Differential Diagnosis for Acute Inflammatory Arthritis
Single Most Likely Diagnosis
- Septic Arthritis: This is often considered the most likely diagnosis in cases of acute inflammatory arthritis, especially if the onset is sudden and the patient presents with significant pain, swelling, and decreased range of motion in a single joint. The risk of joint destruction and systemic infection makes prompt diagnosis and treatment critical.
Other Likely Diagnoses
- Trauma: Traumatic injury can lead to acute inflammatory arthritis, especially if the trauma results in a fracture or significant soft tissue injury within the joint. The history of trauma and the presence of other injuries can help differentiate this from other causes.
- Hemarthrosis: Bleeding into the joint space can cause acute inflammatory arthritis, often seen in patients with bleeding disorders or those on anticoagulant therapy. A history of easy bruising or bleeding, and the presence of blood in the joint aspirate, can support this diagnosis.
- Reactive Arthritis: This form of arthritis occurs as a reaction to an infection elsewhere in the body, typically after a gastrointestinal or genitourinary infection. It is often characterized by the presence of other symptoms such as conjunctivitis, urethritis, and skin lesions, in addition to arthritis.
Do Not Miss Diagnoses
- Gonococcal Arthritis: A form of septic arthritis caused by Neisseria gonorrhoeae, which can present with dermatitis and tenosynovitis in addition to arthritis. It is crucial to consider this diagnosis, especially in sexually active young adults, due to its potential for severe consequences if not treated promptly.
- Lyme Arthritis: Caused by Borrelia burgdorferi, this condition can present with arthritis, particularly of the knee, following a tick bite. Early recognition is important to prevent long-term joint damage and other systemic complications.
- Crystal Arthropathies (Gout or Pseudogout): While not infectious, these conditions can mimic septic arthritis in their acute presentation and require urgent treatment to alleviate pain and prevent joint damage.
Rare Diagnoses
- Rheumatoid Arthritis (RA) with Acute Onset: Although RA typically has a more insidious onset, some patients may experience an acute onset of symptoms, which can be confused with other forms of acute inflammatory arthritis. The presence of autoantibodies and symmetric joint involvement can help differentiate RA.
- Seronegative Spondyloarthropathies: Conditions like ankylosing spondylitis, psoriatic arthritis, and enteropathic arthritis can have an acute onset of arthritis but are generally distinguished by their association with other systemic symptoms, family history, and specific clinical findings.
- Acute Rheumatic Fever: Although rare in developed countries, this condition can follow a streptococcal infection and presents with migratory polyarthritis, among other symptoms. It is crucial to recognize and treat to prevent cardiac complications.