Fever as a cause of hypophosphatemia in patients with malaria

Hypophosphatemia occurs in 40 to 60% of patients with acute malaria, and in many other conditions associated with elevations of body temperature. To determine the prevalence and causes of hypophosphatemia in patients with malaria, we retrospectively studied all adults diagnosed with acute malaria during a 12-year period. To validate our findings, we analyzed a second sample of malaria patients during a subsequent 10-year period. Serum phosphorus correlated inversely with temperature (n = 59, r = -0.62; P<0.0001), such that each 1 degrees C increase in body temperature was associated with a reduction of 0.18 mmol/L (0.56 mg/dL) in the serum phosphorus level (95% confidence interval: -0.12 to -0.24 mmol/L [-0.37 to -0.74 mg/dL] per 1 degrees C). A similar effect was observed among 19 patients who had repeat measurements of serum phosphorus and temperature. In a multiple linear regression analysis, the relation between temperature and serum phosphorus level was independent of blood pH, PCO2, and serum levels of potassium, bicarbonate, calcium, albumin, and glucose. Our study demonstrates a strong inverse linear relation between body temperature and serum phosphorus level that was not explained by other factors known to cause hypophosphatemia. If causal, this association can account for the high prevalence of hypophosphatemia, observed in our patients and in previous studies of patients with malaria. Because hypophosphatemia has been observed in other clinical conditions characterized by fever or hyperthermia, this relation may not be unique to malaria. Elevation of body temperature should be added to the list of causes of hypophosphatemia.     

Acute and chronic phosphate depletion as a modulator of glucose uptake in rat skeletal muscle.

The effect of acute and chronic hypophosphatemia on rat hindlimb skeletal muscle glucose uptake was examined. Acute hypophosphatemia had no effect on glucose uptake whereas chronic hypophosphatemia had a direct linear effect on glucose uptake.     

The Effect of Urography on Renal Function in Patients with Multiple Myeloma

Reports in the medical literature of seven patients with multiple myeloma who died of acute renal failure following intravenous urography prompted a study of 39 patients with multiple myeloma who were subjected to intravenous urography at the Cleveland Clinic from 1940 to 1959. Four developed acute renal failure and two died within three weeks. All four revealed evidence of renal damage, or insufficiency, or both prior to urography. Thirty-five patients, 15 of whom had renal damage, had no untoward reaction to intravenous urography. These observations suggest that urography is associated with a small but definite risk in patients who have multiple myeloma and renal involvement.     

Fluorouracil cardiotoxicity.

Our of 140 patients treated with intravenous 5-fluorouracil, four developed ischaemic chest pain within 18 hours of either the second or third dose. In three of these patients the pain recurred after subsequent doses. Predose electrocardiograms in two cases were normal. None of the four patients had a history of ischaemic heart disease, although all had received left ventricular irradiation. Although cardiotoxicity is a rare complication of fluorouracil treatment, it merits wider recognition.     

Hypophosphatemia

Hypophosphatemia is a common laboratory abnormality that occurs in a wide variety of disorders. When severe and prolonged, it may be associated with rhabdomyolysis, brain dysfunction, myocardial failure and certain defects of erythrocyte function and structure. Other disorders ascribed to hypophosphatemia, including platelet dysfunction and thrombocytopenia, liver dysfunction, renal tubular defects, peripheral neuropathy, metabolic acidosis and leukocyte dysfunction are less well documented. In quantitative terms, the most severe phosphate deficiency is seen in patients who consume a phosphate-deficient diet in conjunction with large amounts of phosphate-binding antacids, in persons with severe, chronic alcoholism and in patients with wasting illnesses who are refed with substances containing an inadequate amount of phosphate. When severe hypophosphatemia occurs in such a setting, the clinical effects appear to be much more pronounced. While there have been some advances in our understanding of the pathophysiology of phosphate depletion and hypophosphatemia, much remains to be learned. Treatment of hypophosphatemia is controversial; however, there is little question that it is indicated in alcoholic patients and those with severe phosphate deficiency.     

WOMAN'S AUXILIARY: MEET YOUR AUXILIARY OFFICERS 1958-1959

Clinical observations have indicated that patients who are in shock and who have coexisting acidosis respond relatively poorly to sympathomimetic amines. In experiments with dogs, it was found that, in the presence of acidosis, the pressor action of epinephrine, norepinephrine and metaraminol was considerably reduced. The effect on cardiac rhythm was also considerably lessened after the pH value of the blood had been lowered. In view of these observations in animals, six human patients with profound shock and acidosis were studied. All had a considerably lessened pressor response to vasopressor agents; then, after elevation of the blood pH by intravenous infusion of a 1-molar solution of sodium lactate, responsiveness was restored. These observations emphasize the desirability of close observation of the acid-base status, and early treatment of acidosis, as an important aspect in the management of patients with shock.     

VASOPRESSOR AGENTS—Influence of Acidosis on Cardiac and Vascular Responsiveness

Clinical observations have indicated that patients who are in shock and who have coexisting acidosis respond relatively poorly to sympathomimetic amines. In experiments with dogs, it was found that, in the presence of acidosis, the pressor action of epinephrine, norepinephrine and metaraminol was considerably reduced. The effect on cardiac rhythm was also considerably lessened after the pH value of the blood had been lowered.In view of these observations in animals, six human patients with profound shock and acidosis were studied. All had a considerably lessened pressor response to vasopressor agents; then, after elevation of the blood pH by intravenous infusion of a 1-molar solution of sodium lactate, responsiveness was restored.These observations emphasize the desirability of close observation of the acid-base status, and early treatment of acidosis, as an important aspect in the management of patients with shock.     

Use of β-Blockade and Hemoperfusion for Acute Theophylline Poisoning

Five adults were treated successfully for severe theophylline poisoning due to intentional overdosage. Clinical features included nausea, tremor, delirium, hypotension and cardiac arrhythmias, metabolic acidosis, hyperglycemia, hypokalemia and hypophosphatemia. No seizures or deaths occurred despite very high serum theophylline concentrations (between 96 and 194 μg per ml). Extreme elevations of plasma catecholamines were documented and are implicated in the toxicity. β-Blockade with intravenous administration of propranolol hydrochloride was the most effective therapy for theophylline-induced hypotension. All patients were treated with resin hemoperfusion, which resulted in significant clinical improvement and rapid lowering of the serum theophylline level.     

Reduced renal cortical ribonucleoside triphosphate pools in three different hypophosphatemic animal models

Renal cortical metabolite quantitation in three different models of hypophosphatemia demonstrates that ribonucleoside triphosphate depletion is a common manifestation of reduced plasma phosphate concentration. Total tissue inorganic phosphate is not necessarily altered as the result of hypophosphatemia. Compensatory increases in mono- and diphosphate pools maintain the total ribonucleotide pool but cause reductions in the energy charge for the adenine, guanine, and uridine nucleotides. The coordinate regulation of all ribonucleoside triphosphate pools suggests cellular dysfunction accompanying hypophosphatemia may be the consequence of a generalized derangement in energy and nucleotide metabolism.     

Delayed thrombocytopenia following abciximab therapy

Inhibitors of glycoprotein (GP) IIb/IIIa are currently approved for the treatment of acute coronary syndromes and during performance of percutaneous coronary interventions (PCIs). More than 500 000 patients annually undergo PCIs in the USA alone. Of these, 35% are receiving GPIIb/IIIa inhibitors. Currently, three different intravenous GPIIb/IIIa inhibitors are commercially available. Profound thrombocytopenia occurs almost exclusively with abciximab. Usually thrombocytopenia develops within 24 hours following abciximab administration. This paper describes three patients who developed delayed profound thrombocytopenia, occurring five days following abciximab therapy. These cases of thrombocytopenia were self-limited and reversible. Absence of serious bleeding complications was noted. The pathophysiology, differential diagnosis, natural history and management of the coronary patients with abciximab-induced thrombocytopenia are discussed.     

Imaging thrombus with radiolabelled monoclonal antibody to platelets.

Indium-111-hydroxyquinoline labelled platelets, though useful in the detection of thrombus, have not gained widespread use owing to the time and technical skill required for their preparation. A study was therefore conducted evaluating a new method of imaging thrombus with platelets radiolabelled with a 111In labelled monoclonal antibody, P256, directed to the platelet surface glycoprotein complex IIb/IIIa. When the number of receptors occupied by P256 was less than 3% of the total available on the platelet surface platelet function, as assessed by platelet aggregometry, was undisturbed. P256 was radiolabelled with 111In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo--that is, by direct intravenous injection of P256--in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The 111In kinetics recorded after intravenous P256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P256, three had documented thrombus, two of whom gave positive results on P256 platelet scintigraphy. The third subject had chronic deep venous thrombosis and was scintigraphically negative. Imaging thrombus using a radiolabelled monoclonal antibody directed to platelets appears to offer great potential as a simple, non-invasive approach to the diagnosis of thrombosis.     

Intact Fibroblast Growth Factor 23 Concentrations in Hypophosphatemic Disorders

ObjectiveEvaluation of circulating fibroblast growth factor 23 (FGF23) concentrations plays a key role in the differential diagnosis of patients presenting with hypophosphatemia. FGF23 concentrations obtained by different immunoassays are not comparable and subsequently, differences in the clinical performance of the assays might arise. In this study, we evaluated the clinical performance of the Medfrontier FGF23 Intact immunoassay (MedFrontier, Minaris Medical Co, Ltd, Tokyo, Japan) in clinically relevant hypophosphatemic conditions.MethodsIntact FGF23 (iFGF23) was measured in serum samples from 61 patients with FGF23-dependent hypophosphatemia (42-tumor induced osteomalacia [TIO] and 19-X-linked hypophosphatemia [XLH]); 8 patients with FGF23-independent hypophosphatemia (6-Fanconi Syndrome and 2-Vitamin D dependent rickets); 10 normophosphatemic patients; 15 chronic kidney disease (CKD) stage-2/3 and 20 CKD stage-4/5 patients; and a healthy control population. Disease-specific differences in measured iFGF23 concentrations and FGF23 concentration association with phosphate concentrations were reported.ResultsiFGF23 concentrations were significantly elevated in 90% and 84% of TIO and XLH hypophosphatemia patients as compared to healthy controls (both TIO and XLH, P = .0001). There was no significant correlation between iFGF23 and phosphate concentrations (P = .74 and P = .86) for TIO and XLH, respectively. Patients with CKD showed a significant increase in serum iFGF23 as the estimated glomerular filtration rate decreased (ρ = -0.79, P ≤ 0.0001).ConclusionsThis study evaluated the clinical performance of the MedFrontier iFGF23 assay in a large cohort of XLH and TIO Caucasian and Asian patients. The clinical sensitivity of this iFGF23 assay is appropriate for clinical use.     

Novel mutations of MYO15A associated with profound deafness in consanguineous families and moderately severe hearing loss in a patient with Smith-Magenis syndrome

Mutations in myosin XVA are responsible for the shaker 2 ( sh2) phenotype in mice and nonsyndromic autosomal recessive profound hearing loss DFNB3 on chromosome 17p11.2. We have ascertained seven families with profound congenital hearing loss from Pakistan and India with evidence of linkage to DFNB3 at 17p11.2. We report three novel homozygous mutations in MYO15A segregating in three of these families. In addition, one hemizygous missense mutation of MYO15A was found in one of eight Smith-Magenis syndrome (del(17)p11.2) patients from North America who had moderately severe sensorineural hearing loss.     

Kidney function after renal arterial embolism

Seven patients with atrial fibrillation had acute unilateral renal pain associated with suppression of function in the affected kidney. This was ascribed to renal embolism. Arteriography performed in four patients showed abnormalities in the renal arterial tree in three, though thrombus in a main artery was present in only one.Considerable function returned spontaneously to the affected kidney in six patients as judged by intravenous pyelography or renography. In two patients the sole functioning kidney was affected, leading to acute oliguric renal failure, but renal function recovered in each case. The routine use of anticoagulants in persistent atrial fibrillation is justified by such cases.     

Subcutaneous calcium heparin versus intravenous sodium heparin in treatment of established acute deep vein thrombosis of the legs: a multicentre prospective randomised trial.

One hundred patients with phlebographically proved acute deep vein thrombosis of the legs were prospectively randomised into two treatment groups to compare the safety and efficacy of subcutaneous calcium heparin versus intravenous sodium heparin administered by constant infusion pump. The dose of heparin was determined by daily measurement of the kaolin cephalin clotting time. Treatment was maintained for up to 14 days, after which phlebography was repeated. Of 49 patients who received subcutaneous calcium heparin, two showed an increase in thrombus size, while eight showed complete lysis. In the 47 patients who received intravenous sodium heparin thrombus increased in size in 13 while only one showed evidence of complete lysis. These differences were significant. There were no significant differences between the two groups in the incidence of serious complications, although almost half of those receiving intravenous heparin had some minor problem with the constant infusion pump and just over half of those receiving subcutaneous heparin had some bruising at the injection site. This study showed that subcutaneous calcium heparin was more effective in helping lyse existing thrombus and preventing its propagation than intravenous sodium heparin.     

Mechanisms of hypophosphatemia in humans with heatstroke

Hypophosphatemia is common in heatstroke, but little is known about its mechanism. We investigated 10 consecutive patients with heatstroke (mean age 58 +/- 2 yr) whose mean rectal temperature at admission was 42.3 +/- 0.2 degrees C. Eight patients presented with hypophosphatemia [0.48 +/- 0.08 mmol/l, normal range (NR) 0.8-1.4 mmol/l], associated with increased fractional excretion of phosphate (19.8 +/- 6.4%, NR 6-20%) relative to plasma phosphate levels and reduced renal threshold for phosphate (0.55 +/- 0.08 mmol/l glomerular filtrate, NR 0.8-1.4 mmol/l). Plasma parathyroid hormone (75.0 +/- 5 pmol/l) and calcium (2.24 +/- 0.02 mmol/l) levels and fractional excretion of calcium were normal (1.66 +/- 0.27%). There was no evidence of uricosuria or aminoaciduria, and only one patient had glucosuria. Arterial carbon dioxide was decreased in eight patients (28 +/- 1.1 Torr); however, none had elevated blood pH (7.35 +/- 0.02). The results suggest that heatstroke-related hypophosphatemia is associated with abnormal phosphaturia independent of the parathyroid hormone level, and there is no evidence of tubular dysfunction.     

Hereditary hypophosphatemic rickets with hypercalciuria is caused by mutations in the sodium-phosphate cotransporter gene SLC34A3

Hypophosphatemia due to isolated renal phosphate wasting results from a heterogeneous group of disorders. Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is an autosomal recessive form that is characterized by reduced renal phosphate reabsorption, hypophosphatemia, and rickets. It can be distinguished from other forms of hypophosphatemia by increased serum levels of 1,25-dihydroxyvitamin D resulting in hypercalciuria. Using SNP array genotyping, we mapped the disease locus in two consanguineous families to the end of the long arm of chromosome 9. The candidate region contained a sodium-phosphate cotransporter gene, SLC34A3, which has been shown to be expressed in proximal tubulus cells. Sequencing of this gene revealed disease-associated mutations in five families, including two frameshift and one splice-site mutation. Loss of function of the SLC34A3 protein presumably results in a primary renal tubular defect and is compatible with the HHRH phenotype. We also show that the phosphaturic factor FGF23 (fibroblast growth factor 23), which is increased in X-linked hypophosphatemic rickets and carries activating mutations in autosomal dominant hypophosphatemic rickets, is at normal or low-normal serum levels in the patients with HHRH, further supporting a primary renal defect. Identification of the gene mutated in a further form of hypophosphatemia adds to the understanding of phosphate homeostasis and may help to elucidate the interaction of the proteins involved in this pathway.     

Sensitivity to Intravenous Anaesthetics: A Report of Three Cases

Three patients with sensitivity to an intravenous anaesthetic—thiopentone, propanidid, and Althesin (alphadolone and alphaxalone)—are described. In the cases of thiopentone and Althesin the reaction was characterized by cardiovascular collapse, while bronchospasm also occurred with thiopentone. The reaction to propanidid was a direct skin sensitivity. All patients had a personal or family history of asthma and all had been previously exposed to the offending drug. A leucocyte challenge test showed an allergic response to thiopentone and Althesin in two patients but gave a negative result in the patient with the skin reaction. Allergic reactions can occur to all types of intravenous anaesthetics in a few patients.     

Up-regulation of liver glucose-6-phosphatase in x-linked hypophosphatemic mice.

We previously showed that a phosphate-deficient diet resulting in hypophosphatemia upregulated the catalytic subunit p36 of rat liver glucose-6-phosphatase, which is responsible for hepatic glucose production. A possible association between phosphate and glucose homeostasis was now further evaluated in the Hyp mouse, a murine homologue of human X-linked hypophosphatemia. We found that in the Hyp mouse as in the dietary Pi deficiency model, serum insulin was reduced while glycemia was increased, and that liver glucose-6-phosphatase activity was enhanced as a consequence of increased mRNA and protein levels of p36. In contrast, the Hyp model had decreased mRNA and protein levels of the putative glucose-6-phosphate translocase p46 and liver cyclic AMP was not increased as in the phosphate-deficient diet rats. It is concluded that in genetic as in dietary hypophosphatemia, elevated glucose-6-phosphatase activity could be partially responsible for the impaired glucose metabolism albeit through distinct mechanisms.     

RENOGRAMS—Correlation with Renal Arteriography and Intravenous Pyelography

A study was carried out to determine how well the information supplied by a radioactive renogram correlates with that obtained by renal arteriography and intravenous pyelography. In 1962 35 patients at the UCLA Medical Center had all three studies. This represents a total of 70 kidneys (one kidney surgically absent). We found the radioactive renogram to be a very reliable and valuable aid in the diagnosis of kidney disease. When compared with the results of the intravenous pyelogram and aortogram, the renogram had false negative result in 11 per cent of cases, and a 14 per cent false positive result.