Bacteria from the genus Paenibacillus are widely distributed in the environment. They are most commonly found in soil and water1. These bacteria rarely cause infections in humans; only a few cases have been reported such as sepsis in neonates and urinary tract infection in immunosuppressed patients2. We report the first case of infectious tenosynovitis caused by this agent in a healthy patient.
This case report has been written following the SCARE 2018 criteria, described by Agha et al3. Patient consent was given through the signing of our institutional consent form, following institutional guidelines.
The case report is of a female patient, 23 years old, a professional Judo athlete, with right hand dominance, with no drug history nor any other notable health issues or family history. At the time of infection she was in her second month of rehabilitation from an anterior cruciate ligament reconstruction of her left knee, which had been operated 2 months ago.
Her main complaint was pain and edema of her right hand for 10 days. She denied any type of trauma or fever. When she came into the emergency room of our tertiary university hospital, she had already been seen in 2 different hospitals and was treated as inflammatory tendinitis caused by overuse. She had been prescribed a forearm splint and sent home.
The patient was afebrile, in good general health, walking without crutches, and with no other complaints other than the right hand. She presented small erythematous papules, irritation from the splint and sweat, in her forarm. She had clear Kanavel signs in her middle, annular, and small fingers of her right hand (Fig. 1). She had intense pain when palpated on the volar side of the distal third of the forearm. Her neurological examination was normal. Her blood count was normal, with 8390 leukocytes and c-reactive protein of 57.2 mg/L. Ultrasonography described liquid in the flexor tendon sheath of the IV and V fingers of the right hand, in zone III of Verdan.
Because of her typical physical examination of pyogenic tenosynovitis, which included intense pain when passive extension of fingers, fusiform swelling, and tenderness along the flexor tendon sheath, surgical drainage was performed.
Surgical technique and intraoperative findings
A combined anesthesia was administered on the patient in a supine position with tourniquet by elevation: brachial plexus block and sedation. A Hand surgery fellow and Associate professor participated in the surgical procedure.
Incisions were made at the distal palmar crease of the anular and small fingers, with another incision at the distal interphalangeal joint level of the same fingers. The digital nerve and artery were protected.
We observed intense synovitis in the pulleys of the flexor tendons but did not observe purulent drainage, even after an irrigation catheter was placed and the tendon sheath irrigated (Fig. 2).
The tissues in the A1 pulley and the proximal portion of the A2 pulley of the small finger, were friable, as well as the subcutaneous tissue around them (Fig. 3). Samples of these tissues were sent for culture analysis.
Another 4 cm longitudinal incision was made over the flexor radialis carpus, proximal to the palmar crease at the wrist and Parona’s space was explored. We found clear serous liquid with abnormal viscosity.
The wounds were irrigated with 10 L of saline solution with the technique described in Green4 and closed with 5-0 nylon.
The patient was admitted for 10 days, waiting for culture analysis and intravenous antibiotics. She was prescribed Oxacillin (2 g intravenous every 4 h) for 10 days and Ceftriaxone (2 g intravenous every 12 h) for 8 days. At discharge, she was prescribed oral Levofloxacin and had good clinical remission of the signs and symptoms, with no other complications after 4 weeks of treatment.
The culture analysis of the tissue was negative, but positive for Paenibacillus sp. through mass spectometry. As culture was negative, the antibiotics prescribed were empirical. She was referred to the occupational therapist for rehabilitation. The sutures were removed after 21 days and the patient was allowed to perform all physical activities. At the present moment, at 6 months follow-up, patient is assymptomatic and satisfied with hand function (Figs. 4–6).
Pyogenic flexor tenosynovitis of the hand is the infection of the tendon sheaths of the flexor tendons, resulting from an infection on the adjacent finger pulp or a small puncture wound to the flexor crease4.
This infection leads to the destruction of the gliding mechanism of the flexor tendons, limiting movement, causes adhesions, and necrosis of the tendons due to the destruction of the blood supply. It can cause infection in the flexor tendon sheath and the radial or ulnar bursae of the hand4.
The most common organisms responsible include Staphylococcus aureus and B-hemolytic Streptococcus4.
Most of the patients with pyogenic flexor tenosynovitis present a history of penetrating trauma in the volar aspect of the proximal or distal interphalangeal joint, typically with a foreign body or an animal bite that inoculates the pathogen in the tendon sheath. Hematogenous dissemination is uncommon, and when it occurs, it should raise suspicion of a disseminated gonococcal infection5.
The diagnosis is clinical and Kanavels signs are present (Kanavel)7.
The 4 signs described by Kanavel are the following:
- Semi-flexed position of the finger.
- Fusiform swelling.
- Excessive tenderness limited to the course of the flexor tendon sheath.
- Excruciating pain on passively extending the finger. The pain should be experienced along the flexor sheath and not localized to a particular joint or abscess.
According to Kanavel, excessive tenderness along the flexor tendon sheath is the most reproducible and reliable sign. Neviaser believes that pain on passively extending the finger is the most important sign. According to Pang and colleagues fusiform swelling was found in 97% of the patients with pyogenic tenosynovitis6–9.
During the investigation, laboratory investigation such as complete blood count, c-reactive protein, erythrocyte sedimentation rate, and radiographs should be ordered to exclude foreign body or osteomyelitis4.
The differential diagnosis includes: herpetic whitlow, local abscess, felon, septic arthritis, reumatoid arthritis, gout, and asseptic tenosynovitis4.
Nonoperative: patients that present <24 hours of the onset of symptoms with moderate symptoms and 1 or 2 incomplete signs of Kanavel can be inicially treated nonoperatively. This includes intravenous antibiotics, dorsal splinting and elevation. Before antibiotic therapy is initiated, aspiration should be done, in order to isolate the agent. If during aspiration purulent material is aspirated, surgical drainage is indicated. Nonoperative treatment has a very limited indication for the treatment of pyogenic tenosynovitis.
Operative: it is considered a gold standard for the treatment of pyogenic tenosynovitis, and is indicated in more severe cases or with >24 hours of symptoms.
This case is of importance because it is the first case reported of pyogenic tenosynovitis caused by a bacteria from the genus Paenibacillus sp.
Paenibacillus sp. is found in common environments, specially in soil and water1. It rarely causes infections in humans. Few cases are reported, such as sepsis in neonatals2, infection of the tibia1, or urinary tract infection in a patient with chronical renal failure10. There has also been a case report of sepsis in a patient with heroin abuse and a splenectomy11.
The increase in the number of bacterias isolated in human samples is due to 2 new techniques used to identify bacteria, ribossomal RNA amplification 16S, and mass spectometry. The online database can assist physicians and microbiologists to assess the pathogenicity of an isolated bacteria that is atypical12. Our institution’s laboratory uses the MALDI-TOF method, based on mass spectometry for identification. This method has high sensitivity and specificity and was able to identify this pathogen.
The patient was a healthy, professional judo heavy weight athlete, which meant that she was not on a diet for fast weight loss, had a limitation of specific food groups or in risk of dehydration. She was in rehabilitation for knee surgery for 2 months, which excluded postoperative imunossupression or by overtraining.
The possibility of contamination of the sample is minimal because the culture was used a solid tissue, taken from the pulley of the tendon after asseptic procedures. This material had a friable aspect, compatible macroscopically with tenosynovitis. The fact that there were no other samples that were positive for this bacteria should be considered, but because of the rarity of this diagnosis, we saw it necessary to report this case.
This is the first case report on pyogenic tenosynovitis caused by Paenibacillus. Even though it was an isolated case, it alerts health professionals of the fact that this can be an agent that causes pyogenic tenosynovitis in the hand in healthy patients. Despite the fact that the diagnosis was made late, the patient had a satisfactory recovery and presented no sequelae.
This study was approved by the ethics committee of our institution.
Sources of funding
All authors contributed in writing and revising of the paper.
Conflicts of interest disclosure
The authors declare that they have no financial conflict of interest with regard to the content of this report.
Research registration unique identifying number (UIN)
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