Review Question - QID 212598

This patient's dysuria, flank pain, and costovertebral angle tenderness are highly concerning for pyelonephritis. Histology would demonstrate suppurative inflammation with interstitial neutrophilic infiltration.

Pyelonephritis describes an infection involving the kidneys/upper urinary tract. Pyelonephritis results from the ascension of the pathogen from the vaginal introitus or urethral meatus to the bladder and then to the kidneys/upper urinary tract. When the kidneys become infected with a uropathogen, neutrophils migrate into the interstitium and tubular lumina, resulting in necrosis and abscess formation. The infected kidneys/upper urinary tract leads to systemic symptoms of fever and nausea and results in flank pain and costovertebral angle tenderness.

Incorrect Answers:
Answer 1: Diffuse capillary and glomerular basement membrane thickening are seen in membranous nephropathy. This condition results in a nephrotic syndrome, which this patient does not have based on the absence of protein in her urinalysis.

Answer 2: Focal and segmental sclerosis of the glomeruli and mesangium describes focal segmental glomerulosclerosis. This nephrotic syndrome (which this patient does not have) can be seen in African Americans and Hispanics and is associated with HIV infection, sickle cell disease, heroin use, and obesity.

Answer 3: Mesangial proliferation is seen in IgA nephropathy, which is characterized by a hematuria that often occurs at the same time as an upper respiratory tract infection. This patient has a remote history of a rhinovirus infection. This patient also does not have proteinuria.

Answer 4: Normal appearing glomeruli is seen in minimal change disease which is more likely to be seen in children and would present with proteinuria.

Bullet Summary:
Histological findings seen in pyelonephritis include suppurative inflammation with interstitial neutrophilic infiltration.