Dengue fever is caused by dengue virus, which has four different serotypes and is transmitted by the Aedes mosquitos. This disease is endemic to Southeast Asian countries, including Nepal. Liver involvement in dengue is a crucial feature, and the effect ranges from an asymptomatic rise in liver enzymes to the development of acute liver failure. Acute liver failure often results in multiorgan dysfunction including hemodynamic instability, renal failure, cerebral edema, and even death because of shock. Prompt diagnosis and management are necessary to prevent complications. However, there is no proven proper treatment for this condition, and the only treatment modality is to prevent the symptoms. We presented the case of a young female with dengue fever who developed a life-threatening acute liver failure because of dengue shock syndrome.

BACKGROUND: The severity of dengue infection has been reportedly associated with patients\' allergic reactions. To further elucidate the role of allergy in dengue severity, we conducted a matched case-control study to assess the association between allergic background and dengue shock syndrome.
METHODS: This is a matched case-control study that was carried out in the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam from January to December 2017. Dengue infection was determined by non-structure protein 1 (NS1) diagnostic quick test or anti-dengue antibodies (IgM). The total and dengue-specific IgE levels were measured using ELISA. Patients\' demographics, clinical, and allergic profiles were collected using a structured questionnaire.
RESULTS: A total of 572 dengue patients with positive NS1 (92.7%) or IgM antibodies (7.3%) results were included in this study. Of these patients, 143 patients developed dengue shock syndrome (case group) while the other 429 patients did not (control group). None of the baseline characteristics including age, sex, or being overweight was significantly different between the two groups (p>0.05). In multivariable analysis, having a history of dengue infection (OR=3.35, 95% CI: 1.8-6.17, p<0.001) and allergic rhinitis (OR=1.95, 95% CI: 1.11-3.4, p = 0.019) were found to be associated with dengue shock syndrome. Higher levels of dengue-specific IgE were not associated with worse outcomes in patients with allergies (p = 0.204) or allergic rhinitis (p = 0.284).
CONCLUSIONS: Dengue patients presenting with a history of a previous dengue infection or allergic rhinitis should be considered high-risk patients for the development of dengue shock syndrome.

BACKGROUND: Dengue fever is one of the most common tropical diseases, with high prevalence in many tropical countries including Sri Lanka. Dengue infection can present from subclinical infection to dengue shock syndrome. Further, the disease also shows a variety of atypical presentations and has been reported to mimic a number of causes of acute abdomen.
METHODS: The authors report two children (a 6-year-old Tamil girl and an 8-year-old Muslim girl) who were diagnosed to have acute appendicitis during the early recovery phase of dengue hemorrhagic fever (DHF) and late recovery period of dengue hemorrhagic fever with platelet count of 92 × 103/cumm and 102 × 103/cumm, respectively. Both children were investigated with abdomen ultrasound as they developed severe abdominal pain and tenderness on palpation during the recovery phase, which was felt to be very unusual. Acute appendicitis was diagnosed in one child, while the other child had a ruptured appendicular abscess. Both children were treated with laparoscopic appendectomy and a 7-day course of intravenous antibiotics. Both children were reviewed in 1 month following treatment and had complete recovery.
CONCLUSIONS: Although precise pathophysiology and associations of the surgical abdomen with dengue fever remain to be elucidated, there are known factors in dengue fever that can potentially lead to secondary bacterial infections and surgical abdomen. Awareness and increased suspicion by the clinician are paramount to detect such complications early, especially in children who demonstrate unusual clinical features during various stages of dengue infection.

BACKGROUND: With the increasing number of dengue virus infections imported into Germany, knowledge about the different phases of the disease and possible complications is essential for the treatment of patients. The virus is endemic in the tropics and subtropics and up to 2.5 billion people are at risk of infection.
METHODS: Here we present a German traveller with dengue shock syndrome after returning from Thailand. After hospitalization the patient developed acute upper abdominal pain. The ultrasound findings were consistent with an acute acalculous cholecystitis, but were interpreted as dengue associated gallbladder wall thickening (GBWT). Therefore a surgical intervention was not indicated and would have been associated with an higher risk of complications in this situation. Under supportive care spontaneous regression of GBWT could be documented by sonography four days later as well as complete resolution of clinical symptoms.
CONCLUSIONS: GBWT in dengue virus infection mimicking acute cholecystitis is a differential diagnosis one should take into consideration in travellers returning from endemic areas and should be managed conservatively because of an high risk of bleeding and increased mortality under surgical therapy.

Hemophagocytic lymphohistiocytosis (HLH) is a rare but potentially life-threatening complication of dengue infection which necessitates early diagnosis and treatment to improve patient outcomes. Severe dengue infection complicated by HLH may require interventions such as systemic corticosteroids, intravenous immunoglobulin, or chemotherapy. Here, we report a case of concurrent dengue-induced HLH and flare of underlying autoimmune hemolytic anemia (AIHA). The disease was refractory to treatment including corticosteroids and intravenous immunoglobulin. The course of illness was later complicated by dengue shock syndrome, severe liver dysfunction, and a large retroperitoneal hematoma. Unfortunately, the patient succumbed on day 10 of illness.

BACKGROUND: Dengue fever is a hemorrhagic fever caused by flaviviruses. Hemorrhagic manifestations are well known to be associated with dengue fever, though the thrombotic events are only seldom reported. Underlying pathophysiology of thrombotic events is multifactorial and the management is challenging due to associated thrombocytopenia and bleeding tendency. We report a case of dengue shock syndrome with severe thrombocytopenia complicated by ilio-femoral deep vein thrombosis.
METHODS: A 16 year old boy presented with dengue fever. He had dengue shock syndrome after entering the critical phase on the fifth day of the illness. With the recovery from the critical phase he developed deep vein thrombosis involving right external iliac, common femoral and superficial femoral veins. There were no provocative factors other than dengue fever itself. His platelet count was 12,000/μl at the time of diagnosis with deep vein thrombosis. Anticoagulation was started with intravenous unfractionated heparin 500 IU/hour while closely being observed for bleeding complications. 1000 IU/hour dose was commenced with the recovery of the platelet count above 50,000/μl. Thrombophilia screening was negative and he was discharged on warfarin. Venous duplex done after 6 weeks showed normal lower limb venous flow and warfarin was omitted after three months.
CONCLUSIONS: With dengue fever, complications like deep vein thrombosis can be easily missed given its rarity and that the major concern is on hemorrhagic complications. Management is challenging due to associated thrombocytopenia and hemorrhagic complications.

BACKGROUND: Dengue fever is a mosquito-borne viral disease with a very high incidence in Southeast Asia. Most patients with dengue fever recover following a self-limiting febrile illness, while a small proportion may progress to develop severe disease with complications such as acute liver failure, acute kidney injury, and multiorgan failure. Secondary bacterial infections and thrombotic events are very rare.
METHODS: A 38-year-old previously healthy Sri Lankan woman from Colombo, Sri Lanka, presented with dengue shock syndrome leading to acute liver failure and kidney injury. She was managed with intravenously administered fluid resuscitation with close monitoring of her hemodynamic status, and hemodialysis. Her renal and liver functions and platelet count improved gradually, but the fever persisted and there was a neutrophil leukocytosis. A clinical examination and investigations to identify a focus of secondary infection revealed staphylococcal infective endocarditis. She was started on intravenously administered vancomycin, but as the response was poor the antibiotic was changed to intravenously administered linezolid, to which the response was good. She also developed right proximal femoral deep vein thrombosis, and was commenced on subcutaneous enoxaparin and warfarin. Enoxaparin was stopped after her international normalized ratio reached the desirable range, and warfarin was continued for 3 months.
CONCLUSIONS: Dengue virus is known to cause endothelial dysfunction that allows bacteria to invade tissues, defective functioning and reduction in the number of cells of the immune system, and alteration of cytokines leading to immune dysregulation, predisposing patients to develop secondary bacterial infections. Evidently, patients with dengue fever who have prolonged fever (more than 5 days) and acute kidney injury are at high risk for concurrent bacteremia. Dengue virus interferes with the components of the anti-clotting pathway, such as thrombomodulin-thrombin-protein C complex. It also activates endothelial cells and increases the expression of procoagulant factors. These factors may predispose patients with dengue viral infections to develop thrombotic complications. Therefore it is important to be aware of the possibility of serious secondary bacterial infections occurring following dengue viral infections, especially in patients with prolonged fever and acute kidney injury, and to keep in mind that thrombotic events may occur as complications of dengue viral infections.

BACKGROUND: Early recognition and treatment of circulatory volume loss is essential in the clinical management of dengue viral infection. We hypothesized that a novel computational algorithm, originally developed for noninvasive monitoring of blood loss in combat casualties, could: (1) indicate the central volume status of children with dengue during the early stages of \"shock\"; and (2) track fluid resuscitation status.
METHODS: Continuous noninvasive photoplethysmographic waveforms were collected over a 5-month period from three children of Thai ethnicity with clinical suspicion of dengue. Waveform data were processed by the algorithm to calculate each child\'s Compensatory Reserve Index, where 1 represents supine normovolemia and 0 represents the circulatory volume at which hemodynamic decompensation occurs. Values between 1 and 0 indicate the proportion of reserve remaining before hemodynamic decompensation.
RESULTS: This case report describes a 7-year-old Thai boy, another 7-year-old Thai boy, and a 9-year-old Thai boy who exhibited signs and symptoms of dengue shock syndrome; all the children had secondary dengue virus infections, documented by serology and reverse transcriptase polymerase chain reaction. The three boys experienced substantial plasma leakage demonstrated by pleural effusion index >25, ascites, and >20 % hemoconcentration. They received fluid administered intravenously; one received a blood transfusion. All three boys showed a significantly low initial Compensatory Reserve Index (≥0.20), indicating a clinical diagnosis of \"near shock\". Following 5 days with fluid resuscitation treatment, their Compensatory Reserve Index increased towards \"normovolemia\" (that is, Compensatory Reserve Index >0.75).
CONCLUSIONS: The results from these cases demonstrate a new variation in the diagnostic capability to manage patients with dengue shock syndrome. The findings shed new light on a method that can avoid possible adverse effects of shock by noninvasive measurement of a patient\'s compensatory reserve rather than standard vital signs or invasive diagnostic methods.