Ten patients on long term lithium therapy (mean four years, range 1-10.5 years) were subjected to various renal, thyroid, haematological, cardiac and endocrine tests. There was impaired urinary concentrating ability in seven subjects, which was not responsive to vasopressin stimulation, suggesting a partial nephrogenic diabetes insipidus. Nine subjects had metabolic acidosis with higher urinary pH than expected suggesting presence of acidification defect in the kidney. No significant change in renal function, thyroid function, ECG or haematological parameters were detected. Our findings concur with previous reports from the West regarding the safety of lithium administration.
Two cases of hypokalaemia with serum potassium levels of 1.4 mmol/L and 1.9 mmol/L causing severe periodic paralysis since childhood are presented. There were associated with muscular aches and markedly raised muscle enzymes suggesting massive rhabdomyolysis. These abnormalities were due to renal tubular acidosis with markedly acidic arterial pH. The hypokalaemia and rhabdomyolysis responded to potassium and bicarbonate replacement. We postulate these patients had sporadic distal type of renal tubular acidosis and that the hypokalaemia and acidosis had caused the rhabdomyolysis.
Distal renal tubular acidosis (RTA) and hereditary elliptocytosis (HE) are apparently distinct, genetic conditions. We report a family with 3 children having both hereditary elliptocytosis and distal renal tubular acidosis. The simultaneous occurrence of these two conditions in three siblings could be due to covariations in the same family, although a possible contiguous gene syndrome for distal RTA and HE cannot be excluded. This report emphasises the importance of excluding a renal tubular defect in any child who presents with elliptocytosis and failure to thrive.
Acute myopathy complicating treatment of status asthmaticus has been increasingly recognized since its original description in 1977. We report a case of an 11-year-old boy with severe asthma requiring mechanical ventilation. He was given high doses of parenteral steroids and neuromuscular blockade with non-depolarizing agents in order to achieve controlled hypoventilation with an ensuing hypercapnoea. He developed rhabdomyolysis with elevated creatinine kinase and renal impairment secondary to myoglobinuria. Electrophysiological studies revealed myopathic abnormalities. The aetiology for this myopathy appears to be related to therapy with parenteral steroids, muscle-relaxant agents and respiratory acidosis. Patients treated with steroids and neuromuscular blocking agents should be regularly monitored for development of myopathy.
One lung anaesthesia in paediatric patients may not always be achievable by bronchial blockade or double lumen tube intubation due to inadequate experiences or facilities. We attempted to isolate right lung by selectively intubating the left bronchus with single lumen tube on a 10 kg child. Optimal surgical condition and satisfactory oxygenation achieved but complicated with severe respiratory acidosis. The possible causes for hypercapnea in this child were discussed.
We describe three mutations of the red-cell anion exchangerband 3 (AE1, SLC4A1) gene associated with distalrenal tubular acidosis (dRTA) in families from Malaysia and Papua NewGuinea: Gly(701)-->Asp (G701D), Ala(858)-->Asp(A858D) and deletion of Val(850) (DeltaV850). The mutationsA858D and DeltaV850 are novel; all three mutations seem to berestricted to South-East Asian populations. South-East Asianovalocytosis (SAO), resulting from the band 3 deletion of residues400-408, occurred in many of the families but did not itselfresult in dRTA. Compound heterozygotes of each of the dRTA mutationswith SAO all had dRTA, evidence of haemolytic anaemia and abnormal red-cell properties. The A858D mutation showed dominant inheritance and therecessive DeltaV850 and G701D mutations showed a pseudo-dominantphenotype when the transport-inactive SAO allele was also present. Red-cell and Xenopus oocyte expression studies showed that theDeltaV850 and A858D mutant proteins have greatly decreased aniontransport when present as compound heterozygotes (DeltaV850/A858D,DeltaV850/SAO or A858D/SAO). Red cells with A858D/SAO had only 3% ofthe SO(4)(2-) efflux of normal cells, thelowest anion transport activity so far reported for human red cells. The results suggest dRTA might arise by a different mechanism for eachmutation. We confirm that the G701D mutant protein has an absoluterequirement for glycophorin A for movement to the cell surface. Wesuggest that the dominant A858D mutant protein is possibly mis-targetedto an inappropriate plasma membrane domain in the renal tubular cell,and that the recessive DeltaV850 mutation might give dRTA because ofits decreased anion transport activity.
Metformin Associated Lactic Acidosis (MALA) is a rare, but serious complications of Type 2 diabetes mellitus treatment with a mortality rate of around 50%. It most commonly occurs in the setting of hepatic, cardiac or renal insufficiency. We report the case of an elderly female with MALA and concomitant starvation ketosis in the absence of any known risk factor, who went undiagnosed for a period of at least a month and made a complete recovery in the hospital.
We have previously demonstrated that compound heterozygous (SAO/G701D) and homozygous (G701D/G701D) mutations of the anion exchanger 1 (AE1) gene, encoding erythroid and kidney AE1 proteins, cause autosomal recessive distal renal tubular acidosis (AR dRTA) in Thai patients. It is thus of interest to examine the prevalence of these mutations in the Thai population. The SAO and G701D mutations were examined in 844 individuals from north, northeast, central, and south Thailand. Other reported mutations including R602H, DeltaV850, and A858D were also examined in some groups of subjects. The SAO mutation was common in the southern Thai population; its heterozygote frequency was 7/206 and estimated allele frequency 1.70%. However, this mutation was not observed in populations of three other regions of Thailand. In contrast, the G701D mutation was not found in the southern population but was observed in the northern, northeastern, and central populations, with heterozygote frequencies of 1/216, 3/205, and 1/217, and estimated allele frequencies of 0.23%, 0.73%, and 0.23%, respectively. The higher allele frequency of the G701D mutation in the northeastern Thai population corresponds to our previous finding that all Thai patients with AR dRTA attributable to homozygous G701D mutation originate from this population. This suggests that the G701D allele that is observed in this region might arise in northeastern Thailand. The presence of patients with compound heterozygous SAO/G701D in southern Thailand and Malaysia and their apparently absence in northeastern Thailand indicate that the G701D allele may have migrated to the southern peninsular region where SAO is common, resulting in pathogenic allelic interaction.
Southeast Asian ovalocytosis (SAO) is a red blood cell abnormality common in malaria-endemic regions and caused by a 27 nt deletion of the band 3 protein gene. Since band 3 protein, also known as anion exchanger 1, is expressed in renal distal tubules, the incidence of SAO was examined in distal renal tubular acidosis (dRTA) in Malays in Kelantan, Malaysia. Twenty-two patients with dRTA and 50 healthy volunteers were examined for complication of SAO by both morphological and genetic analyses. SAO was identified in 18 of the 22 dRTA patients (81.8%), but only two of the 50 controls (4%). The incidence of SAO was significantly high in those with dRTA (p<0.001), indicating a dysfunctional role for band 3 protein/anion exchanger 1 in the development of dRTA.
A 4-month-old healthy male infant underwent left herniotomy under general anesthesia with caudal block. Carbon dioxide (CO2) pneumoperitoneum was created through the left hernial sac for inspection of the right processus vaginalis. Episodes of desaturation associated with significant reduction in chest compliance were noted intraoperatively. This was overcome by increasing the inspired oxygen concentration (FiO2). The infant failed to regain consciousness and spontaneous respiration at the end of surgery. The chest compliance deteriorated further and clinically a CO2 pneumothorax (capnothorax) was suspected. The endtidal carbon dioxide (P(E)CO2) was initially low in the immediate postoperative period. Subsequent to the readministration of sevoflurane and manual ventilation with a Jackson Rees circuit, a sudden surge in P(E)CO2 with improvement of chest compliance was observed. At that time arterial blood gas (ABG) analysis revealed a PCO2 of 17.5 kPa (134 mmHg) and pH of 6.9. The causes of severe hypercarbia and the physiological changes observed in this infant are discussed.
Mutations of the AE1 (SLC4A1, Anion-Exchanger 1) gene that codes for band 3, the renal and red cell anion exchanger, are responsible for many cases of familial distal renal tubular acidosis (dRTA). In Southeast Asia this disease is usually recessive, caused either by homozygosity of a single AE1 mutation or by compound heterozygosity of two different AE1 mutations. We describe two unrelated boys in Sarawak with dRTA associated with compound heterozygosity of AE1 mutations. Both had Southeast Asian ovalocytosis (SAO), a morphological abnormality of red cells caused by a deletion of band 3 residues 400-408. In addition, one boy had a DNA sequence abnormality of band 3 residue (G701D), which has been reported from elsewhere in Southeast Asia. The other boy had the novel sequence abnormality of band 3 (Q759H) and profound hemolytic anemia.
Exposure to highly active antiretroviral therapy (HAART) may lead to adverse effects related to mitochondrial toxicity such as lactic acidosis. We describe two cases of severe lactic acidosis in HIV-positive patients to illustrate the clinical symptoms and abnormal laboratory results associated with this condition. There is a lack of awareness about the risk factors for developing severe lactic acidosis and recognition of its onset with dire consequences.
Gastric outlet obstruction and in particular, pyloric stenosis, is relatively common in developing countries. Acute clinical presentation is often the manifestation of biochemical and electrolyte changes. The presence of metabolic alkalosis in combination with acute renal failure should alarm us to the possibility of adult pyloric stenosis. We report a case of adult pyloric stenosis that presented as acute renal failure and discuss its pathophysiology.