|Year : 2020 | Volume
| Issue : 3 | Page : 139-141
Fractures: The opening batsmen of an autoimmune disease
K Ravi, KR Chaitra
Department of General Medicine, Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India
|Date of Submission||05-Sep-2019|
|Date of Decision||18-Sep-2019|
|Date of Acceptance||06-Nov-2019|
|Date of Web Publication||15-Jul-2020|
Dr. K R Chaitra
No. 368/16 42nd Cross 8th Block, Jayanagar, Bengaluru - 560 070, Karnataka
Source of Support: None, Conflict of Interest: None
Renal involvement is a well-known extraglandular manifestation of primary Sjögren's syndrome (pSS). Most of the manifestations are related to tubular dysfunction. Metabolic bone disease rarely occurs as the first manifestation of a renal tubule disorder due to pSS. Here, we present a 28-year-old female patient whose first presentation of pSS was with multiple skeletal fractures caused by renal tubular dysfunction. Clinicians should always search for the evidence for Sjögren's syndrome in adult patients with unexplained osteomalacia and renal tubular acidosis, even in the absence of sicca syndrome.
Keywords: Osteomalacia, renal tubular acidosis, Sjögren's, tubular dysfunction
|How to cite this article:|
Ravi K, Chaitra K R. Fractures: The opening batsmen of an autoimmune disease. APIK J Int Med 2020;8:139-41
| Introduction|| |
Sjögren's syndrome is a chronic progressive autoimmune disease characterized by lymphocytic infiltration of the exocrine glands resulting in xerostomia and xerophthalmia. It presents with a varied clinical spectrum ranging from organ-specific autoimmune exocrinopathy to systemic disease. Middle-aged females are most commonly affected. This syndrome can present either alone (as the primary Sjögren's syndrome [pSS]) or in the context of an underlying connective tissue disease (as the secondary Sjögren's syndrome). Renal involvement is a well-known extraglandular manifestation of pSS. Most common manifestations are related to tubular dysfunction. Metabolic bone disease (MBD) rarely occurs as the first manifestation of a renal tubule disorder due to pSS.
| Case Report|| |
A 28-year-old female presented with a history of lower back pain for 2 months. The back pain was insidious in onset, localized dull aching type, nonradiating which aggravated with movements and was relieved with analgesics. She also noticed weakness of her lower limbs in the form of inability to get up from squatting position, difficulty in climbing up, and getting down the stairs with a few episodes of buckling at her knees in the past 2 months. She also gave a history of 10 kg weight loss in 6 months. However, there was no history of fever, night sweats, bowel or bladder disturbances, trauma, positive family history, or any symptoms suggesting underlying malignancy. On examination, the patient had spinal tenderness from T11 to L2 vertebrae. Detailed neurological examination revealed spastic paraparesis with brisk reflexes and extensor plantar response. Based on this, a provisional clinical diagnosis of compressive myeloradiculopathy probably of tubercular etiology was made.
Magnetic resonance imaging (MRI) of the spine was done for the same which showed no myelopathic or compressive lesions; instead, multiple pathological fractures were seen as stated below. On further evaluation for the cause of pathological fractures, it was seen that the patient had low serum phosphorus and uric acid with glucosuria and phosphaturia and nonanion gap metabolic acidosis, all features suggesting Fanconi's syndrome. Further evaluation of fanconis syndrome revealed a positive ANA profile with SS-A and Ro 52 recombinant being 3+ and SS-B 1+ which suggested Sjogrens syndrome.
MRI and computed tomography of the spine showed endplate sclerosis in cervical, thoracic, and lumbar vertebrae; fracture of Bilateral pars interarticularis of L1, L2, L3, and L5 vertebrae; iliac bones; B/L superior and inferior pubic rami neck of the right femur; and sacral promontory along with fracture of the posterior aspect of the 7th rib [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5].
|Figure 1: Magnetic resonance imaging of the spine – normal spinal cord with no compression|
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Complete blood count showed hemoglobin – 13.5 g/dl, total count – 6590 cell/mm3, platelet – 2.4 lakhs, erythrocyte sedimentation rate – 40 mm/h, and red blood cell (RBC) – 99 mg/dl.
Serum electrolytes include sodium – 138, potassium – 2.8, and chloride – 117. Serum phosphorus was 1.8 mg/dl, ionized calcium was 4.6 mg/dl, Vitamin D3 was 5.5 ng/dl, and uric acid was 1.5 mg/dl. Urine routine showed albumin – nil, RBCs – nil, 2–3 pus cells, sugar 1+, urinary pH >5.5, and 24 h urine phosphorus 257 mg. Parathormone was 50 pg/ml (normal). ABG showed: pH-7.27, HCO3-13.5, Pco2-23.3 suggesting Non anion gap metabolic acidosis. Antinuclear antibody (ANA) profile showed SS-A 3+, Ro 52 recombinant 3+, and SS-B: 1+. Serum protein electrophoresis showed no monoclonal peak. Schimers testing in both eye was 20mm. Ultrasonography showed that the kidney, ureter, and bladder were normal.
| Discussion|| |
pSS is a disease of exocrine glands presenting with manifestations related to dry eyes and dry mouth. Nonexocrine organ systems may also be involved, including the skin, lung, gastrointestinal tract, central and peripheral nervous system, muscular skeletal apparatus, and the kidney. The prevalence of pSS is 0.5%–1%.
Kidney involvement in Sjögren's syndrome is about 9%. Renal involvement in the primary Sjögren's syndrome was first described in the 1960s with reports of the typical tubular defects. These included tubulointerstitial inflammation as the most common renal lesion. Two distinct pathophysiological processes were seen: epithelial disease with a predominantly mononuclear lymphocytic infiltration resulting in tubulointerstitial nephritis and nonepithelial disease with a secondary immune complex-mediated process resulting in glomerulonephritis.
The mechanisms by which patients with Sjögren's syndrome develop Fanconi's syndrome remain unclear. However, two possible mechanisms have been described.
- Tubular damage occurs by lymphocytic infiltration and hypergammaglobulinemia with deposition of immunoglobulin light chains which results in an inflammatory response
- Direct inhibitory effect on glucose, amino acids, phosphate, Na+ K+ ATPase transpoters in the proximal tubules.
Although the incidence of osteomalacia in pSS patients with renal tubular acidosis (RTA) has been reported to range from 25% to 45%,, to the best of our knowledge, only around 10 cases have been reported with MBD as a primary manifestation in pSS.,, Only four of these cases showed proximal RTA which was found in combination with distal RTA.
Here, we report a case that presented to us with pathological fractures which were caused by osteomalacia secondary to RTA caused by pSS. Our patient had a combined proximal RTA with distal RTA. Fanconi's syndrome is a rare kidney manifestation in Sjögren's syndrome, and very few cases are reported so far with primary Sjögren's syndrome presenting as MBD, with even fewer cases showing proximal RTA.
| Conclusion|| |
Although Fanconi's syndrome is a rare kidney manifestation in Sjögren's syndrome, it may be latent and may precede the sicca symptoms. Therefore, evidence for Sjögren's syndrome should be searched for adult patients with unexplained osteomalacia and RTA, even in the absence of sicca syndrome. Conversely, in patients with Sjögren's syndrome, early investigation and treatment of renal tubular dysfunction may prevent future complications, such as osteomalacia.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]