Impact of genotype on clinical course in sickle cell disease and the utility of neutrophil-lymphocyte ratio: a ten-year single-institution experience.

BACKGROUND: Sickle cell disease (SCD) is a diverse group of blood disorders with significant global disease burden. Contemporary interest in the underlying inflammatory paradigm of SCD has emphasized the role of the neutrophil-lymphocyte ratio (NLR) as a prognostic inflammatory marker. METHODS: We retrospectively reviewed 268 hospitalized patients with SCDs of different genotypes (HbSS, HbSß0 thalassemia, HbSß+ thalassemia, and HbSC), totaling 3329 hospital admissions over a 10-year period. Patients were stratified into SS/Sß0 and Sß+/SC groups for statistical analysis of parameters collected at steady state and at hospital admission. RESULTS: At steady state, per unit increase of hemoglobin values was associated with reduced odds of ≥ 2 hospital admissions per year in SS/Sß0 and Sß+/SC groups; per unit increase in platelet count and white blood cell count was associated with increased odds only in the SS/Sß0 group. The NLR had no association in either group. During admission, a cutoff of NLR = 3.5 discerned infection with a sensitivity of 60% and specificity of 57%. Performance improved when excluding patients on outpatient hydroxyurea therapy (cutoff of NLR = 3.5; sensitivity of 68% and specificity of 64%). CONCLUSION: This study supports the utility of NLR as an accessible adjunctive clinical tool in SCD prognostication.

A Stroke of Luck: Central Diabetes Insipidus Unmasked by a Heat Stroke.

Diabetes insipidus is a rarely encountered cause of hypernatremia, often presenting a diagnostic and therapeutic dilemma for the encountering physician. Patients are often asymptomatic for a number of years due to compensation of their polyuria with polydipsia, but may have dramatic presentations in situations where they lose access to hydration. Our case is of a 62-year-old woman who was found unconscious with signs and symptoms of a heat stroke, and later was found to have resistant hypernatremia that persisted despite extensive free water supplementation. She had dilute polyuria throughout her hospital course, eventually warranting testing for diabetes insipidus with a vasopressin challenge test. She responded well to therapy with intranasal desmopressin and currently remains asymptomatic. Because our patient was reported to have polyuria and polydipsia for a number of years presumed to be due to underlying diabetes mellitus, it is possible that she had pre-existing central diabetes insipidus that was exacerbated by the lack of access to free water while she was in her intubated and sedated state. Alternatively, she may have also developed new-onset diabetes insipidus due to severe hyperthermia. This case serves to highlight a dramatic presentation of diabetes insipidus, and the importance of careful consideration of its diagnosis in patients with persistent dilute polyuria despite signs of intravascular volume depletion.