Rickets–Osteomalacia

Abstract

A 25-year-old female presented with fracture neck of the left femur following trivial trauma. She had history of diffuse aches and pains and proximal muscle weakness for the last 6 months. After sustaining fracture, she became bedbound and was referred to our institute. There was no history of recurrent pain abdomen, diarrhea, steatorrhoea, polyuria, graveluria, or periodic paralysis. She had history of poor exposure to sunlight and deficient intake of dairy products. There was no past history of fracture, renal stone disease, gallstone disease, or pancreatitis. She had no history of use of glucocorticoids in any form, alternative medications, bisphosphonates, or calcium and vitamin D preparations. However, she complained of difficulty in swallowing and foreign-body sensations in her eyes. She had two live children and the last child birth was 3 years earlier, and she continues to menstruate regularly. Family history was noncontributory. On examination, she was lean, thin, emaciated, diffusely hyperpigmented, and had pallor, cheilosis, and glossitis. Her blood pressure was 100/60 mmHg. She had genu varum, kyphoscoliosis, diffuse bony tenderness, proximal muscle weakness, and severe attrition of her teeth with pigmentation. She had no goiter and deep tendon reflexes were delayed. Her eyes were suffused and tongue was dry. Movements at left hip joint were restricted and painful. Systemic examination was unremarkable. On investigations, hemoglobin was 10.2 g/dl, serum creatinine 1.2 mg/dl (eGFR 40 ml/min), Na⁺ 145 mEq/L, K⁺ 3.4 mEq/L, corrected calcium 9 mg/dl, phosphorus 3.0 mg/dl, alkaline phosphatase 919 IU/l (N < 128), iPTH 220 pg/ml (N 15–65), and 25(OH)D 30 ng/ml (N 30–70). Twenty-four-hour urinary calcium was 211 mg, phosphate 500 mg, and protein 1.2 g. Arterial blood gas analysis revealed pH 7.28, HCO₃ 9.5 mEq/L, and calculated anion gap 11 mEq/L, and corresponding urine pH was 6.5. Serum T₄ was 4.6 μg/dl (N 4.8–12.7), TSH 78 μIU/ml (N 0.27–4.2), and anti-TPO antibody 480 IU/ml (N < 34). Antinuclear antibody was present (speckled pattern, 3+) and celiac serology (IgA tTG) was negative. Ultrasonography of the neck and sestamibi parathyroid scan was noncontributory. Ultrasound abdomen showed bilateral small kidneys. X-ray of spine and pelvis showed osteopenia and fracture neck of the left femur, respectively. X-ray of chest revealed pseudo-fracture at the outer border of scapula. ^99mTc MDP bone scan revealed increased uptake in sternum, mandible, ribs, and long bones suggestive of metabolic bone disease. Schirmer’s test was positive and lip biopsy was consistent with Sjogren’s syndrome. With this profile, Sjogren’s syndrome with distal renal tubular acidosis (RTA) and primary hypothyroidism due to Hashimoto’s thyroiditis were considered, and the patient was initiated on sodium bicarbonate, potassium chloride, and calcium carbonate tablets. In addition, she was also started with L-thyroxine. With this treatment, her bone pain resolved, proximal myopathy improved, and she was able to walk with support. Repeat blood gas analysis showed pH of 7.4, HCO₃ of 20 mEq/L, and serum of K⁺ 4.2 mEq/L. Later, calcitriol was added due to declining eGFR. She is planned for renal biopsy for the initiation of immunosuppressive therapy as she had proteinuria and declining eGFR (Fig. 5.1).