Renal Tubular Dysgenesis

A very rare familial disorder characterized by incompletely or abnormally developed cortical tubules. Similar renal pathology is seen in infants born of women who had taken angiotensin-converting enzyme (ACE) inhibitors during pregnancy. Prognosis is poor.

Primitive Renal Tubule Syndrome.

First described by J.E. Allanson in 1992.

Autosomal recessive inheritance.

Probably related to ischemia or hypoperfusion of renal parenchyma with resultant hypoxia affecting those organs requiring a high oxygen tension for normal growth. Another postulation attributed to a lack of angiotensin II growth stimulation, as is found in ACE-inhibitor fetopathy.

Nephromegaly with characteristic histological appearance whereby the cortical tubules lack normal features of the proximal or distal convolutions. The tubules are short and straight, primitive, and reminiscent of collecting tubules. The glomeruli are crowded with the medullary pyramids smaller than usual. Late second-trimester sonographic demonstration of oligohydramnios, with structurally normal kidneys, should suggest the diagnosis. Associated skull abnormalities may help in suggesting the diagnosis.

Gestations are complicated by late-onset oligohydramnios. Liveborns are anuric and develop renal failure. A number of the affected children have skull abnormalities (calvarial hypoplasia, microcephaly, underdeveloped cranial bones, or widely patent fontanelles) with characteristic Potter facies. Hypotonia may occur; respiratory failure, too.

Assess intravascular volume and electrolyte imbalances, especially potassium. Correct all anomalies preoperatively. Systematic review of cardiovascular and respiratory status (clinical, ECG, chest radiographs, echocardiography, arterial blood gas analysis). Investigations: CBC (note severity of anemia), clotting times, urea, creatinine, and electrolytes, liver function tests. The effects of sedative drugs for premedication are unpredictable because of the changes in plasma protein levels and the altered pH.

Fluid balance and electrolytes should be monitored carefully. The use of a regional anesthetic technique may be considered, provided there is no coagulopathy or thrombocytopenia. Postoperative ventilatory support can be necessary in case of respiratory failure.

Use barbiturates in lower doses and with caution because the free drug percentage is increased as a consequence of hypoalbuminemia. Avoid suxamethonium if the serum potassium levels >4 mmol/L or if there is presence or suspicion of peripheral neuropathy. Atracurium, cis-atracurium, and mivacurium are preferred for neuromuscular blockade because of their rapid elimination that is independent of renal and hepatic functions. Remifentanil would probably also be preferred for the same reason. Morphine and pethidine should be used with caution, because their metabolites tend to accumulate. Aminoglycosides should be used with great caution and doses adapted to renal function.

Allanson Panzar McLeod Syndrome (Primitive Renal Tubule Syndrome; Renovascular Dysgenesis Syndrome): An autosomal recessive medical condition characterized by renotubular dysgenesis, Potter facies, pulmonary hypoplasia and oligohydramnios. It is usually lethal at birth. Pathological studies reveal the absence, or abnormal form of, proximal convoluted tubules resembling collecting tubules.