Chronic recurrent multifocal osteomyelitis (CRMO) is a sporadic condition of inflammatory bone pain that occurs as recurrent flares because of osteomyelitis, which presents in the form of multiple aseptic foci. The estimated prevalence of CRMO is 1-2 per million, affecting mostly children, in the age group of 2 to 17. Main symptoms of CRMO are bone inflammation and pain, which are generally worse at night. Other symptoms seen on radiographs indicate osteolytic lesions surrounded by sclerosis, at later stages of the disease. Markers of inflammation, viz. tumor necrosis factor a and C-reactive protein are elevated in many cases. Because of similar symptoms, differential diagnosis is needed to confirm CRMO from infectious osteomyelitis, bone tumors, and other diseases. The genetic component is likely in some cases such as Majeed syndrome, deficiency of IL-1 antagonist, etc. Imaging is the essential part of diagnosing CRMO, and magnetic resonance imaging of the whole body is the most widely used and recommended method for the evaluation of multiple foci, as compared to radiography for reasons of sensitivity as well as prevention of excessive exposure of affected children to radiation. CRMO is considered an autoimmune and auto-inflammatory disorder, but its precise pathophysiology is not clear. Current treatment options are non-steroid anti-inflammatory drugs like naproxen, as the primary choice, and the bisphosphonates such as pamidronate as the second choice, to counter the symptoms and to reduce bone lesions. The surgical option is the choice for recalcitrant cases, even though recurrence may still be a problem.

Juvenile Paget's disease (JPD) is a rare autosomal recessive osteopathy. There is still a question about the most effective treatment modality in long-term prognosis. A 9-month-old boy who suffered from bone pain and deformities with a very high alkaline phosphatase level was diagnosed as JPD by radiographic findings. Genetic analysis showed a homozygous large deletion in TNFRSF11B gene encoding osteoprotegerin. Clinical improvement was observed with intravenous pamidronate therapy. However, the effect of drug reduced in time so the annual dose per kilogram body weight was increased after 2 years. Despite this increment, bone fractures developed and bone pain recurred with high-ALP levels, which suggested resistance to pamidronate. Switching to zoledronate resulted a significant improvement in bone findings radiographically and ALP level. Severe hypocalcemia requiring intravenous calcium treatment complicated the first dose of zoledronate, but not recurred thereafter. Intravenous pamidronate therapy is effective in reducing bone pain, improving bone deformities and motor development in infantile onset JPD. However, this effect can be transient. Switching to another bisphosphonate like zoledronate may provide long-term clinical and biochemical improvement as an alternative treatment in case of resistance to pamidronate therapy.

Osteogenesis imperfecta is a hereditary bone dysplasia characterized by bone fragility, deformity, and short stature. Treatment focuses on preventing bone fractures and symptom relief. Pamidronate, a second-generation bisphosphonate drug that minimizes bone loss, is the chosen treatment in osteogenesis imperfecta. Radiologically, each cycle of pamidronate treatment is depicted as a line of sclerosed nondecalcified cartilage at the metaphysis, termed a pamidronate line. In this case report, we demonstrate that a treatment timeline can be visualized on plain radiographs as the number and spacing of pamidronate lines reflects the number and timing of treatment cycles. The educational value of this is to reassure physicians of the benign nature of "zebra lines," to demonstrate that the pamidronate lines migrate and fade with bone growth, and alert physicians that the lack of expected pamidronate lines during treatment may reflect a change in the patient's condition that reduces the effectiveness of bisphosphonate infusions.

Pachydermoperiostosis (PDP) is a rare disorder characterized by pachydermia, digital clubbing, periostitis, and an excess of affected males. It is the primary form of hypertrophic osteoarthropathy (HOA) and there are some rare associations of PDP with other disorders. Here we describe a patient with Crohn's disease associated with PDP. A 26-year-old man, who was a known case of Crohn's disease, referred with diffuse swelling in the upper and lower limbs and cutis verticis gyrata since 7 years ago. PDP was suspected and endocrinological and radiological studies were conducted for the evaluation of underlying disease. He was prescribed celecoxib, low-dose prednisolone, and pamidronate to control the swelling, periostitis, azathiopurine, and mesalazine according to gastrointestinal involvement. In conclusion, it is important to identify this condition since a misdiagnosis might subject the patient to unnecessary investigations.

Neonatal severe hyperparathyroidism (NSHPT) is a rare autosomal recessive disease. Children present within the first 6 months of life and more commonly in the first few weeks. Common presentation is poor feeding, polyuria, dehydration, lethargy, failure to thrive, hypotonia, gastrointestinal dysmotility, osteopenia and symptoms of respiratory distress due to a poorly developed chest cage. We present a case of a 2-month old girl with severe hypercalcemia and hyperparathyroidism. She was found to have a novel homozygous mutation in the acceptor splicing site of intron 4 (c.1378 -2A>G) of the calcium sensing receptor gene (CASR). This mutation causes frame shift deletion of exon 5 and insensitivity of CASR to calcium. The patient was treated with intravenous fluids, fruosemide, calcitonin, intravenous pamidronate and oral cinacalcet. She did not respond to medical treatment. Parathyroid gland imaging including ultrasound, MRI and sestamibi nuclear scan were not helpful in localizing the glands. Her symptoms resolved following total parathyroidectomy. She is being treated with alfacalcidiol and calcium supplements to maintain normal serum calcium and phosphate. She achieved her normal developmental milestones.