Kidney Diseases

Generally, patients will present with renal problems in two ways—incidentally during a routine exam and/or evidence of hypertension, edema, and hematuria. Evaluation must consider (1) estimation of disease duration, (2) urinalysis, and (3) assessment of the glomerular filtration rate (GFR).

Acute renal failure is a very common entity. It is due to a rapid decrease in renal function, possibly over days or weeks, leading to an increase in nitrogenous products within the blood. This may result from trauma, severe illness, or surgery. A rapid, progressive intrinsic renal disease can lead to acute renal failure very rapidly. It goes into three phases: prerenal due to inadequate renal perfusion, possibly due to depletion by cardiovascular disease; renal due to renal damage or disease—the most common cause being the use of IV iodinated radio contrast agents from renal diagnosis tests, which also causes a decrease in glomerular function; and finally, post-renal, which is commonly due to obstructive nephropathy. Nephropathy consists of various types of obstructions of the voiding and collecting systems.

Cystic kidney disease may be hereditary, congenital, or acquired. Acquired renal cysts are usually simple and are single or multiple within the kidney. Most are clinically insignificant, but they must be distinguished from other renal disorders or renal masses. Multiple cysts are much more common in patients with chronic renal failure, while acquired cysts are only significant within patients who have renal cell carcinoma. Congenital renal cystic dysplasia is a malformation involving the metanephric (embryotic formation of the kidney), malformation, or congenital obstruction uropathies. Nephronophthisis is an autosomal recessive disorder that accounts for 10 to 20 percent of chronic renal failure in children and young adults less than 20 years of age.

There are basically four types of nephronophthisis: juvenile with types 1 and 4, with onset at about age 13; infantile, with the median age of onset being 1 to 3 years old; and adolescent type 3, with the onset age of 19 years old. The causes are seen with gene mutations. Type 1 has extra renal manifestation and disorders.

Polycystic kidney disease is a hereditary disease causing renal cyst formation that will enlarge within both kidneys. It could possibly lead to a progressive renal failure. A familial autosomal-dominant or recessive form causes this illness. The autosomal-dominant form is found mainly in adults, and the recessive form is found in children and is known as [Page 248]infantile polycystic kidney disease (IPKD). Within children, cyst malformations will occur in multiple organ systems. Some children with this type die in the newborn period, but because of improvements in medical management, many progress over an undetermined number of months or years to end-stage renal failure. Autosomal-dominant disease (the adult form) rarely has any clinical significance before the fourth decade. It also may be detected in the newborn period and, depending on the severity, could be fatal.

Idiopathic nephritic syndrome (minimal change disease) is characterized by protein in the urine, low protein production, edema (due to loss of protein), and high lipids in the bloodstream. Affected children are usually under the age of 5, and may show periorbital swelling and low urine formation. This is characterized by glomeruli in the nephron that have a diffuse loss of epithelial foot process.

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