Renal artery stenosis

Renal artery stenosis or the narrowing of the renal artery is responsible for 2-5% of hypertension cases (newly developed hypertension in patients over 50 years of age should trigger suspicion). Atherosclerotic disease, which is the most common form of renal artery stenosis, accounts for approximately 90% of all lesions. As with other forms of atherosclerosis,… Read more »


Nephrolithiasis specifically refers to calculi in the kidneys. Ureteral calculi almost always originate in the kidneys, although they may continue to grow once they lodge in the ureter and at that time are called ureterolithiasis.  Lifetime incidence of kidney stones is approximately 13% for men and 7% for women. Although often asymptomatic—incidental stones are identified… Read more »

IgA Nephropathy

IgA nephropathy (Berger Disease) is highly variable, both clinically and pathologically, and is characterized by deposition of the IgA antibody in the glomerulus. There are other diseases associated with glomerular IgA deposits, the most common being Henoch-Schönlein purpura, which is considered by many to be a systemic form of IgA nephropathy (The photo shows immunostaining showing IgA… Read more »

Post-Strep Glomerulonephritis

Leading cause of acute nephritic syndrome. Acute glomerulonephritis is characterized by the sudden appearance of hematuria, proteinuria, red blood cell casts in the urine, edema, and hypertension with or without oliguria. It can follow streptococcal infections. A latent period always occurs between the strep infection and the onset of symptoms of acute glomerulonephritis. The latent period is 1-2… Read more »

Renal tubular acidosis type 4

Type IV renal tubular acidosis (RTA), or hyperkalemic RTA or tubular hyperkalemia, refer to cases with normal renin and aldosterone production but impaired tubular responsiveness, usually caused by a distal tubular voltage defect.It often occurs in diabetics. Acidosis usually is mild and asymptomatic, and is usually discovered during routine labs. Because several commonly used drugs may unmask… Read more »

Renal tubular acidosis type 2

Disorder of proximal nephron – defective bicarbonate reabsorption in proximal tubule (usually as a part of generalized tubular disorder – Fanconi syndrome) Large amount of bicarbonate is excreted; characterized by normal anion gap acidosis and hypokalemia. Urine may become maximally acid – pH below 5.5. Daily acid excretion is normal, but fractional bicarbonate excretion is… Read more »

Renal tubular acidosis type 1

Disorder of distal nephron – collecting ducts permit excessive back-diffusion of hydrogen ions into the blood, or there is inadequate excretion of hydrogen ions from the blood to urine. Primary forms are passed on in several forms of inheritance (most commonly autosomal dominant). Secondary forms are more common and are associated with systemic disorders such… Read more »

Hemolytic-Uremic Syndrome

Patients present with abdominal pain associated with nausea and vomiting.  There is usually diarrhea (non-bloody at first but if E coli 0157:H7 is present, it can get hemorrhagic in 1 to 2 days).  This commonly follows some sort of infection (bacterial or viral), and there may be a history of antibiotic use. There is usually… Read more »

Bartter’s Syndrome

Bartter’s syndrome is an autosomal recessive disorder of unknown pathophysiology characterized by hypokalemia (due to renal potassium wasting), metabolic alkalosis, and low or normal blood pressure.  The condition is caused by a defect in the kidney’s ability to reabsorb sodium. Persons with Bartter’s syndrome lose too much sodium through the urine. This causes a rise in the… Read more »

Acute Renal Failure

The RIFLE classification of Acute Renal Failure is as follows: Risk (R) – Increase in serum creatinine level X 1.5 or decrease in GFR by 25%, or urine output <0.5 mL/kg/h for 6 hours Injury (I) – Increase in serum creatinine level X 2.0 or decrease in GFR by 50%, or urine output <0.5 mL/kg/h for… Read more »