Differential Diagnosis
The clinical presentation of an adolescent girl with mechanical pain in the back, hips, and fingers, associated with morning stiffness and chilblains of both fingers and toes, along with positive Anti-Ro52 and high serum ACE, suggests an autoimmune or inflammatory condition. Here's a categorized differential diagnosis:
Single most likely diagnosis
- Juvenile Dermatomyositis (JDM): The presence of morning stiffness, mechanical pain, and chilblains, combined with positive Anti-Ro52, points towards an autoimmune myopathy like JDM. High serum ACE can also be seen in some autoimmune conditions, although it's more commonly associated with sarcoidosis.
Other Likely diagnoses
- Mixed Connective Tissue Disease (MCTD): This condition often presents with overlapping features of lupus, scleroderma, and rheumatoid arthritis, and can include positive Anti-Ro52 antibodies. The clinical presentation of mechanical pain and morning stiffness could fit within the spectrum of MCTD.
- Sarcoidosis: Although less common in adolescents, sarcoidosis can present with joint pain, skin manifestations (like chilblains), and elevated serum ACE levels. However, the presence of Anti-Ro52 antibodies is not typical for sarcoidosis.
- Juvenile Idiopathic Arthritis (JIA): Certain subtypes of JIA, especially those with systemic or polyarticular involvement, could present with similar symptoms. However, the specific combination of positive Anti-Ro52 and high serum ACE is less characteristic.
Do Not Miss diagnoses
- Lupus: Systemic Lupus Erythematosus (SLE) can present with a wide range of symptoms, including joint pain, skin rashes, and autoimmune antibodies. Although Anti-Ro52 is more commonly associated with Sjögren's syndrome or MCTD, it can also be positive in lupus. Missing a diagnosis of lupus could lead to significant morbidity if not promptly treated.
- Scleroderma: This condition can cause skin thickening, joint pain, and esophageal dysmotility. While less common in adolescents, it's crucial not to miss due to its potential for severe organ involvement.
Rare diagnoses
- Relapsing Polychondritis: This rare autoimmune condition affects cartilage and can present with joint pain, among other symptoms. However, it would be an unusual diagnosis in an adolescent without other specific findings like cartilage inflammation.
- Ehlers-Danlos Syndrome: Some types of Ehlers-Danlos Syndrome can present with joint hypermobility and skin manifestations, but the presence of specific autoimmune antibodies and high serum ACE would be unusual in this context.