A patient aged 40-years presents with ahritis of PIP and DIP along with carpometacarpal joint of thumb and sparing of wrist and metacarpophalangeal joint. What is the most likely cause?
**Core Concept**
The patient's symptoms suggest a specific pattern of joint involvement that is characteristic of a particular rheumatological condition. This condition is characterized by inflammation and degeneration of specific joints, which leads to pain and stiffness.
**Why the Correct Answer is Right**
The pattern of joint involvement in this patient is consistent with osteoarthritis (OA), particularly the nodal type. OA is a degenerative joint disease that typically affects weight-bearing joints, but can also affect the hands, particularly the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints, as well as the carpometacarpal joint of the thumb. The sparing of the wrist and metacarpophalangeal (MCP) joints is also consistent with OA. The nodal type of OA is characterized by the presence of Heberden's and Bouchard's nodes, which are bony enlargements of the DIP and PIP joints, respectively.
**Why Each Wrong Option is Incorrect**
**Option A:** Rheumatoid arthritis (RA) typically affects the MCP joints and wrists, and is characterized by symmetrical joint involvement, which is not seen in this patient.
**Option B:** Psoriatic arthritis (PsA) can affect any joint, but typically presents with joint pain and stiffness, as well as skin and nail changes, which are not mentioned in this patient.
**Option C:** Gout typically presents with acute, episodic joint pain and swelling, particularly affecting the base of the big toe, which is not seen in this patient.
**Clinical Pearl / High-Yield Fact**
Heberden's nodes (bony enlargements of the DIP joints) and Bouchard's nodes (bony enlargements of the PIP joints) are characteristic of osteoarthritis, particularly the nodal type.
**Correct Answer:** . Osteoarthritis