Sulphadiazine-induced obstructive renal failure complicating treatment of HIV-associated toxoplasmosis.

A patient with newly-diagnosed HIV infection and biopsy-proven cerebral toxoplasmosis was treated with sulphadiazine and pyrimethamine. Despite adequate hydration and daily examination of urine for sulphadiazine crystals obstructive uropathy due to bilateral ureteric stones with hydronephrosis occurred, resulting in rapid onset renal failure. Sulphadiazine was discontinued and clindamycin was substituted. With intravenous fluid hydration and bilateral nephrostomies the urolithiasis resolved. This case serves to remind clinicians of the need for vigilance when treating cerebral toxoplasmosis with sulphadiazine, in order to avoid this potentially serious complication of treatment.

Nodal cryptococcal immune reconstitution inflammatory syndrome masquerading as tuberculosis in an HIV-infected patient.

An African HIV-infected patient presented with widespread necrotic lymphadenopathy five months after starting combination antiretroviral therapy (cART) and was thought to have disseminated tuberculosis in the context of an immune reconstitution inflammatory syndrome (IRIS) on the basis of typical imaging appearances and suggestive appearances from a fine needle aspirate of a nodal mass. The patient deteriorated despite empirical antituberculosis therapy and the correct diagnosis of nodal cryptococcal infection was subsequently established by histological examination of a core biopsy from a lymph node. IRIS should be borne in mind when considering the differential diagnosis in a patient who has recently started cART.

CT colonography: computer-assisted detection of colorectal cancer.

OBJECTIVES: Computer-aided detection (CAD) for CT colonography (CTC) has been developed to detect benign polyps in asymptomatic patients. We aimed to determine whether such a CAD system can also detect cancer in symptomatic patients. METHODS: CTC data from 137 symptomatic patients subsequently proven to have colorectal cancer were analysed by a CAD system at 4 different sphericity settings: 0, 50, 75 and 100. CAD prompts were classified by an observer as either true-positive if overlapping a cancer or false-positive if elsewhere. Colonoscopic data were used to aid matching. RESULTS: Of 137 cancers, CAD identified 124 (90.5%), 122 (89.1%), 119 (86.9%) and 102 (74.5%) at a sphericity of 0, 50, 75 and 100, respectively. A substantial proportion of cancers were detected on either the prone or supine acquisition alone. Of 125 patients with prone and supine acquisitions, 39.3%, 38.3%, 43.2% and 50.5% of cancers were detected on a single acquisition at a sphericity of 0, 50, 75 and 100, respectively. CAD detected three cancers missed by radiologists at the original clinical interpretation. False-positive prompts decreased with increasing sphericity value (median 65, 57, 45, 24 per patient at values of 0, 50, 75, 100, respectively) but many patients were poorly prepared. CONCLUSION: CAD can detect symptomatic colorectal cancer but must be applied to both prone and supine acquisitions for best performance.

Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling.

A carbon-rich black layer, dating to approximately 12.9 ka, has been previously identified at approximately 50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at approximately equal 12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at approximately 12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.