcal infection.

Acute Renal Failure

• Acute renal failure (ARF) is characterized by a sudden loss of kidney function, manifested by reduced urine output.
• This loss of function may be pre-renal, renal, or post-renal in origin.
• Pre-renal failure is a response to reduced blood flow, renal failure is a consequence of kidney damage, and post-renal failure involves an obstruction of urine outflow.

Hematuria

• Hematuria is the presence of blood in the urine.
• Causes can include glomerular issues (post-streptococcal GN, membranoproliferative GN, lupus nephritis), non-glomerular causes (urolithiasis, kidney infections), and diseases such as sickle cell anemia, or physical exertion.
• The presence and characteristics of hematuria (e.g., dark colored urine, blood clots) can provide clues to its cause.

Urinary Tract Infections (UTIs)

• UTIs are classified by site of infection (cystitis or pyelonephritis).
• Ascending infection is the most common route of infection in UTIs.
• Several types of Gram-negative (E. coli, Klebsiella, Proteus, Pseudomonas) and Gram-positive bacteria (Streptococci, Staph) are frequent offenders.
• Factors like anatomic abnormalities and vesico-ureteric reflux may predispose to UTIs.
• Predisposing factors for recurrence include immunodeficiency and other issues.
• Age and sex are also significant factors, with women and children being more susceptible.

Test your knowledge on nephrology with this quiz tailored for medical students. Topics include urine sample collection methods, glomerular disorders, and diagnostic criteria. Challenge yourself to understand the complexities of urinary system anomalies and immune responses.