Disseminated tuberculosis presenting with finger swelling and skin ulcer: a case report

Dear Editors,

Tuberculosis remains a major public health problem causing significant morbidity and mortality in individuals worldwide. Extrapulmonary tuberculosis has become an increasingly important issue, particularly among immune‐compromised patients 1. According to the National Tuberculosis Surveillance System, in the USA, the prevalence of extrapulmonary tuberculosis was reported to increase from 15·7% in 1993 to 21·0% in 2006 2. The proportion of extrapulmonary tuberculosis is also increasing in Korea, from 11% in 2004 to 23% in 2011 3. However, bony lesions found on the hand, foot or leg are still rare presentations of extrapulmonary tuberculosis 4.

We report a case of disseminated tuberculosis in a 48‐year‐old man, whose major complaints were skin ulceration and finger swelling. The aim of this case report was to point out that if non‐healing skin lesions or unknown origin of finger swelling is presented, clinicians should take tuberculosis into consideration as a potential diagnosis.

A 48‐year‐old man visited out‐patient clinic with complaints of a non‐healing skin ulcer on the right medial malleolar area and right‐index finger pain with swelling (Figure 1). He remembered minor trauma history on the right medial malleolus 3 months ago and found ulceration a month before. He then visited a local clinic and treated with cefepime for 1 week. Because, there was no improvement, he admitted to the hospital and treated with intravenous ciprofloxacin. Two weeks after admission, his index finger was swollen without any trauma history and then he referred to our hospital. He denied fever, weight loss or other systemic symptoms. On physical examination, his index finger was swollen and erythematous at the middle phalanx. Small ulceration with swelling and heating sensation on his right medial malleolus was presented. He exhibited limitation of movement at the proximal and distal interphalangeal joints. Probe found that ulceration was connected to his malleolar bone.

Figure 1.

There was a 0·5 × 0·5 cm² sized round‐shaped ulceration on right malleolus (A) and marked swelling on middle phalanx of right index finger (B).

His laboratory values were as follows: white blood cell count 5200 cells/mm³, C‐reactive protein 53·8 mg/l and erythrocyte sedimentation rate were more than 120 mm/hour. A plain radiograph of the finger and ankle was consistent with osteomyelitis (Figure 2A, B). Magnetic resonance imaging (MRI) of the ankle found an intraosseous abscess at medial malleolus and distal tibial shaft to medial malleolar osteomyelitis was suggested (Figure 2C). Plain chest radiograph demonstrated left lower lobe consolidation (Figure 2D). A bone scan showed that multiple hot uptake includes right index finger and right medial malleolus (Figure 3). With tuberculosis in the differential diagnosis, a tuberculin test was performed; the test result was strongly positive with a 30‐mm‐diameter palpable area of induration. Bone biopsy and surgical debridement of malleolus and finger were performed. A percutaneous needle biopsy of the lung was also conducted. There were no properly formed granuloma and acid‐fast bacilli were not observed on either the finger and malleolar bone. In the lung biopsy, there was chronic granulomatous inflammation without acid‐fast bacilli. The bacterial culture of the finger bone, malleolar bone and sputum were negative. Antituberculous treatment was initiated with the drugs of rifampin, isoniazid and ethambutol. After 7 weeks, a bone and lung biopsy samples tested positive for growth of Mycobacterium tuberculosis; a polymerase chain reaction (PCR) test confirmed the presence of M. tuberculosis. The patient maintained a drug regimen for 6 months. Because of paradoxical response, he then changed to a drug regimen of rifampin, isoniazid and pyrazinamide for 12 months. After 18 months of total treatment, the follow‐up bone scan demonstrated resolved hot uptake lesions (Figure 3). The malleolar skin lesion was completely healed without sequelae. Although, the right index finger swelling and pain were resolved, the patient still exhibited limitation of movement at the proximal and distal interphalangeal joints.

Figure 2.

Plain radiograph of the right index finger. (A) Soft tissue swelling and periosteal reaction around the middle phalanx. Distal site of middle phalanx show cystic degeneration change and linear fracture (white arrow). (B) A plain radiograph of the ankle revealed periosteal reaction and lytic lesion around the medial malleolus. T1‐weighted coronal view (turbo skin echo, TSE) of right ankle. (C) Intraosseous abscess (arrow head) at medial malleolus with cortical destruction and skin fistula formation. Joint effusion with intense synovial enhancement was also noted. Cellulitis around both malleolus, tenosynovitis at plantaris tendon and flexor digitorum longus tendon at retromalleolar area and distal tibial shaft to medial malleolar osteomyelitis were suggested. (D) Left lower lobe consolidation was found on chest radiograph.

Figure 3.

(A) Right index finger, right medial malleolus, metatarsal lateral condyle of femur, left both malleolus, metatarsal, lateral condyle of femur and left proximal tibia increased uptake. (B) After 18 months of total treatment, the follow‐up bone scan demonstrated resolved hot uptake lesions.

Disseminated extrapulmonary tuberculosis is an uncommon condition, accounting for about 2% of total tuberculosis cases and occurs chiefly in an endemic area and among patients with immunodepression 5, 6. Lymphadenitis is the most common form of extrapulmonary disseminated sites and osseous involvement of the finger or leg is rare.

The diagnosis was based on clinical features, radiography findings and staining for acid‐fast bacilli and mycobacterial culture. The Mantoux test and chest radiography should be performed for all patients.

Radiologic findings may not allow for differentiation between diagnoses; therefore, the criterion standard for investigation is biopsy, aspiration and culture of the infected site. A biopsy shows granuloma, lymphocytes and giant cells with caseation. However, smears, Ziehl–Nelson stains and tuberculosis cultures are frequently negative. Therefore, in equivocal cases, PCR may be used to confirm the diagnosis of M. tuberculosis 7. Indeed, in patients in endemic areas with typical clinical and radiologic features, a therapeutic trial with antituberculous drugs is frequently employed and the demonstration of a positive smear or culture is not mandatory.

In the disseminated types of tuberculosis, osteomyelitis typically seen in immune‐compromised patients and the bony lesions in this type involves bones of various parts of the body; however, the chest x‐ray is usually negative 6, 7, 8. However, in this case, the patient was not only relatively healthy but also showed pulmonary involvement.

Skeletal tuberculosis is usually treated with 9–12 months of antituberculous therapy with surgical debridement 9. However, some cases of skeletal tuberculosis need longer treatment, such as the patient in this case 10.

Two particular points make this disease difficult to diagnose. First, the rarity of this disease in general population, combined with a lack of awareness by physician, often leads to an unnecessary delay in diagnosis. Second, minor trauma in the affected area can mask the underlying pathology and also cause a delay in diagnosis. Indeed, many cases of tuberculosis osteomyelitis had a trauma history when they visited clinics 6.

Because treatment results are much better if initiated during the earlier stages of the disease, prompt diagnosis and adequate treatment are essential 6.

This case illustrates the importance of a high index of suspicion when evaluating a patient with a destructive bony lesion or non‐healing ulceration. Early biopsy and appropriate microbiologic testing can avoid diagnostic delay so that appropriate curative treatment can be initiated and the disease is cured with less morbidity.

Ja Hea Gu, MD, PhD
Department of Plastic Surgery, Dankook University Hospital, Cheonan, Chungcheongnam, Korea
jaheagu@gmail.com