Differential Diagnosis The patient presents with a range of symptoms including fever, joint and muscle pain, recent illness, skin rashes, and changes in urination, along with laboratory findings of elevated CRP, increased creatinine, and decreased eGFR. The differential diagnosis can be categorized as follows:
- Single Most Likely Diagnosis
- Chronic Kidney Disease (CKD) with Acute Exacerbation: The patient's elevated creatinine and decreased eGFR over time, along with symptoms such as foamy urine, swelling in legs/ankles/face, and changes in urination, suggest CKD. The recent increase in creatinine and decrease in eGFR may indicate an acute exacerbation, possibly due to an infection or other insult.
- Other Likely Diagnoses
- Systemic Lupus Erythematosus (SLE): The patient's symptoms of fever, joint and muscle pain, skin rashes, and recent illness, along with laboratory findings of elevated CRP, are consistent with SLE. The decreased eGFR and increased creatinine may indicate renal involvement.
- Rheumatoid Arthritis: The patient's symptoms of joint pain, muscle pain, and fever, along with laboratory findings of elevated CRP, are consistent with rheumatoid arthritis. The decreased eGFR and increased creatinine may indicate secondary renal involvement.
- Sepsis: The patient's symptoms of fever, recent illness, and elevated CRP, along with laboratory findings of increased creatinine and decreased eGFR, may indicate sepsis with acute kidney injury.
- Do Not Miss Diagnoses
- Vasculitis: The patient's symptoms of fever, joint and muscle pain, skin rashes, and recent illness, along with laboratory findings of elevated CRP, may indicate vasculitis. This diagnosis is critical to consider due to the potential for severe renal and systemic complications.
- Infectious Endocarditis: The patient's symptoms of fever, recent illness, and elevated CRP, along with laboratory findings of increased creatinine and decreased eGFR, may indicate infectious endocarditis with secondary renal involvement.
- Rare Diagnoses
- Goodpasture's Syndrome: The patient's symptoms of fever, joint and muscle pain, skin rashes, and recent illness, along with laboratory findings of elevated CRP, may indicate Goodpasture's syndrome. This rare autoimmune disease can cause renal and pulmonary manifestations.
- Sarcoidosis: The patient's symptoms of fever, joint and muscle pain, skin rashes, and recent illness, along with laboratory findings of elevated CRP, may indicate sarcoidosis. This rare disease can cause renal and systemic manifestations.