Psoas Syndrome: Symptoms, Types, Causes and Treatment

Psoas syndrome is a frequently overlooked but important musculoskeletal and, in rare cases, oncological condition. It involves dysfunction or pathology of the iliopsoas muscle, a deep muscle responsible for flexing the hip and stabilizing the lower spine. Whether caused by overuse in athletes, chronic strain, infection, or even cancer, psoas syndrome can lead to a complex constellation of symptoms that often mimic other disorders. Understanding its symptoms, types, causes, and treatments is essential for effective diagnosis and management.

Symptoms of Psoas Syndrome

Recognizing the symptoms of psoas syndrome can be challenging, as they often overlap with other causes of back, hip, or pelvic pain. However, specific patterns of discomfort and movement limitation can point toward this diagnosis. Early identification is crucial for effective intervention and to prevent chronic pain or complications.

Symptom	Description	Associated Findings	Sources
Low back pain	Aching or sharp pain in the lumbar region	Worse with standing or walking	3 7
Groin pain	Discomfort radiating to the inner thigh	More common in athletes	3
Hip flexion pain	Pain with lifting the knee or hip movement	May cause limping	1 2 4 5
Buttock pain	Aching, may be on the opposite side	Can radiate down to the knee	3 7
Fixed hip flexion	Difficulty straightening the hip fully	Often seen in malignant cases	1 2 5 8
Gait changes	Limp or impaired walking	May be severe in advanced cases	8
Fever	Sometimes present with infectious causes	Common with psoas abscess	9

Table 1: Key Symptoms

Low Back and Groin Pain

• Low back pain is the most frequent complaint and may be either dull or sharp. It is often exacerbated by activities like standing, walking, or transitioning from sitting to standing 3 7.
• Groin pain commonly occurs due to the anatomical path of the psoas; it is especially prevalent among athletes who perform repetitive hip flexion, such as runners, jumpers, and dancers 3.

Hip Flexion and Gait Issues

• Pain is often aggravated by flexing the hip, making actions like climbing stairs or rising from a chair challenging. In severe cases—particularly malignant psoas syndrome—there may be a fixed flexion deformity, where the patient cannot fully extend the hip 1 2 5 8.
• Gait changes such as limping, or even being unable to walk, can develop when the syndrome is advanced or when associated with significant muscle or nerve involvement 8.

Referred Pain and Systemic Symptoms

• Buttock pain may radiate to the knee and is often on the side opposite to the affected psoas muscle 3 7.
• In infectious cases, such as a psoas abscess, fever and systemic illness may be present, typically accompanied by back pain 9.

Key Points

• Symptoms can be subtle or severe.
• Early recognition is vital to prevent chronic issues or complications.
• A high index of suspicion is needed, especially in athletes, cancer patients, or those with risk factors for infection.

Types of Psoas Syndrome

Psoas syndrome is not a single disease but a spectrum of disorders involving the iliopsoas muscle. Its types are defined by their underlying cause, clinical presentation, and severity—from benign muscular dysfunction to malignant involvement.

Type	Description	Distinguishing Features	Sources
Muscular (Classic)	Overuse or strain of the iliopsoas	Common in athletes, no mass or infection	3 7
Malignant	Tumor infiltration of the muscle or nerves	Cancer diagnosis, fixed flexion, neuropathy	1 2 4 5 6 8
Infectious (Abscess)	Infection within the psoas muscle (abscess)	Fever, systemic signs, imaging shows abscess	9

Table 2: Types of Psoas Syndrome

Muscular (Classic) Psoas Syndrome

• Etiology: Typically seen in athletes or those with repetitive hip flexion or poor posture 3.
• Presentation: Localized pain, often without systemic symptoms. Physical exam may reveal tenderness over the psoas and pain with resisted hip flexion.
• Prognosis: Generally good with conservative treatment 3 7.

Malignant Psoas Syndrome (MPS)

• Etiology: Due to direct cancer spread to the psoas muscle or adjacent nerves; most commonly from gynecological, gastrointestinal, urological, or soft tissue tumors 1 2 4 5 6 8.
• Presentation: Severe, often intractable pain; fixed hip flexion; neurological signs from lumbosacral plexus involvement; may be resistant to standard pain therapies 5 8.
• Special Features: May indicate advanced-stage malignancy and require multidisciplinary care.

Infectious Psoas Syndrome (Psoas Abscess)

• Etiology: Bacterial infection, most often caused by Staphylococcus aureus or Mycobacterium tuberculosis 9.
• Presentation: Fever, malaise, localized pain, and sometimes a palpable mass. Imaging (CT or MRI) confirms diagnosis.
• Management: Requires antibiotics and often drainage 9.

Key Points

• Types are defined by etiology: mechanical, malignant, or infectious.
• Each type has distinctive clinical features and implications for treatment.
• Accurate classification is critical for guiding therapy.

Causes of Psoas Syndrome

Understanding the diverse causes of psoas syndrome is crucial for selecting the most appropriate treatment. Causes range from benign musculoskeletal overuse to life-threatening infection or malignancy.

Cause	Mechanism	Typical Patient Population	Sources
Overuse/Strain	Repetitive hip flexion, poor posture, trauma	Athletes, active individuals	3 7
Tumor	Malignant infiltration of muscle/nerve	Cancer patients	1 2 4 5 6 8
Infection	Bacterial/viral spread to psoas muscle	Immunocompromised, TB endemic	9
Abscess	Localized pus collection in psoas	History of infection or IVDU	9
Anatomical	Structural abnormalities or postural imbalances	Varied; often chronic	3

Table 3: Causes of Psoas Syndrome

Overuse and Musculoskeletal Dysfunction

• Overuse and strain are the most common causes, particularly in athletes who perform repetitive hip movements. Poor core strength or posture can also contribute 3 7.
• Structural or anatomical issues such as leg length discrepancies or spinal abnormalities may predispose individuals to chronic psoas dysfunction 3.

Malignant Infiltration

• Cancer-related psoas syndrome (malignant psoas syndrome) occurs when tumors invade the psoas muscle or surrounding nerves. This is most commonly seen in advanced cancers of the pelvis, abdomen, or retroperitoneum—such as gynecological, urological, gastrointestinal, or sarcomatous malignancies 1 2 4 5 6 8.
• Mechanism: Tumor growth leads to inflammation, nerve compression or infiltration, and muscle spasm, resulting in severe, often neuropathic pain 5.

Infection and Abscess Formation

• Psoas abscess is a rare but serious cause. It results from direct infection of the muscle, either through bloodstream spread (hematogenous) or from adjacent structures (e.g., spine, bowel) 9.
• Risk Factors: Immunosuppression, diabetes, intravenous drug use, or tuberculosis. Tuberculous psoas abscess is more common in endemic regions 9.

Key Points

• The cause dictates both the clinical presentation and management approach.
• Always consider malignancy or infection in patients with severe, progressive, or systemic symptoms.
• Imaging is often required to identify the underlying cause.

Treatment of Psoas Syndrome

Effective management of psoas syndrome hinges on identifying the underlying cause. Treatment strategies range from conservative therapy for muscular cases to aggressive interventions for malignancy or infection.

Treatment	Approach	Indication	Sources
Activity modification	Rest, avoid aggravating movements	Muscular/overuse cases	3 7
Physical therapy	Stretching, strengthening, posture correction	Muscular/overuse cases	3 7
Manual therapy (OMT)	Muscle energy, counterstrain techniques	Muscular dysfunction	3 7
NSAIDs/Analgesics	Pain and inflammation control	Most cases	3 7
Opioids	Severe or refractory pain	Malignant cases	5 8
Antineuropathic agents	Gabapentin, antidepressants for neuropathic pain	Malignant cases	5
Muscle relaxants	Reduce muscle spasm	Malignant/neuropathic pain	5
Corticosteroid injections	Local anti-inflammatory effect	Persistent muscular pain	3
Methadone	Opioid with neuropathic pain relief	Malignant cases	8
Cancer therapy	Chemotherapy, radiotherapy, surgery	Malignant psoas syndrome	1 2 5 6
Antibiotics	Targeted antimicrobial therapy	Infectious causes	9
Drainage	Percutaneous or surgical drainage of abscesses	Psoas abscess	9
Surgery	Iliopsoas release, tumor resection	Refractory or severe cases	3 2

Table 4: Treatment Approaches

Conservative Management

• Activity modification and physical therapy are mainstays for non-malignant, non-infectious cases. Techniques focus on stretching the iliopsoas, strengthening core musculature, and correcting posture 3 7.
• Manual therapy, such as muscle energy technique (MET) and counterstrain (CS), can rapidly reduce pain and restore function 3.
• NSAIDs and analgesics help control pain and inflammation 3 7.

Advanced Pain Management

• Opioids and antineuropathic agents may be necessary for severe pain, especially in malignant psoas syndrome. Methadone, in particular, has shown efficacy in controlling both nociceptive and neuropathic pain and improving mobility 5 8.
• Muscle relaxants and corticosteroid injections can be helpful adjuncts 3 5.

Malignant Psoas Syndrome Interventions

• Cancer-directed therapies such as chemotherapy, radiotherapy, or surgical resection can provide symptom relief and sometimes improve quality of life 1 2 5 6.
• Palliative radiotherapy has shown benefits in controlling pain and improving function in select cases 1 2.

Infectious Psoas Syndrome Management

• Antibiotics tailored to the causative organism are essential.
• Drainage (percutaneous or surgical) is often required for abscesses, with minimally invasive retroperitoneoscopic approaches being safe and effective 9.

Surgical Options

• Iliopsoas release may be considered in refractory musculoskeletal cases unresponsive to conservative measures 3.
• Tumor resection is reserved for select malignant cases 2.

Key Points

• Treatment must be individualized based on the type and severity of psoas syndrome.
• Multidisciplinary management is often required for malignant or infectious cases.
• Early intervention improves outcomes and may prevent chronic disability.

Conclusion

Psoas syndrome is a multifaceted disorder with varied presentations depending on its underlying cause. Early recognition and precise diagnosis enable targeted treatment and improve patient outcomes. Here’s a summary of the main points:

• Symptoms: Range from low back, groin, and buttock pain to fixed hip flexion and gait disturbances; systemic features may indicate infection or malignancy.
• Types: Include classic musculoskeletal, malignant, and infectious (abscess) variants, each with distinct features.
• Causes: Vary from overuse and anatomical factors to cancer infiltration or infection—careful evaluation and imaging are critical.
• Treatment: Spans conservative management (rest, therapy, manual techniques), advanced pain control (including methadone), cancer therapy, antibiotics, and surgical intervention where appropriate.

Psoas syndrome may be easily missed, but a structured, evidence-based approach ensures effective management and better quality of life for affected individuals.