Psoas abscess - Symptoms, Causes, Diagnosis, Treatment

Psoas abscess is the purulent collection rarely in the iliopsoas compartment. The iliopsoas is the anatomical peritoneal cavity. This cavity consists of 3 main parts these are psoas major, psoas minor and iliacus muscles. Abscess may spread via lymphatic system or may be hematogenous primarily and may occur due to any nearby infection secondarily. There are 30% cases are reported regarding psoas abscess. Primary psoas abscess most commonly occurs in neonates due to staphylococcus aureus species. Secondary psoas abscess most commonly occurs in adults due to a disease named diverticulitis. The morbidity and mortality rate is high in this condition.

Psoas abscess Causes       

Psoas abscess is classified into two main classes

• Primary psoas abscess.
• Secondary psoas abscess.

Primary psoas abscess frequently occurs in neonates. Most common cause is staphylococcus aureus species. But may also caused by streptococci species, gram negative enteric bacteria and mycobacterium tuberculum.

Secondary psoas abscess occurs in adults and is secondary to any infection in nearby area. Secondary psoas abscess may spread from vertebral osteomyelitis, inflammatory bowel disease and pyelonephritis. 88% cases of primary psoas abscess due to staphylococcus aureus species lead to secondary psoas abscess formation.

Psoas abscess Symptoms       

The main symptom associated with psoas abscess is lower back pain in vertebrae. Pain is acute but have high morbidity and mortality rate. Symptoms associated are mostly nonspecific as the patient may feel fever, abdominal pain and flank. Pain may radiate to the hip and thigh region. Inflammation in abdomen is very rare but sometimes it may occur. Some other symptoms are also seen with psoas abscess i.e. nausea, vomiting, loss of appetite, weight loss, limp and groin lump. Flank in abdomen and limp is also rare. More than 50% of patients are reported with pain.

Psoas abscess Diagnosis           

• Psoas abscess can be diagnosed from three main techniques named computer tomography CT scan, magnetic resonance imaging MRI and ultrasound.
•  Abdominal CT scan can diagnose psoas abscess in the abdominal area and after this there is no need to diagnose from any other technique.
• MRI is considered more sensitive against psoas abscess as compare to CT scan. It is a gold standard procedure. MRI can diagnose other nearby abscess also.
• Ultrasound and other radiographic techniques are not considered useful in front of above mentioned two techniques. The laboratory findings include CRP, UEC, blood cultures and FBC.

Psoas abscess Treatment

In most of the cases, drainage of purulent matter is required via surgery. Surgery may be limited i.e. percutaneous or open. Surgery is performed with continuous supply of antibiotic via IV route. Survival rate with surgery is 16 to 20 %. Percutaneous drainage is more reliable and is treatment of choice. Patient have to stay for short time period in hospital after percutaneous drainage. Percutaneous drainage is suitable for patients who do not tolerate general anesthesia. Open surgical drainage is done when the psoas abscess is more complex, large and involve the surroundings.