H is a 15-year-old adolescent female currently in her junior year. Two months ago, H gradually developed depressive symptoms after a class change, including a lack of desire to interact with classmates, decreased interest in school and life, and slowness. She also experienced light-hearted thoughts and relieved her mood through self-injurious behaviours such as cutting her legs with a penknife. She also developed somatic symptoms such as dizziness, head swelling, and abdominal discomfort. Furthermore, she experienced nervousness, panic, and chest tightness before PE class. The patient’s family brought her to the local hospital 1 month ago, where she was diagnosed with a depressive episode and treated with sertraline hydrochloride. The patient discontinued the medication by herself after 2–3 days (the specific dose was not available), and her depressive symptoms did not improve. After discontinuing antidepressant medication, the patient suddenly developed chills and fever without any apparent cause. The maximum temperature was 40.5 °C. Each episode lasted approximately half an hour, and the number of episodes per day was variable. The fever was accompanied by headache, which manifested as a persistent dull pain in the whole cranial vault. The patients also experienced nausea, vomiting, vomiting with stomach contents, epigastric distention and pain, and exhaustion. Therefore, the patient was admitted to the local general hospital where the diagnosis was “Fever cause: acute upper respiratory tract infection? Gastroenteritis?” The patient received cefuroxime for 7 days to treat the infection, dexamethasone sodium phosphate for 5 days to reduce inflammation, and diclofenac sodium for 7 days to lower her body temperature. Chest CT, head CT, cerebrospinal fluid examination, and abdominal plain film radiography did not reveal any abnormalities. However, the patient did not experience any improvement in depression, high fever symptoms, or other symptoms. Additionally, significant mood swings were present before each fever. After more than 10 days, the patient was admitted to Anshun People’s Hospital. During hospitalization, tumour marker analysis, a new coronavirus nucleic acid test, blood culture and identification, blood gas analysis, and anti-Branchia pneumoniae antibody tests were performed, and no abnormalities were detected. The Chlamydia pneumoniae antibody titre was 1:40, and the Mycoplasma pneumoniae antibody titre was 1:80. The patients received azithromycin (7 days), ceftriaxone (7 days), oseltamivir (5 days), and piperacillin sodium tazobactam (5 days), all of which were ineffective. Paroxysmal high fever recurred, and the patient’s temperature fluctuated around 39–40 °C. The patient’s depressed mood did not improve. After one month of treatment at Anshun People’s Hospital, the patient visited our respiratory medicine department for further treatment. After admission, the patient still had symptoms of high fever, with a temperature fluctuating between 38 °C and 39.5 °C. Each fever lasted approximately half an hour before the temperature returned to the normal range, and the number of episodes was variable. There were still significant mood fluctuations prior to each fever. The respiratory medicine department considered the possibility of an infectious fever, and a viral infection could not be excluded. To clarify the diagnosis, medical tests were conducted for all possible causes of fever (Table 1). The tests showed positive results for anti-cytomegalovirus IgG, anti-EBV-IgG, anti-VCA-IgG, and anti-VCA-IgG-High antibodies. Other test results showed no significant abnormalities. The patient was treated with meropenem for the infection and with XiYanPing for the virus. The patient was administered meropenem and XiYanPing for two days, and no improvement was observed. Unexplained fever occurred after significant depression and stress, with varying frequency throughout the day. The temperature fluctuated between 38 °C and 39 °C. Considering that the patient had been diagnosed with depressive episodes in previous hospitals, the patient’s headache and abdominal discomfort could be relieved by suggestive therapy. The patient's previous medical examinations were reviewed by the respiratory department.The Chlamydia pneumoniae antibody titre was 1:40, and the Mycoplasma pneumoniae antibody titre was 1:80. However, these results can occur in normal individuals, and antibody titre of 1:160 are considered clinically significant. Therefore, Mycoplasma and Chlamydia infections were not considered at this time. Additionally, the patient tested positive for anti-cytomegalovirus IgG, anti-EBV-IgG, anti-VCA-IgG, and anti-VCA-IgG-High antibodies. These results suggest that the patient had a previous viral infection. However, since these results are also present in normal individuals, it is unlikely that the current fever was caused by a viral infection. Thus, a psychiatric consultation was requested.

During the consultation, the patient had symptoms of low mood, emotional stress, reduced interest, reluctance to communicate with others, hallucinations, paranoia, etc. She had thoughts of suicide by slitting her wrists or jumping off a building, and she often relieved her mood by performing self-injurious behaviours. The patient often reported low self-esteem and guilt. The patient reported experiencing abdominal pain, headache, chills, high fever, and other physical symptoms as well as difficulty sleeping at night. She denied any prior psychiatric conditions or family history of mental illness. The patient reported good health and long-term residence in their hometown without any history of long-term residence in foreign countries or infected areas, exposure to toxic or radioactive substances, alcoholism, or smoking. The neurologic physical examination did not reveal any abnormalities. In addition, The patient exhibited febrile symptoms subsequent to experiencing depression and stress on each occasion.Overall, we believe that the patient’s current recurrent high fever, which has no clear explanation, may have bene caused by a depressive mood. We contacted the patient and her family to arrange for her transfer from the Department of Respiratory Medicine to the Department of Psychiatry. The patient’s previous use of sertraline, a 5-serotonin(5-HT) reuptake inhibitor, was less effective. Therefore, venlafaxine 75 mg/d, a noradrenergic and specific 5-HTergic antidepressant, was chosen to improve the patient’s depression. Venlafaxine was also more effective for treating somatic symptoms, pain and fever. Additionally, the patient exhibited symptoms of mood anxiety, nervousness, irritability, and poor sleep at night. To address these symptoms, tandospirone citrate (10 mg bid) and alprazolam (0.4 mg po qn) were prescribed to improve anxiety and sleep. We administered transcranial magnetic stimulation therapy twice a day and visible light therapy once a day to expedite the patient’s mood improvement, as physical therapy has been shown to have a positive impact on mood. It is important to consider that depressed mood among adolescent patients may be influenced by interpersonal and family factors. Therefore, we conducted psychological counselling based on cognitive-behavioural therapy. Over the 6 days of treatment, the patient’s body temperature gradually returned to the normal range, and her mood improved significantly(Fig. 1). The patient and her family requested to be discharged from the hospital. The patient demonstrated good adherence to treatment and consistently adhered to his medications during our several follow-up visits. Her body temperature did not fluctuate again at follow-up.

Clinical data of daily maximum temperature. Note The patient was transferred to our hospital after receiving treatment at other hospitals for one month. Antidepressant treatment was initiated on the second day of admission to our hospital. The patient’s mood improved after four days of treatment, while paroxysmal high fever did not recur