Endometriosis as a Differential Diagnosis in a 17-Year-Old Patient with Low Back and Radicular Pain: A Case Report

Abstract

Endometriosis is a benign and often underdiagnosed condition that affects women of reproductive age, typically between 18 and 45 years. It can cause infertility and pain, including radicular pain and low back pain (LBP). The aim of this case report is to emphasize the importance of making a differential diagnosis when facing LBP and radicular symptoms. We report the case of a 17-year-old female patient, R.A., presented with a significant LBP (NPRS 8/10) radiating from her lumbar spine to her right buttock and occasionally to both legs, accompanied by weakness. She revealed exacerbation of pain during menstruation, despite being under hormonal contraceptive treatment. After three physiotherapy sessions that included education, manual therapy and exercise, the patient’s pain persisted so her physiotherapist recommended an evaluation in the emergency department, where standard radiography did not reveal any significant findings. Physiotherapy continued until the fifth session, when the patient agreed to undergo evaluation at a specialized endometriosis centre. Further investigations revealed endometriotic tissue on the uterosacral ligament, leading to hormonal therapy adjustment, with which pain gradually decreased to a manageable level (NPRS 2/10). This case report highlights the importance of an early differential diagnosis in patients with LBP, as endometriosis can present not only in older women but also in younger patients, including those already on oral contraceptives. Therefore, to mitigate the risk of pattern recognition bias, clinicians must maintain a high index of suspicion for endometriosis, even in atypical or unlikely clinical presentations.

1. Introduction

Endometriosis is a chronic, non-cancerous inflammatory condition that affects between 6% and 10% of women of reproductive-age worldwide [1]; it is characterized by the presence of functional endometrial-like tissue outside the uterus which retains the same functional and morphological characteristics as the endometrium and undergoes periodic revisions, explaining the cyclical nature of symptoms [2]. This tissue commonly implants in areas such as the ovaries, uterine ligaments, pelvic peritoneum, cervix, and vagina [3]. The exact cause of endometriosis remains unclear, with multiple factors and unknown pathophysiological mechanisms believed to contribute to its development [4]. Several theories, such as retrograde menstruation, coelomic metaplasia, and the theory of embryonic rests attempt to explain the origins of the disease [3], but none fully account for all aspects. Endometriotic cells exhibit a high survival potential and their activity outside the perineum is due to several key factors; this includes the expression of anti-apoptotic genes, immune evasion characterized by impaired natural killer (NK) cell activity [2], uncontrolled angiogenesis, and hormonal imbalances, particularly estrogen dominance and resistance to progesterone. In addition, inflammation plays a crucial role, with activated macrophages contributing to nerve sensitization and releasing elevated levels of cytokines associated with pain [1,2,5]. Another source of pain arises from the fact that ectopic endometrial tissue behaves like normal endometrium; therefore, during menstruation, this tissue also bleeds, but since the blood has no way of being expelled, it leads to pain [6].

Endometriosis primarily affects women of reproductive age, particularly those between 18 and 45 years old [7] and is observed in 50–80% of women experiencing pelvic pain [8]. However, endometriosis is often misdiagnosed due to a combination of factors, including normalization of symptoms, their nonspecific nature, limited awareness among clinicians, and the current lack of reliable non-invasive diagnostic tools [6]. It typically takes 7–10 years from the onset of symptoms for a proper diagnosis [4], which can have significant effects on affected women [9]; in fact, the condition is associated with a reduced quality of life, affecting social, psychological, and physical well-being [10], and can have a significant impact on work productivity, sports participation, and relationships [11,12]. Additionally, approximately 90% of women with endometriosis experience psychological issues, such as anxiety, depression, and catastrophizing, due to the chronic pain that limits daily activities [13,14].

The symptomatology of endometriosis is heterogeneous and nonspecific, presenting with cyclic pelvic pain (especially during menstruation), dysmenorrhea, dyspareunia, fatigue, cramping during menstruation, pain during intercourse, infertility, and low back pain (LBP) [3,11,15]. LBP, defined as “pain and discomfort, localized below the costal margin and above the inferior gluteal folds, with or without referred leg pain” [16], is one of the most prevalent conditions globally, with incidence increasing from 1990 to 2019 [17]. LBP is a major reason for seeking medical attention and has significant societal and economic implications due to work absenteeism and the cost of treatment [18]. LBP can be classified as acute (lasting up to 4 weeks) or chronic (lasting more than 3 months). Acute LBP may result from various sources, including muscles, facet joints, intervertebral discs, ligaments, fasciae, nerves, or non-musculoskeletal causes [19]. The literature reports only few cases of patients with LBP accompanied by referred pain in the lower limb [20] or isolated referred pain [21,22] associated with endometriosis, all of which emphasize the challenges in diagnosing these conditions. The association of endometriosis with LBP can be explained by the implant of endometrial tissue on the lumbosacral roots, plexus, or the proximal sciatic nerve [21]. The pain arises from the expression of nerve growth factor in nerves near deep endometriotic lesions, as well as the presence of pro-inflammatory cells, such as interleukins and histamine, which can stimulate sensory nerve endings. Additionally, endometrial lesions may exert pressure and result in inflammation on the nerve, resulting in both localized and radicular pain [22]. Diagnosing endometriosis from LBP can be very challenging, but this pathology must be considered every time there is a cyclical LBP whose cause is unknown. The absence of pathognomonic symptoms significantly contributes to delayed or missed diagnoses [5]. Moreover, the condition may remain clinically silent for prolonged periods, further complicating timely detection and management [5]. Beyond localized pelvic manifestations, endometriosis can lead to systemic effects, including diffuse inflammation and peripheral sensitization, which explain why women with endometriosis often experience pain even after the surgical removal of endometrial tissue [13,23]. Over time, altered nociceptive processing may lead to central sensitization, ultimately resulting in chronic pelvic pain, hyperalgesia, and allodynia [13,24]. Moreover, endometriosis has been associated with other pain syndromes, including fibromyalgia and irritable bowel syndrome, as well as autoimmune conditions such as asthma and Hashimoto’s thyroiditis, and mood disorders in both older women and adolescents [25]. Recent studies have categorized patients with endometriosis into distinct pain phenotypes: the high-pain phenotype, characterized by younger age, poorer quality of life, greater pain severity, and a higher prevalence of comorbidities, and the low-pain phenotype, associated with older age, lower pain levels, and a higher incidence of endometriomas [26].

Endometriosis is also prevalent in adolescents, with a significant impact on personal life and academic performance. The signs and symptoms in adolescents may differ from those in adults, leading to delays in diagnosis, which can take up to 23 months [27]. While it was once believed that endometriosis developed after menarche, it is now recognized that it can occur even prior to the first menstrual cycle [28]. Adolescents with endometriosis are at a higher risk for developing anxiety, depression, and concentration problems [25,29] and are more likely to develop other pain disorders [25,30]. Symptoms in young women typically include acyclic pelvic pain, low energy, abdominal pain, heavy menstrual bleeding, LBP, and other abdominal issues [29].

Diagnosis of endometriosis is based on personal history and symptoms of the patient, both in adolescents and in older women, in association with imaging techniques such as ultrasound or MRI, although negative results cannot rule out the disease. If imaging is inconclusive, laparoscopy, considered as the gold standard, is recommended for both diagnosis and treatment. The delay in diagnosis is also due to the lack of non-invasive methods for its detection. The use of biomarkers, such as blood or uterine fluids, is not currently recommended for diagnosing endometriosis. Diagnosis in adolescents is very challenging, as we can also see with other pathologies, such as polycystic ovary syndrome (PCOS), one of the most common endocrine disorders in women of reproductive age, in which diagnosis is so challenging due to the dynamic physiological and anatomical changes which occur in puberty. Therefore, it is also important to be mindful of the physiological particularities in adolescence which often mimic the symptoms of PCOS [31].

Treatment options include non-steroidal anti-inflammatory drugs (NSAIDs), other analgesics, combined hormonal therapies, and, when necessary, laparoscopy to remove endometriotic tissue, although it is associated with a high risk of relapse [32]; in fact, symptoms may recur in 0–89% of cases, and new endometriotic tissue may grow. Therefore, postoperative medical treatment is advised to minimize the growth of residual endometriotic cells [33].

2. Case Presentation

In this case report, we describe the clinical experience of a 17-year-old female patient who, in March 2024, accessed a private physiotherapy clinic through direct access. She was evaluated by an Orthopaedic Manipulative Physical Therapist (OMPT) due to intense and disabling LBP. An OMPT is a specialized physiotherapist in the “management of neuro-musculoskeletal conditions, based on clinical reasoning, using highly specific treatment approaches including manual techniques and therapeutic exercises” [34].

Written informed consent was obtained from the patient for the publication of this case report. This study was conducted in accordance with the Declaration of Helsinki.

3. Patient History

The patient, R.A., presented with severe and disabling LBP radiating from the lumbar spine to the right buttock and, occasionally, to both legs below the knees. She also reported generalized weakness and claudication. The symptoms had begun approximately one month prior to the physiotherapy evaluation and progressively worsened, with the development of additional knee pain after 20 days (Figure 1). The patient described her pain as very intense on the lumbar tract, 8/10 on the Numerical Pain Rating Scale (NPRS), in which 0 is equal to no pain while 10 is the worst imaginable pain [35], and leg pain was described with an NPRS of 6-7/10.

The patient led an active lifestyle; she attended school, she went regularly to the gym, and she went swimming twice or thrice a week for about 1.5 h, and she had also practiced volleyball a few years earlier; she had healthy eating habits and a regular diet. However, due to her condition, she was forced to suspend all physical and social activities. She became increasingly withdrawn and reported emotional distress and frustration due to the persistent pain, which also interfered with her ability to engage in sexual activity. During the initial evaluation, the patient reported a history of dysmenorrhea since menarche, which occurred at age 11, and dyspareunia since the onset of sexual activity. Both symptoms predated the onset of LBP, although she noted a significant worsening of the pain since then. There were no specific positions or activities that aggravated her symptoms. However, prolonged sitting, particularly at school, was associated with increased discomfort, while lying on either side provided some relief. She also experienced nocturnal pain, though she was able to sleep for a few hours. She had been continuously on a combined oral contraceptive (COC) for approximately one year, with a pill (Zoely) that contained nomegestrol acetate 2.5 mg (a progestin) and estradiol 1.5 mg (an estrogen), reporting occasional side effects such as spotting and water retention. NSAIDs had also been initiated following the onset of symptoms but provided only limited relief. Her medical history included a tibia and fibula fracture, multiple ankle and wrist sprains, and a cholecystectomy. The persistent pain and reduced functionality had a significant negative impact on her quality of life, and she expressed high levels of frustration and concern.

4. Physical Examination

At her initial physiotherapy assessment, the patient reported a pain level of 8/10 on the NPRS. She presented with mild trunk flexion and generalized stiffness. Neurological and neurodynamic assessments [36] were performed. The Straight Leg Raise (SLR) test reproduced lower limb symptoms without modifying lumbar or sacral pain. Reflexes, sensory testing, and strength assessments were unremarkable, although strength testing was limited due to pain severity. The repeated movements test [37,38] appeared to be negative for the absence of centralization. Muscular palpation did not modify symptom pattern. Due to high pain levels, further physical testing was initially deferred. At the second session, repeated movements remained negative. Both seated compression and distraction tests for lumbar provocation were performed, and both were negative. Springing tests were positive at L3–S1, with maximal tenderness over S1, which referred pain to the sacral region. To investigate the hypothesis of pelvic girdle pain (PGP), the Laslett cluster [39] was administered. The Thigh Thrust, Distraction, Compression, and Sacral Thrust tests were all positive, whereas the Gaenslen test was not performed. Palpation of the long dorsal sacroiliac ligament (LDL) [40] reproduced pain bilaterally. Trigger point (TrPs) palpation of the paravertebral and gluteal muscles did not affect symptoms.

The Oswestry Disability Index (ODI) [41] was administered to assess functional impairment. The ODI is a self-administered questionnaire made of 10 items that investigate disability associated with LBP in different daily activities; every item has a score that ranges from 0 to 5, and the sum of the scores is then expressed with a percentage: the higher the percentage, the greater the disability. The baseline ODI score was 64%, indicating severe disability.

5. Treatment

Since the first session of physiotherapy, education of the patient was performed [42]; it focused on pain management strategies, including antalgic postures and frequent position changes. Manual therapy (MT) techniques [42] were introduced, including rotational Maitland mobilizations, sacral mobilizations (counter-nutation of the sacrum on the ilium and anterior rotation of the ilium), soft tissue massage of the gluteal and paravertebral muscles, and neurodynamic mobilizations. A home exercise programme was prescribed, incorporating neurodynamic techniques and active mobilizations of the sacrum on the ilium. After the initial sessions, the patient reported temporary pain relief, with NPRS scores decreasing to NPRS 6/10 for the lumbar region and NPRS 5/10 for the lower limbs. However, by the third session, pain intensity increased to NPRS 9-10/10, prompting a referral to the emergency department.

The patient underwent a radiograph that did not show anything relevant, with exclusion of fractures and a mild disc height reduction at L1–L2 and L2–L3. NSAIDs were prescribed, providing only minimal relief. Physiotherapy treatments continued, but due to persistent high pain levels, the patient underwent MRI imaging on the recommendation of her mother. The MRI revealed annular fissuring at L4–L5 with a protrusion slightly contacting the dural sac.

Symptoms remained unchanged, with short-lasting relief from therapy. At the fifth session, the physiotherapist referred the patient to a specialized endometriosis center. The patient, after 3 months from the first evaluation, underwent a specialist consultation in a specialized centre for endometriosis in Padova (Italy). Further diagnostic evaluation using transvaginal ultrasound identified the presence of endometriotic lesions on the uterosacral ligament. Based on these findings, the patient’s hormonal therapy was adjusted to include a combined oral contraceptive containing ethinylestradiol 0.03 mg and dienogest 2 mg (Novadien). In accordance with current clinical guidelines, which support the initiation of hormonal treatment without the need for surgical confirmation in cases of suspected endometriosis in adolescents, laparoscopy was not performed. At this point, a repeat ODI showed a score of 62%.

With the new pharmacological therapy, the patient referred a progressive and constant reduction in pain in a very short period. A month after the therapy change, a new physiotherapy evaluation was made, in which the irradiated pain was completely resolved, while the lumbar pain was still present but with an NPRS 3/10. She continued active mobilization exercises and initiated lumbar strengthening [42] with the physiotherapist. Pain progressively diminished and became manageable. Four months after diagnosis and hormonal therapy adjustment, the patient reported NPRS 2/10 and ODI 44%, with fewer LBP episodes, and no menstrual exacerbations. At a final follow-up 6 months since diagnosis, her NPRS was 1/10 and ODI 14% (

Table 1. Outcome measures of pain (NPRS) and disability (ODI) in four follow-up moments.

	Baseline	After Diagnosis	4 Months Since Diagnosis	6 Months Since Diagnosis
NPRS	8	9	2	1
ODI	64%	62%	44%	14%

). During this session it was agreed with the patient to have follow-up calls throughout the following months to monitor symptoms.

6. Discussion

This case report emphasizes the critical role of differential diagnosis in cases where musculoskeletal symptoms do not respond to standard treatment; it highlights the value of clinical reasoning performed by the physiotherapist in identifying a pathology outside his area of competence, and it underlines that endometriosis can also show in very young women that already are under contraceptive therapy.

The present work points out that endometriosis can also show in very young women, challenging the previously held belief that it predominantly affects older women, a misconception often due to delayed diagnosis [28]. Early detection of endometriosis is crucial, particularly in adolescents, despite the diagnostic challenges. Endometriosis in adolescents with pelvic pain is very common [43], often presenting with varied and nonspecific symptoms, which contributes to its frequent under-recognition [27]. Prompt diagnosis is essential to prevent disease progression and reduce the risk of future infertility [44].

The research on this topic reveals a central aspect, specifically that endometriosis can mimic musculoskeletal disorders such as LBP and radicular pain, contributing to misdiagnosis. The disease is also associated with systemic inflammation and central sensitization, which promote chronic pain mechanisms such as allodynia and hyperalgesia [4,13,25,45]. Moreover, endometriosis has a documented psychosocial impact: patients frequently experience depression, anxiety, and pain catastrophizing, all of which reduce quality of life and negatively affect social relationships, work performance, and daily functioning [6,13].

Currently, the gold standard for the treatment of endometriosis is hormone therapy, as the condition is estrogen dependent. According to ESHRE guidelines, hormonal treatment can be started in young women when endometriosis is suspected, even prior to surgical confirmation [32]. This treatment has demonstrated excellent results in the reduction of symptoms, particularly pain, without influencing disease progression. Various types of hormone therapies are available and should be selected based on the individual characteristics of each patient. Continuous hormone therapy has been shown to be more effective than cyclic regimens [32]. Combined oral contraceptives are typically used as first-line therapy, as they help stabilize hormone levels and reduce prostaglandin production. Oral progestins are also used for long-term management due to their low incidence of side effects and their anti-inflammatory effect and consequent pain reduction. However, caution is advised when prescribing oral progestins to adolescents, as they may cause temporary reductions in bone density. Gonadotropin-releasing hormone (GnRH) are limited to short-term use because of significant side effects, including hot flashes and bone loss, particularly at higher doses [32,46]. When hormone therapy is unsuccessful, surgical intervention becomes necessary. Laparoscopy remains the gold standard for surgical management and is typically followed by hormone therapy to eliminate residual or microscopic endometrial tissue, thereby reducing the risk of recurrences [46].

A multidisciplinary approach is crucial, combining medical management, physiotherapy, and psychological support to improve outcomes and long-term well-being. Additional research is needed to develop diagnostic criteria that aid physiotherapists in identifying potential gynecological origins of lumbo-pelvic pain [47].

Although cases of endometriosis presenting with low back or radicular pain have been documented in adults [20,21,22,48,49,50], the literature describing similar presentations in adolescent patients remains extremely limited. In previously reported cases, patient age generally range from 25 to 45 years, and only in the work of Uppal et al. [20] was the patient already on contraceptives, as in this present case. Another noteworthy aspect of this case is that, through a multidisciplinary and iterative approach, the diagnosis was achieved without invasive procedures. Consistent with ESHRE guidelines, conservative treatment was employed as the first-line strategy and proved successful. These factors underscore the novelty and clinical relevance of this case, highlighting the importance of early recognition of endometriosis in young females who present with atypical symptoms.

7. Conclusions

This case report highlights the importance of adopting a comprehensive and multidisciplinary approach to patient assessment, emphasizing the need for a thorough review of the patient’s medical history and the application of accurate clinical reasoning. It is imperative not to limit the diagnostic process to musculoskeletal pathologies alone, but to actively perform a comprehensive differential diagnosis. In patients with LBP, the potential involvement of gynecological factors should be considered, even in adolescents in the early post-menarche stage, whose symptoms may be mistakenly attributed to normal pubertal changes. Continuous reassessment of therapeutic progress is essential to ensure that both diagnostic process and treatment strategies remain appropriate and effective. In cases involving endometriosis, it is essential to ensure timely diagnosis, appropriate hormonal management, and patient-centred care with a multidisciplinary approach that integrates the expertise of various healthcare professionals. Given the rarity of such presentations in adolescents, this report serves as a valuable example of how physiotherapists can contribute to the early recognition of non-musculoskeletal pathologies through clinical reasoning and timely referral, ultimately improving patient outcomes.