The incidence of hemorrhagic fever with renal syndrome (HFRS) has decreased significantly in the last decade or so, and many junior physicians are unfamiliar with this disease. In order to reduce misdiagnosis and improve the early diagnosis of this disease, this paper presents the diagnosis and treatment of two patients with atypical HFRS and a review of the literature. I. Clinical data Case 1 Female, 35 years old. She was admitted to the Fifth People’s Hospital of Fudan University on March 6, 2009 with fever and abnormal liver function. 4 d ago, she developed high fever with a maximum temperature of 40.2℃, accompanied by chills, headache and lumbago. 1 d ago, she was admitted to the hospital with outpatient liver function: ALT 215 U/L, AST 165 U/L and total bilirubin 18.5 μmol/L. She was diagnosed with acute hepatitis. There was no previous history of hepatitis. On admission: body temperature 40℃, pulse 110 times/min, respiration 20 times/min, blood pressure 110/65 mm Hg (1 mm Hg=0.133 kPa). Acute disease appearance, no yellow staining and hemorrhagic spots in the dermatomucosa, mild congestion and edema in the bulbar conjunctiva. The abdomen was flat, with no pressure pain or rebound pain. The liver and spleen were not palpable under the ribs, with negative mobile turbid sounds and no percussion pain in both kidney areas. Blood leukocytes were 11.2×109/L, classified neutrophils were 0.70, hemoglobin was 108 g/L, platelet count was 123×1012/L, no heterogeneous lymphocytes were seen, blood urea nitrogen was 4.7 mmol/L, blood creatinine was 65.7 μmol/L, ALT was 195 U/L, AST was 143 U/L, total bilirubin was 16.2 μmol/L. Urine protein ( + ). He was diagnosed as “acute hepatitis” and given treatment of liver protection and enzyme reduction, symptomatic treatment, etc. After 2 d, body temperature returned to normal, headache and back pain disappeared, liver function returned to normal after 7 d. Blood leukocytes were 6.7×109/L, classified neutrophils 0.62, hemoglobin 106 g/L, platelet count 126×1012/L The urine protein ( – ), renal function and other indexes were not found to be abnormal, and the bulbar conjunctival edema subsided, but the urine volume was monitored and found to be >2500 ml per day. Case 2 Male, 38 years old, was the husband of case 1 patient. He was admitted to the Fifth People’s Hospital of Fudan University on March 11, 2009 due to fever and abnormal liver function. 3 d earlier, the patient developed a high fever with a maximum temperature of 40.3°C, accompanied by chills, headache, and lumbago, and was admitted to the ward for “acute hepatitis” after an outpatient investigation of abnormal liver function. No previous history of hepatitis. On admission: temperature 40.2℃, pulse 112 times/min, respiration 21 times/min, blood pressure 120/85 mm Hg. Acute appearance, skin congestion, obvious on the face and neck, moderate congestion and edema of the bulbar conjunctiva. The abdomen was flat, with no pressure pain or rebound pain. The liver and spleen were not palpable under the ribs, with negative mobile turbid sounds and no percussion pain in both kidney areas. Blood leukocytes were 13.4×109/L, classified neutrophils 0.69, hemoglobin 108 g/L, platelet count 147×1012/L, no heterogeneous lymphocytes, blood urea nitrogen 5.1 mmol/L, blood creatinine 66 μmol/L, ALT 257 U/L, AST 164 U/L, total bilirubin 15.2 μmol/L. Urine protein (+), urine occult blood (+). Urine protein ( + ), urine occult blood ( + ). The couple was working in Shanghai and had been living in Fengxian rural area for half a year. They had many large rats living in the pig pen, and they often saw rats when feeding the pigs and had the experience of driving them away. On March 14, the couple’s blood specimens were sent to Shanghai Center for Disease Control for immunofluorescein-labeled IgM antibody test against renal syndrome hemorrhagic fever virus. HFRS is an acute infectious disease caused by hantavirus, and is a natural epidemic disease, The main source of infection is the rat. The main clinical manifestations are fever, hemorrhage and renal damage, and the typical clinical course includes fever, hypotensive shock, oliguria, polyuria and recovery period. Typical HFRS patients should have five clinical phases, and atypical patients should have a polyuric phase (urine volume >3000 ml/d). The diagnosis of mild or atypical cases is often made with the help of laboratory virological tests. The disease is endemic in many countries around the world, and China is a highly infected area. The disease is serious and complex, and has been one of the key infectious diseases in China. In recent years, the epidemic area has been expanding, and there has been a significant increase in the number of mild cases with atypical manifestations, probably due to the increase in human immunity, the low amount of invasive virus, and vaccination. Only a small number of patients have a dangerous onset, with overlapping phases of fever, hypotensive shock and oliguria, and are in critical condition. Since the 21st century, the incidence of this disease has decreased significantly in China, and the incidence in the traditional high incidence areas has also decreased significantly, while new outbreaks have emerged in some large cities. The infectious disease department of the Fifth People’s Hospital, formerly known as Minhang District Infectious Disease Hospital, is located in Shanghai, which is the junction of urban and rural areas, with a large number of rural residents and foreign workers living around, and a large number of acute infectious diseases such as measles and chickenpox, but the infectious disease department of the Fifth People’s Hospital has never treated any HFRS patients in the past 5 years. The discovery of these two cases of HFRS provides first-hand information for the prevention and treatment of infectious diseases in our city and district, and provides reference for our clinicians to diagnose and treat febrile diseases more comprehensively. After these two cases of HFRS were reported, the staff of Shanghai Center for Disease Control sent special personnel to the district to disinfect and exterminate the rats and instruct the prevention, and gave vaccination to other family members of the patients, so no other cases of HFRS were found. The early diagnosis of HFRS mainly refers to the diagnosis of patients in the febrile phase, and one should be familiar with various clinical manifestations in the febrile phase, such as acute onset of high or moderate fever, obvious headache, congested flushed skin on the face, neck and upper chest, bilateral axillary skin blebs and mucosal blebs on the soft palate, and conjunctival edema of the eyes; moderate or severe edema of the bulbar conjunctiva is the most characteristic or unique clinical manifestation in the early stage of the disease. Patients with peripheral blood and urine routine after 3 to 5 days of illness have obvious changes, such as early routine blood tests appear “three highs and one low” (i.e. peripheral blood leukocytes, increased percentage of classified neutrophils, increased ratio of heterogeneous lymphocytes and reduced platelet count), and urine protein “+++ “HFRS is often associated with liver function impairment, and ALT and AST are mostly elevated in the early stage of the disease. Although this group of patients had fever, headache, lumbago, bulbar conjunctival edema, increased blood leukocytes and abnormal liver function, they did not have the typical passage of fever, hypotensive shock, oliguria, polyuria and recovery period of HFRS. Therefore, in the future, for rural patients with fever and abnormal liver function, we should pay attention to inquire about the contact history and not ignore the changes of bulbar conjunctival edema and early blood and urine routine to further differential diagnosis to prevent The reasons for misdiagnosis in this case were: ① the discovery of liver function abnormalities, the infectious physician preconceived the diagnosis of acute hepatitis, ignoring the differentiation from other febrile diseases; ② inexperience, lack of knowledge of early manifestations or atypical manifestations, early changes in blood and urine routine; ③ because the disease has been disseminated in our city, many young physicians have forgotten about the disease, and the diagnostic thinking is limited, lack of comprehensive analysis.