An initial evaluation of hypokalemia turned out distal renal tubular acidosis secondary to parathyroid adenoma.

Primary hyperparathyroidism (PHPT) usually presents with hypercalcemia related symptoms and signs. Kidneys play an important role in calcium homeostasis. PHPT has been reported to be associated with hyperchloremia, defective urinary acidification, and renal tubular acidosis (RTA). The dysfunction of distal renal tubules is proposed to be secondary to calcium deposition in distal tubules. This case report highlights an initial presentation of parathyroid adenoma as hypokalemia due to distal RTA secondary to medullary nephrocalcinosis.

Is NESTROFT sufficient for mass screening for beta-thalassaemia trait?

OBJECTIVES: Prevention of beta-thalassaemia trait will, for the foreseeable future, hinge on effective screening strategies. Routine use of haematological data from automated cell counters may complement the results of the Naked Eye Single Tube Red cell Osmotic Fragility Test (NESTROFT), especially because of the high cost of a false-negative error. Our objective was to assess the potential additive value of routine haematological data in screening for beta-thalassaemia trait. SETTINGS: Community survey of asymptomatic volunteers. METHODS: Using the NESTROFT results, haematological data and haemoglobin A(2) concentration from 1435 young, asymptomatic Sindhi subjects recruited in a population-based survey, and statistical analysis by classification tree approach, we examined whether haematological parameters have discriminatory utility additional to that of NESTROFT in screening for beta-thalassaemia trait. RESULTS: We observed that in the derivation subset from which the classification tree was generated, there was only a marginal--albeit statistically significant--improvement in the screening performance of NESTROFT, whereas there was no such improvement attributable to the use of haematological parameters in a separate validation subset. CONCLUSION: Our results further substantiate the claim that the use of NESTROFT is highly indicated for screening for beta-thalassaemia trait in regions where the prevalence is high and the resources are constrained.

Erythrophagocytosis in sickle cell anemia: statistical evidence for a biological phenomenon.

The precise role of erythrophagocytosis in sickle cell disease is not known. Using hematological data from three studies and 791 subjects comprising of eight epidemiological groups, we found a strong statistical support for the hypothesis that erythrophagocytosis is increased in sickle cell trait, that neutrophils and lymphocytes are the most likely cells involved in erythrophagocytosis in these subjects and that increased erythrophagocytosis may for a mechanistic explanation for an increased risk of vaso-occlusive crisis in sickle cell trait. Statistically, erythrophagocytosis was not increased in subjects with homozygous sickle cell disease. Our findings offer an interesting mechanistic implication about the presence of a strong autoimmune component of sickle cell trait that can be explained by the well recognized interplay between the receptor molecule signal regulatory protein-alpha (SIRP-alpha) on the phagocyte and its ligand, CD47, on the red blood cell. Our findings also support further and closer evaluation of the other hypothesized mechanisms by which neutrophils and lymphocytes partake in differential degree of erythrophagocytosis in subjects heterozygous for the sickle hemoglobin. Finally, translation of these findings into a clinical realm suggests that the extent of erythrophagocytosis, as measured by peripheral blood hematological indicators, can serve as an important indicator of the likelihood of future vaso-occlusive crisis events in subjects of sickle cell trait.

Bias-corrected diagnostic performance of the naked-eye single-tube red-cell osmotic fragility test (NESTROFT): an effective screening tool for beta-thalassemia.

It is being increasingly recognized that a majority of the countries in the thalassemia-belt need a cost-effective screening program as the first step towards control of thalassemia. Although the naked eye single tube red cell osmotic fragility test (NESTROFT) has been considered to be a very effective screening tool for beta-thalassemia trait, assessment of its diagnostic performance has been affected with the reference test- and verification-bias. Here, we set out to provide estimates of sensitivity and specificity of NESTROFT corrected for these potential biases. We conducted a cross-sectional diagnostic test evaluation study using data from 1563 subjects from Central India with a high prevalence of beta-thalassemia. We used latent class modelling after ensuring its validity to account for the reference test bias and global sensitivity analysis to control the verification bias. We also compared the results of latent class modelling with those of five discriminant indexes. We observed that across a range of cut-offs for the mean corpuscular volume (MCV) and the hemoglobin A2 (HbA2) concentration the average sensitivity and specificity of NESTROFT obtained from latent class modelling was 99.8 and 83.7%, respectively. These estimates were comparable to those characterizing the diagnostic performance of HbA2, which is considered by many as the reference test to detect beta-thalassemia. After correction for the verification bias these estimates were 93.4 and 97.2%, respectively. Combined with the inexpensive and quick disposition of NESTROFT, these results strongly support its candidature as a screening tool-especially in the resource-poor and high-prevalence settings.