Q: My brother had undergone treatment for gastroenteritis a fortnight ago and recovered well. But he has again developed symptoms such as very high fever, nausea, vomiting, body ache and weakness. The doctor asked us to get a test done for malaria and typhoid. Both the tests were negative. He has been given artemether to treat malaria. Why did the doctor prescribed antimalarial drugs inspite of a negative report of MP test? Does taking antimalarial drugs cause serious side effects if someone is not suffering from malaria and what is the fever pattern in malaria? Does it occur every 24, 48 or 72 hours or it can occur anytime without any particular cycle? My brother's fever cycle is not fixed. The fever reaches upto 103 degree Fahrenheit twice or thrice a day. What is the test that can diagnose malaria with surety? What other tests are necessary to check for other infections? What should be done to increase his appetite? My brother has almost stopped taking solid food.

A:Fever of undetermined origin is a common and often vexing problem since the cause may be an infection but could be a collagen vascular disease, cancer, lymphoma, valvular heart disease, metabolic derangement, or many other diseases. It can be difficult to prove the presence or the absence of malaria in susceptible people and the only certain proof is finding the elusive organisms in the blood. The pattern of fever with malaria may be helpful when there is a characteristic periodicity every 2, 3 or 4 days, but this pattern may not be seen, particularly in early disease before the waxing and waning characteristics appear on the temperature chart. The treatment for malaria is usually well tolerated, especially when artemisin is used, and prolonged courses are sometimes given, with no marked increase in toxicity. Decisions have to be made by an experienced physician as to whether courses of chloroquine and perhaps primaquine are justified. Recovering from a perplexing fever often occurs spontaneously, but continued ill health such as poor appetite and weight loss may indicate that a complete body cat scan is needed. In selected cases more advanced radiologic testing is indicated. The final approach may be an exploratory laparotomy to determine whether there is a hidden collection of infected material or a latent tumour in the abdomen. If the patient begins to improve without therapy, a policy of supervised observation for a few weeks may be a good alternative, but continued ill health indicates the need for expert intervention by an appropriate specialist with a training in infectious diseases.