Introduction

• Bone disorder caused by excess parathyroid hormone (PTH) usually the result of poor nutrition.
• Cause: diet with excess phosphorus or low calcium.
• Signs: bone pain, stiffness, neurological signs.
• Diagnosis: history, laboratory data, radiography.
• Treatment: strict rest, dietary modification.
• Prognosis: good if treated early.

Pathogenesis

Etiology

• Feeding diet with inappropriate calcium:phosphorus ratio (should be 1.2:1).
• Usually seen in animals fed on pure meat diet.

Pathophysiology

• Excess PTH secretion due to inadequate dietary calcium → demineralization of bones → clinical signs.

• Hypocalcemia (ionized calcium) as a result of inadequate intake or excess phosphate → increased PTH secretion.
• Inability to compensate by increased dietary uptake of calcium → skeletal demineralization → osteopenia.
• Weakness of bones may → pathological fractures → vertebral collapse and neurological signs in some cases.

Timecourse

• Months.

Diagnosis

Treatment

Prevention

Outcomes