The tourniquet test, which is particularly useful in settings where no laboratory investigations are readily available, involves the application of a blood pressure cuff at between the diastolic and systolic pressure for five minutes, followed by the counting of any petechial hemorrhages; a higher number makes a diagnosis of dengue more likely with the cut off being more than 10 to 20 per 1 inch2 (6.25 cm2).The diagnosis should be considered in anyone who develops a fever within two weeks of being in the tropics or subtropics. It can be difficult to distinguish dengue fever and chikungunya, a similar viral infection that shares many symptoms and occurs in similar parts of the world to dengue. Often, investigations are performed to exclude other conditions that cause similar symptoms, such as malaria, leptospirosis, viral hemorrhagic fever, typhoid fever, meningococcal disease, measles, and influenza. Zika fever also has similar symptoms as dengue.The earliest change detectable on laboratory investigations is a low white blood cell count, which may then be followed by low platelets and metabolic acidosis. A moderately elevated level of aminotransferase (AST and ALT) from the liver is commonly associated with low platelets and white blood cells. In severe disease, plasma leakage results in hemoconcentration (as indicated by a rising hematocrit) and hypoalbuminemia. Pleural effusions or ascites can be detected by physical examination when large, but the demonstration of fluid on ultrasound may assist in the early identification of dengue shock syndrome. The use of ultrasound is limited by lack of availability in many settings.
March fracture, is the fracture of the distal third of one of the metatarsals occurring because of recurrent stress. It is more common in soldiers, but also occurs in hikers, organists, and people whose duties entail much standing (such as hospital doctors). March fractures most commonly occur in the second and third metatarsal bones of the foot. It is a common cause of foot pain, especially when people suddenly increase their activities. Signs and symptoms
The onset is not dramatic. When the boot or shoes are taken off, there is a cramp-like pain in the affected forefoot, and moderate local edema appears on the dorsal aspect. On moving each toe in turn, that of the involved metatarsal causes pain, and when the bone is palpated from the dorsal surface, a point of tenderness is found directly over the lesion. Radiography at this stage is negative, but the condition is diagnosed correctly by military surgeons without the aid of x-rays. In civil life, it is seldom diagnosed correctly for a week or two, when, because of lack of immobilization, there is an excessive deposit of callus (which may be palpable) around the fracture. Diagnosis
X-ray is seldom helpful, but a CT scan and an MRI study may help in diagnosis. Bone scans are positive early on. Dual energy X-ray absorptiometry is also helpful to rule out comorbid osteoporosis. Differential diagnosis
Acute metatarsal fracture
Hallux rigidus
Jones fracture
Sesamoid stress fracture
Acute sesamoid fracture
Proximal fifth metatarsal avulsion fracture

Treatment
The first line treatment should be reduction of movements for 6 to 12 weeks.