Dactylitis: A pictorial review of key symptoms

Dactylitis refers to a global swelling of a finger or a toe giving it a clinical sausage-shape presentation. It is an extremely suggestive symptom as it guides the rheumatologist towards a shortlist of diagnoses. However, radiologists are less familiar with dactylitis. The aim of this review is to detail and illustrate the main causes of dactylitis using standard X-ray imaging, ultrasound, computed tomography and magnetic resonance imaging in order to make radiologists more familiar with this symptom by illustrating the various conditions that are associated with dactylitis including infection, peripheral spondyloarthritis, sarcoidosis, microcrystalline deposition, osteoid osteoma, and sickle cell disease.

[Stress fractures]

In 1892, J. Wolff, an orthopedic surgeon, stated that the internal architecture and shape of a bone were related to the direction of stresses placed upon it. Conventional radiographs and MRI can demonstrate the adaptability of bones to stresses. Imaging also demonstrates that this adaptability has limitations, and that excessive stress may lead to fracture.

[Diagnostic approach to the rheumatoid wrist from plain radiographs]

OBJECTIVE

Monitor a reproducible analysis method based on a simple algorithm.

DIAGNOSIS OF RHEUMATOLOGIC DISEASE IN WRISTS

The first step is to examine the joint space. When the space is preserved, diagnosis may be established on the presence of bony defects, demineralization or erosions.

DIAGNOSIS OF RHEUMATOLOGIC DISEASE IN FINGERS

The first step is to determine whether the patient has degenerative or inflammatory joint disease involving the joint space or bone disease where bony lesions predominate.

Mycobacterium xenopi spinal infections after discovertebral surgery: investigation and screening of a large outbreak

BACKGROUND

Mycobacterium xenopi spinal infections were diagnosed in 1993 in patients who had undergone surgical microdiscectomy for disc hernia, by nucleotomy or microsurgery, in a private hospital. Contaminated tap water, used for rinsing surgical devices after disinfection, was identified as the source of the outbreak. Several cases were recorded in the 4 years after implementation of effective control measures because of the long time between discectomy and case detection. The national health authorities decided to launch a retrospective investigation in patients who were exposed to M xenopi contamination in that hospital.

METHODS

Mailing and media campaigns were undertaken concurrently to trace exposed patients for spinal infections. Patients were screened by magnetic resonance imaging (MRI), and the scans were reviewed by a radiologist who was unaware of the diagnosis. Suspected cases had discovertebral biopsy for histopathological and bacteriological examination.

FINDINGS

Of 3244 exposed patients, 2971 (92%) were informed about the risk of infection and 2454 (76%) had MRI. Overall, 58 cases of M xenopi spinal infection were identified (overall cumulative frequency 1.8%), including 26 by the campaign (mean delay in detection 5.2 years, SD 2.4, range 1-10 years). Multivariate analysis showed that the risk of M xenopi spinal infection was related to nucleotomy and high number of patients per operating session.

INTERPRETATION

Failures in hygiene practices could result in an uncontrolled outbreak of nosocomial infection. Patients who have been exposed to an iatrogenic infectious hazard should be screened promptly and receive effective information.

[Spinal neurenteric cyst revealed by a cauda equina syndrome]

BACKGROUND

Intraspinal neurenteric cysts are exceptional formations which develop from incomplete separation of the neural tube and the endodermis during the third week of gestation. Symptoms generally appear before the age of 40 years and are associated with spinal malformations. Most neurenteric cysts lie in an extra-spinal position in the lower cervical and upper dorsal spine. We report a case involving the cauda equina with no associated spinal lesion.

CASE REPORT

A 63-year-old woman was admitted for low back pain and right L3 radiculalgia triggered by exertion. Urinary disorders had developed over the preceding year. Physical examination found a spinal syndrome with hypoesthesia of the right para-anal area, an atonic anal sphincter and a globular bladder. Plain films showed a widened interpedicular space between L1 and L2 interpreted as the consequence of an expansive intraspinal lesion. Saccoradiculography led to the diagnosis of an intradural lesion involving L1 and L2. At magnetic resonance imaging, the lesion's signal intensity was similar to cerebrospinal fluid on T1 and T2 sequences, deforming the cauda equina and displacing the nerve roots. Surgical resection of the cyst was incomplete due to adherences to several roots and was followed by persistent radiculalgia and sphincter disorders.

DISCUSSION

This case demonstrates an exceptional cause of cauda equina syndrome. Fissuration or rupture of the cyst might explain symptom exacerbation following trauma. Magnetic resonance imagining can confirm the cystic nature of the intradural lesion and help guide surgery. Resection is often incomplete with the risk of long-term recurrence.

[The hand and rheumatism]

The hand is a major site of musculoskeletal disorders. Clinical features to be studied include the patient's age and sex, pain, stiffness, range of motion of the various joints of the wrists and hands, soft tissue swelling (particularly tendons sheaths), bone excrescences, skin changes. Radiological abnormalities in the hands, if any, may confirm the clinical diagnosis. The main features of rheumatoid arthritis, systemic lupus erythematosus, psoriatic arthritis, erosive degenerative changes, Südeck syndrome, calcium pyrophosphate dihydrate deposition disease, etc., are reviewed.

-Arthrography of the hip prosthesis-

Arthrography of hip arthroplasties is a safe, easy-to-perform procedure. It is mainly indicated when infection of the arthroplasty is suspected: the contrast agent fills bone defects that may be present between normal bone and the prosthesis and reaspiration of injected fluids may lead to bacteriological diagnosis. Another indication for arthrography of hip arthroplasties is unexplained painful hip prosthesis.

[Coxitis after surgical excision of intracapsular osteoid osteoma of the femur neck]

A case of destructive arthropathy of the hip with onset two years after surgical removal of an intracapsular osteoid osteoma of the femoral neck is reported. Coincidental occurrence in the same joint of an osteoid osteoma and a destructive arthropathy of unknown etiology cannot be ruled out. However, another hypothesis which deserves discussion is that self-perpetuating synovitis was triggered by the release of mediators of inflammation due to presence of the osteoid osteoma.

[How to evaluate the long-term course of osteoarthritis. Tests for trials of fundamental treatments (spine excluded)]

The best assessment tests for long term trials on osteoarthritis (OA) of the hip and knee are the following, in order of relevance value (consensus of french experts): 1) the loss of joint space thickness on successive radiographies; 2, 3) the indices of the severity for OA of the hip and knee; the investigator's overall opinion; 4) the patient's overall opinion (visual analogue scale of handicap); 5, 6, 7) the pain level (visual analogue scale); the time for going up and down a standard flight of stairs and the time of pain in this distance; the limitation of two articular movements; 8) the increase of either analgesics or NSAIDs consumption; 9) concerning OA of fingers, the number of joints newly involved on successive radiographies. At present, only the radiological tests 1 and 9 are validated. The clinical tests 2 to 8, valuable for short term trials, have yet to be validated for long term follow-up. Recommended duration of trials is three years. A rigorous organisation is necessary to avoid erroneous inclusions: all data recorded in the pre-inclusion visit have to be checked by the principal investigator. Since we have not yet a validated chondroprotective agent as a reference drug, the trial must be randomised, double blind, placebo controlled, parallel group study.