**Core Concept**
Hyperparathyroidism is a disorder characterized by the excessive production of parathyroid hormone (PTH), leading to hypercalcemia and various systemic manifestations. The clinical symptoms of hyperparathyroidism are a result of the complex interplay between PTH, calcium, and vitamin D metabolism, affecting multiple organ systems.

**Why the Correct Answer is Right**
The symptoms of hyperparathyroidism include a wide range of gastrointestinal, neuromuscular, and renal manifestations. **Gastrointestinal symptoms** such as anorexia, nausea, vomiting, and constipation are common due to the hypercalcemia-induced inhibition of gastric emptying and intestinal motility. **Neuromuscular symptoms** like muscle weakness, fatigue, and osteoporosis occur due to the increased calcium levels affecting muscle function and bone turnover. **Renal symptoms** such as polyuria and polydipsia are caused by the hypercalcemia-induced nephrocalcinosis and impaired renal function. The combination of these symptoms is a result of the complex pathophysiology of hyperparathyroidism.

**Why Each Wrong Option is Incorrect**
**Option A:** Constipation and muscle weakness are symptoms of hyperparathyroidism, but they do not encompass the full spectrum of symptoms. Other symptoms like anorexia, weight loss, and polyuria are also present.

**Option B:** Anorexia and weight loss are indeed symptoms of hyperparathyroidism, but they do not represent the entire range of symptoms. Polydipsia and polyuria are also characteristic features of this disorder.

**Option C:** Polydipsia and polyuria are symptoms of hyperparathyroidism, but they do not account for the gastrointestinal and neuromuscular manifestations of this disorder.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the symptoms of hyperparathyroidism can be non-specific and may mimic other conditions, making a thorough evaluation of calcium and PTH levels crucial for diagnosis.

**✓ Correct Answer: D. All of the above**