The Case | Microhematuria in a patient with beta-thalassemia major: a casual or a causal association?

Chapter 4: Differential diagnosis of primary hyperparathyroidism

The differential diagnosis of primary hyperparathyroidism can be considered clinically, biologically and radiologically. Clinically, primary hyperparathyroidism should be suspected in case of diffuse pain, renal lithiasis, osteoporosis, repeated fracture, cognitive or psychiatric disorder, or disturbance of consciousness. Nevertheless, the differential diagnosis of primary hyperparathyroidism is mainly biological, particularly in atypical forms, which must be differentiated from hypercalcemia with hypocalciuria or non-elevated PTH on the one hand, and from normo-calcemia with elevated PTH, hypophosphatemia or hypercalciuria on the other. Any differential diagnosis must be preceded by an analysis of the factors likely to disturb phospho-calcium parameters: vitamin D deficiency (assay), renal insufficiency (eGFR measurement), malabsorption (inflammatory disease of the digestive tract, celiac disease, bariatric surgery, etc.), insufficient calcium intake (GRIO questionnaire) and iatrogenic causes (diuretics, anti-osteoporotic drugs, excessive vitamin D or calcium supplementation, lithium, corticosteroid therapy, phosphorus intake). Once these factors have been eliminated, hypercalcemia with hypocalciuria should suggest a genetic cause. Hypercalcemia with non-elevated PTH may be secondary to neoplasm, hypervitaminosis D (excessive intake, production or catabolism), immobilization or endocrine causes. Elevated PTH values without hypercalcemia must be differentiated from normo-calcemic hyperparathyroidism. High PTH levels are found in PTH-resistant patients, as well as in hypophosphatemic (especially X-linked) or hypercalciuric tubulopathies (certain rare diseases, immobilization, loop diuretics or idiopathic causes favored by a metabolic syndrome). Radiologically, brown tumor must be differentiated primarily from bone metastasis, chondrosarcoma and giant cell tumor.

Clinical features and risk factors of renal dysfunctions in thalassemic patients

INTRODUCTION

Chronic anemia, iron overload, and iron chelation therapy are the main contributing factors for renal complications in thalassemia, e.g., nephrolithiasis, glomerular disease, and renal tubular dysfunction. The prevalence and associated factors for developing renal dysfunctions in Thai patients with thalassemia, however, remained limited. This study aimed to determine the prevalence and risk factors of renal dysfunctions in patients with thalassemia.

METHODS

A cross-sectional study was conducted on adult patients with thalassemia disease at Srinagarind Hospital, Khon Kaen University, Thailand. All patients were evaluated for complete blood count, blood chemistry, urinalysis, and urine biochemistry. Renal tubular dysfunction was defined as existing in at least one of the following parameters including; proteinuria, hypercalciuria, hypouricemia with uricosuria, or hypophosphatemia with phosphaturia. Logistic regression analysis was used to identify associated factors for renal dysfunctions.

RESULTS

Of 105 patients, renal tubular dysfunction was found in 60 patients (57.1%). In multivariate analysis of the clinical risk factors for renal tubular dysfunction in thalassemia patients, age per 10 year increase (adjusted odds ratio [AOR] = 1.4, 95% CI: 1.0-2.0, p value 0.01) and Hb E/beta-thalassemia (AOR = 3.6, 95% CI: 1.3-10.3, p value 0.01) were statistically proven to be associated with renal tubular dysfunction. Hyperuricosuria was a significantly associated factor for microhematuria. (AOR = 2.9, 95% CI: 1.1-8.0, p value 0.03).

CONCLUSIONS

Renal dysfunctions are prevalent in thalassemia patients, with older age and Hb E/beta-thalassemia genotype as significant risk factors for renal tubular dysfunction. Hyperuricosuria is a risk factor for microhematuria. Renal dysfunctions should be recognized and monitored in aging patients with Hb E/beta-thalassemia.