What are the main clinical manifestations and stages of hemorrhagic fever with renal syndrome?

Generally, the main clinical manifestations of hemorrhagic fever with renal syndrome (HFRS) include oliguria, polyuria, fever, hypotension, and shock. The disease progresses through several stages: febrile phase, hypotensive phase, oliguric phase, polyuric phase, and convalescent phase. Patients are advised to follow medical instructions for symptomatic treatment. Detailed analysis is as follows:

I. Clinical Manifestations

1. Oliguria
This symptom is primarily associated with uncorrected hypotension and impaired kidney function. Patients may experience reduced urine output, generalized edema, and even uremia. Under medical guidance, patients can use medications such as furosemide tablets or spironolactone tablets to alleviate symptoms.

2. Polyuria
As the patient's condition improves and renal function recovers, polyuria may occur, with daily urine output reaching 3,000–5,000 ml, which could potentially lead to electrolyte imbalances. Therefore, timely management based on specific disease characteristics is essential to prevent worsening of the condition. Under medical guidance, patients may be treated with medications such as cefaclor dry suspension or amoxicillin granules.

3. Fever
Fever in patients with hemorrhagic fever differs from typical infectious fever and is characterized by "three reds" and "three pains." The "three reds" refer to redness of the conjunctiva, face, and upper chest; the "three pains" include headache, lumbar pain, and orbital pain. Under medical guidance, patients can use medications such as ibuprofen suspension or rifampicin capsules to relieve symptoms.

4. Hypotension
If the disease progresses rapidly, patients may develop hypotension, shock, cold extremities, altered consciousness, and tachycardia. Under medical guidance, medications such as midodrine hydrochloride tablets or nimodipine tablets may be used for treatment.

5. Shock
Shock caused by hemorrhagic fever with renal syndrome is primarily hypovolemic shock, typically occurring during the hypotensive phase. Prompt volume replacement is required to restore circulation.

II. Disease Stages

1. Febrile Phase
During this stage, in addition to fever, patients may exhibit signs of systemic intoxication, "three reds," "three pains," organ edema, and renal dysfunction, among which systemic intoxication symptoms are particularly prominent.

2. Hypotensive Phase
This phase usually occurs on days 4–6 of illness. In mild cases, blood pressure fluctuates slightly and briefly. In severe cases, blood pressure drops sharply and may become unmeasurable.

3. Oliguric Phase
This phase commonly appears on days 5–7 of illness. Gastrointestinal symptoms, neurological manifestations, and bleeding are prominent. Patients may experience thirst, hiccups, and intractable vomiting. Blood pressure is often elevated with increased pulse pressure. Significant tenderness upon percussion at the costovertebral angle is common. Urine output is markedly reduced—less than 400 ml in 24 hours—and may progress to anuria. Severe cases may develop complications such as uremia, acidosis, and hyperkalemia.

4. Polyuric Phase
This phase typically occurs on days 10–12 of illness. As circulating blood volume increases and glomerular filtration improves, renal tubular epithelial cells gradually regenerate. However, reabsorption function remains impaired. Combined with the excretion of accumulated urea and other metabolic waste products from the oliguric phase, osmotic diuresis occurs, leading to polyuria and nocturia.

5. Convalescent Phase
Recovery generally begins in the fourth week of illness. Urine output gradually returns to normal, nocturia resolves, and urinary concentrating ability recovers. Overall health improves, and aside from feelings of weakness, most patients report no significant discomfort.

If patients experience any discomfort, they should seek prompt medical attention for timely and targeted treatment to avoid disease progression.