The Kainos Intact assay was the most sensitive, followed by the Immunotopics C-terminal assay. The findings of normal FGF23 concentrations in some patients with TIO may indicate that FGF 23 is not responsible for the hypophosphatemia in these patients or that FGF23 secretion by some tumors is partially responsive to serum phosphate. Normal FGF23 concentrations should be interpreted in relation to the serum phosphate and 1,25-dihydryxyvitamin-D concentrations.
The clinical, biochemical, and radiographic features of ectopic ACTH-dependent Cushing's syndrome are often indistinguishable from those of pituitary ACTH-dependent hypercortisolism (Cushing's disease). We prospectively evaluated 29 patients with ACTH-dependent hypercortisolism by means of bilateral inferior petrosal sinus ACTH sampling with ovine CRH (oCRH) stimulation. Patients with Cushing's disease (n = 20), had a maximal basal inferior petrosal sinus to peripheral ACTH ratio (IPS:P-ACTH) of 11.7 +/- 4.4 (+/- SE) from the dominant IPS, which increased to 50.8 +/- 18.3 after oCRH administration. Bilateral IPS sampling was necessary to correctly identify patients with Cushing's disease, since the maximal basal nondominant IPS:P-ACTH was less than 2.0 in over 50% of the patients and remained less than 2.0 after oCRH administration in one third. In contrast, patients with occult ectopic ACTH-secreting neoplasms (n = 9) had maximal basal IPS:P-ACTH of 1.2 +/- 0.1 that did not change after oCRH administration. Occult ectopic ACTH-secreting neoplasms were found in 7 of 9 patients from 0.4-14 yr after the recognition of Cushing's syndrome, and 4 of these patients had intermittent hypercortisolism with prolonged periods of remission. Selective endobronchial lavage for ACTH correctly localized a radiologically occult ACTH-secreting bronchial carcinoid in 1 patient, and magnetic resonance imaging identified a similar neoplasm in a patient with a normal chest computed tomographic scan. Basal ACTH and urinary free cortisol excretion were significantly higher in patients with ectopic ACTH than in those with Cushing's disease, but overlap existed between groups. High dose dexamethasone suppression testing inaccurately classified 24% of patients, and radiological imaging of the pituitary and adrenal glands was misleading. The occult ectopic ACTH syndrome is a common form of ACTH-dependent hypercortisolism that cannot be distinguished from Cushing's disease with routine clinical studies. The accurate differential diagnosis of ACTH-dependent Cushing's syndrome requires bilateral inferior petrosal sinus ACTH sampling with oCRH stimulation.
We diagnosed Fanconi's syndrome (phosphate depletion and dysfunction of the renal tubules) in three HIV؉ patients. This was temporally related to their HIV treatment. Physicians caring for patients with HIV should recognize the association of this rare syndrome with antiretroviral medications and monitor their patients carefully.Introduction: Fanconi's syndrome is caused by increased excretion of phosphate, glucose, amino acids, and other intermediary metabolites, and can result in osteomalacia.
Materials and Methods:We diagnosed this syndrome in three HIV ϩ patients. Results: The first was a 43-year-old woman referred for multiple painful stress fractures. She demonstrated hypophosphatemia, metabolic acidosis, phosphaturia, glucosuria, and generalized aminoaciduria. These abnormalities resolved with oral phosphate replacement and discontinuation of the antiretroviral medication tenofovir. The second patient was a 39-year-old man with hypophosphatemia and bone pain. His symptoms improved with discontinuation of adefovir and supplementation of phosphate, potassium, and calcitriol. The third patient was a 48-year-old man who presented with symptomatic tetany caused by hypocalcemia (total serum calcium of 6.5 mg/dl [8.5-10.5 mg/dl]). Nine months before presentation, he had been treated with cidofovir for retinitis caused by cytomegalovirus. With calcium, phosphate, potassium, and calcitriol therapy, his laboratory abnormalities improved substantially, although he continues to require daily electrolyte replacement. Conclusions: Each patient demonstrated generalized renal tubular dysfunction temporally related to treatment with antiretroviral drugs. The mechanism responsible for these abnormalities is not known; however, physicians caring for patients with HIV disease should recognize the association of Fanconi's syndrome with antiretroviral medications and monitor susceptible patients to prevent potential skeletal and neuromuscular complications.
Paget's disease of bone is a common disorder which may affect one or many bones. Although many patients are asymptomatic, a variety of symptoms and complications may occur. Fortunately, effective pharmacologic therapy, primarily with potent bisphosphonates, is now available to treat patients with complications or symptoms. This review of Paget's disease of bone will include epidemiology and pathophysiology, complications and clinical findings, indications for treatment, and the drugs currently available to treat this condition.
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