A 71-year-old woman with polymyositis presenting with left thigh pain and an intermittent fever came to Osaka Rosai Hospital for treatment. She had been diagnosed with polymyositis by a muscle biopsy 17 years previously and placed on prednisolone therapy at that time. Initially, the dose of prednisolone was 30 mg/day, which was gradually tapered; however, her polymyositis relapsed many times with a dose of 15 mg/day. One month before admission, her creatine kinase, myoglobin, and aldolase levels became elevated when taking a dose of 12.5 mg/day. Considered a recurrence of polymyositis, she began taking 25 mg/day. After that, she lost 3 kg of body weight during a 2-week period and had concurrent diarrhea, vomiting, and loss of appetite. She experienced pain in her left thigh and a fever that were not present 1 month prior to admission, but no night chills. The patient was then admitted to our ward for examination and treatment. Her past medical history indicated that she underwent right hemicolectomy for colon cancer at 61 years of age and suffered cellulitis in her leg at 69 years of age. The patient had no history of TB.
On admission, the patient's body weight was 35.8 kg, blood pressure was 116/76 mmHg, heart rate was 88 bpm, and body temperature was 37.0 C. From dawn to noon, the patient had an intermittent fever of 39.5 C, but from noon to midnight, her body temperature decreased to 36 C. The pattern of her body temperature was unrelated to the medications she was taking, such as prednisolone; moreover, she had never taken nonsteroidal anti-inflammatory drugs throughout her admission period. The patient showed no symptoms of a cough or sputum. On physical examination, the patient's left posterior thigh showed swelling and tenderness in the absence of any redness or rash. The anterior side of the thigh was free of symptoms, which led us to conclude that the cause of pain was not polymyositis but a soft tissue infection. Her chest and abdomen were quite normal. Laboratory data from the patient's blood tests are shown in Table 1. Briefly, the white blood cell (WBC) count was within the normal range [7,400/muL (normal range: 3,000-8,000/muL)] and C-reactive protein (CRP) levels were elevated [6.61 mg/dL (normal range: <0.30 mg/dL)]. The creatine kinase levels were found to be within normal limits [53 U/L (normal range: 45-163 U/L)]; although high, her myoglobin [94 ng/mL (normal range: <60 ng/mL)] and aldolase levels [9.3 U/L (normal range: 2.1-6.1 U/L)] were not considered to be elevated when compared with ambulatory practice data. Therefore, it was concluded that the patient's polymyositis was under control.
The procalcitonin levels were slightly high [0.37 ng/mL (normal range: <0.05 ng/mL)] and an interferon gamma release assay (QuantiFERON(R)) was positive. Because she had been taking prednisolone for 17 years, we considered her to be an immunocompromised host and repeatedly examined her blood and urine specimens for bacterial cultures and blood, urine, sputum, and gastric fluid specimens for mycobacterial cultures. All of the results were negative. Her chest X-ray appeared normal. No malignancy was found using gastrointestinal endoscopy nor was vegetation found using transthoracic echocardiography. Thus, a diagnosis of left thigh cellulitis was made.
Cefazolin treatment was initiated on the day of admission. Fifteen minutes later, the patient's face turned red and her blood pressure decreased to 80/48 mmHg. Because the patient was already undergoing corticosteroid therapy, we considered this allergic reaction to be anaphylactic shock. We then changed the patient's treatment from cefazolin to clindamycin, however, the same phenomenon occurred. On our third attempt, we placed the patient on teicoplanin treatment, but this also failed. Although we were able to safely administer meropenem and vancomycin for one week, her febrile state and left thigh pain did not improve.
Because the antibiotic treatments were ineffective, we conducted further tests to determine the cause. Enhanced computed tomography (CT) of the chest and abdomen, which were examined on day 5, did not show any significant signs of inflammation or malignancy (Fig. 1a and b). There was no sign of vegetation using transesophageal echocardiography. Lower limb CT and magnetic resonance imaging (MRI) on day 7 showed inflammation that was limited to the left fascia and was not intramuscular (Fig. 2a and b). Thus, cellulitis or fasciitis was suspected. Positron emission CT using fluorodeoxyglucose revealed marker accumulation in the liver, spleen, ileocecum, and left inguinal lymph node, which suggested the presence of malignant lymphoma. We planned muscle and lymph node biopsies to confirm these diagnoses, however, before we could perform them, the patient suddenly complained of swelling in her left lower limb. The edema worsened over three days, and venous ultrasonography revealed deep vein thrombosis. Urgent enhanced chest CT on day 22 revealed no pulmonary thromboembolism but indicated small-diffused nodules, which were not apparent in previous enhanced CT (Fig. 1c and d). A liver biopsy was performed, and the pathological study of the specimen showed epithelioid cell granuloma. Acid-fast bacilli were detected by Ziehl-Neelsen staining. Thus, the patient was diagnosed with miliary TB. Mycobacterium tuberculosis detected on culture showed susceptibility to all tested anti-TB drugs. The patient received anti-TB drug therapy, including 200 mg/day of isoniazid, 300 mg/day of rifampicin, 500 mg/day of ethambutol, and 875 mg/day of pyrazinamide; the doses were based on her body weight (35.8 kg). Her intermittent fever resolved the following day and her left thigh pain and swelling vanished after five days. CT and MRI on day 33 showed that the patient's lower limb inflammation had improved (Fig. 2c and d), and her thigh pain was diagnosed as tuberculous fasciitis. She was moved to a TB hospital 12 days after commencing anti-TB drug therapy to receive advanced treatment.