Inguinoscrotal pain resistant to conventional treatment.

Inguinoscrotal pain (ISP) is a common complaint that affects almost all age groups. The etiology may be vascular, neurogenic, visceral, muscular or psychological. Most causes of ISP are benign, but Pott's spine as a cause of ISP, when missed, may lead to serious outcomes.

INTRODUCTION

Inguinoscrotal pain (ISP) is a common complaint that affects almost all age groups. The etiology may be vascular, neurogenic, visceral, muscular or psychological. Local infectious causes are easier to diagnose and treatment. Non-infectious causes of ISP are usually difficult to diagnose and treat and patients may have to undergo orchidectomy because of unrelenting ISP. At times, even orchidectomy may not relieve symptoms, an entity popularly referred to as “Phantom pain.”[1] We present a case of ISP due to an uncommon etiology.

CASE REPORT

A 48-year-old male reported to the pain clinic at our institution with a history of chronic ISP. The pain was 8/10 on the visual analog scale (VAS). The patient had consulted a urologist, a neurologist, and rheumatologists with no relief of symptoms.

The patient was suffering from ISP for the last 3-4 years, the pain was nagging in character and was associated with a perception of swelling and heaviness in the inguinoscrotal region. There was restriction of forward bending along with mild pain. The pain in the inguinal region worsened when the patient tried to stand from a sitting position. He complained of morning stiffness in the back with gluteal pain that was suggestive of sacroilitis. He had a restricted and painful forward flexion. The only significant finding was paramedian tenderness in the upper lumbar region. There was no history of fever or any previous surgery. There was no tenderness in the inguinal or scrotal region. Ultrasonography of the testis did not reveal any abnormality. Abdominal hernial sites were normal. Erythrocyte sedimentation rate was persistently raised. Rheumatoid arthritis screening and HLA B27 were negative.

The clinical workup of the patient led to the provisional diagnosis of myofascial pain involving the psoas muscle. A trigger point injection of 8 mL of 0.25% lignocaine in 5% dextrose was performed under ultrasound guidance in the psoas muscle. The back pain was partially relieved along with complete relief in the inguinoscrotal pain. Pain relief lasted only for a few hours, correlating with the duration of action of the local anesthetic. After the trigger point injection, the patient reported gradual progressive worsening of the back pain so much that he had to take time off work.

On re-examining the patient after 15 days, tenderness was elicited in the upper lumbar region. A repeat MRI of the lumbosacral spine was advised which revealed Pott's spine at the L2-3 level with associated edema in the psoas muscle of the affected side [Figures 1 and 2]. The patient was started on antitubercular therapy (ATT) and was relieved of his symptoms in 4 weeks. The patient is still on ATT and is under our follow-up.

Figure 1

Magnetic resonance imaging of the lumbosacral spine showing Pott's spine at the L2-3 vertebrae

Figure 2

T1-weighted axial magnetic resonance imaging section showing contrast enhancement in the psoas major muscle of the left side

DISCUSSION

ISP may have a long list of causes. The somatic nerve supply of the inguinoscrotal region is from the ilioinguinal and genitofemoral nerves that arise from the L1-2 and L2-3 spinal levels, respectively. Any pathology at that spinal level such as trauma, tumor or infection can lead to referred pain in thisl region. The myofascial trigger point of the psoas muscle, due to its anatomical proximity to the ilioinguinal and genitofemoral nerves, can irritate them and pain due to irritation of the nerve can lead to referred to the inguinoscrotal region.

The possibility of myofascial trigger point in the psoas muscle was supported by the findings of clinical examination (deep-seated paramedian tenderness in the upper lumbar region). The myofascial pain syndrome theory was supported by the theoretical possibility of the scrotal pain being referred pain from the upper lumbar region.[2]

The MRI revealing a Pott's spine at the L2-3 level was a surprise finding, and presence of edema in the ipsilateral psoas muscle could explain the deep-seated tenderness in the upper lumbar region and also explained the pain worsening in standing from sitting position. The diagnosis of myofascial trigger points was the closest as far as the origin of pain was concerned, but it was still far from the actual etiology of the pain. This case highlights that pain in the inguinal region could be an indicator of pathology elsewhere and this referred pain should not be missed.

Rarer causes of groin pain may vary from ureteric colic, abdominal aortic aneurysm,[3] spinal nerve root involvement from arachnoiditis, facet joint arthropathy, intervertebral disc prolapsed[4] entrapment neuropathies of the ilioinguinal nerve and iliohypogastric nerves after appendectomy or pelvic laparotomy. Ostetis pubis,[5] hip joint arthropathy, adductor tendinitis and enthesopathy of the pubic attachment of the inguinal ligament can also present as groin pain. Pott's spine as a cause of groin pain, when missed, may lead to serious outcomes in the form of psoas abscess and epidural abscess leading to spinal cord compression resulting in paraplegia. A high index of suspicion on the part of the clinician is needed to diagnose Pott's spine as the cause of ISP. This presentation becomes even more important with increasing cases of impaired immunity due to acquired immunodeficiency syndrome or the use of immunosuppressant drugs being administered in organ transplant recipients.