Dengue is an arboviral infection that is hyperendemic in tropical and subtropical climates. Clinical manifestations of dengue can range from asymptomatic infection to severe infection with multi-organ failure. Dengue haemorrhagic fever (DHF) is a subcategory in dengue infection with a hallmark of plasma leak (ie critical phase). The plasma leak in DHF is selective (pleuroperitoneal spaces), transient and dynamic, and needs careful monitoring and meticulous fluid resuscitation. In addition, dengue fever may present with extended and unusual manifestations affecting any organ, including the heart, liver, kidney and brain. Studies on vaccine development and vector control are ongoing to prevent this infection of global importance. In this article, the clinicopathological features and management aspects of dengue are discussed.

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In a prospective study of snake bites involving 10 hospitals in Sri Lanka, 302 (35%) of 860 patients with bites by identified snakes proved to have been bitten by hump-nosed pit vipers (301 by Hypnale hypnale and 1 by H. nepa). Most victims were males aged between 11 years and 50 years who had been bitten on their feet or ankles while walking at night close to their homes. There was local swelling in 276 (91%) and local necrosis in 48 (16%). Eleven (4%) required amputation of fingers or toes and 12 (4%) received skin grafts. In 117 patients (39%) blood incoagulability was first detected between 15 min and 48 h after the bite, and in 116 of them this was present on admission to hospital. Spontaneous systemic bleeding was observed in 55 patients (18%). Acute renal failure developed in 10%, five of whom died to give an overall case fatality rate of 1.7%. Thus, bites by hump-nosed pit vipers can cause debilitating local and fatal systemic envenoming. In Sri Lanka and southwestern India where bites by these snakes are common, the only available antivenoms (raised against cobra, krait, Russell's viper and saw-scaled viper venoms) are ineffective and carry a high risk of reactions.

In Sri Lanka, the Spectacled cobra (Naja naja) inflicts fatal bites. This hospital-based prospective study describes 25 cases of proven cobra bites, including 10 (40%) males and 15 (60%) females with a median age of 36 years (range 13-70 years). In 22 cases (88%) bites occurred in the daytime and in 13 cases (52%) they occurred at the victim's home compound. The site of the bite was the upper limb in 10 cases (40%), and 12 patients (48%) had applied a tourniquet. There were 5 dry bites (20%), 20 local reactions (80%), 9 cases of neurotoxicity (36%) and 3 cases of coagulopathy (12%). Eight patients (32%) had severe local necrosis-five underwent desloughing and skin grafting and two (including one of the above) had fasciotomy and compartmental decompression of the upper limb. Two patients died (case fatality rate 8%; 95% CI 0.98-26.03) due to rapidly spreading necrosis of the upper limb. Four patients (16%; 95% CI 4.53-36.08) developed respiratory paralysis; their median time from bite to assisted ventilation was 2h (range 2-5h) and the median duration of ventilation was 24h (range 18-24h). Envenomed patients received Indian polyvalent antivenom. The findings highlight the magnitude of local necrosis, respiratory paralysis and antivenom failure in Spectacled cobra bite in Sri Lanka. Coagulopathy requires verification with robust laboratory tests.

Objectives: To compare the clinical and laboratory features of confirmed cases of Chikungunya and Dengue fever; to validate the clinical diagnosis based on serology. Methods: Cases with a clinical diagnosis of Chikungunya and Dengue fever were recruited for seroconfirmation during a concurrent epidemic in 2006–07, at the General Hospital, Peradeniya, Sri Lanka. Results: Of 54 patients with fever, serology confirmed 21 with Chikungunya infection, 20 with Dengue infection, and three co-infections, with sensitivity of the clinical diagnosis of 92% for Chikungunya fever and 95% for Dengue fever. The mean age of patients with Chikungunya fever was 45 years (range 21–74 years), and patients with Dengue fever was 30 years (range 15–63 years) (p = 0.005). Sixteen (70%) of Chikungunya fever patients were females, while 15 (71%) of those with Dengue fever were males (p = 0.007). Arthralgia was common to both groups (p = 0.155), while headache and a bleeding tendency were observed more in patients with Dengue fever. Twelve (57%) Chikungunya cases had acute arthritis compared with none in the Dengue group (p = 0.001), lasting mean 6 days (range 1–14 days). They developed chronic arthritic disability (range 1–6 months). Leucopenia was common to both Chikungunya and Dengue fever patients. However, thrombocytopenia was more pronounced in the Dengue patients (mean (SD) platelet count 75 (34)×10⁹/l) than in the Chikungunya patients (117 (70)×10⁹/l) (p = 0.001). In the Chikungunya group there was a positive correlation between duration of the illness and the platelet count (r = 0.181, p = 0.194), but the Dengue group showed a negative correlation (r = −0.309, p<0.001). Conclusion: Most of the clinical and laboratory features of patients with Chikungunya and Dengue fever are similar. Arthritis is the pathgnomonic sign in patients with Chikungunya fever.

A high incidence of cardiac complications was observed in an outbreak of dengue fever at General Hospital, Peradeniya, Sri Lanka, in 2005. This report describes 120 serologically confirmed dengue fever patients who presented during the outbreak. Seventy-five (62.5%) of these patients had electrocardiogram changes (T inversion, ST depression, bundle branch blocks) and were assigned to the 'cardiac group' (50 females, 25 males; median age 34 years, range 13-76). These patients were more susceptible to fatigue, dyspnoea, low peripheral oxygen saturation in room air (P=0.001), chest pain (P=0.001) and flushing of skin (P=0.05) than 45 (37.5%) patients who had normal electrocardiograms and made up the 'non-cardiac group'. In the cardiac group there were 31 primary and 44 secondary dengue patients. In the cardiac group, 17 (23%) patients had hypotension and 58 (77%) developed tachycardia and bradycardia (P<0.001) compared to four (9%) in the non-cardiac group, suggestive of significant cardiac dysfunction. There was no correlation between pulse rate and body temperature: cardiac group (r=0.05; P=0.63); non-cardiac group (r=0.11, P=0.46). RT-PCR detected DEN-3 in three cardiac patients.