From the Research
The next test to order for this 21-year-old man with Type 1 Diabetes Mellitus would be a throat culture for Group A Streptococcus (GAS). This patient's presentation strongly suggests erythema nodosum secondary to streptococcal pharyngitis, which is particularly concerning in a patient with recent diabetic ketoacidosis. A rapid strep test could be performed initially, but a formal throat culture remains the gold standard for diagnosis, as stated in 1. Blood cultures should also be considered to rule out bacteremia. Additional helpful tests include a complete blood count to assess for leukocytosis and elevated inflammatory markers (ESR and CRP). The erythematous nodules on the lower legs are characteristic of erythema nodosum, which can be a reactive process to streptococcal infection. This is particularly important to diagnose promptly in patients with T1DM as infections can trigger metabolic decompensation and recurrent DKA. Early identification and treatment of streptococcal pharyngitis with appropriate antibiotics (typically penicillin or amoxicillin for 10 days, or macrolides if penicillin-allergic) can prevent complications and help maintain glycemic control in this vulnerable patient. According to 2, penicillin is the treatment of choice due to its cost, narrow spectrum of activity, and effectiveness.
Some key points to consider in the diagnosis and management of this patient include:
- The use of clinical scoring systems, such as the modified Centor score, to help decide which patients need testing or empiric antibiotic therapy, as mentioned in 2.
- The importance of differentiating between bacterial and non-bacterial causes of pharyngitis to ensure adequate use of antibiotics, as discussed in 3.
- The potential role of near-patient measurement of C-reactive protein (CRP) in improving diagnostic accuracy, as described in 3.
- The need for prompt diagnosis and treatment to prevent complications, such as recurrent DKA, and to maintain glycemic control in patients with T1DM.
Overall, the diagnosis and management of streptococcal pharyngitis in this patient require careful consideration of the clinical presentation, laboratory results, and treatment options to ensure the best possible outcome.