Complications and unusual manifestations

00000000As dengue infections have become more common, an increasing number of cases of DF or DHF-like disease have been associated with unusual manifestations. These include such central nervous system phenomena as convulsions, spasticity, changes in consciousness and transient pares. A subtle form of seizure is occasionally observed during the febrile phase in infants. This may be only a simple febrile convulsion, since the cerebrospinal fluid has been found to be normal in such cases. Water intoxication resulting from the excessive administration of hypotonic solution to treat DHF/DSS patients with hyponatraemia may lead to encephalopathy. Patients with encephalopathy as a complication of disseminated intravascular coagulation have also been reported.

00000000 Patients with neurological manifestations who have died have been reported in India, Indonesia, Malaysia, Myanmar, Puerto Rico and Thailand. While there have been a few reports of isolation of the virus or of anti-dengue IgM from cerebrospinal fluid, to date there is no evidence of the direct involvenent of dengue virus in neuronal damage. Intracranial bleeding may occur, and brain-stem herniation due to cerebral oedema has been observed. In general, patients who have died with neurological signs or symptoms have not been subjected to an autopsy study. Both gross and microscopic studies are essential to establish the nature and etiology of any neurological manifestations accompanying a fatal DHF/DSS-like disease.

00000000 Great care must be taken to prevent iatrogenic complications in the treatment of DFH/DSS, to recognize them quickly if they occur and not to mistake preventable and treatable iatrogenic complications for normal DHF/DSS findings. Such complications include seps, pneumonia, wound infection and overhydration. The use of contaminated intravenous lines or fluids can result in Gram-negative sepsis accompanied by fever, shock and severe haemorrhage; pneumonia and other infections can cause fever and complicate convalescence. Over hydration can cause heart or respiratory failure, which may be mistaken for shock (see Chapter 3).

00000000 Liver failure has been associated with DHF/DSS, particularly during the epidemics in Indonesia in the 1970s and the 1987 epidemic in Thailand. This may be due either to the successful resuscitation of patients with severe circulatory failure, or to an unusual liver topism of certain viral strains. Dengue virus serotypes 1, 2 and 3 have been isolated from patients dying from liver failure, with both primary and secondary dengue infections. Necrosis of hepatocytes was found to be extensive in some of these cases. Dengue antigen was detected in hepatocyte, in Kupffer cells and occasionally in acute inflammatory cells. The histopathological findings were distinct from those seen in Reye syndrome. Whether liver injury is due to the direct effect of dengue infection or to the host's response to infection remains to be determined. Encephalopathy associated with acute lever failure is commonly observed, and renal failure is a common terminal event.

00000000 Other unusual reported manifestations include acute renal failure and haemolytic uraemic syndrome, sometimes in patients with underlying conditions, e.g. glucose-6-phosphate dehydrogenase (G6PD) deficiency and haemoglobinopathy. Simultaneous infections, such as leptospirosis, viral hepatitis B, typhoid fever, chickenpox and melioidosis, have been reported and could contribute to unusual manifestations of DHF/DSS.