Easy Pediatrics

Bartter syndrome is caused by an inborn autosomal recessive defect, in the Na-K-2Cl co transporter in the thick ascending limb of the loop of Henle, leading to NaCl and water wasting.

Clinical Symptoms

The patient presents with polyuria, polydipsia, episodes of dehydration, flattering growth and constipation. sometimes there may be maternal polyhydramnios with an affected fetus.

Pathophysiology

Since there is NaCl and water wasting the resultant ECF volume contraction causes secondary renin secretion and raised aldosterone levels, with avid Na and water reabsorption in the distal tubule and reciprocal K and H secretion into the urine. Imprtant to note is that blod pressure is normal. There is also increases renal prostaglandin E2 secretion.

The above changes produce the characteristic biochemical disturbance of hypochloraemic hpokalaemic alkalosis.

Diagnosis

Crucial to the diagnosis is the finding of inappropriately high levels of urinary Cl and Na- usually more than 20mmol/L ; urine Ca is normal or high.

Treatment

Therapy involves K supplementation combined with prostaglandin synthetase inhibitors, usually indomethacin. Continue reading »

 Pediatric Nephrotic syndrome is defined by the presence of:

1. nephrotic proteinuria > 1 g/m²/day,
2. hypoproteinemia - albumin usually < 25 g/l, based on protein loss to urine,
3. hypercholesterolemia - based on increased lipoprotein synthesis (caused by hypoproteinemia),
4. edema - based on increased naturism resorption in tubules.

Nephrotic syndrome is a constellation of clinical findings that is the result of massive renal losses of protein. Thus, nephrotic syndrome is not a disease itself, but the manifestation of many different glomerular diseases.

Minimal Change Disease

Minimal Change Disease (also known as lipoid nephrosis) is a disease of thekidney that causes nephrotic syndrome and usually affects children (peak incidence at 2–3 years of age).

Pathophysiology

Nephrotic syndrome is a nonspecific disorder in which thekidneys are damaged, causing them to leak large amounts of protein from the blood into the urine.

Kidneys affected by nephrotic syndrome have small pores in the podocytes, large enough to permit proteinuria (and subsequently hypoalbuminemia, because some of the protein albumin has gone from the blood to the urine.

NS is believed to have an immune pathogenesis. Evidence of the immune-mediated nature of NS is demonstrated by the fact that immunosuppressive agents, such as corticosteroids and alkylating agents, can result in remission of nephrotic syndrome.

Pathology of Edema in Nephrotic Syndrome

The classical explanation for edema formation is a decrease in plasma oncotic pressure, as a consequence of low serum albumin levels, causing an extravasation of plasma water into the interstitial space. The resulting contraction in plasma volume (PV) leads to stimulation of the renin-angiotensin-aldosterone axis and antidiuretic hormone. The resultant retention of sodium and water by the renal tubules contributes to the extension and maintenance of edema.

A more recent theory of edema formation posits that massive proteinuria leads to tubulointerstitial inflammation and release of local vasoconstrictors and inhibition of vasodilation. This leads to a reduction in single-nephron glomerular filtration rate and sodium and water retention.

Thrombosis

Patients with nephrotic syndrome are at increased risk for thrombosis.

Various factors play a role in the increased incidence of thrombosis. Abnormalities described in INS include the following:

• Increased platelet activation and aggregation
• Elevation in levels of factors V, VII, VIII, and XIII and fibrinogen Continue reading »