Deeper and darker groin fold with ilio-psoas abscess

Any swelling near the inguinal ligament area requires the exclusion of common disorders such as hernia and hydrocele. Groin swelling clinically visible at both above and below the inguinal ligament area usually results from ilio-psoas muscles disorder and may occasionally show cross-fluctuation on either side of the ligament [1]. Increased pus collection leads to a tense swelling beneath the inguinal ligament which then appears like a tightrope tied over a bulging mass. Apparent deepening and dark discoloration of the area, though not widely reported, may be associated features in selective cases.

A 10-year-old male child was brought to us following treatment at multiple places for his difficulty bearing weight on his left lower limb which rendered him non-ambulatory for the last 2 weeks. The insidious inset of mild hip region pain at the initial days was neglected and only consulted when hip pain increased along with restriction of movement. For the last 5 days, the hip has increasingly being held in flexed posture. There was a history of on-and-off fever and nocturnal increased pain. Fever and loss of appetite were not pronounced. On clinical examination, there was mild flexion of the left hip with restriction of extension along with increased lumbar lordosis. There was visible swelling near the inguinal ligament area compared to the opposite side. Raised localised temperature and tenderness were noted over the groin lump with intact distal neurovascular status. The swelling was not well defined and cross fluctuation was not possible probably due to tense mass. The inguinal area, however, appeared deeper with dark discoloration (Figure 1).

Figure 1.

The clinical image of the left groin showing swelling with the apparent deep and darker area over the inguinal ligament (a) which is outstanding when compared to the opposite normal side (b).

The radiograph showed abnormal pelvic obliquity and hip joint flexion corresponding to clinical attitude (Figure 2).

Figure 2.

The lower limb attitude with hip flexion deformity and external rotation of limb (a) which corresponds to radiographic appearance of flexed and externally rotated femur (b).

Magnetic resonance imaging (MRI) of the pelvis showed the presence of severe diffuse ilio-psoas abscess along with adjoining hip, medial thigh involvement (Figure 3a and b) and inguinal lymph node enlargement (Figure 3c).

Figure 3.

Coronal T-2 weighted MRI showing diffusely hyperintense involvement of ilio-psoas muscle and up to the upper thigh across the inguinal ligament (a). The iliacus muscle is involved (shown by star) along with psoas muscle with hip joint sparing (b). The associated enlargement of inguinal lymph nodes (indicated by arrow) also noted (c).

The blood tests showed leukocytosis with increased neutrophils and raised C-reactive protein and erythrocyte sedimentation rate. The aspiration of about 250 ml of purulent material was done which revealed Staphylococcus aureus susceptible to cephlosporins. The antibiotic treatment, skin traction and symptomatic management resulted in gradual clinical recovery in 2 weeks.

Psoas muscle begins from the lateral border of T12 and L1 vertebrae and courses down behind the inguinal ligament, in front of hip and ends in a tendon attached to the lesser trochanter and is contributed by iliacus muscle so is also called ilio-psoas muscle [2]. Ilio-psoas abscess may present itself in the groin, medial hip region, upper thigh and rarely up to the knee. The clinical features of inflammation are more marked in primary psoas abscess which is usually caused by S. aureus whereas the secondary type is usually related to abdominal, spinal or genitourinary tuberculosis [3]. Lesions like abdomino-scrotal hydrocele with intra-abdominal component communicating with inguino-scrotal component may rarely present with similar features [4]. Careful clinical and radiological assessment is critical to diagnose iliopsaos abscess for good outcome. Clinical examination for inguinal region disparity may be a quick key to suspecting underlying sinister pathology.

CONFLICTS OF INTEREST

The authors declare no conflict of interest.

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ETHICAL APPROVAL

Signed informed consent for participation and publication of medical details was obtained from the parents of this child. Confidentiality of patient’s data was ensured at all stages of manuscript preparation. Ethics clearance and approval of publication were granted by our institute.