Tuberculous Dactylitis in Adult - A Case Report and Review of Literature.

INTRODUCTION: Tubercular dactylitis is an uncommon form of musculoskeletal tuberculosis (TB), especially after the age of 5 years without any risk factors. CASE REPORT: A case of 49-year-old male presented with pain, swelling, and discharging sinus of proximal phalanx of third digit of the right hand with no constitutional symptoms for 2 years, with multiple failed treatment in form of antibiotic therapy. There were no risk factors such as immunodeficiency or any co-morbidities. The plain radiograph was suggestive of increased bone density with mild periosteal reaction; magnetic resonance imaging was suggestive of tubercular osteomyelitis. A biopsy was performed, the gene expert of the sample revealed TB with no drug resistance. The patient was managed with anti-tubercular drugs with complete resolution of clinical and radiological symptoms at 1-year follow-up.
CONCLUSION: TB should be considered a differential in patients with chronic soft-tissue or skeletal lesions even in the absence of the usual risk factors because with treatment it still carries a good prognosis. Copyright: © Indian Orthopaedic Research Group.

Anti-tubercular chemotherapy is the main treatment of tuberculous dactylitis.

Introduction

Osteoarticular tuberculosis (TB) accounts for only 1–3% of all the TB infections [1]. Hand and feet are involved in 14 and 10 % of the case of osteoarticular TB [1, 2]. Tuberculous infection of the metatarsal, metacarpal, and phalanges of hand and feet is known as tuberculous dactylitis. Tubercular dactylitis is rare and it constitutes 2–4% of skeletal TB [3, 4]. The hand is more commonly involved than a foot in tuberculous dactylitis [5, 6, 7]. Tuberculous dactylitis is uncommon after the age of 5 years. It poses a serious diagnostic challenge due to its unusual presentations, inadequate diagnostic skills, limited understanding of the management, and many overlapping features with other diseases. Here, we report a rare case of TB dactylitis in adults without any risk factor diagnosed and treated successfully with anti-tubercular therapy.

Case Presentation

A 49-year-old male presented with pain, swelling, and discharging sinus over the proximal phalanx of the third digit of the right hand for 2 years. The patient was apparently asymptomatic 2 years back when he developed pain and swelling of the third digit which was insidious in onset and gradually progressive finally culminating with a discharging sinus 1 year back. There was no history of trauma, cough, weight loss, decreased appetite, and any other risk factors. The patient was previously treated at other centers with incision and drainage followed by antibiotics. On examination, there was a firm, globular swelling at the base of the third digit with a discharging sinus over the proximal phalanx of the third digit of the right hand (Fig. 1). No local inflammatory signs were found. The finger range of motion was painful and restricted.

Figure 1

A swelling at proximal phalanx of third digit.

Plain radiographs showed increased bone density, mild periosteal reaction with an osteolytic lesion of proximal phalanx of the third finger (Fig. 2). The chest radiograph was normal. Local ultrasonography revealed dense internal echoes measuring about 1.25 × 1.37 ×1.30 cm. Magnetic resonance imaging (MRI) was suggestive of tubercular osteomyelitis. Erythrocyte sedimentation rate (ESR) and C reactive protein were elevated. Other laboratory parameters were normal. An open biopsy was done through Brunner’s incision over the dorsal aspect of the lesion, sinus tract excised and the samples were sent for histopathology which revealed chronic granulomatous inflammation. Gene-Xpert was done which detected TB and no resistance to first-line drugs was found.

Figure 2

Posteroanterior plain radiograph increase bone density of proximal phalanx of third digit.

Anti-tubercular therapy was started which included four drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 2 months, followed by three drugs (isoniazid, rifampicin, and ethambutol) for 7 months. The patient finger was immobilized for 1 month. The patient responded to the anti-tubercular therapy with complete resolution of the pain, swelling, and discharging sinus was satisfactorily healed. Radiographs of the right hand after the completion of the treatment course at 1 year revealed a decrease in the size of the osteolytic lesion with the resolution of associated sclerosis (Fig. 3). At 1 year follow- up, the patient had a full range of motion of fingers with no other symptoms (Fig. 4).

Figure 3

Oblique and posteroanterior view at 1-year follow-up.

Figure 4

Clinical picture at 1-year follow-up.

Discussion

Tuberculous infection of the metatarsal, metacarpal, and phalanges of hand and feet is known as tuberculous dactylitis. Tuberculous dactylitis is a rare <2–4% of skeletal TB [3, 4]. It is most common by hematogenous spread from the lungs. Fingers are more commonly affected than the toes, proximal phalanx of the index, and middle fingers are the most common sites involved [8, 9, 10]. Tuberculous dactylitis is uncommon beyond the age of 5 years after the formation of the epiphyseal center. It usually becomes symptomatic after 1–3 years following the initial infection. In children, the disease usually involves multiple bones. Children tubular bone has an abundant blood supply through a large nutrient artery. Infection is usually in the center of the marrow cavity and short tubular bone is gradually becomes tuberculous granuloma. When the nutrient artery of involved bone is occluded it leads to formation of the sequestrum, there is endosteal destruction and simultaneous new bone formation. It is also sometimes called “Spina ventosa” because radiologically it appears to be a cystic expansion of the phalanges. Typically, the disease presents as a chronic, painful, and progressive swelling of the fingers or toes, affecting most commonly the proximal phalanx and metacarpals of the hand. Multifocal involvement, sequestration, discharging sinus, and mutilation of the fingers occur more often in children or patients who are suffering from concomitant immunodeficiency. Abscess and sinus formation is common leading to secondary bacterial infections. A radiologic picture usually shows an osteolytic lesion, mild to no periosteal reaction, areas of bone sclerosis, and destruction. MRI is the modality of choice to see early marrow and soft-tissue involvement. In spina ventosa, the bone may take shape of honey combing, diffuse infiltration, cystic lesion, or rarely bone atrophy. Tuberculous dactylitis commonly occurs in the background of tubercular contagion or a state of immunosuppression and for it to present in the absence of both is a rare entity, as it was in our case. The mainstay of diagnosis of tubercular dactylitis remains the histopathological examination of the biopsy specimens, demonstration of mycobacterium TB on Gene-Xpert studies, localizing acid-fast bacilli on Z-N stain. The culture of mycobacterium from bone tissue remains the Gold standard. Laboratory investigations such as white blood counts, differential counts, ESR, and CRP do not aid in the diagnosis of tubercular dactylitis; however, they tend to help in ruling out the other possible diagnosis. The treatment of TB dactylitis consists of long-term anti-tubercular therapy consisting of four drugs isoniazid, rifampicin, pyrazinamide, and ethambutol for 2 months, followed by isoniazid and rifampicin for 6–12 months [11]. Excellent clinical-radiological response is seen irrespective of the stage of the disease in which it is started [9, 11]. Ankylosis of the joint remains one of the dreaded complications of the disease; however, in most cases; complete remission is seen following the completion of anti-tubercular chemotherapy.

Differential diagnosis includes chronic pyogenic osteomyelitis, syphilitic dactylitis, fungal dactylitis, and conditions with lytic lesions (enchondroma or fibrous defect). Other conditions include sarcoidosis, brucellosis, psoriasis, hyperparathyroidism, and leukemia. Pyogenic osteomyelitis of the fingers should be considered when there is a local rise of temperature, severe tenderness over the affected parts, high-grade fever, and loss of finger movements with elevated white counts. Tuberculous dactylitis usually progresses through an indolent course, rarely manifesting systemic symptoms. The lack of sequestration and the presence of diffuse osteopenia distinguish tuberculous infection from pyogenic infection.

Khanna et al. reported a case of TB of distal phalanx of great toe presenting as painless paronychia with pseudopterygium and nail dystrophy [12].

We have done a review of literature in the past 10 years on tuberculous dactylitis in adults and tabulated (Table 1).

Table 1

A brief summary of the previous studies.

Conclusion

Tuberculous dactylitis usually affects children <5 years of age; it needs to be considered as a differential diagnosis in adults with unusual soft-tissue or skeletal lesions even in the absence of usual risk factors such as tubercular contagion, immunodeficiencies, and primary foci of TB elsewhere in the body. A high degree of suspicion accompanied by proper clinical examination and radiology helps in diagnosing this rare entity. Once the diagnosis is confirmed by biopsy, Anti-tubercular chemotherapy is the treatment of choice.

Tuberculous dactylitis should be considered a differential diagnosis when a patient presents with soft-tissue or skeletal lesion of hand and foot so early diagnosis can be done.