What Are the Symptoms of a Psoas Abscess?

A psoas abscess — a fairly rare condition where a pus-filled cavity forms in the psoas muscles that run from the lower back to the upper thigh — can cause several unpleasant symptoms. Patients with this condition may feel pain along their back, abdomen, or hip. They often develop a fever and may feel nauseated or generally ill, and may also feel the need to urinate often. If the abscess is located in the part of the muscle located in the groin or top of the thigh, the person may have trouble walking. It is important to note these symptoms are rather non-specific and can be associated with a variety of other issues, so it is important for a doctor to confirm the diagnosis with tests such as ultrasound or CT scans.

The presence of a psoas abscess typically causes a certain amount of pain in patients. This is due to the swelling and inflammation caused by the infected material in the abscess, and may range from mild to severe. Many patients experience the pain in their lower back, side, or abdomen, though it may also radiate down into the groin and thigh.

Another common symptom of a psoas abscess is fever. These abscesses form due to a bacterial infection, typically caused by staphylococcus, which can be a direct primary infection of the muscle or a secondary infection that spreads from elsewhere in the body. As the body tries to fight off the infection, the patient may develop a fever along with the associated chills, body aches, and general feelings of malaise. They may also feel nauseous or lose their appetites, which can cause them to lose weight.

Frequent urination may also be the result of a psoas abscess. This is often the case particularly when the formation of the abscess is due to secondary infection from an existing infection in the kidney or bladder. Some patients, however, may not have any issues with urination, so it is important for a doctor to review all other symptoms during diagnosis.

Some patients with a psoas abscess have difficulty walking if the abscess is near their hip or thigh. The swelling from the abscess may limit the range of motion in the hip, or the inflammation and pain may make movement uncomfortable. People with this problem typically favor the affected leg and walk with a modified gait or limp.