Hi. I am Dr. Saddiq. First of all i woulds like to wish a healthy recovery for your sister in law. Your concerns regarding the disease progression and some insight into it is quite relevant. Some diseases, caused by certain bacteria, which initially present with flu and sore throat can involve heart or kidney by different disease mechanisms. Judging by the kind of brief symptoms, you have mentioned, it appears as if, your sister in law has suffered from such disease, which may have involved her heart valves and lead to inadequate pumping of heart forwards and hence backward pooling or accumulation of fluids in the lungs as well as in the rest of the body. Here it would have been more appropriate if we had known the status of her heart, the reports of 2-D echo, Chest radio-graphs, Blood cultures, Kidney function tests to guide you further. Regarding her prognosis and the course of actions, Offcourse she needs an indoor hospitalization and a critical care management which may involve removing the extra water to relieve her shortness of breath with the drugs which take out extra water by increased urination along with intravenous antibiotics and regular monitoring and occasional oxygen assistance along with pharmacological measures to relieve stress off her heart. Hoping her a rapid recovery. Thanks for trusting in HCM. Bye.