Scaphoid Tuberculosis Difficulties of Diagnosis

Abstract

Tuberculosis [TB] usually has prolonged course and not identified before it becomes a full blown disease. TB scaphoid is very rare accounting for less than 1% of all musculo skeletal TB.Scaphoid has a precarious vascularity in which the proximal pole receives the blood supply from the distal pole through the waist of scaphoid which is the narrowest and weakest part of scaphoid; hence fracture is very commonly suspected and most commonly occurs in waist causing proximal pole prone for avascular necrosis and bone resorption. TB scaphoid has been commonly reported due to dog bite or IV canulation 12 but not otherwise. Our patient is a 79 years old male patient with no history of any injury, presented to us with wrist pain and difficulty in using the wrist. On examination he had swelling over dorsal aspect, anatomical snuffbox tenderness with range of movements restricted due to pain but no localized warmth or erythema. There was no neuro vascular deficit. We took an X-ray and found that there ismore than three fourths resorption of proximal pole of scaphoid. We investigated the patient. He had elevated polymorphs 72% (normal 45 – 70%) in total blood count, C – Reactive Protein(CRP) is 2.4 mg/dl (normal is 0 – 0.6), fasting sugars (FBS) 130 (normal 70 – 110mg/dl ), post prandial sugars (PPBS)142 mg/dl (normal 80 – 140), erythrocyte sedimentation rate (ESR) 42 mm/hr(normal 4 – 30), calcium 10.4 mg/dl (normal 8.5 – 10.1), globulin 3.9 g/dl (normal 2 – 3.5). He had decreased lymphocytes 22.5% (normal 25 – 40) and monocytes 1.4% (normal 2 – 10) in total count, Hb 12.6 gms/dl (normal 13 – 17), PCV 37.3 (normal 40- 50%). We did a magnetic resonance imaging (MRI) of the scaphoid done. It showed resorption of proximal three fourths of scaphoid, except pisiform all other carpals are involved, small erosion in lateral aspect of distal radius, synovial thickening with effusion in lateral aspect of wrist, around scaphoid and along abductor pollicis longus and extensor pollicis brevis tendons. Nextdirect smear for AFB, Gram Staining, Fungal Stain and Tissue Culture all came as negative. ELISA screening for HIV for type 1 and 2 came negative. Biopsy of the scaphoid bone done and it came as tuberculous infection with granulomatous lesion.Under higher resolution it showed slipper shaped epithelioid cells with Langhans Giant Cells surrounded by lymphocytes. Post operatively we started on anti tuberculous treatment. The limb was immobilized in plaster of paris posterior slab for eight weeks. After two months there was excellent range of movements in the wrist with no pain. Chronic wrist pain is among the most difficult to diagnose 3 .The most common non traumatic causes of wrist pain are tendinitis and nerve problems. Causes of symptomatic inflammation of upper extremity tendons and peritendons are poorly understood 4 .Tuberculosis of wrist is very rare 5 .Foci of infection is usually distal radius and primarily in synovium. From there it permeates into carpals and flexor and extensor tendons. In patients with normal immunity tuberculous infection starts as synovitis and the course is slow. There will be Figure 2 - MRI of wrist showed resorption of proximal three fourths of scaphoid with softtissue involvements. Figure 3 - Under higher resolution it showed slipper shaped epithelioid cells with Langhans Giant Cells surrounded by lymphocytes. Figure 1 - Plain XR of wrist AP view showing more than three fourths resorption of scaphoid