Perinephric Abscess Clinical Presentation

Updated: Jan 16, 2020
  • Author: Edward David Kim, MD, FACS; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Because of nonspecific findings, in many cases, diagnosing a perinephric abscess can be difficult. Typically, patients present with a history of skin infection or urinary tract infection (UTI). Such infections may be followed in 1-2 weeks by fever and unilateral flank pain. However, this is an uncommon presentation. 

Onset of symptoms is often insidious, and 58% of patients have had symptoms for more than 14 days.

Presenting symptoms are often nonspecific. Only occasionally, a patient presents with a syndrome suggestive of acute pyelonephritis, with fever and abdominal and flank pain (usually unilateral). One distinguishing feature to note is that most patients with uncomplicated pyelonephritis are symptomatic for less than 5 days before hospitalization, whereas most patients with perinephric abscesses are symptomatic for more than 5 days.

The most common symptoms include fever (66-90%), flank or abdominal pain (40-50%), chills (40%), dysuria (40%), weight loss, lethargy, and gastrointestinal symptoms (25%). Pleuritic pain may occur due to diaphragmatic irritation. If the abscess is pressing on the adjacent nerves, referred pain may be felt in the groin, thighs, or knees.


Physical Examination

Physical findings include flank or costovertebral tenderness. When abdominal tenderness is present (60%), it may complicate the diagnosis. Patients may present with rigidity and fullness. A flank mass is palpable if the abscess is large or located in the inferior pole of the kidney space (9-47%). A renal malignancy must be ruled out in these patients with appropriate radiographic studies (eg, computed tomography, magnetic resonance imaging).

Splinting may be present, with resultant scoliosis. Patients may experience pain upon bending toward the contralateral side, upon active flexion of the ipsilateral thigh against resistance, and upon extension of the thigh while walking. Features that suggest the possible diagnosis of perinephric abscess include the following:

  • Unilateral flank pain and fever
  • No response to treatment for acute pyelonephritis
  • Pyrexia of unknown origin
  • Unexplained peritonitis, pelvic abscess, and empyema