Ultrasound in diagnosis of nontraumatic lower extremity pain syndromes: A case report

Introduction. Musculoskeletal impairment is the most prevalent impairment in people over 65. The spine involvement is the most frequently reported. However, common regional pain syndromes usually arise from undefined mechanical, musculoskeletal or soft tissue disturbances. Use of imaging methods is becoming a mandatory tool in the clinical practice in order to achieve the prompt and accurate disease definition. Case report. The Caucasian 79-year-old-male patient attended with the history of an acute, piercing pain along the postero-medial side of the right Achilles tendon and the medial side of the right sole. According to the spine magnetic resonance imaging, X-rays and electrodiagnostic studies, diagnoses of the radicular, neurogenic pain and plantar fasciitis was suspected. However, the popliteal groove ultrasound assessment revealed the presence of hypertrophied semimembranosus-gastrocnemius bursa, compressing the popliteal neurovascular bundle. Conclusion. In patients with a symptomatology of peripheral neuropathy, use of imaging techniques such as ultrasound may be essential for accomplishing patients’ diagnostic approach.


Introduction
Degenerative spondylarthropathy includes a vast spectrum of symtomatology due to joints and their surrounding soft tissues involvement.Clinical course can last for many decades of profound disability and may be compatible with a variety of presentations.
Use of ultrasound (US) in the musculoskeletal system assessment has proved to be an accurate mean in the joint, ligament and synovial evaluation, so that calcifications, bone, tendon and ligament lesions may be assessed even when the X-ray exams are negative 1,2 .Improvement of the US equipment has established the US technique as an indispensable tool in the clinical management of degenerative and inflammatory musculoskeletal system diseases [3][4][5][6][7] .Lately, there has been a huge progress in the assessment and management of peripheral nerves [8][9][10][11][12][13][14][15] .
In this case presentation, the US evaluation will be decisive in the differential diagnosis and therefore in the following therapeutic choice.

Case report
The Caucasian 78-year-old male patient attended with a history of an acute, piercing, devastating pain along the posteromedial side of the right Achilles tendon, particularly of its distal-third, the ankle, heel and the medial half of the same side sole.The most painful point was localized around the tip of the medial malleolus.Pain aggravation was observed during the midnight hours.Patient also reported the prolonged whole-body morning stiffness (an hour) without body-weight loss, general weakness or pyrexia.
No swelling, bruising, skin breaks, palpable prominences or defects in the heel and mid-foot region, were detected.No tenderness at the points of peroneal and tibial tendons' insertions was noticed either.The Lasègue's sign, crossed Lasègue's sign, Bell, hyperextension and the Cough tests were negative [16][17][18] .Heel pain was increased when the plantar fascia was stretched by ankle and toes' passive dorsiflexion.The pronation (active or passive) was extremely limited and painful.The heel pain was accompanied by neuropathic symptoms such as a tingling, burning and numbness, so the tarsal tunnel assessment was performed (nerve percussion) and the Tinel's sign proved positive.
During the last two decades the patient has been suffering from the bilateral knee osteoarthritis.Varus alignment, tenderness, swelling, crepitus and limited range of motion were detected bilaterally.Enlarged Baker cysts were palpated in popliteal grooves.
Blood tests indicative of systemic inflammation (blood sedimentation rate and C-reactive protein) as well as the rest of biochemical markers were in the normal range.
Nerve conduction velocities and electromyography (EMG) indicated a radiculopathy due to pathological involvement of lower lumbar roots.Lumbosacral X-rays depicted severe, degenerative lumbar scoliosis.The scoliotic curve was associated with intervertebral osteochondrosis (vacuum phenomena, disc space narrowing) and large bone spurs at the vertebral epiphyseal edges and facet joints.Magnetic resonance imaging (MRI) scan showed multiple herniated discs.
Ankles and knee X-rays were performed and the both side calcaneal spur as well as a severe knee osteoarthritis (OA), grade 4 -according to Kellgren and Lawrence 19 were detected.
Musculoskeletal US examination of involved joints and periarticular soft tissues was conducted, by using a standardized scanning technique and international definitions of pathology 20,21 [Ultrasound Subcommittee of the European Society of Musculoskeletal Radiology 22 and the European League Against Rheumatism (EULAR) guidelines 20 ].A General Electric Logiq P6 Pro machine, equipped with a 10-13 MHz linear transducer was used, depth was adjusted depending on the joint size just at the point of interest, gain was set at the 55-65%; high power Doppler (PD) frequency was used (6.7 MHz), pulse-repetition frequency (PRF) was set to 500 Hz, gain was set just below the level at which colour noise appeared below the bone.Colour priority was maximised and the wall filter was decreased to minimum 60-80 Hz.
Posterior left knee scans revealed enlarge hypertrophied both-side Baker cyst (Figure 2).The right Baker cyst was compressing the popliteal neurovascular bundle (Figure 3).The compressed and dislocated tibial nerve appeared swollen and surrounded by an incomplete-anechoic hallo due to the presence of fluid between the nerve and its epineurium (Figures 4 and 5).
Medial longitudinal plantar scans revealed the large, both side calcaneal spur, accompanied by a respective plantar fasciitis (Figure 6).
laboratory tests were compatible with common inflammatory fluids (low viscosity, low white cell count/mm 3 and low percent of polymorphonuclear cells).No glucose, rheumatoid-factor or antinuclear-antibody was detected either.Betamethasone (10 mg) was injected within the bursal cavity and the symptoms resolved.While the similar signs and symptomatology reappeared 12 days later, the cyst aspiration was performed again.Four aspirations were necessary for the patient's full recovery.At patient's last visit, the right knee US evaluation revealed no fluid within the hypertrophied Baker cyst and the tibial nerve appeared normal.Ultimately, the patient was reported for the total right knee arthroplasty.

Discussion
Many different conditions can cause low-back and lower-extremity pain.While patients may have more than one disorder, it is necessary to undergo further testing to confirm or rule out these diagnoses.There is no gold standard for the diagnosis of degenerative spondylarthropathy and radiculopathy, so the combination of history, physical examination, imaging and EMG is used to obtain the diagnosis.The lack of the EMG sensitivity is its biggest limitation: though positive, the EMG is unable to ascertain the exact level of the involved root.
The peripheral nerve compression can occur acutely or chronically.In acute compression, the distal nerve portion retains normal function which tends to resolve after a decompression.Prolonged ischemia may cause significant damage of the myelin-sheath and/or axonal degeneration due to the intraneural microvascular supply and venous congestion that may produce endoneural edema.Increased fluid pressure in between the fascicles induces the microcompartment syndrome, producing the clinical image of the nerve impairment 23 .
Thus, taking into account the patient's symptoms, blood tests, MRI, EMG and X-rays findings, the patient had been assumed as a patient with a lumbal radiculopathy and heel spur symptomatology correlated with plantar fasciitis.However, the cause of his symptomatology was clarified by means of the US-imaging.
US seems to be powerful weapon for clinicians, more sensitive and accurate method comparatively to the clinical examination.It is also relatively cheap, bed-side, not timeconsuming and with no any radiation technique.The accuracy of the US-guided aspirations and local injections is also its great advantage [24][25][26][27][28][29] .
The US is an efficient, appropriate and quick technique for diagnostic and treatment purposes (aspirations, injections) 30,31 as well as for the patients' follow-up.Specifically, in patients with a symptomatology of peripheral neuropathy, use of imaging techniques such as ultrasound may be essential for patients' diagnostic accomplishment [8][9][10][11][12][13][14][15] .

Conclusion
In patients with a symptomatology of peripheral neuropathy, use of imaging techniques such as ultrasound may be essential for accomplishing patients' diagnostic approach.