The male, 35-year-old patient was admitted to hospital with a tender and swollen left ankle, pain and limited movements in the shoulders, as well as low back pain (LBP) and pain in the area around the lumbar vertebrae (L1-L4). Three intramuscular injections with betamethasone were made before admission to the hospital.
The laboratory results were as follows: haemoglobin 139 g/l (n: 135-180); erythrocytes 4.6 x 1012 (n: 4.4-5.9); leucocytes 11.76 x 109 (n: 3.5-10.5); platelets 166 x 109 (n: 130-360); C-reactive protein 102 mg/l (< 5 mg/l); erythrocyte sedimentation rate (ESR) 78 mm/h (n: < 15 mm/h); AspAT 81 U/l (n: < 32 U/l); AlAT 49 U/l (n: < 33 U/l); GGTP 111 U/l (n: < 40 U/l); AP 141 U/l (n: < 105 U/l); total bilirubin 31.9 mumol/l (n: < 21 mumol/l); direct bilirubin 12.3 mumol/l(n: < 8.5 mumol/l). Also laboratory tests revealed rheumatoid factor positivity for IgM, IgA and IgG classes of immunoglobulin (n: 243.8; 182.1 and 95.1 U/ml respectively), as well as anti-citrullinated peptide antibodies (ACPA) 93.6 U (normal range < 20 U), and anti-mutated citrullinated peptide antibody (anti-MCV) 20.8 U/ml (normal range < 20 U/ml). HLA-B27 was negative.
Ultrasound examination of the left ankle showed synovitis with positive power Doppler signal. Ultrasound of the small joints of the hands did not present pathological features. X-ray of sacroiliac joints revealed a rough right sacroiliac joint (Fig. 1). X-ray of ankles, hands and the thoracolumbar part of the spine with sacroiliac joints did not show pathological changes.
Cultures (blood culture, sterile urine) were negative for infectious organisms. Blood serological tests for Chlamydia trachomatis antibodies (IgG, IgM, IgA class) and polymerase chain reaction (PCR) testing for Chlamydia trachomatis in a urine specimen were negative. The X-ray of the lungs and the ultrasound examination of the abdomen also did not reveal abnormalities.
The patient had no comorbidities or family history of arthritis, but he was diagnosed with hepatitis A virus in November 2016.
Analysis of symptoms and additional tests were taken into consideration diagnosis as follows:
seronegative spondyloarthropathy,
rheumatoid arthritis,
undifferentiated arthritis.
Seronegative spondyloarthropathy (SpA) was initially diagnosed - inflammatory back pain, onset before 45 years of age, in the X-ray image of the right sacroiliac joint there was a suggestion of sacroiliitis, despite the absence of the HLA-B27 antigen. MRI of the spine or sacroiliac joints had not been performed at this stage.
The patient did not fulfil the criteria for classification (ACR/EULAR classification criteria from 2010) of rheumatoid arthritis (RA); he had ACPA antibodies and rheumatoid factor (RF), but had only one joint involvement.
Undifferentiated arthritis was considered but LBP and arthritis strongly suggested an early stage of SpA, even though HLA-B27 was not present.
Corticosteroid was applied locally in the left ankle. Therapy with sulfasalazine 2 g/daily and a non-steroidal anti-inflammatory drug (NSAID) was initiated.
Also the patient consulted a gastroenterologist who concluded that the patient had protracted hepatitis A infection. Therapy with ademetionine 500 mg twice daily was prescribed.
One month later the patient presented to the rheumatologist with fever, low back pain, pain in vertebrae and spinous processes located in the lumbar region of the spine. Laboratory tests showed high inflammatory serum markers: ESR 84 mm/h and CRP 51.2 mg/l. Computed tomography of the spine demonstrated destruction of the L1-L2 disk space with the adjacent L1 and L2 vertebral bodies (the image corresponded with spondylodiscitis), as the contiguous iliopsoas muscle was affected (Fig. 2).
Blood cultures were negative. The Mantoux test and QuantiFERON (QFT) test for tuberculosis or latent tuberculosis infection were performed and were negative. Sulfasalazine treatment was discontinued. Therapy with ceftriaxone 4 g/daily and lincomycin 600 mg three times daily intravenous application was initiated. The antibiotic therapy was discontinued after 21 days after MRI examination of the lumbar spine, which showed destruction of the L1-L2 and L3-L4 disk spaces with the adjacent vertebral bodies. The T2-weighted MR image demonstrated discitis and osteomyelitis persisting as an abscess in the structure of right iliopsoas muscle (Fig. 3).
Methicillin-resistant Staphylococcus aureus (MRSA) was detected in the next three consecutive blood cultures. The patient consulted a neurosurgeon who stated that there was considered an indication for surgery if the patient did not show improvement on treatment with targeted antibiotics. Antibiotic therapy with teicoplanin 400 mg daily and levofloxacin 500 mg daily intravenous application was started and was applied for six consecutive weeks. Rifampicin 300 mg daily was prescribed for three months. Intravenous immunoglobulins were applied in a dose of 400 mg/kg in three contiguous months.
After the end of the antibiotic course the laboratory results were as follows: haemoglobin 161 g/l (n: 135-180); erythrocytes 5.25 x 1012 (n: 4.4-5.9); leucocytes 10.5 x 109 (n: 3.5-10.5); platelets 181 x 109 (n: 130-360); C-reactive protein 4.6 mg/l (n: < 5 mg/l); erythrocyte sedimentation rate (ESR) 28 mm/h (n: < 15 mm/h); AspAT 39 U/l (n: < 32 U/l); AlAT 22 U/l (n: < 33 U/l); GGTP 69 U/l (n: < 40 U/l); AP 105 U/l (n: < 105 U/l); total bilirubin 20.5 mumol/l (n: < 21 mumol/l); direct bilirubin 11.9 mumol/l (< 8.5 mumol/l). There was no deterioration of the liver function test, but the liver enzymes and bilirubin remaining elevated.
Three months later control MRI was performed and visualized in the structure of the bodies of L1, L2, L3, L4 vertebrae and the adjacent disc surfaces irregular shaped areas with characteristic bone marrow oedema and fat bone marrow transformation. The height of the L1-L2, L3-L4 vertebrae decreased with the pathologically increased signal intensity. Zones of changed signal intensity were visualized in the structure of the two psoas muscles, at level L1-L2, with high signal intensity in T2 dependent sequences (post-inflammatory changes).