Rheumatology Case:The Heartbreak of Sausage Digits

The distribution of joint symptoms and the nailbed onycholysis in this patient also suggest Reiter’s syndrome . “Sausage digits” (dactylitis) are caused by inflammation of the interphalangeal joints plus flexor tenosynovitis and are characteristic of both psoriatic arthritis and Reiter’s syndrome. Reiter’s syndrome may present with a rash that appears similar to pustular psoriasis, but which is usually located on the palms, soles, or glans penis. Psoriatic arthritis and Reiter’s syndrome, along with ankylosing spondylitis and inflammatory bowel disease-associated arthritis, are all members of the HLA-B27-associated arthropathies and share many clinical features .

Gout rarely presents in the hands during the initial episodes and is usually a mono- or oligoarthritis. Moreover, crystalline arthritis is rare in young women. Calcium pyrophosphate dihydrate crystal-induced arthropathy may present in an acute and asymmetrical manner (pseudogout), but the usual hand involvement in CPPD is localized to the second and third MCPs and the wrist. Gonococcal arthritis may be associated with skin lesions (pustules or hemorrhagic bullae), but the joint pain is usually migratory in nature and subsequently monarticular. Erosive osteoarthritis , which is an aggressive form of OA, may cause painful swelling of the DIPs and/or PIPs, but its onset is more insidious and it is not associated with dactylitis.

HIV infection may be associated with arthritis that resembles either psoriatic arthritis or Reiter’s syndrome. The arthropathy is usually explosive in onset, and both joint and skin manifestations are severe. HIV infection has also been associated with an indolent, destructive lower-extremity arthropathy. This patient’s symptoms do not fit with these arthritis syndromes.

In the first several months of rheumatoid arthritis , the typical symmetrical joint involvement of RA may not be apparent, which may lead to confusion with asymmetrical arthropathies like psoriatic arthritis or Reiter’s syndrome. DIP joint involvement with swelling is common in psoriatic arthritis, but rare in rheumatoid arthritis. Spinal involvement in psoriatic arthritis is usually lumbar or sacral (sacroiliitis), whereas cervical involvement is more characteristic of rheumatoid arthritis. While cutaneous psoriasis and “true” rheumatoid arthritis are common and may co-exist, the features of the arthritis in this woman make RA highly unlikely.

Even though her low-back symptoms have been intermittent and mild, an x-ray of the SI joints may show changes of unilateral or asymmetrical sacroiliitis that are characteristic of psoriatic arthritis and of Reiter’s syndrome.

Establishing the nature of this patient’s skin and nail abnormalities is crucial to determining the diagnosis. Observing the typical nail changes of psoriasis is important, since they eventually occur in 85% of patients with psoriatic arthritis. Nail clippings may need to be examined to distinguish onycholysis from a fungal infection.

The other diagnostic options would have little utility at this stage of the work-up. Neither her history nor the physical exam findings are suggestive of lupus or other connective tissue diseases, and therefore the ANA is not indicated. For reasons stated above, RA is not a serious diagnostic consideration in this patient, and RF should be negative in psoriatic arthritis and Reiter’s syndrome. Similarly, the multiple cultures for gonococcus are not germane since this is not a migratory arthritis, which might suggest disseminated GC. While hyperuricemia and gout are said to occur commonly with psoriasis, this woman’s present manifestations are not those of gout.

Although the mild nature of the patient’s symptoms speak against HIV infection, you should still inquire about potential risk factors. HIV testing is not necessarily indicated unless risk factors are present or the nature of the arthropathy changes dramatically, becoming more severe. However, patients are not always forthcoming about the presence of risky behavior and may be unaware of such behavior in sexual partners. It may be helpful to offer HIV testing for these patients.

HLA-B27 typing may be positive in up to 50% of patients with psoriatic arthritis, but it is most common in patients with spinal involvement (psoriatic spondylitis) and much less so in those who have only peripheral arthropathy, with or without sacroiliitis. Since the HLA-B27 antigen is also present in approximately 8% of the white population, and since the clinical features of psoriatic arthritis are present, testing for HLA-B27 is not indicated.

Recurrent acute mono- or oligoarthritis is typical of early gout or rheumatoid arthropathy. Palindromic rheumatism can be seen early in rheumatoid arthritis or as an idiopathic condition. Acute migratory polyarthritis is characteristic of GC arthritis and may also occur in meningococcal disease and acute rheumatic fever. None of these three patterns is characteristic of psoriatic arthritis.

Oral corticosteroids are not usually given for this disorder, since high doses are usually required and withdrawal of the steroids can result in a flare of both the joint and skin disease. Intraarticular steroids may be useful for mono- or oligoarthritis, but the needle should not pass through psoriatic plaques, since these harbor many pathogenic bacteria and usual skin preparation for arthrocentesis is inadequate.

Despite the widely held belief that the joint symptoms of psoriasis will abate if the skin lesions are cleared, there is little evidence to support this claim. Therefore, although PUVA and other therapies directed at the cutaneous lesions may be important to your patient’s cutaneous health and self-esteem, they cannot be relied on to improve joint pain.

Patients who are resistant to NSAID therapy or who progress to more extensive disease with joint erosions may benefit from treatment with sulfasalazine, methotrexate, cyclosporin A, or hydroxy-chloroquine

Evidence from controlled studies suggests that sulfasalazine may have disease-modifying effects in psoriatic arthritis and is well tolerated with few side effects. Many physicians prescribe methotrexate for extensive or progressive psoriatic arthritis; skin lesions of psoriasis also respond to this drug.

Cyclosporine has also been found to be effective for both the skin lesions of psoriasis and psoriatic arthritis. It is FDA-approved for the former but not the latter.

Antimalarials such as hydroxychloroquine have been used in psoriatic arthritis, but reports of skin lesion flares have now made some physicians reluctant to prescribe antimalarials for psoriatic arthritis.

Gold therapy is effective for some patients with psoriatic arthritis but may cause a skin disease flare and has largely been replaced with newer, more effective, and less toxic agents.

Newer therapies approved for use in RA, such as leflunomide, etanercept, and infliximab, may also be effective in patients with psoriatic arthritis.

While this patient attributes her recurrent low-back pain to sitting at work, there are objective signs of sacroiliac involvement and limited spinal mobility. She should be referred to physical therapy to assess spinal mobility and posture. The therapist should teach her appropriate exercises to improve trunk flexibility, strength, and posture. The patient should be instructed in proper body mechanics during ADLs, work, and recreation. Suggestions should be made for modifications to the workplace to reduce back pain during tasks requiring long periods of sitting.

Bed rest is not recommended to address this patient’s low-back symptoms, since eliminating physical activity would result in additional muscle weakness and decreased endurance.

Heavy resistance exercises for the low-back muscles are not appropriate for this patient, because high-intensity weight-lifting with maximum loads carries an increased risk of injury. Her strengthening regimen should be monitored by the physical therapist and should emphasize the postural muscles of the thoracic spine and the abdominal, gluteal, and quadriceps muscles.

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