Introduction
Guillain-Barré syndrome (GBS), first described in 1916 by French neurologists Jean-Alexandre Barré
and Georges Charles Guillain, is a mainly acute, incidentally chronic,
inflammatory polyneuropathy affecting the myelin-protein sheathing and the
axons of spinal nerve roots and peripheric nerves (motor neuron) in humans.
It is a frequently post-infectious, immune-mediated disease with mainly immunoglobulin G
(IgG)auto-antibodies being formed against endogenous myelin and gangliosides.
There are numerous infectious agents, either viral, bacterial, or even
parasitic, that can trigger the onset of GBS such as herpes viruses,
i.e., varicella zoster virus (Creswell et al., 2010), Epstein–Barr virus (Kim
et al., 2016) or cytomegalovirus (Steger et al., 2012); human immunodeficiency virus, HIV (Varshney et
al., 2014); mycoplasma (Topcu et al., 2013); Brucella melitensis
(Namiduru et al., 2003); Campylobacter jejuni (C. jejuni);
Toxoplasma gondii (Pascual et al., 1984); or influenza
vaccines (Martìn Arias et al., 2015). Preceding C. jejuni infection can be found in a high percentage of GBS patients. This
association was initially reported in the early 1980s (Kaldor and Speed,
1984). Recent publications report that GBS is also associated with the Zika virus
infection (Cao-Lormeau et al., 2016). In animals, GBS-like diseases have been
reported following a rabies (Hemachudha et al., 1988) or swine influenza
vaccination (Langmuir et al., 1984).
Myelin sheath antigens and C. jejuni antigens show an equal
configuration, which can lead to a cross-reaction of the antibodies. It is
assumed that at least some strains of C. jejuni express a
carbohydrate epitope on their lipopolysaccharides that can also be found on
peripheral nerves (Wirguin et al., 1994).
Why some patients develop GBS after an infectious disease while others do
not is so far unknown.
There is an average of 1–2 cases yr-1 in 100 000 people worldwide (Fujimura,
2013). An age accumulation in humans at the ages of 20–30 and 50–70 can be
seen, but people at every age can be affected (Sindern and Malin, 1996).
The main symptom of GBS is an ascending paralysis with a mild to
severe progression up to total paralysis including the respiratory muscles,
cranial nerves and, in the worst case, affecting the autonomic nervous system
(heart frequency, circulatory system, temperature regulation and urination).
While sensitivity is preserved, more than 60 % of the patients suffer from
mild to severe myalgia (Ruts et al., 2010).
Although the disease can last for weeks to months, mortality in humans is
low (about 5 %; Sindern and Malin, 1996). With adequate
treatment, 60 % of the patients show a total recovery or remission.
However, more-or-less mild symptoms remain, e.g., some weakness, muscle
wasting, impaired walking or pain in some patients. The most severe, therapy-resistant
cases can lead to high tetraplegia and persistent failure of
cranial nerves (Tan and Chee, 1995).
GBS can mainly be diagnosed through clinical findings. An anamnesis often
reveals previous infectious diseases, trauma or severe stress. Blood
analysis can yield a high lymphocyte count, while there are no special findings in
the CSF (cerebrospinal fluid) at the beginning of paralyses, whereas in the disease's progression total CSF protein rises due to the swelling of myelin sheaths
resulting in an impaired CSF flow (Reiber, 1994, 2016). In most
cases CSF cell count remains normal. In case of a suspected GBS the reduced
muscular and nerve conduction can be monitored by means of electromyography (EMG)
and/or electroneurography (ENG).
There is no causal therapy for GBS. Patients need intensive care according
to the degree of severity. If needed, artificial respiration as well as a
urinary catheter has to be
provided, and prophylaxis of decubitus and thrombosis is required.
The application of glucocorticoids
to reduce the immune reaction and that of immunoglobulins as well as plasmapheresis for the reduction of autoimmune antibodies,
complement and mediators of inflammation, can be helpful (Sindern
and Malin, 1996; Yuki and Hartung, 2012).
GBS-like diseases in animals
Several GBS-like illnesses have been described in different animal species,
either naturally occurring or experimentally induced. Coonhound paralysis
(CHP), first described in 1954, resembles human GBS and can be found in
coonhounds 1–2 weeks after a raccoon bite or scratch (Kingma and Catcott,
1954). CHP could also be experimentally reproduced through the injection of
raccoon saliva into healthy coonhounds (Holmes et al., 1979). Idiopathic
acute polyradiculoneuropathy is the most commonly recognized peripheral
neuropathy in dogs that closely resembles the acute axonal or intermediate
form of human GBS and has been observed following rabies vaccination
(Hariharan et al., 2011; Cuddon, 1998; Collins, 1994). Rabbits, guinea pigs,
mice and rats are used as widely accepted animal models for GBS. In these
laboratory animal species, so-called experimental autoimmune neuritis
can be induced by injecting peripheral nerve emulsion in complete
Freund's adjuvant (Smith et al., 1979; Saida et al., 1981).
Marek' s disease in chickens has formerly been discussed as
another natural model for GBS as it leads to an autoimmune response to
myelin and peripheral nerves; however, it is initiated by a viral infection
in neuronal supporting cells (Hariharan et al., 2011).
In horses, cauda equina neuritis also clinically resembles GBS, and
circulating antibodies to a myelin protein have been detected in affected
animals (Kadlubowski and Ingram, 1981). Upper respiratory infections
involving streptococci have been discussed as a cause (Martens et al.,
1970).
Cases of GBS or GBS-like diseases in nonhuman primates seem to be rare.
There is one single report of a chimpanzee (Pan troglodytes) that,
after several months of treatment, made a total recovery from a GBS-like
condition with albuminocytologic dissociation in CSF following a rabies
revaccination and tooth extraction (Alford and Satterfield, 1995). Another
case about an entellus langur (Presbytis entellus) with a four-week duration of clinical signs and a tenfold rise of CSF proteins during
the course of the disease (Schultz, 1987) is known.
We here report about an eight-year-old rhesus macaque (Macaca mulatta)
showing tetraplegia after previous campylobacteriosis.
Case Report
Anamnesis, Patient
The patient, Simon, was a male rhesus macaque. When the clinical signs
appeared, he was eight years old and weighed 9 kg. He was born in China and
imported to Europe via the Netherlands at the age of four. Since then, the
monkey was kept at the Department of Cognitive Neuroscience at the German
Primate Center. Simon was tested Herpes-B negative and group housed with
three
other B-virus negative males, with the present group existing since 18 months.
Simon wore two chronic head implants, i.e., a titanium head post
(∼ 3 years) and a recording chamber over a craniotomy
(∼ 1 year) fixed to the bones of the skull. He was trained for
his monkey chair, performing self-controlled neuroscientific experiments on
a weekday basis. During the experimental sessions (∼ 1–2 h) a single parylene-C coated tungsten electrode was introduced into the
upper cortical layers of the brain using a guide tube to just penetrate the
dura under the craniotomy. This allowed the recording of single
neuron's responses during the given experimental task. All
procedures were done under locally sterile conditions.
Two weeks prior to the events reported here, the monkey had suffered from
mild to moderate diarrhea with C. jejuni isolated from the feces.
In a routine microbial sensitivity test the antibiotic Cefquinome was found
highly efficient and a therapy with Cobactan®
(2 mg Cefquinome kg body weight-1) was applied for five consecutive days.
Clinical Course
Day 1
Around noon, Simon was found in his cage not being able to move his
hind limbs. Apart from that, his general condition seemed to be unimpaired.
A visual veterinary examination confirmed these findings, with the left leg being
even more severely affected by sudden lameness than the right and the
muscles of both hind limbs appearing atonic. An immediate clinical
examination under Ketamine sedation (10 mg kg-1) revealed no special findings
in particular and no injuries such as hematomas, wounds or fractures either on
the legs or on other body parts. A blood sample was taken (serum, EDTA)
for general routine blood works and Prednisolone (1.0 mg kg-1) as well as
Meloxicam (0.2 mg kg-1) were injected. A blood analysis was performed on the
same day and revealed no special findings.
Differential Diagnoses
At this point several differential diagnoses were discussed. First of all a
spinal cord tumor was considered, such as a malignant lymphoma caused by
the Epstein–Barr virus, as it had been found in another monkey in the same unit
20 months earlier. Any other tumor of either the spinal cord or vertebral
column was also conceivable, as was any other type of compressive
lesion, e.g., a herniated disk. There could have been a brain injury due to
the insertion of an electrode during the experiment; however, the electrodes
were never inserted near the motor cortex and there had been no recording in
the last 48 h. Additionally, a spinal cord infarction could have taken place.
Despite no visible external injury and without the caretakers having observed
any accident or fight, a spinal cord trauma could have still happened. Acute
muscle degeneration or neurological diseases, e.g., myasthenia gravis, and
even highly improbable options like botulism or other neurotropic
intoxications had to be taken into account as well. Since Simon was wearing
chronic head implants, we also thought about a possible unrecognized
infection of the brain or its surrounding tissues even if there had been no
indication of a recording chamber infection or an infection of the skin
margins around the head post prior to this clinical
event.
Analysis of two different CSF and serum samples (a and b)
taken on day 2 and 7, respectively. Since cytology required fresh CSF while
these samples were frozen at -80 ∘C prior to analysis, cells could not
be differentiated into lymphocytes, monocytes, granulocytes, and plasma
cells and thus were labeled “other cells”. Reference value for rhesus
monkeys for albumin is 29–228 mg L-1 and 0.5–4.3 for albumin ratio (Q Albumin).
Total protein should not exceed 60–350 mg L-1 and cell count should be < 4 µL; reference value for IgG
is 6–50 mg L-1 and 0.4–4.0 for IgG ratio (Q IgG)
(Smith and Lackner, 1993). The counts that exceed the references are
marked in bold.
CSF
Serum × 103
Q (CSF/Ser) × 103
a
b
a
b
a
b
Albumin mg L-1
61.8
295
24.8
24.6
2.5
12.0
IgG mg L-1
10
45.2
8.7
8.4
1.1
5.4
IgA mg L-1
0.6
2.9
0.91
0.92
0.7
3.1
IgM mg L-1
< 0.14
0.54
0.38
0.4
< 0.4
1.4
Total protein mg L-1
145
542
Cells µL
2
29
Clinical Course
Day 2
On day 2 Simon's condition seemed to be unchanged. With the
help of his arms he pulled himself through the cage, apparently coping quite
well with his situation and eating and drinking as usual.
We injected Dexamethasone (0.2 mg kg-1, i.m.) and Enrofloxacin (5 mg kg-1, s.c.)
and gave him Vitamin B complex supplements (2.5 mL p.o.).
The monkey was then sent under sedation to Hannover's veterinary school for
an X-Ray and a CT scan. A clinical examination as well as a spinal tap and an immediate
CSF analysis were performed by veterinary neurologists of the veterinary
school's small animal hospital. All these efforts submitted
no special findings as the suspicion of a spinal cord infarction was
discussed. The specialists suggested waiting for about two weeks and
recommended medication for bladder constriction (Bethanechol chloride,
Myocholine®) and sphincter relaxation
(Phenoxybenzamine
hydrochloride, Dibenzyran®) to support urinary bladder
function. The administration and continuation of glucocorticoids, both for
immune suppression and to control local inflammation, antibiotics and
supplementation with Vitamin B were recommended.
Day 3 and 4
The third day found Simon in an unchanged condition. He showed spontaneous
defecation and surprisingly scratched his right leg after an injection,
indicating at least a certain degree of sensitivity.
Medication was administered as recommended: Myocholine® (10 mg day-1, p.o.),
Dibenzyran® (10 mg day-1, p.o.), Enrofloxacin, Dexamethasone and
Vitamin B supplements.
His general condition was still good and, besides the reaction to the needle
puncture, he showed no signs of pain.
The next day was the same, although the caretakers reported polyphagia,
polydipsia and polyuria, which did not come unexpectedly due to the
glucocorticoid therapy.
Day 5
Since the monkey got quite dirty from dragging himself around in the cage and
through his feces, we washed and dried him under sedation and added soft and
dry bedding to his cage. Furthermore, we tried some physiotherapy by
massaging and passively moving his legs for a while.
Medication, as above, was continued.
Day 6
On the morning of day 6 the caretakers found Simon only being able to handle
large pieces of food. Both of his hands were flaccidly paralyzed, his fingers
were bent and both fists were atonic. He reclined a lot and had trouble sitting up.
His arms seemed to be weaker than the days before.
After a second consultation of the veterinary neurologists, GBS was suspected.
Day 7
On day 7, Simon's condition worsened. He was in lateral recumbency,
sometimes resting on one elbow and rolling over to change his position. He was
still able to eat, drink and defecate and showed no signs of pain.
Another CSF and blood sample was taken and all CSF and blood samples were
sent to the neurochemistry lab of the Göttingen university hospital.
As the blood counts revealed no special findings, there was a rise in total
protein, albumin, IgG and cells in the second CSF sample in comparison to
the first puncture (Table 1). Reibergrams displaying IgG, IgA, IgM and
albumin ratios are shown in Fig. 1.
Oligoclonal IgG bands were identical in CSF and serum, indicating a systemic
inflammation without intrathecal IgG synthesis.
Reibergrams for IgG, IgA, IgM, and albumin ratios in CSF and serum samples (a) and (b) (see Table 1)
taken on day 2 (left, CSF/serum sample a) and day 7 (right, CSF/serum sample b), respectively.
The position of the black square dot within the vertically hatched areas of the right reibergram (day 7)
indicates a simple progressive disturbance of the blood-brain barrier, i.e., a reduced CSF flow,
in comparison to day 2 (square dots are displayed within the blank normal area or below the limit).
It also indicates that there is no intrathecal synthesis of antibodies, which would result in the black square dot
being displayed within the percentage lines above the dotted line (Reiber, 2016).
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We arranged electroneurography and electromyography measurements for the
late afternoon of the following day.
Day 8
On day 8, Simon's condition was unchanged, with the monkey being
still in a lateral position and unable to use his arms and hands properly.
ENG and EMG, which could both be performed in the monkey unit using portable
devices, revealed signs resembling those of advanced GBS in humans: ENG of
both legs and arms indicated a highly reduced nerve conduction speed and a
reduction of amplitudes as a sign of demyelination up to the nerve roots.
EMG showed fibrillations and positive sharp waves in almost
every tested peripheric muscle due to a serious axonal impairment, which can
be seen secondarily to the demyelination in severe cases of GBS. Some back
muscles, though, still showed normal potentials.
Mild polyneuritis, rhesus macaque (Macaca mulatta).
Sciatic nerve with moderate vacuolar degeneration and focal lymphocytic
infiltration. Scale bar: 20 µm.
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Given these grave findings and the bad prognosis for a fast recovery as well
as the impracticality of long-lasting intensive care for an adult male
rhesus macaque, especially with regard to animal welfare, we decided to
euthanize the monkey.
Day 9
Simon was euthanized by intravenous injection of a barbiturate
(Pentobarbital, 80 mg kg-1) under deep sedation (Ketamine, 5 mg kg-1 and Xylazine,
1 mg kg-1) and sent to DPZ's (German Primate Center) pathology department where
an immediate autopsy was performed.