What is the management approach for a patient with an adrenal mass and a psoas abscess?

Management of Adrenal Mass with Psoas Abscess

The psoas abscess requires immediate treatment with CT-guided percutaneous drainage (for abscesses >2 cm) or antibiotics alone (for smaller abscesses <2 cm), while the adrenal mass management is determined by its imaging characteristics and hormonal status—but critically, you must first exclude pheochromocytoma before any invasive procedure to prevent hypertensive crisis. 1, 2

Immediate Priority: Rule Out Pheochromocytoma

• Before any drainage procedure or biopsy of either the psoas abscess or adrenal mass, you must obtain plasma free metanephrines or 24-hour urinary fractionated metanephrines to exclude pheochromocytoma. 3, 4
• Failure to exclude pheochromocytoma before invasive procedures can precipitate life-threatening hypertensive crisis during drainage or surgery. 3, 4
• This is non-negotiable and takes precedence over drainage timing unless the patient is in septic shock requiring emergent intervention.

Concurrent Management Algorithm

Step 1: Psoas Abscess Treatment (Primary Focus for Mortality)

• For abscesses ≥6 cm: CT-guided percutaneous drainage plus broad-spectrum IV antibiotics is the first-line approach (90% success rate). 1
• For abscesses <2 cm: IV antibiotics alone are sufficient without drainage. 1
• Open surgical drainage is reserved only for failed percutaneous drainage or complicated recurrences (required in <10% of cases). 1
• The mortality rate for psoas abscess is approximately 3% with appropriate treatment, but can reach higher rates if septic shock develops. 1, 2
• Most common organisms are Staphylococcus species in primary abscesses; secondary abscesses (from adjacent pathology) have polymicrobial flora. 2, 5

Step 2: Adrenal Mass Characterization (Parallel Workup)

• Obtain unenhanced CT to measure Hounsfield units (HU) if not already done—this determines if the adrenal mass is benign or requires further investigation. 6, 4
• Complete hormonal evaluation is mandatory for all adrenal masses regardless of appearance: 6, 4
  • 1 mg overnight dexamethasone suppression test (cortisol ≤50 nmol/L or ≤1.8 µg/dL excludes autonomous secretion) 6, 4
  • Plasma free or urinary fractionated metanephrines (to exclude pheochromocytoma—critical before any procedure) 6, 4
  • Aldosterone-to-renin ratio only if hypertension or hypokalemia present 6, 4

Step 3: Determine Adrenal Mass Management Based on Findings

If adrenal mass is benign-appearing (HU ≤10 and <4 cm):

• No immediate intervention required for the adrenal mass itself. 6, 4
• Proceed with psoas abscess treatment as outlined above. 1
• No follow-up imaging needed for the adrenal mass per some guidelines, though others recommend reimaging at 12 months. 7, 6

If adrenal mass is indeterminate or suspicious (HU >10 or ≥4 cm):

• Multidisciplinary discussion is recommended regarding timing of additional imaging versus immediate surgery. 7
• Options include repeat imaging in 3-12 months, second-line imaging (MRI or CT with washout), or immediate surgical resection. 7
• However, if the mass shows obvious malignancy features, surgical resection should be planned after the acute infection is controlled. 7

If adrenal mass is hormone-secreting:

• Surgical resection is indicated, but timing depends on infection control. 7, 4
• For pheochromocytoma: alpha-blockade must be initiated before any procedure, and surgery should be expedited after infection treatment. 4
• For aldosterone-secreting adenoma: adrenal vein sampling may be needed for lateralization, followed by laparoscopic adrenalectomy. 7

Critical Pitfalls to Avoid

• Never perform biopsy of the adrenal mass before excluding pheochromocytoma—this can cause fatal hypertensive crisis. 3, 4
• Do not delay psoas abscess drainage for extensive adrenal workup if the patient has sepsis or large abscess (>6 cm)—mortality from untreated infection supersedes adrenal concerns. 1, 2
• Be aware that psoas abscess can rarely be a metastatic presentation of adrenal malignancy rather than true infection—if imaging shows lytic bone lesions or the "abscess" doesn't respond to drainage, consider biopsy after excluding pheochromocytoma. 8
• Classic psoas sign (fever, flank pain, hip flexion limitation) is present in only a minority of cases—high clinical suspicion is essential. 2, 5

Sequencing Summary

1. Immediately obtain metanephrines to exclude pheochromocytoma 3, 4
2. Treat psoas abscess based on size (drainage if ≥6 cm, antibiotics if <2 cm) 1
3. Complete adrenal hormonal workup and imaging characterization in parallel 6, 4
4. Plan definitive adrenal management after infection control based on mass characteristics 7