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spinal cord infarction ( sci ) is a rare but important cause of acute myelopathy , accounting for 58% of all cases .
differential diagnosis , mainly with acute inflammatory diseases , is mandatory , and diffusion - weighted imaging ( dwi ) mri  although seldom performed due to technical issues  has been described as a useful tool in this distinction .
the most common cause of sci is aortic disease ; nevertheless , a definite cause is not found in 6075% of the cases , which is a higher rate than that found in brain infarction [ 3 , 4 ] .
the presence of a patent foramen ovale ( pfo ) with atrial septum aneurysm ( asa ) has been described as a risk factor for cryptogenic brain infarction .
this is not clearly established for sci , as there are only 3 reported cases of sci associated with a pfo [ 5 , 6 , 7 ] . however , right - to - left shunting has also been related to spinal infectious diseases by septic embolism [ 8 , 9 , 10 ] .
we describe the case of a sci associated with a pfo with a borderline asa and discuss the possible role of right - to - left shunting on cryptogenic spinal infarction .
a 24-year - old female patient , under oral contraceptive treatment with 0.015 mg ethinylestradiol and 0.006 mg gestodene , woke up in the middle of the night with sudden , intense and self - limited interscapular pain and paresthesias in both hands .
she went back to sleep and , when she woke up again a few hours later , she noticed weakness in both hands and abdominal wall numbness .
she had no relevant medical , surgical or family history and denied alcohol , tobacco or other drug use or having suffered a relevant trauma in the previous days . on admission , her blood pressure was 132/90 mm hg .
the general examination was unremarkable , and neurological examination disclosed flaccid distal paresis of the upper limbs with decreased osteotendinous reflexes in the upper limbs and abnormal plantar responses .
mri of the cervical and dorsal spine showed t2-weighted sequence change in the signal between c5 and d1 at the levels of the anterior horns of the spinal grey matter , which was more evident on the left where they also involved the anterolateral white matter and the lateral cord ( fig .
brain mri showed no changes . a diagnostic workup with complete blood count , biochemical testing , erythrocyte sedimentation rate , diabetes screening , cerebrospinal fluid examination , immunological study , including complement levels , anti - nuclear antibodies and anti - phospholipid antibodies and infections , with syphilis screening and hiv , was negative .
abnormalities of the spinal cord vascular system ( namely arteriovenous malformations ) were excluded on the ground of normal - selective digital subtraction angiographic findings .
transcranial doppler showed patency of major cerebral arteries , and saline iv infusion detected a right - to - left at - rest grade iii shunt according to the spencer grading scale ( 1650 microembolic signals ) , with an uncountable number of microembolic signals ( shower effect , grade v+ ) after a valsalva maneuver .
transesophageal echocardiogram showed a pfo and an interatrial septum protruding to the right atrium 10 mm beyond the original position of the interatrial septum .
a 24-hour holter ecg did not detect any potentially embolic arrhythmias . in the absence of other causes ,
the patient was treated with oral anticoagulation therapy until a percutaneous pfo closure was performed with an amplatzer device .
one year after the primary event , the patient scored 2 on the modified rankin scale with a forearm paralysis .
right - to - left shunts have been discussed as relevant causes of cryptogenic stroke . the role of pfo in stroke , mainly when associated with asa , is well described .
unfortunately , however , there are no systematic studies of its prevalence in or impact on cryptogenic sci .
pfo has also been linked with cryptogenic brain abscess , and some studies have shown the co - occurrence of pfo with intramedullary abscesses of the spinal cord ( iasc ) [ 8 , 9 ] .
iasc is a rare condition that usually occurs secondary to bacteremia from cardiac , pulmonary or urinary foci .
hoche demonstrated that the introduction of micro - organisms into the circulation of experimental animals did not result in the development of isca ; however , if both microorganisms and thrombi were introduced , isca developed .
this is a well - known oral low - pathogenicity agent that can cause transient asymptomatic bacteremia in healthy patients . in their case report , terterov et al
.   suggested that this transient bacteremia infected a subclinical deep vein thrombosis and the paradoxical embolism was facilitated by the patient pfo .
the right - to - left shunting would allow pathogens to bypass pulmonary capillary filtering and enter arterial circulation easier .
besides these reports , arteriovenous pulmonary malformations or atrial septal defects have been reported in patients with iasc [ 8 , 10 ] .
the co - occurrence of pfo and iasc makes the hypothesis of the mechanism of paradoxical infections through pfo plausible .
we propose that the same rationale could be considered for sci , and that paradoxical embolism through a pfo can be a possible cause of sci in the presence of an associated asa . as the onset of symptoms in our patient happened during her sleep
nevertheless , while sleeping , there can be changes of intrathoracic pressures that can facilitate a transient rise in atrial pressure and co - occurring embolism .
simultaneously , we have evidence that the valsalva maneuver significantly increased the number of microembolic signals detected by transcranial doppler ; thus , we admit the possibility that a valsalva - like mechanism could have a role in the paradoxical embolism . due to its specific vascular anatomy ,
the rarity of this event , facing the high frequency of pfo and asa in the normal population , probably explains the difficulty of establishing the role of pfo or pfo with asa in spinal vascular disorders .
we propose that the search for a right - to - left shunt is reasonable in the presence of a sci with an unknown cause , and , although the role of pfo is not clearly established in the etiology and long - term follow - up , its closure can be considered , probably in the same way as in cerebral stroke .
based on the current evidence , it is impossible to establish a definite association between pfo , a frequent condition , and sci , a rare disorder . facing the lack of studies on the management of infarction in the presence of pfo or even sci , we considered closing the pfo a safe and effective approach in our case , as we reckoned that the recurrence of embolic events might be significant in this young patient . with this report
, we try to fundament the role of pfo as a potential cause to be considered in cryptogenic sci .
the relative rarity of sci and the difficulties in its diagnosis make research in this area difficult . with this report , we expect to have highlighted the need to understand the role of right - to - left shunts in spinal disorders and to motivate further studies
. the creation of a multinational sci registry would probably be a helpful effort to understand the sci epidemiology and pathology and to optimize its management .
spinal cord infarction ( sci ) is an uncommon but important cause of acute myelopathy . 
 nevertheless , contrary to cerebral stroke , the discussion about paradoxical embolism as a cause of cryptogenic sci remains dubious . 
 we describe the case of a 24-year - old woman who developed sudden - onset back pain followed by upper limb paralysis . 
 t2-weighted mri demonstrated hyperintense signal , extending from c5 to d1 with corresponding restricted diffusion on diffusion - weighted mri and reduction of the apparent diffusion coefficient . 
 diagnostic workup , including lumbar puncture , showed no changes . 
 transcranial doppler showed a right - to - left shunt with an uncountable number of microembolic signals after valsalva maneuvers , and a patent foramen ovale ( pfo ) with an atrial septum aneurysm was identified . 
 we discuss the paucity of evidence of right - to - left shunting in spinal diseases compared to cerebral events and the potential role of paradoxical embolism through pfo as a possible mechanism of sci .