**Core Concept**
Hyperparathyroidism is a disorder of calcium and phosphate metabolism caused by an excessive production of parathyroid hormone (PTH). This hormone regulates the concentration of calcium in the blood by acting on the bones, kidneys, and intestines.

**Why the Correct Answer is Right**
Osteosclerosis, which refers to an abnormal hardening of bone tissue, is not typically associated with hyperparathyroidism. In fact, hyperparathyroidism is often characterized by bone resorption, which leads to bone softening and increased susceptibility to fractures. The increased PTH levels lead to the activation of osteoclasts, which break down bone tissue, resulting in osteoporosis, not osteosclerosis.

**Why Each Wrong Option is Incorrect**
**Option A:** Generalised osteoporosis is a common feature of hyperparathyroidism due to the increased bone resorption caused by elevated PTH levels.
**Option B:** Renal calculi (kidney stones) are indeed associated with hyperparathyroidism, as the increased calcium levels in the blood can lead to the formation of calcium oxalate stones in the kidneys.
**Option C:** Hypercalcemia, or elevated calcium levels in the blood, is a hallmark of primary hyperparathyroidism, resulting from the excessive production of PTH.

**Clinical Pearl / High-Yield Fact**
In primary hyperparathyroidism, the increased PTH levels can also lead to peptic ulcer disease, due to the increased calcium absorption in the gut, which can stimulate gastric acid secretion.

**✓ Correct Answer: D. Osteosclerosis is not typically associated with hyperparathyroidism.**