The cardinal feature of flexor tenosynovitis is pain along the tendon sheath, with associated swelling around the joint adjacent. The finger is usually flexed slightly and there is pain on passive movement along the tendon.

In infectious tenosynovitis there may be associated fever. In gonococcal tenosynovitis, not associated penile or vaginal discharge occurs and the wrist, hand and sometimes the ankle are the most common sites. In traumatic cases the site of inoculation may be overtly infected, but many times there is no obvious wound [7].

Laboratory diagnosis

• The diagnosis may be made on clinical grounds. If there is associated discharge then a swab for gram stain and culture should be sent. Aspiration may also be required. The samples should be sent for exam for the usual bacteria including fungal causes and mycobacterium. 
• If there is an associated joint effusion it should be aspirated and sent for white cell count, glucose levels, gram stain and cultures. 
• Other tests like a complete cell count should be done if an infectious cause is suspected. Other tests such as rheumatoid factor and other autoimmune markers should be asked for if there is a suspicion. 
• A biopsy should be done if the cause is not found to rule out causes such as mycobacterium which has a protracted culture time.

Imaging

Plain radiographs should be done to rule out bone involvement. Magnetic resonance imaging (MRI) is an accurate modality for diagnosis.

Usually the treatment includes surgery and antibiotics. For stage 1, irrigation and drainage are necessary. Stage 2 or 3 may be treated with surgical debridement and irrigation, amputation if necessary. Depending on the results of fluid and gram stain, antibiotics should be started promptly, a drug that covers Staphylococcus aureus and streptococci will be advisable; this includes ciprofloxacin or a third generation cephalosporin. Vancomycin may be used if a methicillin-resistant species is suspected.

The inflammatory causes respond to anti-inflammatory drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) and steroids, but an infectious etiology must be ruled out. The involved joint should be immobilised [8] [9] [10].

Infectious causes who present early and get treatment, will have an excellent outcome. Those who have chronic infection and disseminated disease will have a poorer outcome. Poor outcomes include loss of range of movement and tendon rupture. Other comorbidities such as a decreased immunity or diabetes are a poor prognostic markers, and tend to have multiple tendons and joints involved.

Most of the time the cause is not known, but the etiology may be divided into infectious and non-infectious.

Infectious 

• Streptococcus and Staphylococcus aureus (most common)
• Mycobacterium tuberculosis
• Pseudomonas aeruginosa
• Nesseria gonorrhoeae (secondary infection from the genital tract, rectum or pharynx) 

Non-infectious

• Rheumatoid arthritis 
• Systemic lupus erythematosus
• Diabetes mellitus
• Ankylosing spondylitis
• Overuse 
• Sarcoidosis [1] [2] [3]

There is very little data on the incidence of this condition, but it has been noted that up to one third of the patients are diabetic. Gonococcal tenosynovitis is usually common in the young sexually active individuals. Also this condition is very common in rheumatoid arthritis sufferers [4].

Infectious

The infection occurs by various mechanisms: Trauma with inoculation into the tendon, contagious spread from infected adjacent soft tissues, and through the blood stream. Most infections will occur acutely after inoculation except for a few organisms such as mycobacterium which may have a subacute presentation. Usually animal bites and lacerations are associated with polymicrobial infections including gram negative bacteria. Different forms of trauma have associated bacteria, such as puncture wounds form thorns and trees may result in fungal infections, while animal bites may give rise to polymicrobial infections with Pasteurella multocida and others [5]. Infections to tendon from other sites via hematogenous spread, is common for Mycobacterium and Nesseria gonorrhoeae.

The infections usually progresses in stages:

• Stage 1: Distension of the tendon sheath with an exudate.
• Stage 2: Distension of the tendon sheath with an purulent fluid.
• Stage 3: Septic necrosis [6]

Non-Infectious

This occurs due to a different mechanism. There is fibrous proliferation, until there is impingement and constriction of movement.

Prompt treatment of the underlying cause is the best mode to avoid complications. Since most cases of infectious causes are related to trauma, necessary protective gear and equipment should be used at potentially dangerous sites. For gonococcal infections, protected intercourse is the best prevention.

The most common sites for tenosynovitis are the shoulder, the tendon of the long head of the biceps, popliteus tendon, Achilles tendon and the abductor pollicis longus. It is thought that continuous microtears and degenerative changes are the most common cause of the condition.

• Definition: Tenosynovitis is a disease that affects the tendons in your body. Tendons are the strong band that connect your muscles to your bones to allow movement. The most common places are the hands and shoulder.
• Cause: There are two main causes, infection and overuse. Other causes may be due to underlying diseases that may affect your tendons such as rheumatoid arthritis. Infections are caused by direct inoculation via trauma. 
• Symptoms: There will be pain around the site of the diseased tendon, with pain on movement. There also may be a discharge if there is associated trauma like from an animal bite.
• Diagnosis: Usually diagnosis is clinical but extra tests will be required to find out the cause especially if the cause if infectious. The doctor will take sample form the infected site for tests. The may be other blood tests to find out other underlying cause. Your doctor may order X-rays to make sure the bone is not infected. They may also order a magnetic resonance image (MRI) of the affected site 
• Treatment: The treatment for infected tendons is urgent surgery and antibiotics to kill the infection. The type of surgery and extent will depend how bad the infection is. For non-infectious causes the doctor will prescribe anti-inflammatory drugs or steroids to help reduce the pain and discomfort. You will also be told to rest the joint and a sling may be ordered for you.

1. Tsai E, Failla JM. Hand infections in the trauma patient. Hand Clin 1999; 15:373.
2. Small LN, Ross JJ. Suppurative tenosynovitis and septic bursitis. Infect Dis Clin North Am 2005; 19:991.
3. Mateo L, Rufí G, Nolla JM, Alcaide F. Mycobacterium chelonae tenosynovitis of the hand. Semin Arthritis Rheum 2004; 34:617.
4. Kour AK, Looi KP, Phone MH, Pho RW. Hand infections in patients with diabetes. Clin Orthop Relat Res 1996; :238.
5. Goldstein EJ. Bite wounds and infection. Clin Infect Dis. Mar 1992;14(3):633-8.
6. Nikkhah D, Rodrigues J, Osman K, Dejager L. Pyogenic flexor tenosynovitis: one year's experience at a UK hand unit and a review of the current literature. Hand Surg 2012; 17:199.
7. Pang HN, Teoh LC, Yam AK, et al. Factors affecting the prognosis of pyogenic flexor tenosynovitis. J Bone Joint Surg Am 2007; 89:1742.
8. Gosain AK, Markison RE. Catheter irrigation for treatment of pyogenic closed space infections of the hand. Br J Plast Surg. May-Jun 1991;44(4):270-3.
9. Harris PA, Nanchahal J. Closed continuous irrigation in the treatment of hand infections. J Hand Surg Br. Jun 1999;24(3):328-33.
10. Kanavel, AB. Infections of the hand: a guide to the surgical treatment of acute and chronic suppurative processes of the fingers, hand, and forearm. Lea and Febiger, Philadelphia, 1912.