Mechanism of low serum sodium levels in Mediterranean spotted fever.

Prominent degrees of hyponatremia are detected in the severe forms of Mediterranean spotted fever and the intensity of this abnormality parallels the severity of the infectious process. In order to determine the incidence, degree and evolution of hyponatremia in 110 patients with Mediterranean spotted fever and to explore the feasible renal mechanism that could lead to this phenomenon, serum and urinary osmolality and levels of urea, creatinine and electrolytes were measured in samples obtained at selected points (up to the fifth week) in the course of the disease, and parameters of renal function were calculated. Mean serum sodium levels of 135.6 +/- 5.5 mEq/l were detected during the acute phase of the infection. At this point, 42 patients (38.2%) had sodium concentrations less than or equal to 135 mEq/l. After recovery, mean serum sodium values were 142.5 +/- 2.5. The analysis of the parameters of renal function indirectly rules out an inappropriate antidiuretic hormone secretion or renal failure as the cause of hyponatremia. As tubular incompetence to reabsorb sodium is also rejected in these patients, a shifting of sodium to the interstitial or intracellular space may account for the phenomenon.     

Endoscopic sphincteroplasty: a novel and safe alternative to papillotomy in the management of bile duct stones.

Removal of bile duct stones during endoscopic retrograde cholangiopancreatography (ERCP) usually includes papillotomy. Papillotomy is associated with occasional complications and in addition, the longterm sequelae of papillotomy in young patients having laparoscopic cholecystectomy remain unclear. As an alternative to papillotomy, this study prospectively evaluated the efficacy and safety of endoscopic balloon sphincteroplasty to facilitate bile duct clearance. Of 32 patients with bile duct stones (diameter 3-30 mm) at ERCP, sphincteroplasty was considered inappropriate in four patients because of stone size (> 20 mm) necessitating papillotomy for bile duct clearance. Sphincteroplasty was performed in the remaining 28 patients to permit duct clearance by dormier basket, balloon or mechanical lithotripsy. The bile duct was cleared in 22 patients (79%) while additional measures including papillotomy or stent insertion were required in the remaining six patients (21%) because of stone size or technical difficulties. There was no associated papillary haemorrhage. Pancreatitis was seen in one patient (4%) but resolved within 24 hours. Our preliminary experience suggests that sphincteroplasty is a safe and effective sphincter preservation technique that significantly reduces the necessity for papillotomy in the management of bile duct stones.     

The high sensitivity of a PCR-ELISA in the diagnosis of cutaneous and visceral leishmaniasis caused by Leishmania infantum

In general, the conventional techniques available for the diagnosis of leishmaniasis have relatively low sensitivity. This means that parasite-rich samples (which can usually only be collected by very invasive methods, such as bone-marrow aspiration) must be employed. This problem has not yet been solved even by use of the PCR-based techniques currently available. However, a new PCR-ELISA has been developed for the diagnosis of cutaneous (CL) and visceral leishmaniasis (VL) caused by Leishmania infantum. This assay appears to have sufficient sensitivity to be effective in the diagnosis of VL not only when bone-marrow aspirates are investigated but also when the samples are of peripheral blood. Overall, the ability of the PCR-ELISA to detect Leishmania, in 76 samples (22 of peripheral blood, 36 bone-marrow aspirates and 18 skin samples) from 72 patients living in a endemic region, was better than that of culture or the examination of Giemsa-stained smears. For example, L. infantum kDNA was detected by PCR-ELISA in 15 (83%) of the 18 skin samples from suspected cases of CL, whereas the combined use of several classical techniques only confirmed the presence of amastigotes in five (28%) of these samples. Similarly, only 21 individuals were diagnosed as having VL by conventional techniques whereas 30 were found Leishmania-positive in the PCR-ELISA. The new PCR-ELISA also appears to be a suitable technique for detecting leishmanial kDNA in samples of peripheral blood from cases of L. infantum-HIV co-infection. The assay is more sensitive than the combined use of several conventional techniques in the diagnosis of subclinical VL, probably because those with subclinical infection have relatively low parasitic loads that are generally undetectable using the other techniques.     

Diabetes insipidus and adipsic hypernatremia in a patient with a craniopharyngioma

A fourteen-year male patient presented a retrochiasmatic craniopharyngioma. Aer transcranial surgical resection, the patient had diabetes insipidus, which presented an interphase with manifestations of inadequate secretion of ADH. The patient was adequately treated with intranasal desmopresin, but aer i.v. fluid replacement was withdrawn, severe dehydration occurred. This was attributed to loss of the thirst reflex, due to surgical lesion of the lamina terminalis, where the osmoreceptor neurons are located. This case underscores the complications with body fluids and osmolality which may occur after surgery of hypothalamic lesions; i.e. diabetes insipidus (which may have a triphasic course), and adipsia, an infrequent complication due to absence of thirst.     

Selective immediate hypersensitivity to cefepime.

Cefepime is a fourth-generation cephalosporin with a broad antimicrobial spectrum and good activity against both gram-positive and gram-negative organisms. We present the case of a 61-year-old man who developed an immediate urticarial reaction after receiving a single dose of cefepime. Skin tests were positive to cefepime and negative to the other beta-lactam antibiotics. Controlled administration of amoxicillin-clavulanic acid and ceftazidime was well tolerated by the patient. To the best of our knowledge, this is the first report of selective hypersensitivity to cefepime demonstrated by skin and challenge tests. Complete allergological studies, including challenge tests with other beta-lactam antibiotics that produce a negative result in skin tests, should be considered in these patients.     

The inhibition of gastric ghrelin production by food intake in rats is dependent on the type of macronutrient

Ghrelin is a peptide mainly produced by the stomach that increases food intake and body weight. Ghrelin expression increases with fasting and is diminished by re-feeding, but although the expression of this hormone is regulated by the feeding state, the relation with diet composition is not yet well established. We have studied the inhibitory effect of the intake of two different macronutrients (fat and carbohydrates) on ghrelin production by the stomach in fasted rats, as well as the relation with another important signal in the regulation of energy balance, leptin. Ghrelin mRNA expression in the gastric mucosa was determined by Northern blotting, and leptin mRNA expression was determined by Northern blotting in the adipose tissue and by RT-PCR in the stomach; circulating and gastric concentrations of ghrelin and leptin were measured by enzyme immunosorbent assay and ELISA, respectively. Our results showed an increase in ghrelin mRNA levels in response to 14 h of fasting. Food intake for 20 min after the fast produced a decrease in ghrelin mRNA expression that was recovered in 45 min in rats that ate the fat diet, whereas levels remained low when rats ate the carbohydrate diet. Serum ghrelin followed a similar tendency. The decrease in ghrelin expression by feeding was associated with an increased expression of gastric leptin only when animals ate carbohydrates. We conclude that the inhibition of ghrelin production by the stomach after re-feeding of fasted rats is dependent on diet composition and can be related to the different satiating capacity of the ingested macronutrients, which is higher for carbohydrates than fat.