An Unusual Case of Tuberculosis Infection of the Hand with Peritonitis

Summary

A 19-year-old male presented with rare co-occurring tuberculosis (TB) hand osteomyelitis and peritonitis. Initially misdiagnosed as an enchondroma, the diagnosis was confirmed by histopathology, acid-fast staining, and FISH. Combined surgical debridement and 12-month antitubercular therapy led to full recovery without sequelae, highlighting TB's atypical presentations and multidisciplinary management.

Abstract

Tuberculosis (TB), primarily a pulmonary disease, manifests extrapulmonary involvement in 20% of cases, though concurrent infections in distant sites like the hand and abdomen are exceedingly rare. This report presents an exceptionally rare case of concurrent tuberculosis osteomyelitis of the hand and peritoneal tuberculosis in a 19-year-old male-an unusual dual presentation not commonly documented in the literature. The patient had an 8-month history of progressive right little finger swelling, initially misdiagnosed as an enchondroma, and subsequently developed acute abdominal pain and ascites, with computed tomography (CT) revealing diffuse peritoneal thickening and peritonitis. Ascitic analysis showed exudative fluid with elevated CA-125, and an interferon-gamma release assay (IGRA) was positive, prompting TB suspicion. Histopathology of debrided hand tissue revealed granulomatous inflammation with necrosis, and Mycobacterium tuberculosis was confirmed by acid-fast staining and fluorescence in situ hybridization (FISH). Treatment combined surgical debridement, bone grafting, and vacuum-assisted drainage for the hand lesion with a 12-month HRZE regimen. Abdominal TB resolved with medical therapy alone. The patient achieved complete recovery with restored finger function and no recurrence over 2 years. This case underscores TB's protean manifestations, emphasizing diagnostic challenges in paucibacillary disease and the utility of IGRA and molecular confirmation (FISH). Clinicians should maintain high suspicion for TB in atypical osteolytic lesions or idiopathic serositis, particularly in endemic regions, to ensure timely multidisciplinary management.

Introduction

Tuberculosis (TB) remains a global epidemic. In 2023, an estimated 10.8 million people developed TB, and there were approximately 1.25 million deaths, making it once again the leading cause of death from a single infectious agent, according to the WHO Global Tuberculosis Report¹. The incidence has risen over the last decade as worldwide travel has become more common and the number of immunocompromised patients has climbed.

After lung and lymph nodes, osteoarticular TB is the third most common site of TB and accounts for 10% to 20% of all extrapulmonary TB cases^2,3. Hand involvement is considerably infrequent, occurring in 10% of individuals with osteoarticular TB⁴. Following involvement of the lymphatic, genitourinary, bone and joint, miliary, and meningeal systems, abdominal TB is the sixth most frequent location of extrapulmonary TB⁵. Isolated TB infection of the hand or abdomen is uncommon; co-infection of both the hand and abdomen is even more scarce. Hand TB is insidious, often mimicking benign tumors (e.g., enchondroma) or chronic infections due to its nonspecific presentation: localized swelling, pain, and lytic bone lesion, the radiographs showing a well-defined, lytic, and slightly expansile lesion in the phalanx, features that commonly mimic benign cartilaginous tumors such as enchondroma. Diagnostic delays are common, as cultures frequently yield negative results in paucibacillary lesions. Similarly, peritoneal TB is diagnostically elusive, with ascitic fluid analysis and imaging (e.g., CT) serving as cornerstones. Elevated CA-125 and positive interferon-gamma release assays (IGRAs) may heighten suspicion, yet histopathological confirmation by biopsy remains critical⁶.

To our knowledge, the rare report presents a case of concurrent tuberculous osteomyelitis of the hand and peritoneal TB in a 19-year-old male with no overt risk factors⁶. Initially misdiagnosed as an enchondroma due to lytic bone changes, the patient later developed acute peritonitis, prompting a re-evaluation. The case underscores the protean manifestations of TB, emphasizing the role of advanced diagnostics (e.g., fluorescence in situ hybridization [FISH]) and multidisciplinary

Case presentation:
A 19-year-old male college student presented with an 8-month history of progressive swelling and pain of the right little finger and 10 days of abdominal discomfort. He denied trauma, animal bites, or prior TB contact but reported a family history of TB in his grandfather. At a local hospital, finger radiographs showed a lytic expansile lesion, leading to a presumptive diagnosis of enchondroma and planned excision. Preoperative chest CT revealed a small pleural effusion, and abdominal CT showed ascites with diffuse peritoneal thickening. Ascitic analysis confirmed exudative fluid (Rivalta test positive), with elevated CA-125 (85.7 U/mL) and a positive IGRA (Table 1), suggesting tuberculous peritonitis. The finger operation was cancelled, and he was referred to our hospital.

There were no complaints of systemic infection signs, such as cough, weight loss, fever, or night sweats. Physical examination demonstrated a painful, tender little finger with diffuse swelling centered at the lateral side of the proximal phalanx. Nodular lesions and chronic inflammatory changes could be seen on the surface of the skin (Figure 1A). There was no erythema or abnormal warmth. Except for mild tenderness in the right lower quadrant, there were no other positive abdominal signs.

Diagnosis, Assessment, and Plan:
The laboratory evaluation revealed a slight rise in CA-125. Blood count and erythrocyte sedimentation rate were within normal limits. Anteroposterior and lateral radiographs of the little finger were taken (Figure 2A,B). The only indication of a current or previous infection on the chest CT scan was a small pleural effusion. Abdomen CT showed diffuse thickening of the peritoneum and omentum, peritonitis, and a small amount of ascites (Figure 2C).

Initial treatment regimens were amikacin, levofloxacin, and azithromycin. A consultation was sent to us for the treatment of a hand lesion. The bone changes of the little finger were initially diagnosed as enchondroma due to imaging findings of a lytic and slightly expansile lesion. The initial operation involved the patient having a deep tumor removed and the nodule being incised and drained. The subcutaneous region had a significant quantity of necrotic and myxomatous granulation tissue excised, with considerable bone involvement (Figure 1B,C). A hole could be seen in the bone clearly after debridement. Inflammatory tissue in the bone could be seen through the hole. The involved tissue was mostly colorless. All the removed tissue was sent for histopathology as well as for regular microbial culture and acid-fast bacilli culture. Surgical debridement was undertaken not only to relieve local symptoms and remove necrotic tissue, but also to obtain adequate specimens for histopathology and culture, and to reduce bacterial load. A vacuum-sealing drainage device was used for adequate drainage. After 7 days from the first surgery, bone grafting to fill the hole of bone and local flap transfer were performed to cover the wound.

Regular microbial culture and acid-fast bacilli culture were negative. Histopathology examination of the lesions showed granulomatous inflammation with necrosis (Figure 3), and TB infection was excluded. Immunohistochemical results showed positive acid-fast staining (Figure 4A), and fluorescence in situ hybridization (FISH) results showed positive for Mycobacterium tuberculosis (Figure 4B). Notably, fluorescence in situ hybridization (FISH) offered a critical diagnostic advantage in this paucibacillary lesion: unlike conventional staining and culture that often fail due to the very low bacterial load, FISH enabled direct visualization of M. tuberculosis within tissue sections, thereby providing timely confirmation when other methods were inconclusive

Based on the FISH results, the treatment regimen was adjusted to an HRZE course (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 12 months, with amikacin and levofloxacin administered for an initial 2-week course. The patient was advised to follow up with an outpatient for further care. Home-based antituberculosis chemotherapy lasted 12 months.

Protocol

This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the First Affiliated Hospital, Zhejiang University School of Medicine. Written informed consent was obtained from the patient for participation in and publication of this study. All procedures involving the handling of tissue samples suspected of containing Mycobacterium tuberculosis were performed under Biosafety Level 2 (BSL-2) laboratory conditions, adhering to national and institutional biosafety regulations.

1. Initial clinical assessment

1. Comprehensive patient history was obtained, focusing on symptom duration (8-month hand swelling, 10-day abdominal pain), prior trauma, TB exposure, BCG vaccination status, and family TB history.
2. Physical examination of the right little finger was done for tenderness, swelling, mobility limitation, and abdominal assessment for tenderness, ascites, or peritoneal signs.

2. Imaging studies

1. Anteroposterior and lateral radiographs of the right little finger were obtained to evaluate lytic bone lesions and soft tissue swelling. For the affected right little finger, anteroposterior and lateral radiographs were obtained using a digital radiography system.
   1. The patient was seated with the hand placed flat on the detector for the AP view and in a true lateral position with the ulnar aspect against the cassette for the lateral view. Exposure parameters were set at 45-50 kVp and 2-3 mAs with a focus-film distance of 100 cm.
   2. Images were collimated to include the distal metacarpal to the fingertip and stored in DICOM format.
2. A chest CT scan was done to exclude pulmonary TB and assess pleural effusion.
   1. Chest CT was performed using a 64-slice CT scanner to assess pulmonary involvement. The patient was positioned supine with arms elevated to minimize artifacts, and scanning was carried out from lung apices to costophrenic angles during inspiratory breath-hold. Typical acquisition parameters included 120 kVp, 200-250 mAs with automatic exposure control, 0.6 mm collimation, 0.5 s rotation time, pitch 1.2, and reconstruction slice thickness of 0.75-1.25 mm.
   2. Images were reconstructed in axial, coronal, and sagittal planes with both lung and mediastinal windows. Non-contrast scans were performed in this case to evaluate pleural effusion.
3. Abdominal CT scan with contrast was carried out to identify ascites, diffuse peritoneal thickening, and omental involvement.
   1. Abdominal CT was performed on the same 64-slice system to evaluate peritoneal tuberculosis. The patient fasted for at least 6 h prior to the study and was positioned supine with arms overhead. Scanning was performed from the dome of the diaphragm to the pubic symphysis. Parameters included 120 kVp, 250-300 mAs with dose modulation, 0.6 mm collimation, pitch 1.0-1.2, and 1-2 mm slice thickness with 1 mm reconstruction intervals.
   2. Intravenous contrast was administered using non-ionic iodinated medium (iohexol 300 mgI/mL) at a dose of 1.5 mL/kg (maximum 120 mL), injected at 3 mL/s through an 18-20 G antecubital catheter, with portal venous phase acquisition at 70-80 s.

3. Laboratory and diagnostic tests

1. Diagnostic paracentesis for ascitic fluid analysis was done, which includes the Rivalta test, cell count, biochemistry (albumin and glucose), and cytology. Diagnostic paracentesis was performed under sterile conditions to evaluate ascitic fluid.
   1. The patient was positioned supine with the head elevated at 30°. The puncture site was selected in the left lower quadrant, approximately 3 cm above and medial to the anterior superior iliac spine, or alternatively at the midline 2 cm below the umbilicus, avoiding prior surgical scars and engorged vessels.
   2. After skin preparation with 2% chlorhexidine in 70% alcohol and sterile draping, local anesthesia was achieved using 2-3 mL of 1% lidocaine. A paracentesis catheter set (18-20 G spinal needle or disposable catheter with stylet) was inserted with a Z-track technique until ascitic fluid was aspirated. Approximately 20-30 mL of fluid was collected: 5 mL in a plain serum tube for biochemistry (albumin, protein, glucose, LDH), 20 mL in a sterile 50 mL conical tube for cytology (with heparin if available), and 2-3 mL fresh fluid tested immediately for Rivalta reaction by dripping into a beaker containing 100 mL of distilled water with 1 drop of 98% acetic acid.
   3. Samples for biochemistry were transported at room temperature and processed within 2 h, while cytology specimens were delivered fresh to the pathology laboratory and centrifuged for smear preparation. After aspiration, the ascitic fluid is typically clear to straw-colored in tuberculous peritonitis; excessive turbidity, frank pus, or bloody aspirates should prompt evaluation for alternative or superimposed pathology.
2. Interferon-gamma release assay (IGRA) to screen for TB infection. A total of 3-4 mL of venous blood was drawn directly into the specialized collection tubes (nil control, TB antigen 1 and 2, mitogen control), which contain proprietary anticoagulants and antigens.
   1. Tubes were shaken gently 10x to ensure mixing and immediately incubated upright at 37 °C for 16-24 h in a CO₂-free incubator.
   2. Plasma was harvested by centrifugation at 2,000 x g for 15 min and stored at 2-8 °C until ELISA measurement of interferon-gamma levels. IGRA should be considered when unexplained osteolytic or serosal lesions raise suspicion for tuberculosis despite negative cultures, while FISH offers confirmatory utility in paucibacillary tissue but is limited by cost and availability.
3. Microbial cultures of hand lesion tissue and ascitic fluid were performed for bacteria, fungi, and acid-fast bacilli. Tissue and fluid samples were also submitted for microbial culture.
   1. Excised bone or soft tissue specimens of ≥ 1 cm³ were placed aseptically into sterile screw-cap containers without fixative and delivered to the microbiology laboratory within 1 h of collection. If immediate transport was not feasible, specimens were refrigerated at 4 °C for no longer than 24 h.
   2. Samples were inoculated onto medium and into liquid culture systems for the detection of Mycobacterium tuberculosis, as well as onto standard blood and agar for bacterial and fungal cultures. Ascitic fluid was inoculated similarly after centrifugation at 2,000 x g for 15 min to concentrate bacilli.
4. Histopathological examination of debrided hand tissue was conducted to assess granulomatous inflammation and caseous necrosis. For histopathological examination, part of the excised tissue was fixed in 10% neutral buffered formalin at a ratio of 1:10 (tissue: fixative) for at least 24 h, embedded in paraffin, sectioned at 4 µm thickness using a rotary microtome, and stained with hematoxylin and eosin.
5. Confirmatory testing by acid-fast staining and fluorescence in situ hybridization (FISH) on tissue specimens to detect Mycobacterium tuberculosis. Acid-fast bacillus (AFB) staining was performed on deparaffinized tissue sections and smears using the Ziehl-Neelsen technique.
   1. Slides were fixed, covered with carbol fuchsin, and heated until steaming for 5 min, then decolorized with 3% acid-alcohol, counterstained with methylene blue, and examined under oil immersion at 1000x magnification on a light microscope. Positive bacilli appeared as slender red rods against a blue background.

4. Surgical intervention

1. The surgical procedure was carried out under sterile operating room conditions with continuous monitoring of vital signs. Regional anesthesia was preferred, using a brachial plexus block (20-30 mL of 0.5% ropivacaine administered under ultrasound guidance with a high-frequency linear probe) to provide optimal analgesia and motor blockade; alternatively, general anesthesia was administered if required.
2. A pneumatic tourniquet was applied to the upper arm and inflated to 250 mmHg after exsanguination with an Esmarch bandage, maintaining a bloodless field throughout the procedure. The patient was placed supine on the operating table with the affected arm extended on a hand table. The skin was prepared with povidone-iodine solution followed by 75% alcohol and draped in a sterile fashion.
3. A longitudinal incision was made along the ulnar side of the proximal phalanx of the right little finger, using a No. 15 scalpel blade. Standard hand surgery instruments (Metzenbaum scissors, Adson forceps, periosteal elevator, and bone curettes) were used for dissection.
4. The incision was deepened through subcutaneous tissue to expose the lesion. All necrotic subcutaneous granulation tissue was excised using curettes and rongeurs, and affected bone was debrided until healthy, bleeding surfaces were encountered. Following debridement, the osseous defect was prepared for grafting. Autologous cancellous bone was harvested from the iliac crest through a 2-3 cm incision over the anterior superior iliac spine.
5. After infiltration with local anesthetic, a gouge and curettes were used to harvest spongiosa. Hemostasis was achieved with bipolar cautery. The bone graft was morselized into small fragments (1-2 mm) and packed firmly into the phalangeal bone defect until completely filled. The wound edges were assessed for tension, and if primary closure was not possible, a local advancement flap was raised to provide soft tissue coverage.
6. A vacuum sealing drainage (VSD) system was applied when the wound cavity was extensive. A sterile polyurethane sponge was trimmed to fit the defect, placed in contact with the bone surface, and connected to suction tubing. The wound was sealed with an adhesive semi-permeable dressing, and continuous negative pressure of −80 to −125 mmHg was applied through a portable suction device. This ensured continuous drainage of exudates, improved local perfusion, and promoted granulation tissue formation.
   1. The vacuum sealing drainage (VSD) system should be carefully applied and monitored to ensure effectiveness. The procedural checkpoint confirms that the polyurethane sponge visibly collapses under continuous negative pressure, verifying system integrity and airtight function.
7. Expected visual outcomes include clear to serosanguinous drainage, which indicates a normal postoperative wound response. However, sudden increases in purulent or bloody output, loss of suction evidenced by the sponge failing to collapse, development of a foul odor, or spreading erythema around the dressing are red flags that signal possible infection, device malfunction, or wound deterioration and should prompt earlier clinical intervention or device replacement.
8. The incision was closed with layered sutures: 4-0 absorbable polyglactin for subcutaneous closure and 5-0 nylon for skin closure. A sterile dressing was applied, and the finger was immobilized with an aluminum splint in a functional position. The tourniquet was released after wound closure, and hemostasis was verified.
9. Postoperatively, the patient was instructed to keep the hand elevated to minimize edema and was started on intravenous antibiotics for 48 h until definitive culture results were available. Early passive finger mobilization was encouraged once wound stability was achieved.

5. Medical management

1. Antitubercular therapy (ATT) was initiated immediately after histopathological and molecular confirmation of tuberculosis, following WHO and national guidelines for bone and extrapulmonary TB. The patient was prescribed the HRZE regimen for a total duration of 12 months. 2
2. Isoniazid was given orally at 5 mg/kg/day (maximum 300 mg) in a single morning dose; rifampicin at 10 mg/kg/day (maximum 600 mg) in a single morning dose; pyrazinamide at 25 mg/kg/day divided into two daily doses; and ethambutol at 15 mg/kg/day (maximum 1200 mg) as a single dose.
3. Body weight was measured at baseline and monthly thereafter using a calibrated electronic scale to adjust dosages to maintain weight-based accuracy. Fixed-dose combination tablets were recommended to minimize pill burden and improve adherence, while single-drug formulations were used when necessary. Directly observed therapy (DOT) was implemented when feasible, and patients were instructed that if a dose was missed within 12 h, it should be taken immediately, whereas if more than 12 h had passed, the missed dose should be skipped and the regular schedule resumed without doubling the dose.
4. Adjunctive measures
   1. To monitor potential drug-induced hepatotoxicity, monthly liver function tests were performed. Venous blood samples (3-5 mL) were collected in serum separator tubes and centrifuged at 2,000 x g for 10 min. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, and total bilirubin were measured using an automated chemistry analyzer. Reference ranges were recorded, and any ALT or AST elevation >3x upper limit of normal with symptoms, or >5x without symptoms, prompted regimen reassessment.
   2. For ethambutol-related optic neuropathy, visual acuity was assessed at baseline and every 3 months thereafter using a standardized Snellen chart placed at 6 m under controlled illumination (160-300 lux). A contrast sensitivity test and color vision test with Ishihara plates were also conducted. Examinations were performed by an ophthalmologist using a slit-lamp biomicroscope and, if indicated, optical coherence tomography to detect early retinal nerve fiber layer changes.
   3. For prevention and early detection of isoniazid-induced peripheral neuropathy, pyridoxine (vitamin B6) supplementation at 25 mg/day was prescribed concurrently. At each monthly visit, a clinical assessment was performed to evaluate symptoms such as paresthesia, numbness, or gait disturbance. Neurological examination included tendon reflex testing and monofilament testing with a 10 g monofilament applied to the plantar and digital surfaces. If neuropathy developed, isoniazid was continued at a reduced dose while pyridoxine supplementation was increased to 50-100 mg/day, and a neurologist consultation was obtained.
5. All monitoring results were documented in a standardized TB treatment logbook and cross-verified with the hospital electronic medical record (EMR) system. This ensured continuous pharmacovigilance, dose adjustment, and early detection of adverse events during the 12-month course of therapy.

6. Follow-up and monitoring

1. Postoperative wound inspection was carried out at 48 h after surgery. The dressing was removed under aseptic conditions, and the wound was examined for signs of infection (erythema, warmth, purulent discharge) or flap/graft necrosis. Sterile saline irrigation was performed if necessary, and the wound was redressed with sterile gauze.
2. At 2 weeks postoperatively, the sutures were removed using sterile fine scissors and forceps, provided that the wound edges were well-healed with no signs of dehiscence. In cases where a vacuum sealing drainage (VSD) system was applied, the device was inspected daily, ensuring continuous negative pressure (−80 to −125 mmHg) and checking for patency and volume of exudate.
3. Serial radiographs of the hand were taken at 3, 6, 12, and 24 months to assess bone remineralization and healing. Standardized anteroposterior and lateral digital radiographs were obtained using a digital X-ray system. Exposure parameters were typically 45-50 kVp and 2-3 mAs with a 100 cm focus-film distance. The field of view included the metacarpophalangeal joint to the fingertip. Radiographs were evaluated for trabecular bridging, cortical thickening, and absence of lytic progression. Images were stored in DICOM format and reviewed on PACS.
4. Abdominal follow-up was conducted biannually using ultrasonography or CT to monitor the resolution of ascites and peritoneal inflammation. For ultrasound, a high-resolution abdominal ultrasound system was used. The patient was examined in the supine and left lateral decubitus positions. Gain and depth settings were adjusted to visualize peritoneal fluid pockets, peritoneal thickening, and omental echogenicity. If ultrasound findings were equivocal, contrast-enhanced CT of the abdomen was performed with parameters matching the initial study: 120 kVp, 250-300 mAs, 1-2 mm slice thickness, portal venous phase after injection of 1.5 mL/kg nonionic iodinated contrast at 3 mL/s.
5. Annual immunological surveillance was performed with interferon-gamma release assays (IGRA) and clinical evaluations for TB recurrence over a 2 year period. Blood samples (3-4 mL) were collected into tubes, mixed by gentle inversion, and incubated at 37 °C for 16-24 h before plasma separation and ELISA analysis using a calibrated microplate reader.
6. Clinical follow-up included assessment of constitutional symptoms (fever, night sweats, weight loss), physical examination of the operated hand for tenderness, swelling, or recurrence, and abdominal palpation for ascites. All results were documented in a standardized follow-up chart, and any abnormal findings triggered immediate multidisciplinary treatment.

7. Biosafety, safety, and waste management in Tuberculosis-suspect specimen handling

1. Biosafety and Safety Considerations
   1. All tissue and fluid specimens suspected of Mycobacterium tuberculosis infection were handled with strict adherence to biosafety practices. Personnel wore appropriate personal protective equipment (PPE), including N95 respirators, disposable gowns, gloves, and protective eyewear. Manipulation of specimens was performed exclusively within a certified Class II biosafety cabinet to minimize aerosol exposure.
   2. Specimens were transported in sealed, leak-proof primary containers placed within secondary protective packaging, in compliance with institutional biosafety transport protocols. In the operating room, sharps were handled with extreme caution using a hands-free technique whenever possible. Aerosol-generating procedures, such as curettage and high-speed drilling during debridement, were performed with local exhaust ventilation and minimal personnel in the field to reduce occupational exposure risk. All staff were trained in standard precautions and tuberculosis-specific infection control measures.
2. Waste disposal guidance
   1. Infectious materials (swabs, tissues, suction canisters, VSD disposables): All items contaminated with suspected Mycobacterium tuberculosis were collected in biohazard-labeled, puncture-resistant containers and autoclaved at 121 °C for 30 min prior to disposal. Where autoclaving was not feasible, materials were incinerated at licensed medical waste facilities.
   2. Sharps: Needles, scalpel blades, and other sharps were disposed of immediately after use in rigid, puncture-proof sharps containers. Containers were sealed when 3/4 full and treated as infectious medical waste according to hospital infection control policies.
   3. Chemical waste (staining/fixation reagents such as carbol fuchsin, methylene blue, formalin, and xylene): Collected separately in labeled, chemical-resistant containers. Disposal followed institutional hazardous waste protocols and local environmental regulations, with transfer to certified chemical waste treatment providers. All disposal procedures complied with the Regulations on Medical Waste Management (China, 2021 revision) and equivalent institutional biosafety policies.

Results

Clinically, the wound had healed by 2 weeks postoperatively, at which time the sutures were removed. The final results of the therapy included radiologic evidence of remineralization, sinus healing, and trabecular repair, as well as the elimination of local symptoms, pain-free mobility, and no increase in repeated blood counts or ESR. The outcome satisfied the patient. The patient experienced no recurrence of infection in the hand or abdomen during the 2-year follow-up and healed well with normal function of the finger (...

Discussion

Extrapulmonary tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis that affects organs outside the lungs⁷. It can impact practically every organ system, including the lymph nodes, genitourinary tract, central nervous system, bones/joints, abdomen (intra-abdominal organs, peritoneum), and pericardium. Microbiologic evidence is essential for diagnosis and therapy, and tissue biopsy is usually necessary, but extrapulmonary lesions are paucibacillary, and sampling,...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
CT Scanner (64-slice)	GE Healthcare	LightSpeed VCT	For chest and abdominal imaging with contrast
Digital Radiography System	Siemens Healthineers	SOMATOM go.Now	Used for AP and lateral radiographs of the hand
ELISA Reader	Bio-Rad	iMark Microplate Reader	Measurement of IGRA interferon-gamma levels
Fluorescence in situ Hybridization (FISH) Kit	Abbott Molecular	06N38-020	Probe-based detection of M. tuberculosis in tissue
Histopathology Staining Reagents	Leica Biosystems	N/A	H&E staining of biopsy tissue
IGRA Test Kit	Qiagen	QuantiFERON-TB Gold Plus	Interferon-gamma release assay for TB screening
Microscope (Fluorescence)	Zeiss	Axio Imager 2	For visualization of FISH fluorescence signals
Microscope (Light)	Olympus	BX43	Used for histopathology and Ziehl–Neelsen examination
Vacuum Sealing Drainage (VSD) System	Smith & Nephew	RENASYS	Negative pressure wound therapy, –80 to –125 mmHg
Ziehl–Neelsen Stain Kit	Sigma-Aldrich	ZN-100	Acid-fast staining for M. tuberculosis