Tuberculous Tenosynovitis and Ulnar Bursitis of the Wrist
A 65-year-old man presented with a 1-week history of an insidious flexor weakness of the right fifth finger. All traumatic causes were ruled out. Physical examination revealed paresthesia over the fifth finger and hypothenar region of the right hand. According to the Medical Research Council scale [], the strength of the right fifth finger flexor was grade 2, while the strengths of the fifth finger adductor and fourth finger flexor were both grade 3 (). The muscle strengths of the right upper extremity, including the first dorsal interosseous, abductor digiti minimi and flexor carpi ulnaris muscles, was all grade 5. No significant atrophy was identified on the right hand and forearm. Simple X-rays revealed no abnormal findings in bone, joint, and soft tissue ().\nThe patient had been treated for diabetes mellitus and hypertension over a period of 5 years at an outpatient clinic. A chest radiograph revealed tiny calcific nodules, suspicious for old tuberculous infection; however, no significant differences were found in patterns and sizes of these lesions when compared to previous films. There was no past or family history of tuberculosis. He did not have any complaints of respiratory symptoms, including cough, sputum, or chest discomfort. The levels of white blood cell count, erythrocyte sedimentation rate, and C-reactive protein were within normal range. However, plasma glucose level and glycosylated hemoglobin level were 477 mg/dL and 13.1%, respectively, which revealed poorly controlled diabetes mellitus.\nElectrodiagnostic studies were performed in the right upper extremity to rule out an atypical type of ulnar neuropathy. Nerve conduction studies of latency, amplitude, and conduction velocity exhibited normal findings in motor and sensory components. Abnormal needle electromyographic findings, including abnormal spontaneous activities and motor unit action potentials, were not observed.\nFor further evaluation, contrast-enhanced magnetic resonance imaging (MRI) of the right hand was performed, and this revealed a partial tear of the fifth finger flexor tendon with a fluid collection in the tendon sheath and in the flexor compartment along the ulnar side. This finding was suggestive of flexor tenosynovitis associated with ulnar bursitis (). There were no abnormal findings in bone, soft tissue, or neurovascular structure.\nBased on the spontaneous occurrence of flexor tenosynovitis along the ulnar side and tiny calcific nodules in chest radiographs, a decision was made for a PCR analysis to identify the potential infectious cause. Under ultrasound guidance, an 18-gauge needle was introduced into the hypoechoic area beneath the interrupted fifth flexor tendon (). From that point, 0.3 mL of synovial fluid, which was slightly turbid and yellowish, was aspirated. From the area, but did not contain loose bodies. Nested PCR analysis was positive for Mycobacterium tuberculosis gene probe in the aspirated fluid, confirming the diagnosis of tuberculous tenosynovitis (). A follow up serologic test was negative for human immunodeficiency virus (HIV) antibody.\nAlthough partial tear of fifth finger flexor tendon was highly suspected based on the MRI finding and motor weakness, a nonoperative medical treatment was preferentially followed due to the uncontrolled diabetes mellitus. The patient was started on combination chemotherapy of isoniazid, rifampin, pyrazinamide, and ethambutol along with additional hypoglycemic agents. Two weeks after the commencement of therapy, paresthesia along the ulnar side had begun to improve; however, there were no interval changes to the motor weakness of the fifth finger flexor. Extension block splint and range of motion exercise were maintained to support fourth and fifth finger flexor tendons. Three months later, sensory symptom disappeared and motor weakness had improved to grade 4.