ACCIDENTAL dural puncture is the most frequent complication after performing an epidural technique. Its incidence ranges between 0.16–1.3% in experienced hands. Postdural puncture headache (PDPH) develops in 16–86%1,2of these cases, depending on the studied population. It is generally accepted that the continuous loss of cerebrospinal fluid (CSF) through the dural hole produced by the needle causes a decrease in the CSF pressure. For patients in the upright position this pressure decrease would traction the meningeal structures, nerves, and vessels, producing the painful symptoms. 3,4
Typically the PDPH manifests as postural frontal, frontotemporal, or occipital headache, worsened by ambulation, and improved by decubitus. The accompanying symptoms are usually nausea, vomiting, and neck stiffness. 2,4Atypical symptoms after accidental dural puncture have been sparsely described. The current authors present a case of severe upper back pain without headache after an accidental dural puncture, which required an epidural blood patch.
A 39-yr-old, 92 kg, 170 cm man presented to our pain clinic with severe lumbar pain accompanied by radicular symptoms. His medical history revealed previous opioid addiction, chronic hepatitis B and C, knee arthritis, dislipemia, and heavy smoking. His physical examination revealed an obese and anxious patient with acute lumbalgia (acute lumbar pain). Magnetic resonance imaging showed vertebral disk herniation at the L2–L3, L3–L4, and L4–L5 levels and sacralization of L5. Two epidural steroid injections were proposed and accepted as initial treatment. They were performed in an ambulatory setting. The epidural procedure was performed with an 18-gauge Tuohy needle, with loss of resistance to air technique, in the L3–L4 interspace. The drugs used were paramethasone 40 mg diluted in 4 ml bupivacaine, 0.25%. During the first epidural injection the patient had a vasovagal syncope that was treated with 1 mg intravenous atropine. In the second block an accidental dural puncture at L3–4 occurred. The steroid injection was eventually performed one space above. The patient was asked to remain supine for 2 h. Intravenous paracetamol 2,000 mg and 1,500 ml lactated Ringer's solution were given. The asymptomatic patient was discharged home with written instructions to contact the clinic in case of headache or other symptoms. Paracetamol 500 mg plus codeine 30 mg taken orally twice a day, and copious liquid intake was recommended.
Twenty-four hours later the patient complained of moderate upper back pain that was attributed to anxiety and muscle spasm. Forty-eight hours after the procedure light neck pain with stiffness developed, along with severe incapacitating upper back pain. The pain was described as severe, continuous, interscapular pressure without radiation. The patient reported no headache. Neurologic evaluation was normal. A PDPH syndrome was suspected because the symptoms increased when the patient was in the upright position. After orally taking 300 mg caffeine the patient developed great anxiety and insomnia, with a slight improvement in the intensity of the pain. The dorsal pain recurred, and 72 h after the procedure an epidural blood patch was proposed to the patient (additional caffeine was not accepted). Under sterile conditions an epidural blood patch was performed at L2–L3 with 20 ml blood injected through an 18-gauge Tuohy needle. After 15 ml of blood was injected the dorsal pain disappeared, and after 20 ml the neck pain had almost completely gone. The patient was totally asymptomatic 24 h later. The neck pain recurred throughout the next 2 months but paracetamol 500 mg taken orally was enough to control it. In a follow-up examination 4 months after the steroid injection, the patient had significant improvement of the lumbar radicular pain, and the upper back pain had disappeared.
Although somewhat controversial, the initial treatment of acute lumbalgia and radiculopathy with epidural steroids could be effective. 5
After an unintended dural puncture, PDPH should be expected and treated as such. 2Prevention with hydration, prophylactic epidural blood patch, caffeine infusions, or other therapies are preferred by some. 6The diagnosis is fairly easy when the headache presents typically. The decision to perform an epidural patch depends on the patient and the severity and duration of the headache. The effectiveness of the blood patch is about 91–100%. Conversely, the blood patch could have undesirable effects such as lumbar pain, neck pain, nerve root irritation, infection, and fever. 3,4Moreover, despite an uneventful epidural blood patch, PDPH could recur.
In the patient discussed herein, the atypical presentation of postdural puncture symptoms in the form of dural puncture-related dorsal thoracic pain delayed the correct diagnosis and treatment. The neck pain, the clinical features of the upper back pain, the slight improvement with caffeine, and the severity of the pain led us to recommend an epidural blood patch. The absence of headache and other related symptoms (dizziness, nausea, vomiting, nystagmus, tinnitus) contributed to the delay in diagnosis and treatment.
Differential diagnosis must be carried out before making the diagnosis of atypical postdural puncture event. Spinal abscess, septic or aseptic meningitis, spinal hematoma, arachnoiditis caused by intrathecal steroids, myofascial syndrome, transient neurologic syndrome or related symptoms, unspecific postdural puncture lumbalgia, neural toxicity of the drugs, and anterior spinal artery syndrome should be ruled out. 5,7,8The absence of fever, meningeal rigidity, or other meningeal features helped us with the diagnosis in this case. The relative short time it took for symptoms to develop meant that infection was unlikely. In addition, radicular symptoms improved in this patient despite the appearance of dorsal pain. However, additional tests such as magnetic resonance imaging could be performed in cases with atypical postdural puncture symptoms, to exclude the possibility of developing serious complications.
Few cases of atypical postdural puncture symptoms have been reported in the literature. Lybecker et al. 4classified the PDPH based on the intensity and characteristics of the cephalalgia, and cited the interscapular pain as “related musculoskeletal symptom,” however, no instances of upper back pain are cited among the 75 cases of PDPH reported by the authors. Neck stiffness is frequently reported (43%), always together with headache. McGrady and Freshwater 9reported a case of posterior neck pain (C2–4) without headache after spinal anesthesia. Very recently, Schabel et al. 10reported a case of arm pain with dysesthesia after an unintended dural puncture, and explained it as irritation of the C5 and C6 nerve roots caused by central traction. Two cases of postdural puncture thoracic pain were reported by Dunbar, 11one after an inadvertent lumbar puncture, another after a cervical puncture, both, as in the current scenario, for therapeutic steroid injection. All cases reported received a lumbar epidural blood patch that was always curative.
The pain sensation is probably transmitted via the V cranial nerve (n. trigeminus, pars frontalis) to the frontal and periorbital regions; through the IX and X cranial nerves (n. glossopharyngeal and n. vagus) to the occipital, and through the cervical nerve roots C2 and C3 to the neck and shoulders. Sometimes the III, IV, VI (diplopia), and VIII (tinnitus, hypacusia) cranial nerves are involved. 2,5
This case report and others suggest that the thoracic nerve root and meningeal traction could be involved in atypical cases of pain related to dural puncture, despite the fact that high thoracic nerve roots would be less anchored to the vertebral foramen, 10and theoretically less tractioned than the upper roots. An atypical thoracic, dorsal, or arm pain, appearing after an accidental or intended dural puncture, should be considered as a possible PDPH (provided other causes are excluded), and should be treated as such, including treatment with an epidural blood patch.
The authors thank Carlo D. Franco, M.D. (Department of Anesthesiology, Cook County Hospital, Chicago, IL) for critically reviewing the manuscript.