PSOAS ABSCESS. Dr Noman Ullah Wazir

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2 PSOAS ABSCESS Dr Noman Ullah Wazir

3 Psoas Major muscle The psoas major is a long fusiform muscle located on the side of the lumbar region of the vertebral column and brim of the lesser pelvis.

4 Psoas Major muscle Origin:- The psoas muscle arises from the transverse processes and the lateral aspects of the vertebral bodies of T12 - L5 vertebrae.

5 Psoas Major muscle Insertion:- courses downward across the pelvic brim, passes deep to the inguinal ligament and anterior to the hip joint capsule to form a tendon that inserts into the lesser trochanter of the femur.

6 Psoas Major muscle It joins the iliacus muscle to form the iliopsoas muscle and insert via the same tendon. The tendon is separated from the hip capsule by the iliopsoas bursa. Iliopsoas muscle is located in an extra peritoneal space called the iliopsoas compartment.

7 Psoas Major muscle Innervation:- Innervation of the psoas major is through lumber plexus via anterior rami of L1 to L3 nerves..

8 Psoas Major muscle Action:- As part of the iliopsoas, psoas major contributes to flexion in the hip joint.

9 Psoas Minor muscle The psoas minor is a long, slender muscle, only being present in about 27% of humans. is located anterior to the psoas major.

10 Psoas Abscess Psoas (or iliopsoas) abscess : Is a collection of pus in the iliopsoas muscle compartment. Pathogenesis : Psoas abscesses may be divided into primary and secondary abscesses according to the pathogenesis.

11 Primary psoas abscess It may arise by the hematogenous or lymphatic seeding from a distant site Most frequently due to infection with a single organism.

12 Primary psoas abscess In regions where Mycobacterium tuberculosis is endemic, this is a frequent cause of psoas abscess. The most common bacterial cause is Staphylococcus aureus, including methicillinresistant Staphylococcus aureus (MRSA).

13 Primary abscess Risk factors include : Diabetes Intravenous drug use Human immunodeficiency virus (HIV) infection Renal failure And other forms of immunosuppression.

14 Primary Psoas Abscess Primary psoas abscesses tend to occur in children and young adults. They are more common in tropical and developing countries. It may be difficult to distinguish between primary and secondary abscesses in some circumstances

15 Secondary Psoas abscess Secondary psoas abscess occurs as a result of direct spread of infection to the psoas muscle from an adjacent structure.

16 Secondary Psoas abscess Risk factors for secondary abscess include: Trauma And instrumentation in the inguinal region, lumbar spine, or hip region. Secondary psoas abscess may be monomicrobial or polymicrobial and frequently consist of enteric organisms (both aerobic and anaerobic bacteria

17 Clinical Manifestation Psoas abscesses are more common in males than females. The median age 44 to 58 years in developed countries.

18 Clinical Manifestation Psoas abscess occurs on the right and left sides with roughly equal frequency. Bilateral psoas abscesses are uncommon. In most cases the frequency of bilateral abscesses is 1 to 5 %

19 Signs and symptoms Signs and symptoms of psoas abscess include : Back or flank pain Fever Inguinal or back mass Limping Anorexia Weight loss

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21 Signs and symptoms Psoas abscesses occasionally extend distally and present as a painful or painless mass below the inguinal ligament. When an inguinal mass in a patient with a psoas abscess is painless (ie, a cold abscess), tuberculosis is a more likely cause than a bacterial infection The mass may rarely mimic inguinal lymphadenopathy or a femoral hernia

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23 Signs and symptoms Pain is exacerbated when performing movements in which the psoas muscle is stretched or extended The "psoas sign" is pain brought on by extension of the hip. Limitation of hip movement is common and patients frequently prefer to be in a position of less discomfort that includes hip flexion and lumbar lordosis.

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25 Laboratory tests Leukocytosis (>10,000/mL) is observed in up to 83 % of cases Anemia:- HB <11 g/l is frequent Thrombocytosis is observed less frequently. An elevated ESR may be observed (>50 in 73 % of cases) The C-reactive protein is often elevated Elevated aspartate aminotransferase has also been described

26 Complications Complications of psoas abscess include: Septic shock Deep venous thrombosis due to extrinsic compression of the iliac vein Paralytic bowel ileus Hydronephrosis due to ureteric compression

27 Differential diagnosis Retroperitoneal and intraperitoneal lesions including inflammation, hematoma, or tumor of the psoas muscle can mimic a psoas abscess Retrocecal appendicitis, Enlargement of the iliopsoas bursa Infection of adjacent structures not involving the psoas muscle (eg, septic hip arthritis)

28 DIAGNOSIS CT Scan MRI Ultra sound Culture Blood tests

29 Treatment Most cases require percutaneous (PCD) or open surgical drainage with parenteral antibiotic treatment. CT-guided PCD is the initial procedure of choice. PCD is associated with a shorter hospital stay. Suitable for patients intolerant of general anesthesia

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31 Open or Surgical drainage Open drainage indicated for large, complex, or multiloculated abscesses, significant involvement of adjacent structures or if PCD fails. Primary surgical intervention is more likely to be successful in patients with gas-forming abscess.

32 Surgical Drainage Psoas abscesses associated with inflammatory bowel disease, ruptured appendicitis, or infected aortic ruptures are effectively managed with open drainage and surgical treatment of the underlying disease

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