Contrast mimicking a subarachnoid hemorrhage after lumbar percutaneous epidural neuroplasty: a case report
© Oh et al.; licensee BioMed Central Ltd. 2013
Received: 14 January 2013
Accepted: 15 February 2013
Published: 2 April 2013
Subarachnoid hemorrhage is one of the most feared acute neurologic events. Accurate diagnosis of subarachnoid hemorrhage is essential, and computed tomography of the brain is the first diagnostic imaging study. However, in rare circumstances, a similar appearance may occur in the absence of blood in the subarachnoid space. The contrast enhancement of subarachnoid space is a rare complication after lumbar percutaneous epidural neuroplasty, with, to the best of our knowledge, no previous report in the literature.
A 42-year-old Korean male patient, who underwent a spinal operation five years previously at the level of L4 to S1, visited our clinic with persistent and aggravating low back pain. An imaging study revealed the focal and diffuse disc protrusion at the level of L4/5 and L5/S1. The clinician decided to perform a lumbar percutaneous epidural neuroplasty. During the procedure, dural adhesion was suspected at the previously operated level, and the neuroplasty catheter was malpositioned into the intradural space on the first attempt. After the catheter was repositioned, the scheduled epidural neuroplasty was completed. Our patient had no definite abnormal neurological signs. But, after a day, our patient complained of severe headache with sustained high blood pressure without neurological disorientation. Computed tomography of his brain showed a subarachnoid hemorrhage-like appearance with intracranial air. Sequential angiography, subtractional magnetic resonance imaging and examination of the cerebrospinal fluid revealed no abnormalities. Follow-up computed tomography after one day revealed no definite intracranial hemorrhage, and our patient was discharged with improved low back pain without neurological deficit.
We report a rare case of contrast mimicking a subarachnoid hemorrhage after lumbar percutaneous epidural neuroplasty. The physician should keep in mind a rare case like this, and the supine position with head elevation is necessary to avoid a similar complication after lumbar percutaneous epidural neuroplasty.
Subarachnoid hemorrhage (SAH) is one of the most feared acute cerebrovascular events. Accurate diagnosis of SAH is essential because several diagnostic tests and therapies are indicated in the management of patients with SAH that are not routinely applied to patients with other acute neurologic events . Cranial computed tomography (CT) is one of the first diagnostic imaging studies performed in suspected SAH. Although CT is less sensitive than magnetic resonance imaging (MRI), its sensitivity for SAH detection has been reported to be as high as 95% to 98% in patients scanned within 24 hours of symptom onset, and it is considered the study of choice for identification of SAH . SAH appears on CT as hyperdensity in the subarachnoid space, a finding generally believed to be extremely specific . However, in rare circumstances, a similar appearance may occur in the absence of blood in the subarachnoid space, a finding that has been termed pseudo, mimicking, or false positive SAH [1, 3–8]. Contrast enhancement of subarachnoid space is a rare complication after lumbar percutaneous epidural neuroplasty (L-PEN). To the best of our knowledge, there have been no previous reports in the literature.
A SAH-like appearance in imaging has received only limited attention in the medical literature. In a previously reported case , the clinical presentation was compatible with spontaneous SAH and the CT images were interpreted as showing SAH with diffuse cerebral edema. The incidence of erroneous diagnoses of an apparent SAH has not been determined, but several radiographic mimics of SAH have been reported, including idiopathic intracranial hypertension, viral or pyogenic leptomeningitis, diffuse cerebral edema, pseudotumor cerebri, metabolic disorder, septic shock, CT appearance of intrathecally administered contrast material, and leakage of high-dose intravenous contrast medium into the subarachnoid spaces [3, 5, 7–10]. This above described situation has been alluded to, and increased density of the dura on CT mimicking a SAH has been reported in an autopsy study in patients who had increased intracranial pressure of non-SAH etiology . But, the contrast enhancement of the subarachnoid space after an L-PEN has not previously reported in the literature.
To understand the etiology of a SAH-like appearance after L-PEN, we here review the modified procedure of L-PEN . A specially designed RK® needle (RK® needle, Epimed International Inc.) was introduced into the sacral epidural space under fluoroscopy. Once the needle was confirmed to be in the epidural space, we carried out a lumbar epidurogram, using approximately 2 to 5mL of contrast. The filling defects were identified by examining the contrast flow into the nerve roots. Intravascular or subarachnoid placement of the needle or contrast was avoided; if such malpositioning occurred the needle was repositioned, as in this case (Figure 2). After appropriate determination of epidurography, a Racz® catheter (Racz® catheter, Epimed International Inc.), which is a spring guided reinforced catheter, was slowly passed through the needle to the area of the filling defect or the site of pathology determined by MRI, CT or patient symptoms. Following positioning of the catheter into the appropriate area, adhesiolysis was carried out by mechanical means and the injection of sodium chloride solution. Following completion of the injection, the catheter was taped using a bio-occlusive dressing, and the patient was turned to supine position and transferred to the recovery room. The catheter was flushed with normal saline and was removed and checked for intactness after a scheduled flushing for 1 or 2 days. The patient was ambulated if all parameters were satisfactory, intravenous access was removed and the patient was discharged home with appropriate instructions.
The contrast mimicking an SAH could have originated from the malposition of the neuroplasty catheter to the intradural space on the first attempt (Figure 2). The intracranial air that was shown in the brain CT scan with an SAH-like appearance could also have derived from the puncture of the dural sac (Figure 3). But, it is not well understood how the contrast in the lumbar subarachnoid space reached the intracranial cistern space. There is a considerable distance between the intracranial cistern and lumbar subarachnoid space, and the heavy contrast medium settles into lower lesions through gravity . Indeed, experimental results indicate that contrast media are normally eliminated directly from the lumbar subarachnoid space into the vascular circulation without significant accumulation in the intracranial cisterns [13, 14]. We believe that our patient’s position in the recovery room and his high blood pressure may have contributed to this rare complication after L-PEN.
During an L-PEN, the most important factor to prevent a similar complication is to avoid malpositioning the catheter, but it is always a risk. Therefore, we believe that the clinician should always be prepared for a similar complication, although it is not always as dangerous as in our case. An interesting study by Haughton et al. in 1982  compared cisternal cerebrospinal fluid concentration in Macaque monkeys undergoing metrizamide myelography in sitting and recumbent positions. Serum iodine concentrations were lower when animals were kept supine than when kept sitting, and observed cisternal iodine concentrations were higher in supine animals than in the sitting ones. These results may indicate how to prevent similar complications of L-PEN. The authors recommended that, in the recovery room, the patient should be placed in a supine position with the head elevated and adequate fluid hydration and blood pressure control. As the results from the study by Haughton et al. show, this position and management are helpful for reducing the contrast concentration in the cranial cisterns even though the contrast was administered to the lumbar subarachnoid space.
We have reported a rare case of imaging contrast mimicking a SAH after L-PEN. The physician should keep in mind a rare case like this, and placing the patient in a supine position with head elevation is necessary to avoid similar complications after L-PEN.
Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
Lumbar percutaneous epidural neuroplasty
Magnetic resonance imaging
- Cucchiara B, Sinson G, Kasner SE, Chalela JA: Pseudo-subarachnoid hemorrhage: report of three cases and review of the literature. Neurocrit Care. 2004, 1: 371-374. 10.1385/NCC:1:3:371.View ArticlePubMedGoogle Scholar
- Latchaw RE, Silva P, Falcone SF: The role of CT following aneurysmal rupture. Neuroimag Clin North Am. 1997, 7: 693-708.Google Scholar
- Al-Yamany M, Deck J, Bernstein M: Pseudo-subarachnoid hemorrhage: a rare neuroimaging pitfall. Can J Neuro Sci. 1999, 26: 57-59.Google Scholar
- Chute DJ, Smialek JE: Pseudo-subarachnoid hemorrhage of the head diagnosed by computerized axial tomography: a postmortem study of ten medical examiner cases. J Forensic Sci. 2002, 47: 360-365.View ArticlePubMedGoogle Scholar
- Given CA, Burdette JH, Elster AD, Williams DW: Pseudo-subarachnoid hemorrhage: a potential imaging pitfall associated with diffuse cerebral edema. Am J Neuroradiol. 2003, 24: 254-256.PubMedGoogle Scholar
- Rabinstein AA, Pittock SJ, Miller GM, Schindler JJ, Wijdicks EF: Pseudosubarachnoid haemorrhage in subdural haematoma. J Neurol Neurosurg Psychiatry. 2003, 74: 1131-1132. 10.1136/jnnp.74.8.1131.View ArticlePubMedPubMed CentralGoogle Scholar
- Mendelsohn DB, Moss ML, Chason DP, Muphree S, Casey S: Acute purulent leptomeningitis mimicking subarachnoid hemorrhage on CT. J Comput Assist Tomogr. 1994, 18: 126-128. 10.1097/00004728-199401000-00025.View ArticlePubMedGoogle Scholar
- Spiegel SM, Fox AJ, Vinuela F, Pelz DM: Increased density of tentorium and falx: a false positive CT sign of subarachnoid hemorrhage. Can Assoc Radiol J. 1986, 37: 243-247.PubMedGoogle Scholar
- Eckel T, Breiter SN, Lee HM: Subarachnoid contrast enhancement after spinal angiography mimicking diffuse subarachnoid hemorrhage. Am J Roentgenol. 1998, 170: 503-505. 10.2214/ajr.170.2.9456974.View ArticleGoogle Scholar
- Osborn AG, Anderson RE, Wing DS: The false falx sign. Radiology. 1980, 134: 421-425.View ArticlePubMedGoogle Scholar
- Manchikanti L, Rivera JJ, Pampati V, Damron KS, McManus CD, Brandon DE, Wilson SR: One day lumbar epidural adhesiolysis and hypertonic saline neurolysis in treatment of chronic low back pain: a randomized, double-blind trial. Pain Physician. 2004, 7: 177-186.PubMedGoogle Scholar
- Haughton VM, Eldevik OP, Lipman B: Excretion of contrast medium from the lumbar subarachnoid space of monkeys. Radiology. 1982, 142: 673-676.View ArticlePubMedGoogle Scholar
- Eldevik OP, Haughton VM, Sasse EA: Elimination of aqueous myelographic contrast media from the subarachnoid space. Invest Radiol. 1980, 15 (Suppl 6): S260-S263.View ArticlePubMedGoogle Scholar
- Eldevik OP, Haughton VM, Sasse EA, Ho KC: Excretion of aqueous myelographic contrast media in animals undergoing a repeat myelogram. Invest Radiol. 1980, 15: 507-510. 10.1097/00004424-198011000-00008.View ArticlePubMedGoogle Scholar
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