Musculoskeletal involvement of syphilis – a forgotten lesson

Abstract

Syphilis is a sexually transmitted disease with a myriad of presentation and called ‘the great impostor’ for the variety of the symptoms. As a venereal disease it is transmissible mainly by sexual contact with infectious lesions but can spread by blood contamination. Without treatment it progresses through early and late syphilis. Since the introduction of penicillin its prevalence has strongly dropped but was never eradicated entirely. As the frequency and the progression are largely controlled there are several symptoms which are not common and can be a difficult differential diagnostic problem nowadays. The authors present a case where decades passed between the primary event and the actual hospitalisation with fever of unknown origin and coexistent swollen joint deformities. The patient was not treated entirely from his primary event and later, psoriasis was settled as a diagnosis, which was the cause of neglecting the secondary phase’s skin lesions.

Background

Syphilis has a myriad of presentation and called ‘the great impostor’ for the variety of the symptoms.^{1 2} Since the use of penicillin its prevalence strongly dropped but was never eradicated entirely.³ As the frequency and the progression are largely controlled there are several symptoms which are not common and can be a difficult differential diagnostic problem nowadays.

Case presentation

A 50-year-old male patient was treated several times with the initial diagnosis of ‘psoriasis’ (psoriatic arthritis) by our Department including recurrent elbow bursitis and destructive artrosis of the right knee (figure 1). The diagnosis was made first by a rheumatologist 20 years ago on the basis of Moll and Wright’s criterias of psoriatic arthritis,^{4 5} which are: inflammatory arthritis, presents of psoriatic like skin lesions and negative serologic test for rheumatoid arthritis. Later the patient was treated by a dermatologist (as our Hospital was and is lacking in a rheumatologist). A skin biopsy has never taken. The latest treatment of his psoriatic disease was with infliximab, 3 years ago. A bursectomy of the right elbow with delayed skin closure and arthroscopic debridement of the right knee was realised prior to his actual admission. Due to the above mentioned very bad skin conditions and recovery capacity (delayed skin closure of the elbow) the total knee arthroplasty had been abandoned.

Figure 1.

Destructive artrosis of the right knee (anteroposterior and lateral projections).

In the present admission, he entered with a fever of 40°C with an unknown origin. The right knee was swollen without the classic signs of Galenus and Celsus and he had an elbow fistula of the earlier bursectomy site. He had general cutaneal erythemas, macular, desquamative and hyperkeratotic lesions – which was already known as a psoriatic disease (figure 2). There were no signs of meningitis nor neurological alteration and his physical examination otherwise was negative.

Figure 2.

Psoriatic like skin lesions.

From his medical history venereal disease was revealed due to a risky relation at the age of 16, which was treated (as he mentioned) but did not remember the treatment (no data available). Beside the already mentioned psoriasis and its previous treatment with infliximab, chronic liver disease with elevated levels of transaminases (three times) are also included in his history. The liver disease was controlled by a gastroenterologist. The serologic test for hepatotropic viruses was negative but he denied a liver biopsy and disclaimes alcohol intake.

Investigations

General laboratory tests detected an elevated C reactive protein, Western-Green level and also detected elevated liver transaminase with leucocytosis. Serological test was positive for FTA-Abs (fluorescent treponema antibody absorption) – which has a very low false positive error⁶ – but negative for veneral disease research laboratory, Lyme-disease, Brucella, cytomegalovirus, Epstein–Barr virus, HIV, viral hepatitis and autoimmune study. A second confirmatory test (Treponema pallidum particle agglutination assay) had been done but evaluated only later during the follow-up in the outpatient clinic.

Differential diagnosis

As the basic diagnosis of the patient was psoriasis with psoriatic like skin lesions, another source of the fever was investigated without suspicion of direct relation between the fever and psoriatic like skin lesions.

In the primary evaluation we tried to examine the more frequent causes of fever: pulmonary (x-ray and auscultation) and genitourinary (urine analysis) infection was disclosed. The conventional abdominal echography was indifferent and the 2D echocardiography did not show vegetations or lesions suggestive of endocarditis.

Laboratory tests for knee purulent arthritis were negative (culture, analysis, leucocytes).

Haemocultives were negative in two distinct examinations, as was the Mantoux reaction. Bone scan revealed the already known elbow and knee processes. The initial lumbar puncture was unsuccessful for technical reasons and later the patient declined to authorise the test. Due to the possibility of a concomitant psoriasis and positive FTA-Abs or unspecific results, we decided to observe the skin lesions and make a biopsy in case of an unsuccessful initial treatment.

Treatment

As the patient had a fever of unknown origin, swollen but not acute purulent arthritic knee and elbow deformities, diverse skin lesions and positive serologic tests for lues, our suspected diagnosis was tertiary syphilis with or without asymptomatic neurosyphilis. So on an empirical basis we initiate penicillin G (benzylpenicillin commonly known as ‘gold standard’) 4 000 000 IU treatment every 4 h intravenously during 14 days as he was hospitalised.

Outcome and follow-up

Due to the correct treatment his signs and symptoms were disappearing (fever, articular signs, skin lesions), so we decided to release him from the ward and continue the control in our outpatient clinic. As the skin lesions had disappeared for this empirical treatment, no biopsy was realised later on.

Discussion

Syphilis is a sexually transmitted disease with a myriad of presentation and called ‘the great impostor’ for the variety of the symptoms.^{1 2} Sir William Osler was the first who stated: ‘the physician who knows syphilis knows medicine’.⁷

As a venereal disease it is transmissible mainly by sexual contact with infectious lesions but can spread by blood contamination: transfusion, skin lesions, inutero, etc.⁸ Without treatment it progresses through early and late syphilis. The early stage consists of primary, secondary and early latent, while the late stage of late latent and tertiary phases.⁹ Since the introduction of penicillin its prevalence has strongly dropped but was never eradicated entirely.³ As the frequency and the progression are largely controlled there are several symptoms which are not common and can be a difficult differential diagnostic problem nowadays. Unfortunately these late sequelaes are hardly treatable and there is little evidence in the literature about successful recovery.¹⁰

In our case there were decades (34 years) between the primary event and the actual hospitalisation. Furthermore, we are also not able to discount later reinfections. Another source of error was the psoriatic diagnosis and treatment and it was the cause of neglecting the secondary phase’s skin lesions. The patient was admitted with fever of unknown origin, swollen and deformed joints and was diagnosed as a tertiary syphilis. After the proper treatment and recovery of the mentioned signs and symptoms he was released from the hospital and decided to control ambulatory.

Learning points.

• Syphilis has a myriad of presentation and called ‘the great impostor’ for the variety of the symptoms.

• A specialist should never forget to study the entire medical history and should examine the patient not only his skin lesions or swollen articulations.

• If a patient presents a coexistence of skin lesions, articular deformities and fever of unknown origin, one should investigate syphilis as the cause.