Ans. is 'c' i.e., Decreased calcium Clinical features of Hyperparathyroidism|||Symptomatic signs and symptomsAsymptomatico Recurrent nephrolithiasiso Peptic ulceration (abdominal pain)o Extensive bone resorptiono Mental changes; Psychiatric manifestations'Manifestation may be subtle and the disease many have a benign course with no symptoms and signs other than Hypercalcemia and elevated level of PTH'"'Subtle presentation ' may simulate 'asymptomatic ' hypercalcemia ' ". Bone in Hyperparathyroidism|||Healing responseResorptiono Osteitis fibrosa Cystica(Distinctive bone manifestation) Characterized by replacement of normal cellular and marow elements by fibrous tissueOther Manfestationso Absence of lamina durao Pinhead stippling of skullo Marrow fibrosiso Diffuse bone Resorptiono Subperiostal bone resorption of phallangeal tuftso "Brown tumor" of hvperparathvroidism (well circumscribed dark brown area in the region of severe bone resorption|o Osteoporosiso Deformityo Pathological fracturesMarkers of Hyperparathyroidism (|ed PTH):1. Increased serum calcium# Stimulates Vit D which causes increased absorption of Ca+ + from gut# Increased calcium reabsorption from tubules# Increases osteoblastic activity in bones and mobilizes calcium from bone into serum.2. Decreased serum phosphorus# PTH acts on tubules to increase excretion of phosphorus3. Increased 24 hr urine calcium# Despite increased reabsorption of Ca++ in renal tubules urinary calcium is increased owing to increased filtration of calcium in glomerular filtrate.4. Increased alkaline phosphatase# Increased resorption of bone leads to compensatory elevation of osteoblastic activity.5. Radiological changes :# Subperiosteal resorption of phalanges is characteristic (hand X Rays are always advised).# Bone resorption i.e., osteitis fibrosa et cystica (brown tumours)# Loss of lamina dura