Differential Diagnosis

The patient presents with severe pain and swelling in his right ankle, low-grade fever, recurrent pedal edema, insomnia, and frequent voiding episodes. The following differential diagnoses are considered:

• Single most likely diagnosis
  • Gout: The patient's history of recurrent ankle pain and swelling, especially with the involvement of the big toe (podagra), is highly suggestive of gout. The presence of hyperuricemia (indicated by the urinalysis showing CHON +2) and the relief of symptoms with Diclofenac (an NSAID commonly used to treat gout) further support this diagnosis. The patient's kidney disease and hypertension may also be related to his gout.
• Other Likely diagnoses
  • Chronic Kidney Disease (CKD): The patient's elevated creatinine and BUN levels, along with the presence of parenchymal disease on the KUB ultrasound, suggest CKD. The patient's hypertension and hyperuricemia may be contributing factors to his kidney disease.
  • Hypertension: The patient's blood pressure is elevated, and he has a history of hypertension. Uncontrolled hypertension can lead to kidney disease, cardiovascular disease, and other complications.
  • Septic Arthritis: The patient's symptoms of severe pain, swelling, and erythema of the right ankle, along with a low-grade fever, could suggest septic arthritis. However, the absence of a clear history of trauma or infection makes this diagnosis less likely.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Infective Endocarditis: The patient's history of hypertension, kidney disease, and the presence of a heart murmur (not explicitly mentioned but possible given the cardiomegaly on chest X-ray) increase his risk for infective endocarditis. Although the patient does not have a clear history of valvular disease, the presence of fever, anemia, and kidney disease should prompt consideration of this diagnosis.
  • Cellulitis or Osteomyelitis: The patient's symptoms of swelling, erythema, and warmth of the right ankle could suggest cellulitis or osteomyelitis. These conditions can be serious and require prompt treatment.
• Rare diagnoses
  • Pseudogout (Calcium Pyrophosphate Deposition Disease): Although less common than gout, pseudogout can cause similar symptoms of joint pain and swelling. The patient's kidney disease and hyperparathyroidism (suggested by the elevated phosphate level) may increase his risk for pseudogout.
  • Amyloidosis: The patient's long-standing kidney disease, hypertension, and anemia could suggest amyloidosis. However, this diagnosis is rare and would require further evaluation, including a kidney biopsy.