Infectious diseases are one of the major threats to human health, along with cancer. Infectious diseases can be transmitted through both humans and animals, leading to a large number of people infected. Epidemic hemorrhagic fever is an infectious disease that poses a significant risk to human health. Generally, hemorrhagic fever is transmitted through rodents, and the incidence rate is relatively high among young and middle-aged adults, with a long incubation period. Hemorrhagic fever, also known as renal syndrome hemorrhagic fever, is an important infectious disease that poses a threat to human health. It is caused by the epidemic hemorrhagic fever virus (Hantavirus) and is a naturally occurring epidemic disease with rodents as the main source of transmission. The main clinical manifestations include fever, bleeding, congestion, hypotension shock, and kidney damage. The incubation period of hemorrhagic fever is generally 2 to 3 weeks. The typical clinical course is divided into five stages: febrile stage, hypotensive shock stage, oliguric stage, polyuric stage, and recovery stage.

Febrile Stage

The febrile stage is mainly manifested by symptoms caused by infectious viremia and damage to systemic capillaries. The onset is acute, with fever (38℃~40℃), three pains (headache, low back pain, and orbital pain), as well as symptoms such as nausea, vomiting, chest tightness, abdominal pain, diarrhea, and joint pain throughout the body. There may be redness of the skin and mucous membranes in the face, neck, and upper chest, conjunctival hyperemia, and a severe appearance resembling drunkenness. Bleeding spots or bruises of varying sizes may appear on the oral mucosa, chest and back, and underarms, or they may appear as streaky or scratch-like bleeding points.

Hypotensive Shock Stage

The hypotensive shock stage usually occurs 4 to 6 days after the onset of fever, when the body temperature begins to decrease or shortly after the fever has subsided. It is mainly manifested as hypovolemic shock due to loss of plasma. Patients may experience hypotension, and severe cases may develop shock.

Oliguric Stage

The oliguric stage is characterized by a urine volume of less than 400ml in 24 hours. There is often no clear boundary between the oliguric stage and the hypotensive stage.

Polyuric Stage

During the polyuric stage, kidney tissue damage gradually repairs, but due to incomplete recovery of renal tubular reabsorption function, urine volume significantly increases. This stage is most commonly seen on the 8th to 12th day and lasts for 7 to 14 days. The daily urine volume is approximately 4000 to 6000ml, which can easily lead to dehydration and electrolyte imbalance.

Recovery Stage

As kidney function gradually recovers and urine volume decreases to below 3000ml, the patient enters the recovery stage. Urine volume and symptoms gradually return to normal, and recovery may take several months.