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Year : 2023  |  Volume : 66  |  Issue : 2  |  Page : 350-351
A rare case of smear positive tuberculous arthritis

1 Department of Microbiology, Vinayaka Mission's Kirupananda Variyar Medical College, Vinayaka Missions Research Foundation (Deemed to be University), Salem, Tamil Nadu, India
2 Department of General Medicine, Vinayaka Mission's Kirupananda Variyar Medical College, Vinayaka Missions Research Foundation (Deemed to be University), Salem, Tamil Nadu, India

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Date of Submission02-Apr-2021
Date of Acceptance21-Jun-2021
Date of Web Publication27-Apr-2022


TB arthritis is a very rare extrapulmonary presentation in an immunocompetent host. It is usually the result of direct hematogenous spread from the primary focus. Our patient presented with pain and swelling of the right knee for 6 months. The blood investigations and CT chest revealed findings consistent with active tuberculosis. Synovial fluid was positive for acid-fast bacilli (AFB) which is a very rare finding. Cartridge-based nucleic acid amplification test (CBNAAT) revealed Mycobacterium tuberculosis and sensitivity to rifampicin. Establishing the diagnosis of Mycobacterium tuberculosis beyond doubt is very important, and early initiation of antitubercular treatment (ATT) is important as delay in treatment may lead to irreversible damage to the joint and restriction of joint mobility.

Keywords: Acid-fast bacilli, CBNAAT, extra-pulmonary, M. tuberculosis, synovial fluid, Tb arthritis

How to cite this article:
Sureshkumar M, Rajamani S, Ravindran V, ArvindhKrishnan E. A rare case of smear positive tuberculous arthritis. Indian J Pathol Microbiol 2023;66:350-1

How to cite this URL:
Sureshkumar M, Rajamani S, Ravindran V, ArvindhKrishnan E. A rare case of smear positive tuberculous arthritis. Indian J Pathol Microbiol [serial online] 2023 [cited 2023 Jun 3];66:350-1. Available from:

   Introduction Top

Tuberculous (TB) arthritis, an extrapulmonary manifestation of tuberculosis, is a rare and potentially devastating condition which is treatable. Tb arthritis results from direct lymphohematogenous dissemination of Mycobacterium tuberculosis.[1] About 10%–35% of extrapulmonary tuberculosis is constituted by osteoarticular manifestations.[2] Tuberculous arthritis of the knee is the third most common manifestation in skeletal tuberculosis next to the spine and hip.[3] The presentation is mostly monoarticular with pain and joint swelling.[4] Laboratory findings are usually inconclusive of tuberculosis due to their very low sensitivity.[4] Rapid and prompt identification and early initiation of antituberculous drugs are very essential to prevent devastating effects of joint injury. This case is published in the context of the very rare finding of acid-fast bacilli (AFB) in synovial fluid aspirated from a patient with joint pain and swelling for the past 6 months.

   Case Presentation Top

A 36-year-old male presented to our Orthopaedics Department with complaints of pain and swelling on the right knee for the past 6months. There was the gradual onset of pain and swelling which was progressive in nature. The patient also gave a history of cough with sputum production, fever, morning rise of temperature, and weight loss. The patient was nondiabetic, nonhypertensive, and not a known case of tuberculosis. He had tried multiple treatment modalities but of no use.

On examination, swelling and deformity were present in the right knee with no scar, sinus, or dilated veins. The patient had tenderness, boggy swelling, and an intact sensorium with no warmth over the swelling. Restricted movement of the involved joint was noted due to pain.

CT chest showed multiple cavitary lesions in the right lung fields. Tree in bud patterns was noted in bilateral lung fields indicative of active tuberculosis infection. Furthermore, high-resolution computed tomography (HRCT) thorax showed mild volume loss of the right lung, extensive centrilobular nodules with a tree in bud appearance in the bilateral lung fields.

The blood investigations revealed a white blood cell count of 17,200 cells and erythrocyte sedimentation rate (ESR) of 35 mm at ½ h and 60 mm at 1 h and a CRP value of 30.84 mg/L.

Synovial fluid was aspirated and subjected to Gram staining and acid-fast staining. Gram staining revealed plenty of pus cells with no organisms. The acid-fast staining of synovial fluid revealed the presence of acid-fast bacilli [Figure 1] which is a very rare finding due to the very low sensitivity of smear microscopy. Acid-fast staining of sputum also showed the presence of acid-fast bacilli (2+). The synovial fluid and sputum were subjected to CBNAAT which was positive for Mycobacterium tuberculosis and sensitive to rifampicin.
Figure 1: The acid-fast staining of the synovial fluid performed by Ziehl–Neelsen method with 20% sulphuric acid as decolorizer showed many pus cells with acid-fast bacilli

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   Management and Outcome Top

The patient was enrolled under the National Tuberculosis Elimination Program (NTEP) and started on antitubercular treatment (ATT) as per the recently revised treatment protocol.

   Discussion Top

Risk factors for tuberculous arthritis include trauma, immunocompromised state (HIV, corticosteroids, etc.,), rheumatoid arthritis, smoking, alcohol, and joint prosthesis.[5],[6] As Tb arthritis is always due to dissemination, identification of primary lesion should be made. Pulmonary involvement is seen in only 29% of cases.[7] Our patient had evidence of pulmonary tuberculosis.

Sugar and protein analysis of synovial fluid is not of much help.[8] All samples should be subjected to microbiological diagnosis. The sensitivity of direct smear microscopy in synovial fluid varies from 1.4% to 5%.[9] In our case, we were able to detect AFB in smear microscopy. The sensitivity can be increased when synovial biopsies are done. Culture is the gold standard diagnostic test for the diagnosis of tuberculosis with a sensitivity of 80%. But the disadvantage of extended turnaround time can cause a delay in the treatment leading to more damage to the joints.

This can be overcome by the current molecular methods available like CBNAAT, which are highly specific and less time-consuming making it an excellent tool for early diagnosis.[10] CBNAAT also helps in early species identification and along with simultaneous testing of rifampicin sensitivity makes it a better tool for early targeted treatment. The sensitivity of CBNAAT for extrapulmonary specimens varies from 27.2%–to 63%.[11],[12],[13]

   Conclusion Top

Establishing the diagnosis of Mycobacterium tuberculosis beyond doubt plays a major role in reducing the cost and duration of treatment. In addition, preventing irreparable damage and restoration of joint mobility can be done by early diagnosis and timely initiation of antitubercular treatment (ATT).[14]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Madeleine G. Moule and Jeffrey D. Cirillo. Mycobacterium tuberculosis dissemination plays a critical role in pathogenesis. Front Cell Infect Microbiol 2020;10:65.  Back to cited text no. 1
Ji Yeon Lee. Diagnosis and treatment of Extrapulmonary tuberculosis. Tuberc Respir Dis 2015;78:47-55.  Back to cited text no. 2
Uboldi FM, Limonta S, Ferrua P, Manunta A, Pellegrini A. Tuberculosis of the knee: A case report and literature review. Joints 2017;5:180-3.  Back to cited text no. 3
Matta Ramos RF, Cancian L, Calcagnotto F, Zeni R, Varela G, Burgues T, et al. Synovial tuberculosis of the hand: An ancient disease in an unusual localisation. Indian J Plast Surg 2017;50:130-7.  Back to cited text no. 4
Fortun J, Martín-Davila P, Rodríguez JM, Navas E, Moreno S. Mycobacterium tuberculosis infection. Medicine 2010;10:3808-19.  Back to cited text no. 5
Jagtap SA, Sonawane DV, Saraogi AA. Isolated tuberculosis of scapula in a young adult. Int J Mycobacteriol 2013;2:114-7.  Back to cited text no. 6
  [Full text]  
Pigrau-Serrallach C, Rodríguez-Pardo D. Bone and joint tuberculosis. Eur Spine J 2013;22(Suppl 4):556-66.  Back to cited text no. 7
Dlimi F, Abouzahir M, Mahfoud M, Berrada MS, El Bardouni A, El Yaacoubi M, et al. Multifocal bone tuberculosis: A case report. Foot Ankle Surg 2011;17:47-50.  Back to cited text no. 8
Pathrikar TG, Bansal VP, Mulay MV, HS Ghogare. Comparison of Ziehl-Neelsen smear microscopy and AFB culture in a resource limited setting from various clinical samples. Int J Health Sci Res 2020;10:46-51.  Back to cited text no. 9
Tseng C, Huang RM, Chen KT. Tuberculosis arthritis: Epidemiology, diagnosis, treatment. Clin Res Foot Ankle 2014;2:131.  Back to cited text no. 10
Barik S, Choudhury AK, Singh V, Bali S. Extra-spinal osteoarticular tuberculosis: A retrospective analysis of 103 cases. Curr Health Sci J 2019;45:142-7.  Back to cited text no. 11
Sharma SK, Ryan H, Khaparde S, Sachdeva KS, Singh AD, Mohan A, et al. Index-TB guidelines: Guidelines on extrapulmonary tuberculosis for India. Indian J Med Res 2017;145:448-63.  Back to cited text no. 12
[PUBMED]  [Full text]  
Lall H, Nag SK, Jain VK, Khare R, Mittal D. Tuberculous extensor tenoarthritis of the wrist with extensor pollicis longus rupture: A case report. J Med Case Rep 2009;3:142.  Back to cited text no. 13
Pal CP, Goyal A, Sharma B, Kumar H, Rawat SS, Prakash A, et al. Synovial biopsy: Role in diagnosis and management of unilateral arthritis knee. J Bone Jt Dis 2017;32:43-7.  Back to cited text no. 14

Correspondence Address:
Mathavi Sureshkumar
Professor and Head, Department of Microbiology, Vinayaka Mission's Kirupananda Variyar Medical College, Vinayaka Missions Research Foundation (Deemed to be University), Salem - 636 308, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijpm.ijpm_341_21

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