Discussion
In 1987, Renlund et al. reported the first case of CABG associated GBS
in a 65 year old man who developed symptoms three days after surgery,
successfully treated with plasmapheresis. (7) Since then, nine
additional cases have been reported including the current case (Table
1). (8-13) While there are other extant reports of GBS following
cardiothoracic surgery, the temporal precedence between surgery and GBS
of 12 and 48 months seems an unlikely etiology (14,15). In nine of the
ten cases, patients were male; all patients developed symptoms within 15
days after surgery. All patients were successfully treated with either
IVIG, plasmapheresis or plasma exchange, and demonstrated either
significant improvement or complete recovery. Six patients required
mechanical ventilation, as in the current case. Average age of the
patients was 61.4 years; average time between the surgical procedure and
symptom onset was 7.6 days (range 1-15, median 7.5 days). Only four
patients in the series underwent valvular repair, one of which was
replacement, as is our case. Table data suggests either increasing
incidence or reporting of cardiothoracic surgery associated GBS.
National surveillance data from the Centers for Disease Control and
Prevention has documented a 5 percent incidence of GBS within 8 weeks
post-surgery. (4) However, 45 percent of those patients reported an
antecedent illness within that same time period. There was a direct
correlation between increasing age and the incidence of GBS, as well as
a male preponderance. Our patient denied any preceding upper respiratory
or gastrointestinal symptoms.
In a series published by Gensicke, et.al. the risk of developing GBS
during 6 weeks following surgery was 13.1 times higher than the risk in
the general population. (5) None of the patients in their study had
prior open heart surgery. In a very recent retrospective review of 208
cases of GBS, Nagarajan et al. reported that 15 percent of patients
developed postsurgical GBS within 8 weeks of surgery. (6) Median
duration from the surgical procedure to the onset of first GBS symptoms
was 19 days. Interestingly, 61 percent of patients had a known diagnosis
of malignancy and 29 percent had an underlying autoimmune condition.
Multivariate analysis demonstrated a statistically significant
association of post-surgical GBS with age, malignancy, and presence of
an autoimmune disorder. (6) In Nagarajan’s series only one patient
underwent CABG.
The mechanism and pathogenesis of GBS after cardiac surgery is unknown.
Surgery may cause exposure of nerve roots leading to
oncoantigen-mediated misdirection of autoimmune responses to epitopes
within the peripheral nervous system. Immune dysregulation may be
secondary to lipid soluble anesthetic agents. (6) Additionally,
cardiopulmonary bypass has been associated with activation of
complement, secretion of both pro- and anti-inflammatory cytokines
(IL-8, IL-10), tumor necrosis factor (TNf-α), and activation of
neutrophils. (16)
GBS incidence within 8 weeks of a surgical procedure appears to be more
common than previously thought. GBS following open heart surgery is
exceedingly rare, perhaps under diagnosed or under reported given
surveillance data incidence. Clinicians should be keenly aware of this
association and quickly consider the diagnosis in any patient who
develops progressive weakness, pain and diminished reflexes
post-operatively.