[HIV as a new diagnose in older patients]. / Hiv als nieuwe diagnose bij oudere patiënten.

We describe two patients diagnosed with an HIV-1 infection at an older age. In this article we emphasize the importance of knowledge of HIV indicator diseases and keeping a low threshold for HIV-testing.

Thiazide-induced hyponatraemia is associated with increased water intake and impaired urea-mediated water excretion at low plasma antidiuretic hormone and urine aquaporin-2.

BACKGROUND: Hyponatraemia is a common, potentially life-threatening, complication of thiazide diuretics. The mechanism of thiazide-induced hyponatraemia is incompletely understood. Previous experiments have suggested a direct effect of thiazide diuretics on the plasma membrane expression of aquaporin (AQP)2. METHODS: We examined the effects of a single re-exposure to hydrochlorothiazide (HCTZ) 50 mg on water balance, renal sodium handling and osmoregulation in 15 elderly hypertensive patients with a history of thiazide-induced hyponatraemia and 15 matched hypertensive controls using thiazide diuretics without previous hyponatraemia. RESULTS: Patients with thiazide-induced hyponatraemia had significantly lower body weight and lower plasma sodium and osmolality at baseline. After HCTZ administration, plasma sodium and osmolality significantly decreased and remained lower in patients compared with controls (P < 0.001). Plasma antidiuretic hormone (ADH) and urine AQP2 were low or suppressed in patients, whereas solute and electrolyte-free water clearance was significantly increased compared with controls. Ad libitum water intake was significantly higher in patients (2543 ±â€Š925 ml) than in controls (1828 ±â€Š624 ml, P < 0.05), whereas urinary sodium excretion did not differ. In contrast, urea excretion remained significantly lower in patients (263 ±â€Š69 mmol per 24 h) compared with controls (333 ±â€Š97 mmol per 24 h, P < 0.05) and predicted the decrease in plasma sodium following HCTZ administration. CONCLUSION: Thiazide diuretics are associated with markedly impaired free water excretion at low ADH and AQP2 in elderly patients. The higher water intake and lower urea excretion in patients points to an important role for polydipsia and urea-mediated water excretion in the pathogenesis of thiazide-induced hyponatraemia.

Multislice computed tomography angiography screening for new aneurysms in patients with previously clip-treated intracranial aneurysms: Feasibility, positive predictive value, and interobserver agreement.

OBJECT: Multislice computed tomography (CT) angiography may be useful for screening patients with intracranial aneurysms that are treated with clip occlusion. However, cobalt clips produce much more artifact on CT scans than titanium clips, which may hamper the evaluation of the image obtained at the clip site. METHODS: The authors screened 415 patients with previously ruptured aneurysms that had been treated using cobalt clips. Screening was performed using multislice CT angiography. The feasibility of this modality for screening these patients (based on the complication risk, CT angiography quality, and artifact avoidance) and interobserver agreement were evaluated. Patients in whom the presence of an aneurysm was suspected based on results of CT angiography studies underwent digital subtraction (DS) angiography. False-negative and false-positive findings were recorded, and the positive predictive value (PPV) was calculated. Eight patients (1.9%) had allergies to the contrast material. The quality of the CT angiography image was suboptimal in 14%. In 52%, clip artifacts hampered evaluation of the clip site. In 65 patients who underwent DS angiography, there were nine false-positive and eight false-negative reports related to aneurysms that were either small, located at the clip site, or were infundibula. The PPV on a per-patient basis was 86% (95% confidence interval [CI] 75-94%); for aneurysms at the clip site it was 83% (95% CI 61-95%); and for aneurysms at different locations it was 91% (95% CI 81-97%). The interobserver agreement was good (kappa = 0.69; 95% CI 0.60-0.78). CONCLUSIONS: Except for the evaluation of images from the clip site, CT angiography has good feasibility with good PPV and interobserver agreement. Drawbacks are that very small aneurysms can be missed and that visualization is poor at the clip site in patients in whom cobalt clips have been placed for occlusion. This second problem can be expected to resolve with the increasing use of titanium clips.