Differential Diagnosis

The patient's symptoms of fever, chills, right-sided costovertebral angle pain, tachycardia, and dysuria suggest a urinary tract infection (UTI) with possible involvement of the kidney. Here is a differential diagnosis for the patient:

• Single most likely diagnosis
  • Pyelonephritis: This is the most likely diagnosis given the patient's symptoms, particularly the costovertebral angle pain, which is a classic sign of pyelonephritis. The presence of fever, chills, and dysuria also supports this diagnosis.
• Other Likely diagnoses
  • Urinary tract infection (UTI) with cystitis: While the patient's symptoms suggest upper urinary tract involvement, a UTI limited to the bladder (cystitis) could also cause dysuria and fever.
  • Kidney stone with infection: A kidney stone could cause severe pain and, if infected, could lead to symptoms similar to pyelonephritis.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Sepsis: Any infection, including pyelonephritis, can lead to sepsis, a life-threatening condition that requires immediate attention.
  • Emphysematous pyelonephritis: This is a rare but serious complication of pyelonephritis, particularly in diabetic patients, where gas forms in the kidney tissue.
  • Perinephric abscess: An abscess formation around the kidney can occur as a complication of pyelonephritis and requires prompt drainage.
• Rare diagnoses
  • Renal infarction: Although rare, renal infarction could cause severe pain and might be considered in the differential diagnosis, especially if there are risk factors for thromboembolism.
  • Renal cell carcinoma with infection: A tumor in the kidney could become infected, leading to symptoms similar to pyelonephritis, although this would be less common.

Diagnostic Plan

• Imaging: A CT scan of the abdomen with contrast or an ultrasound to evaluate the kidneys and urinary tract for signs of infection, stones, or other abnormalities.
• Urinalysis: To confirm the presence of a UTI, including urine culture to guide antibiotic therapy.
• Blood tests: Complete blood count (CBC), blood culture, and serum creatinine to assess for signs of infection and renal function.

Pharmacological Plan

• Antibiotics: The patient should be started on broad-spectrum antibiotics that cover common urinary pathogens, such as fluoroquinolones (e.g., ciprofloxacin) or cephalosporins (e.g., ceftriaxone), pending urine culture results. Local resistance patterns should guide the choice.
• Pain management: Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or acetaminophen can be used for pain and fever reduction. In severe cases, opioids might be necessary, but their use should be carefully considered due to the risk of addiction.

Non-pharmacological Plan

• Hydration: Encourage the patient to drink plenty of fluids to help flush out the bacteria from the urinary tract.
• Rest: Advising the patient to get plenty of rest can help the body recover from the infection.
• Follow-up: Close follow-up with a healthcare provider to monitor the response to treatment and adjust the antibiotic regimen based on culture results.