Ans. is 'b' i.e.. Decreased Serum Calcium, phosphorus and alkaline phosphatase is seen o Osteoporosis is a state of decreased mass per unit volume of a normally mineralized bone. Osteoporosis is the commonest metabolic bone disease. Osteoporosis is characterized by an abnormally low bone mass (low bone density) and defects in bone structure, a combination of which renders the bone unusually fragile and at greater than normal risk of fracture. Bone depletion may be brought about by predominant bone resorption, decreased bone formation or a combination of the two.Causes of osteoporosiso Causes of osteoporosis can be : -In old agePost-menopausal osteoporosis (Type I osteoporosis).Age related senile osteoporosis (Type II osteoporosis)In adults (Pathological)Hypogonadal stateso Turner syndromeo Klienfelter syndromeo Anorexia nervosao Hypothalamic amenorrheao Hyperprolactinemiao Other primary or secondary hypogonadal statesEndocrine disorderso Cushing's syndromeo Hyperparathyroidismo Thyrotoxicosiso Type 1 diabetes mellituso .Acromegalyo Adrenal insufficiencyNutritional and gastrointestinal disorderso Malnutritiono Parenteral nutritiono Malabsorption syndromeso Gastrectomyo Severe liver disease, especially biliary cirrhosiso Pernicious anemiaRheumatologlc disorderso Rheumatoid arthritiso Ankylosing spondylitisHematologic disorders/malignancyo Multiple myelomao Lymphoma and leukemiao Malignancy-associated parathyroid hormone (PTHrP) productiono Mastocytosiso Hemophiliao ThalassemiaSelected inherited disorderso Osteogenesis imperfecto Marfan syndromeo Hemochromatosiso Hypophosphatasiao Glycogen storage diseaseso Homocystinuriao Ehlers-Danlos syndromeo Porphyriao Menkes' syndromeo Epidermolysis bullosaOther disorderso Immobilizationo Chronic obstructive pulmonary diseaseo Pregnancy and lactationo Scoliosiso Multiple sclerosiso Sarcoidosiso AmyloidosisDrugs causing osteoporosiso Glucocorticoidso Cyclosporino Cytotoxic drugso Excessive alcoholo Aromatase inhibitorso Heparino Lithiumo Excessive thyroxineo Aluminiumo GnRh agonistsClinical features of osteoporosiso Osteoporosis is an asymptomatic disorder unless complications (predominantly fractures) occur,o Most common symptom of osteoporosis is back pain secondary to vertebral compression fracture.o Dorso-lumbar spine is the most frequent site.o Other common sites of fracture are lower end radius (Colic's fracture) and fracture neck femur.o Osteoporotic fracture (fragile fractures) are : i) Fracture vertebrae (most common), (ii) Colic's fracture, (iii) Fracture neck femur.o Serum calcium, phosphate and alkaline phosphatase are normal in osteoporosis.Radiological features of osteoporosiso At least 30% of the bone mass must be lost before it becomes apparent on x-ray.o X-ray findings are : -i) Loss of vertical height of a vertebra due to collapse.Cod fish appearance: The disc bulges into the adjacent vertebral bodies so that the disc becomes biconvex.Ground glass appearance of the bones, conspicuous in bones like the pelvis.Singh's index : Singh et al. graded osteoporosis into 6 grades based on the trabecular pattern of the femoral neck trabeculae. Details are outside the scope of this book.Metacarpal index and vertebral index are other methods of quantification of osteoporosis.