Advances in Bioscience and Biotechnology, 2013, 4, 147-152 ABB Published Online January 2013 (
Recurrent intrathecal catheter-tip granuloma in a patient
receiving high dose hydromorphone: A case report*
Teena Varghese1, Joshua Bemporad2, Stefano Camici2, Steven Mortazavi1
1Valley Pain Specialists PC, Bethlehem, USA
2Lehigh Valley Hospital and Health Network, Allentown, USA
Received 15 November 2012; revised 24 December 2012; accepted 11 January 2013
Study Design: Case report. Patient Sample: A 42-
year-old Caucasian male. Results: Catheter-tip gra-
nuloma formation is possible despite a normal cathe-
ter access study in patients with intrathecal (IT) infu-
sion systems and its recurrence is possible after sur-
gical excision. Increasing concentrations of hydro-
morphone from 50 mg/ml to 100 mg/ml without alte-
ring the daily dosage may have precipitated granu-
loma formation. Conclusions: In patients with pre-
viously implanted spinal ca theters for i nt r athecal drug
delivery, catheter access studies cannot be relied upon
to rule out catheter-tip granulomas, which should be
included in the differential diagnosis in patients with
worsening clinical conditions or new onset neurologic
symptoms. Caution should be exercised when increa-
sing concentrations of intrathecal opioids while moni-
toring for signs or symptoms of intrathecal catheter-
tip granuloma formation. Removal of previously im-
planted catheters and/or reductions in opioid concen-
trations may be necessary to prevent recurrent gra-
nuloma formations, which can occur quickly after
surgical excision.
Keywords: Catheter-Tip Granuloma; Intrathecal;
Hydromorphone; Morphine; Spinal Cord; Catheter
Access Study
Intrathecal drug infusion systems have been utilized
since the 1980s to manage a variety of chronic pain
conditions and spasticity. Thus far, over 150,000 pumps
have been implanted worldwide [1]. An intrathecal (IT)
granuloma is a well described condition which can result
in serious, irreversible neurological deficits in patients
with implanted subarachnoid catheters for opioid in-
fusion therapy. The development of an inflammatory
mass at the tip of an intrathecal catheter in patients
receiving high dose narcotics was first described in 1991
[2]. It has been published less frequently in radiology
journals [3] and is still being mistaken for other pro-
cesses such as a hematoma on magnetic resonance ima-
ging (MRI) .
Although often associated with high concentrations of
opioid therapy, most commonly morphine, other medi-
cations such as hydromorphone may result in catheter
granulomas near the tip of the subarachnoid catheter
[1,4]. For example, according to a case review of 41
patients, 31 patients receiving morphine and 9 patients
receiving hydromorphone intrathecally were found to
have inflammatory mass lesions at the catheter tip [5].
Another likely reason for the majority of patients re-
ceiving morphine is that it is the only opioid approved by
the Food and Drug Administration for delivery of con-
tinuous drugs intrath ecally [4].
In the current case, we report a 42-year-old male who
presented to our pain clinic in 2009 with chronic low
back pain, which began after he was rear-ended in a
motor vehicle accident in 1993 while at work. He
eventually went on to have a lumbar laminectomy in
1994 followed by an L4-5, L5-S1 fusion in 1995.
However, due to ongoing chronic low back pain, the
patient then went on to have a spinal cord stimulator
implanted which was later removed within one year due
to lack of efficacy. Subsequently an intrathecal pump and
subarachnoid catheter was placed in August 1997 by an
another pain management physician which provided
good relief of pain. His pump was replaced in 2001 for
normal end of life battery and pump site revision one
year later due to pump discomfort after losing over 100
lbs of weight due to respiratory illness and development
of skin excoriation over the pump site. The patient also
underwent catheter removal and replacement at that time
with the catheter tip placed to approximately T5 spinal
level. However, the patient still continued to have dif-
*The author(s) received no financial support and have no conflict o
interest to disclose.
T. Varghese et al. / Advances in Bioscien ce and Biotechnology 4 (2013) 147-152
ficulty ambulating and decreased sensation in his lower
extremities, thus leading him to utilize a wheel-chair for
next 7 year s.
At the initial visit in our clinic in 2009, the patient
complained of 10/10 low back pain, right greater than
left, radiating down bilateral lower extremities described
as sharp, stabbing, burning, aching and constant. In
addition, the patient reported weakness and numbness in
his bilateral lower extremities, but no bowel or bladder
incontinence. On physical exam, the patient had mild
tenderness of bilateral iliolumbar lig aments, sciatic notch
and SI joint as well as mild limitation of flexion,
extension and bilateral lateral flexion with pain. In ad-
dition, the patient had a positive straight leg raise bila-
terally as well as hyperesthesia on the left L4, L5 and S1
and motor strength of 4+/5 for the bilateral lower extre-
mities. Reflexes were intact with negative clonus and
Examination of available pump telemetry printouts
indicate that the patient was receiving intrathecal hy-
dromorphone 50 mg/ml at a daily rate of 19.00 mg/day
as early as March 2000, prior to revision of his original
pump. Prior to this, the patient was receiving intrathecal
morphine 50 mg/ml with clonidine 30 mcg/ml at a dose
of 32 mg/day morphine. His most recent pump was
replaced in August 2006 from which time he had been
maintained on a stable dose of intrathecal hydromor-
phone 50 mg/ml at a rate of 17.59 mg/day from 2006
until presenting to our clinic in September 2009. In
February 2010, we changed the patient’s hydromor-
phone from 50 mg/ml to 100 mg/ml in an effort to reduce
refill intervals and maintained the same daily dose of
17.59 mg/day. However, approximately 16 months after
increasing the concentration of the intrathecal hydromor-
phone, the patient dev eloped increasing pain followed by
new onset of numbness in his feet. A catheter access
study was undertaken which failed to reveal catheter
occlusion (Figures 1 and 2) and thus the patient was
maintained on his daily dose of hydromorphone 17.59
mg/day at a concentration of 100 mg/ml. Over the next
two months the patient continued to complain of in-
creasing pain and was treated with a variety of oral
opioid medications. In addition , he began complaining of
a gradually progressive ascending numbness from the
feet up to his waist and a more pronounced “heaviness”
sensation in his legs which had not been present pre-
viously. At that point an MRI was obtained (two months
after catheter access study) (Figures 3-5). Films were not
available for review but concern of a catheter-tip gra-
nuloma was raised with the interpreting radiologist.
However, the report was read as, “likely [a] hemorrhagic
focus abutting the posterior aspect of the spinal cord at
T5/6” [with] “a diffusely increased T2 signal intensity
Figure 1. AP fluoroscopic image of catheter-
access study revealing distal end of catheter
(solid arrow) and myelogram (dashed arrows).
Figure 2. Lateral fluoroscopic view of tho-
racic spine at catheter end revealing the ca-
theter (solid arrow) and the filling defect (da-
shed arrows).
(a) (b) (c)
Figures 3. Sagittal T2-, T1- and postcontrast T1-weigh-
ted images demonstrating an extradural intramedullary
lesion (solid arrows) with mass effect on the cord. The
mass shows low signal on T2-weighted images and high
signal on T1-weighted images. There was peripheral en-
hancement and linear pial enhancement (dashed arrow)
with contrast.
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T. Varghese et al. / Advances in Bioscien ce and Biotechnology 4 (2013) 147-152 149
Figure 4. Axial T2-weighted image at the level
of the granuloma (solid arrow) shows displace-
ment of the spinal cord anteriorly and to the
left (dashed arrow).
Figure 5. Axial T2-weighted image was obta-
ined caudal to Fig. 4 to demonstrate abnormal
high T2-weighted signal in the cord, consistent
with edema (dashed arrow). Part of the catheter
is seen along the posterior aspect of the canal
(solid arrow).
involving the thoracic cord from T2-T9”. Thus, the ini-
tial MRI interpretation unfortunately did not appreciate
catheter-tip granuloma but rather spinal cord hematoma
of uncertain chronicity (Figures 3(a)-(c) and 4). The
patient continued to have numbness below the waist with
perineal anesthesia and presented to another hospital six
days later. On this admission a subsequent MRI revealed
a large catheter-tip granuloma which enhanced with con-
trast, as well as extensive T2 signal prolongation within
the spinal cord from T5 - T7 (Figures 6 and 7). The
patient underwent semi-urgent surgical exploration, ca-
theter tip removal and excision of the granuloma. How-
ever, a portion of the granuloma c ould no t be re sect e d du e
to tenacious adherence to the spinal cord (Figures 8(a)
and (b)). At three months post-operative the patient
showed no change in neurologic function with persistent
sensory gait ataxia, and hypoesthesia below T6. After
approximately five months, repeat MR imaging was
obtained revealing recurrent catheter-tip granuloma just
inferior to the original granuloma location and, just
proximal to the newly trimmed catheter tip (Figures
9(a)-(c)). No changes in the patient’s dose or concen-
tration of hydromorphone were made after the first sur-
gery and he continued to receive a daily medication in-
fusion of 17.59 mg/day of hydromorphon e 100 mg/ml, in
addition to taking Percocet 10/325 mg every 4 - 6 hours
orally. Repeat laminectomy and resection of his recurrent
granuloma was performed, as well as removal of his ca-
theter and pump system. No significant changes in his
clinical condition or neurologic function were observed
Figure 6. Sagittal T2-weighted
image obtained 6 days after ini-
tal MRI revealing an intradural
lesion (solid arrow) and exten-
sive spinal cord edema (dashed
Figure 7. Sagittal T1-weighted
fat saturated post-contrast im-
age redemonstrates an enhance-
ing intramedullary lesion (solid
arrow) with peripheral and pial
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T. Varghese et al. / Advances in Bioscien ce and Biotechnology 4 (2013) 147-152
(a) (b)
Figure 8. (a) Intraoperative image of granuloma (arrow)
with dura retracted. Catheter is seen to the left (asterisk); (b)
Resection of granuloma from catheter reveals necrotic core
of devitalized tissue (arrow) within fibrotic inflammatory
layer (small arrows). Note the devitalized mass is proximal
to catheter tip near side fenestration (dashed arrow).
(a) (b) (c)
Figure 9. (a) Sagittal T2-weighted image shows a more cau-
dal location of recurrent catheter-tip granuloma (solid arrow) 4
months after original decompressive surgery. A small seroma is
seen cranial and posterior to the recurrent granuloma (dashed
arrow); (b) Granuloma (solid arrow) demonstrates high T2-
weighted signal centrally with peripheral low T2-weighted sig-
nal. The spinal cord (dashed arrow) is displaced anteriorly by
the mass; (c) Axial T1-weighted post-contrast image reveals
peripheral enhancement (solid arrow). Note the post-surgical
changes in the posterior elements (star). The spinal cord (d ashe d
arrow) is displaced anteriorly by the mass.
Catheter-tip granulomas remain a rare but potentially
devastating complication from intrathecal (IT) infusion
therapy [1]. First described after epidural infusion in
1986 [6] and intrathecal infusion in 1991 [3], the number
of reported cases has continued to grow with 92 reported
cases to the US Food and Drug Administration and
Manufacturers as of 2002 [7]. It is likely the tr ue number
of cases is much higher given the voluntary reporting
basis [8]. Originally used to treat patients with short life
expectancies, IT therapy is being increasingly utilized to
treat patients with chronic non-malignant pain with
approximately 15,000 new pumps implanted each year
Although the majority of cases have been with
morphine, hydromorphone may also result in granuloma
formation as seen in our case. Thus far, baclofen and
diamorphine (heroin) have also been associated with IT
granulomas [9]. Preclinical studies have revealed a dose-
dependent local inflammatory reaction within 28 days at
the catheter-tip in Beagle dogs [7] with h istopathology of
these masses revealing increased vascularity and compo-
sition of lymphocytes, macrophages, and ultimately
hypervascular fibrous tissue surrounding an inner core of
necrotic, devitalized tissue [6,7]. Our case illustrates a
concentration-dependent response of granuloma for-
mation to hydromorphone. In addition, our case demon-
strates one of the longest time intervals to granuloma
diagnosis after implant (approximately 14 years after
initial pump implantation and 9 years after catheter
revision). The patient had maintained a relatively stable
clinical course and was on an extremely steady dose and
concentration of hydromorphone for 7 years. However,
within 16 months of doubling his hydromorphone con-
centration, but not changing his daily dose, he developed
a clinically significant granuloma. The mass was later
resected but then a second granuloma was diagnosed 4.5
months later [10]. Previously, granuloma reformation
had been reported to occur as early as 6 to 9 months [11].
Previous case reports have demonstrated recurrence of
granulomas up to three times in one individual [9] as
well as very fast granuloma formation within 5 weeks of
IT morphine therapy [12].
Our case supports the notion that the concentration of
medication, rather than the daily dose as originally once
thought, was the primary causative agent which pre-
cipitated granuloma formation [13]. A 2007 Consensus
Conference recommended maximum concentrations of
hydromorphone of 10 mg/ml with maximum daily doses
of 4 mg/day [14] intrathecally. However, hydromorphone
concentrations as low as 10 mg/ml and daily doses of 1
mg/day have been reported to cause granuloma for-
mation [5]. This patient initially was receiving IT mor-
phine 50 mg/ml combined with clonidine with a daily
dose of 32 mg/ml morphine. Receiving IT clonidine in
combination with morphine has been postulated, although
not proven, to have a “protective” effect and reduce
granuloma formation [7]. However, due to lack of effi-
cacy with no apparent neurologic sequelae this patient
was converted to IT hydromorphone. In our case, the
hydromorphone concentration reached 10 times the re-
commended maximum concentration and 4 times the re-
commended maximum daily dosage of 20 mg/ml and 4
mg/day respectively [14].
The location of the catheter-tip has also been sug-
gested to play a role in granuloma formation [5,7,14].
Initially this patient had a granuloma form at T5 and then
again at T6 after catheter-tip trimming. Given the rela-
tively small space of cerebrospinal fluid (CSF) at such
rostral thoracic locations, some authors have postulated
higher catheter-tip placement may predispose to higher
local concentrations of drugs at the catheter-tips thus
inducing the cellular inflammatory cascade [5,15]. In-
deed, granulomas that form at catheter-tips placed in-
Copyright © 2013 SciRes. OPEN ACCESS
T. Varghese et al. / Advances in Bioscien ce and Biotechnology 4 (2013) 147-152 151
ferior to the conus medularis generally result in less se-
vere neurological deficits as well as a more complete re-
covery should they develop a compressive granuloma [7].
Some IT opioids are lipophilic and thus require place-
ment close to the target spinal segments for maximal
effect. We would suggest with hydrophilic medications,
such as morphine or hydromorphone which would be
expected to spread several segments within the CSF, that
catheter-tip location be as caudal as possible in order to
secure the catheter and prevent dislodgment.
Although the true yearly incidence of granuloma
formation for all pain patients may be dependent on
several factors such as the drug, concentration, catheter-
tip location, daily dose, or patient sen sitivity as discu ssed,
the estimated cumulative risk of developing an inflam-
matory mass was 0.04% over one year, 0.12% over two
years, but 1.15% over 6 years [7]. Note the increasing
yearly risk such that in this patient who had been
implanted approximately 14 years previously, by extra-
polating the published data, the estimated risk of granu-
loma formation would likely be higher than 3% [7].
More recent publications have placed the incidence of
granuloma formation to be as high as 0.49% to 3% [4,16].
The duration of infusion therapy exposure to granuloma
diagnosis ranges from 5 weeks to 72 months, with an
average time of 24 months until diagnosis is made [16].
As mentioned, our case represents the longest known
duration from initiation of infusion therapy until granu-
loma diagnosis (14 years).
It is important to note that the majority of radio-
graphically diagnosed granulomas are asymptomatic [16].
Neurologic deficits occurring in response to catheter-tip
granulomas are generally slowly progressive and range
from loss of drug effect to new-onset of radicular pain or
parethesias [5,7,17]. More severe neurological deficits
can include paralysis or cauda equina syndrome [7,2,11].
Diagnosis in our case was made more difficult in that the
patient exhibited opioid seeking behavior with compla-
ints of significant pain and requests for oral analgesics
since his initial visit. In addition, the patient had also
been discharged from his prior treating physician for
recreational drug use. He also had a history of bilateral
lower extremity numbness and difficulty with ambu-
lation dating back to his original injury. Our initial eva-
luation also documented weakness in his lower extre-
mities. As with previous case reports, foot hypoesthesia
in this case was the sentinel symptom [11]. The initial
catheter access study was undertaken to ensure pump
patency and a low index for granuloma formation was
entertained given the chronicity and stability of his IT
infusion dose and medication. As previously mentioned,
this study was originally interpreted as normal, however,
on further review of his catheter access study myelogram
(Figure 2) a filling defect located just proximal to the
catheter-tip can be appreciated, which is consistent with
a side fenestrated catheter. Our patient remained ambu-
latory both before and after each granuloma excision
with minimal clinical improvement.
Catheter-tip granulomas, although well reported in the
neurosurgical and pain medicine literature are less well
described in the radiological literature [3]. In this par-
ticular case, diagnosis of the granuloma was delayed
slightly as it was initially interpreted as a “hemorrhagic
focus” abutting the spinal cord. (Figures 3(a)-(c)). Rela-
ying pertinent clinical information to interpreting radio-
logist may aid in diagnosis and hasten treatment. In addi-
tion, documenting catheter-tip location as well as model
type (end hole vs. side fenestration) in the patient’s me-
dical record at the time of implant may facilitate dia-
gnosis [17]. The patient’s first MRI revealed the typical
ring-like enhancement on contrast-enhanced T1-weigh-
ted imaging (Figure 3(c)). Because some catheters have
a metallic marker at the tip, contrast-enhancement is
crucial [3]. As seen in Figure 8(b), the peripheral fib-
rotic, hypervascular shell surrounding the inner necrotic
core explains the peripheral ring-like enhancement.
Treatment of catheter-tip masses should take into acc-
ount the patient’s clinical condition, as well as the phy-
sician’s experience [17]. Once a catheter-tip mass is ra-
diographically confirmed, a decision to leave the drug
infusion system in place or remove all or part of it must
be made. If the decision to leave the infusion system in
place is made the clinician must decide whether to change
the dose, concentration, or medication administered alto-
gether [17]. Some clinicians may also choose to pull the
catheter back one or two caudal segments under light
sedation [16]. Although multiple exit catheters may have
an advantage over single exit catheters [16], this patient
in fact had a six-orificed, side-fenestrated catheter. If a
compressive lesion is suspected and surgery contem-
plated, the pump should be stopped immediately and the
patient should be referred to a spine surgeon. However,
stopping the pump for more than a few days may damage
the catheter near the rotors [16]. In our case the patient
underwent semi-urgent surgical granuloma excision and
catheter trimming without any changes to the concen-
tration and daily dose of his medication. We, however,
recommend medication adjustments be made in future
similar situations.
In summary, benefits of IT therapy include localized
and improved analgesia, decreased side effects compared
with systemic medications and more alert, less hyper-
somnolent patients when compared to oral opioids [18].
Although rare, catheter-tip granulomas remain a serious
complication of IT infusion therapy and clinicians
managing patients with implanted subarachnoid infusion
pumps should maintain a high index of suspicion for
granuloma formation in any patient with decreasing res-
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T. Varghese et al. / Advances in Bioscien ce and Biotechnology 4 (2013) 147-152
Copyright © 2013 SciRes.
[9] Miele, V.J., Price, K.O., Bloomfield, S., Hogg, J. and Ba i-
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ponsiveness to therapy or subtle changes in neurologic
function. We believe this case represents the longest in-
terval to diagnosis after initiation of IT infusion therapy,
as well as one of the shortest intervals of recurrence of a
catheter-tip mass. In addition, the filling defect during
the catheter access study was not appreciated, nor was
the granuloma appreciated on the patient’s initial MRI.
This case report is intended to educate practitioners in
recognizing the presentation of a possible catheter-tip
granuloma, both clinically and radiographically, to help
improve recognition and institute treatment in a quick
and effective manner, and to decrease the prevalence of
mistakenly unidentified catheter-tip granulomas.
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The authors would like to gratefully acknowledge Ashley Zimmerman,
PA-C for her editorial assistance in preparation of this manuscript.
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