Case Study: Patient Presenting With Long-Term Right-Sided Lower Abdominal Pain

Psoas syndrome is characterized by inflammation or irritation of the psoas muscle and/or tendon.
Psoas syndrome is characterized by inflammation or irritation of the psoas muscle and/or tendon.

A 19-year-old female with no past medical history presents with right-sided lower abdominal pain for 2 years. One year ago, the patient was worked up and found to have a case of appendicitis. Subsequently, she underwent an appendectomy. Her pain persisted after the appendectomy, and 3 months later, she underwent a diagnostic laparoscopy in search of endometriosis. As the patient still complained of pain, she was referred to my office for an evaluation by her gynecologist. The patient has had a full gynecological and gastrointestinal work up, which did not reveal any etiology for her symptoms.

The patient reported an exacerbation of pain with movement, and relief with rest. Of note, for 1 week after both appendectomy and laparoscopy, she reported resolution of her symptoms, which subsequently returned to her baseline pain levels of 8 out of 10 on the visual analog scale. The patient has tried anti-inflammatories, muscle relaxants, opiate medications, but non of these medications provided any relief.

Today, she presents with her mother for evaluation:

Upon questioning, the pain is not related to any changes in urination or defecation, however there is a slight increase in pain upon straining.

MRI of her abdomen was unremarkable.

The patient denies drinking, smoking, drug abuse and is not sexually active. On exam, she has a right-sided lower quadrant abdominal tenderness on deep palpation, but has no guarding and is not distended.

Sensory and motor exams are normal, however, the patient does have pain upon raising her right leg against gravity. Straight leg raise is normal, and so are her reflexes. When palpating her lower back, she mentions that her pain occasionally radiates to the mid-lumbar region as well as anterior thigh.

-Upon hearing this what is your differential diagnosis?

-What other maneuvers or features would you look for on physical exam?

-Would you consider any other imaging?

-How would you treat this suspected diagnosis?

-Is there a connection between the case of appendicitis and your working diagnosis?


With the added information of a back and leg component, the differential diagnosis changes somewhat. A purely abdominal component would lead me down the pathway of differentiating somatic vs visceral pain, and maneuvers that may stress the abdominal musculature should be performed to look for tenderness or strain of the obliques or recti abdominis muscles, etc. This may cause a worsening of symptoms, or in the case of a visceral component, one should inquire about a linkage to visceral activities such as defecation, sex or urination.

Pain upon raising her leg makes me suspect a pelvic pathology such as hernia, hip problem, muscle spasm, or nerve entrapment.
MRI of the pelvis and lumbar spine may be considered to further elucidate whether or not there is an impingement, arthritis of the hip, hernia, or other pathology.

I would examine her hip carefully to rule out arthritis, and perform maneuvers to stress the joint, or look for nerve defects.

Upon passive stretching of her hip in extension and asking her to flex her hip against resistance, her pain was once again elicited.

The hip joint was otherwise quite mobile and did not provoke any other symptoms.

After the initial evaluation, the patient was diagnosed with psoas syndrome. With that, patient immediately said that having had a diagnosis after 2 years of not understanding why she was suffering, contributed to reducing her anxiety and frustration with her illness. The patient was given tizanidine and a prescription for physical therapy. At one-month follow-up, the patient reported near resolution of her symptoms.

Discussion

Psoas syndrome is characterized by inflammation or irritation of the psoas muscle and/or tendon. During her 2 surgeries the patient was given neuromuscular blocking agents, which relax her muscles. This suggests a muscle component and may explain why her pain improved for 1 week post operatively.    

The Psoas syndrome will typically present as a lower back abdominal/pelvic pain, and may radiate to the leg as the branches of the lumbar plexus pass through the muscle. Pain may worsen by hip flexion, passively or against resistance, as well as during extension of the hip joint. The psoas muscle is deep to the appendix, and therefore may be irritated with appendicitis. It also may present as a deep abdominal pain. As the muscle inserts on the transverse process of T12-L5 and the lateral aspects of the discs between them, the patient may also have back pain.

Treatment includes physical therapy, muscle relaxants, anti-inflammatories, and rest. If the pain does not improve, a poses muscle trigger point or a tendon injection may alleviate symptoms.

Dr Rosenblum is the director of pain management at Maimonides Medical Center. 

Gain free access to pain management board review and practice management content: Pysicians, visit PainExam.com; Registered Nurses, visit PainExamRN.com.

 

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