Hantavirus pulmonary syndrome is a disease that results from infection by one of the Hantaviruses, which are carried by rodents. It is marked by multiple respiratory symptoms due to pulmonary edema, and it may be fatal.
Hantavirus pulmonary syndrome (HPS) is an infectious disease that is acquired through exposure to rodents carrying the causative virus, the Hantavirus. A few cases have been documented, where the infection was acquired through human to human contact  .
HPS usually occurs in specific geographical locations, such as north and south America. The disease appears to affect all individuals equally, although men may have a higher incidence rate due to more recurrent exposure to the vector. For the same reason, HPS typically does not present in young children or the elderly.
HPS is one of many syndromes that can arise from Hantavirus infection  . The affected organ systems depend on the specific type of Hantavirus an individual has come in contact with. The severity of illness varies greatly between cases, ranging from mild to severe. Furthermore, it demonstrates significantly high case mortality rates, estimated at up to 50%. This syndrome is characterized by severe respiratory compromise. The illness has several stages entailing a prodromal phase, respiratory phase, and convalescent phase. The disease has an incubation period of one week to one month, after which prodromal symptoms manifest.
Prodromal symptoms are often nonspecific and may involve gastrointestinal discomfort, vomiting, headache, and muscle pain . These individuals also experience pyrexia. The typical signs usually last up to 5 days.
Subsequently, the host immune system attacks endothelial cells lining the lungs, displaying viral antigens. This process leads to increased permeability of the endothelium and thus pulmonary edema. The cardiopulmonary phase lasts up to 48 hours and is characterized by the emergence of respiratory findings such as coughing, tachypnea, crepitations, and dyspnea. Patients frequently require mechanical ventilation during this time. Some individuals may develop hypotension and circulatory collapse due to cardiogenic shock, the latter being the main cause of death in HPS   . Oliguria is not an uncommon observation during this phase, and in a few cases, may lead to renal failure.
The third stage is preceded by an episode of diuresis and is made evident by the resolution of cardiopulmonary features.
Upon presentation, baseline blood tests, as well as more specific laboratory testing should be carried out. Often requested laboratory studies include:
CBC may reveal low platelets and elevated white blood cells, with an unusually high proportion of immature cells . Serum lactate dehydrogenase (LDH) is also high. Other parameters may reflect the distributive shock experienced in Hantavirus pulmonary syndrome  . One such finding is hemoconcentration. A peripheral blood smear, in addition to the above, may reveal the presence of atypical immune cells, as well as immunoblasts . Once these findings are observed, HPS can be diagnosed.
Imaging studies are usually carried out in the form of a chest radiograph. Signs of pulmonary edema that may be visualized include increased hilar markings, diffuse bilateral infiltrates, Kerley B lines, and peribronchial thickening. The cardiac silhouette is of normal size, and pleural effusions might also be present.