STRUCTURED ABSTRACT Objectives We aimed to determine the correlation between coronary artery calcium (CAC) scores on 3mm ECG-gated computed tomography (CT) scans and standard 6mm chest CT scans, and to compare relative strength of associations of CAC on each scan type with mortality risk. Background Coronary artery calcification predicts cardiovascular disease (CVD) and all-cause mortality, and is typically measured on ECG-gated 3mm CT scans. Patients undergo standard 6mm chest CTs for various clinical indications much more frequently, but CAC is not usually quantified. To better understand the usefulness of standard chest CTs to quantify CAC, we conducted a case-control study among persons who had both scan types. Methods Between 2000–03, 4,544 community-living individuals self- or physician-referred for “whole body” CT scans, had 3mm ECG-gated CTs and standard 6mm chest CTs, and were followed for mortality through 2009. In this nested case-control study, we identified 157 deaths and 494 controls frequency matched (1:3) on age and gender. The Agatston method quantified CAC on both scan types. Unconditional logistic regression determined associations with mortality, accounting for CVD risk factors. Results Participants were 68±11 years old and 63% male. The Spearman correlation of CAC scores between the two scan types was 0.93 (p<0.001); median CAC scores were lower on 6mm CTs compared to 3mm CTs (22 vs.104 Agatston units, p<0.001). Adjusted for traditional CVD risk factors, each SD higher CAC score on 6mm CTs was associated with 50% higher odds of death (OR=1.5; 1.2–1.9), similar to 50% higher odds on the 3mm ECG-gated CTs (OR=1.5, 1.1–1.9). Conclusions CAC scores on standard 6mm chest CTs are strongly correlated with 3mm ECG-gated CTs and similarly predict mortality in community-living individuals. Chest CTs performed for other clinical indications may provide an untapped resource to garner CVD risk information without additional radiation exposure or expense.

Serum sickness‐like reaction is a rare immunological condition which may develop following exposure to certain drugs such as penicillins, cephalosporins, and trimethoprim‐sulfamethoxazole, among many others. It is described classically as a type III hypersensitivity response to heterologous proteins. Its true mechanism is still unclear. We present a case of serum sickness‐like reaction to clarithromycin, a commonly prescribed drug for the treatment of respiratory tract infections. The patient had been taking this drug for 3 days when she experienced generalized body aches, rash, arthralgia, and shortness of breath, prompting presentation to the emergency department. Laboratory studies showed decreased C4 and total complement with a slightly elevated sedimentation rate. After exclusion of other possible causes, the diagnosis of serum sickness‐like reaction was made. The patient responded well to nonsteroidal antiinflammatory medication, antihistamines, and a short, tapering dose of steroids. To our knowledge, serum sickness‐like reaction to clarithromycin has never been reported previously. This case emphasizes the need for increased clinical awareness of such an adverse outcome to clarithromycin use. Journal of Hospital Medicine 2011. © 2011 Society of Hospital Medicine.

SUMMARYA 52-year-old man with a history of HIV (CD4 count 155, and viral load 154 K), who is on antiretroviral treatment presented in the emergency room with acute onset of headache. The patient had lumbar puncture and found to have elevated intracranial pressure and cryptococcal antigen was positive. The patient was started on flucytosine. After 10 days of treatment, the patient developed watery diarrhoea. An extensive infectious workup was carried out, which did not reveal any infectious aetiology. A colonoscopy was carried out which revealed acute colitis in the colon and the pathology confirmed the colonoscopic findings with severe colitis in the colon. At this time, the patient's diarrhoea was attributed to flucytosine and it was stopped. The patient's diarrhoea improved after 5 days of stopping flucytosine. BACKGROUND