Bacillus cereus is a spore forming bacterium that produces toxins that cause vomiting or diarrhoea. Symptoms are generally mild and short-lived (up to 24 hours). B. cereus is commonly found in the environment (e.g. soil) as well as a variety of foods. Spores are able to survive harsh environments including normal cooking temperatures. Description of the organism B. cereus is a Gram-positive, motile (flagellated), spore-forming, rod shaped bacterium that belongs to the Bacillus genus. Species within this genus include B. anthracis, B. cereus, B. mycoides, B. thuringiensis, B. pseudomycoides and B. weihenstephanensis (Rajkowski and Bennett 2003; Montville and Matthews 2005). Genomic sequencing data has shown B. anthracis, B. cereus and B. thuringiensis to be very closely related (Rasko et al. 2004) with their 16S rRNA gene sequence sharing more than 99% similarity (Ash et al. 1991). B. cereus is widespread in nature and readily found in soil, where it adopts a saprophytic life cycle; germinating, growing and sporulating in this environment (Vilain et al. 2006). Spores are more resistant to environmental stress than vegetative cells due to their metabolic dormancy and tough physical nature (Jenson and Moir 2003). B. cereus produces two types of toxins-emetic (vomiting) and diarrhoeal-causing two types of illness. The emetic syndrome is caused by emetic toxin produced by the bacteria during the growth phase in the food. The diarrhoeal syndrome is caused by diarrhoeal toxins produced during growth of the bacteria in the small intestine (Ehling-Schulz et al. 2006). Growth and survival characteristics Strains of B. cereus vary widely in their growth and survival characteristics (refer to Table 1). Isolates from food and humans can be subdivided as either mesophilic or psychrotrophic strains. Mesophilic strains grow well at 37°C but do not grow below 10°C; psychrotrophic strains grow well at refrigeration temperatures but grow poorly at 37°C (Wijnands et al. 2006a). All isolates of B. cereus associated with emetic toxin production have been found to be mesophilic in nature (Pielaat et al. 2005; Wijnands et al. 2006b).

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A 53-year-old male patient with a history of hepatocellular carcinoma developed gastroesophageal varices refractory to endoscopic injection sclerotherapy (EIS). He required EIS six times in 2 years for recurring variceal bleeding. After hepatic resection, he developed massive splenomegaly. Partial splenic embolization (PSE) was performed to reduce the portal pressure. Varices and variceal bleeding were not detected during 13-year follow up, until the patient died of hepatocellular carcinoma. This is a unique case of gastroe-sophageal varices controlled by PSE and improved portal hypertension.

Virchow-Robin spaces (VRS) or the perivascular spaces are small pial lined, cystic structures in the brain and are filled with interstitial fluid. They are normal spaces, identified in all age groups and are common in places where the penetrating vessels enter into the substance of brain. Occasionally, these spaces can be enlarged and are termed as giant tumefactive perivascular spaces (GTPVS). When enlarged, these cysts are commonly confused with other lesions such as cystic neoplasms. The pathognomonic imaging appearance helps in the diagnosis of this condition in most instances and invasive management is unwarranted. We report a 4-year-old male with GTPVS. In our patient, GTPVS were diagnosed incidentally on brain imaging ordered for a head trauma and he was managed conservatively. During 1-year follow-up, he remained asymptomatic and the size of the cysts was virtually unchanged.

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