In adults, a long term deficiency of vitamin D leads to which characteristic bone disease?

Introduction / Context:
Vitamin D plays a crucial role in calcium and phosphate metabolism, which are essential for healthy bone formation and maintenance. In adults, a prolonged deficiency of vitamin D leads to characteristic changes in bone structure and strength. This question asks you to identify the specific bone disease associated with vitamin D deficiency in adults, which is an important topic in nutrition and clinical medicine.

Given Data / Assumptions:

Vitamin D is involved in intestinal absorption of calcium and phosphate.
Deficiency can occur due to poor diet, limited sun exposure, or malabsorption.
Different deficiency diseases are associated with different vitamins.
We focus on adult patients, not growing children.

Concept / Approach:
In adults, vitamin D deficiency leads to osteomalacia, a condition in which bones become soft, weak, and more prone to fractures because mineralization of bone matrix is impaired. In children, the corresponding deficiency disease is rickets, which presents with bone deformities such as bowed legs. Scorbutus, or scurvy, results from vitamin C deficiency and primarily affects collagen formation and connective tissue, not vitamin D. Petechiae are small pinpoint hemorrhages that may appear in various conditions, including vitamin C deficiency or platelet disorders, but they are not the main name of a vitamin D deficiency disease. Avitaminosis is a general term referring to lack of vitamins, not a specific bone disease. Therefore, osteomalacia is the correct specific term for adult vitamin D deficiency bone disease.

Step-by-Step Solution:
Step 1: Recall the main functions of vitamin D in helping absorb calcium and phosphate from the diet. Step 2: Understand that without enough vitamin D, bones cannot mineralize properly, leading to softening and increased fracture risk. Step 3: Distinguish between rickets in children and osteomalacia in adults, both related to vitamin D deficiency. Step 4: Compare the options and recognize that osteomalacia is specifically linked to adult vitamin D deficiency. Step 5: Confirm that other options refer to different vitamins or general terms and are therefore incorrect.

Verification / Alternative check:
Medical textbooks list osteomalacia as the adult counterpart of rickets, both associated with vitamin D deficiency and impaired bone mineralization. Symptoms in adults include bone pain, muscle weakness, and increased fracture risk. In contrast, scorbutus or scurvy is linked to vitamin C deficiency, presenting with bleeding gums, poor wound healing, and petechiae. These distinctions confirm that osteomalacia is uniquely associated with vitamin D deficiency in adults.

Why Other Options Are Wrong:
Avitaminosis: This is a general term for deficiency of one or more vitamins and does not name a specific bone disease.
Scorbutus: This term refers to scurvy, the deficiency disease of vitamin C, not vitamin D.
Petechiae: These are small skin hemorrhages that can result from various conditions, including vitamin C deficiency or clotting disorders, but they are not a bone disease name.

Common Pitfalls:
A common confusion is mixing up rickets and osteomalacia or assuming that only children are affected by vitamin D deficiency. Another pitfall is to focus on general terms like avitaminosis without remembering the specific disease names used in exams. To avoid mistakes, remember the pair: rickets in children and osteomalacia in adults, both caused by vitamin D deficiency and characterized by poor bone mineralization.

Final Answer:
The vitamin D deficiency disease in adults is known as osteomalacia, characterized by soft and weakened bones.