Público alvo: técnico.
A publicação desta semana no The Rheumatologist, órgão escrito do American College of Rheumatology, dá a dimensão exata de onde estamos na compreensão da Síndrome Anti-Fosfolípide. A descrição minuciosa é feita por seus descobridor, o Dr. Graham Hughes, do St. Thomas Hospital em Londres. As referências ao final do texto são as mais importantes sobre o tema. Deleite-se com o texto fácil e correto do Dr. Hughes.
The problem that dogs the work of all of those treating patients with antiphospholipid syndrome (APS) is the apparent lack of knowledge of the syndrome, both by the general public, as well as by swaths of the medical fraternity.Perhaps it was ever thus—a syndrome less than 40 years old could be described as new, but a syndrome that is common, touches all branches of medicine and, above all, that is potentially treatable, surely deserves wider recognition.
Some of the difficulties derive from the complex clinical nature of APS: the half diagnoses, such as the migraine patient’s diagnostic pathway, which stops at “migraine”; the “atypical angina” in a 40-year-old woman that goes no further than “atypical angina”; the second or third miscarriage that is accepted as one of nature’s misfortunes; or, especially, the memory loss in that same 40 year old who goes undiagnosed. And most troublesome, the common failure to appreciate the limitations of antiphospholipid (aPL) testing and the vital, pivotal concept of seronegative APS.
The story of APS has, for me, been an incredible journey, from the early days in the late 1970s and early 1980s, followed by the original series of publications describing the clinical features and antibody studies resulting in our description of the anti-cardiolipin syndrome and later, to the (still technically not totally correct) anti-phospholipid syndrome.1-8 In the Third International Antiphospholipid Conference in 1994 in Leuven, Belgium, my colleagues honored me by naming the syndrome,Hughes syndrome.
Thirty years on, there is still great satisfaction in diagnosing and treating APS patients with such discordant-seeming features as cataplexy and stillbirth, avascular hip necrosis and vertigo, or abdominal angina and multiple fractures—to give examples from recent clinics.
Why the Brain?
For me, APS/Hughes syndrome is very much a neurological condition. Brain function does seem to be especially targeted—the more APS patients one sees, the wider and wider the neuropsychiatric ripples spread.
There have, of course, been many promising lines of research into the pathogenesis of cerebral APS, and many mechanisms have been proposed, ranging from platelet activation, induction of tissue factor, disruption of the annexin A5 anticoagulant shield, endothelial activation and, of course, alteration of the permeability of the blood–brain barrier and direct binding to neuronal cell surfaces, some harking back to earlier forays by Bluestein, Denburg and ourselves into possible cross-reactivity between anti-lymphocyte antibodies and brain.9-13
Interactions between brain and clotting process have a long history, including the observation that the coagulation mechanism within the central nervous system has a number of differences from that found in other organs—the brain’s endothelium expressing little thrombomodulin, for example.
Whatever the mechanism, it’s difficult to avoid the observation that treatment with anticoagulation (e.g., with low molecular weight [LMW] heparin) often dramatically reverses the symptoms, including the migraine, the memory difficulties and the chorea. Such observations suggest that the brain pathology in many cases might not be so much infarction, but might relate more to “sludging” of the blood supply and impaired oxygenation.
Migraine & Stroke
“Did you suffer from headaches as a teenager?”
“Yes, doctor. They were almost weekly for a time. They went away for a few years, but they came back with a vengeance now. They run in my family.”
So speaks the 30-year-old female patient with APS (the male members of the family appear less often in APS clinics).
This is such an important diagnostic clue in the assessment of a patient with possible APS. Yet despite many years of experience of APS, there are surprisingly few data assessing the true role of APS in the wider world of migraine. There are so many reasons to study the association—the response to anticoagulation—usually good, often striking—the study of siblings and other family members of migraine/APS patients. And above all else, the links now being reported between migraine and stroke.
APS/Hughes syndrome is very much a neurological condition. Brain function does seem to be especially targeted—the more APS patients one sees, the wider & wider the neuro-psychiatric ripples spread.
Like migraine, stroke is one of the recognized complications of APS/Hughes syndrome. Figures as high as 1 in 5 young strokes (under 45) having positive aPL tests have been reported.14-19
However, as with migraine, recognition of aPL in the etiology of stroke is, in general, still poor. For example, childhood stroke—well recognized clinically—is a prime target for aPL studies.
Some years ago, the U.K. government launched a major stroke initiative, educating the public about the symptoms, signs and treatment of stroke. The antiphospholipid syndrome wasn’t on the list.
In 1985, we observed that in lupus patients, seizures were more common in those patients with positive aPL tests.20 Since then, it has become clear that epilepsy, in all its forms, is an important accompaniment of APS. So much so, that in one study of idiopathic epilepsy in teenagers, 1 in 5 was found to be aPL positive.21
Firstly, temporal lobe epilepsy in APS may be under-recognized. One of my patients, a woman with classical APS, became an EEG technician. During her training she used four of her siblings as guinea pigs. Three had abnormal temporal lobe activity. It’s interesting to see how often a family history of epilepsy crops up in the history taking of patients with APS.The ramifications of these observations are many. Let me give two clinical examples:
The second clinical anecdote has been published elsewhere.22 A 42-year-old patient had a past history of mild lupus. However, her major problem—and one with a significant impact on her busy life—was recurrent seizures, both petit mal and grand mal, the latter requiring specialist care and the combination of a number of anti-epileptic drugs. During her stay in London, she developed a DVT (she was found to be aPL positive), and routine anticoagulation with warfarin was started. An immediate and unexpected bonus was a marked reduction in the frequency and severity of the seizures, requiring far less aggressive anti-epileptic treatment.
‘THE STILLBIRTH SCANDAL: Every day as many as three babies in the UK are stillborn who could have lived. One in 200 births to British women will be stillborn. It is time for the NHS to adapt new policies and a new attitude.’ —The Times (London), Nov. 28, 2012
Possibly the commonest manifestation of APS is memory loss. Often, the problem only sees the light of day when the patient is asked about the symptom. So many patients confess to worries about Alzheimer’s. To date, detailed clinical studies are few and far between. From time to time, and, it must be said, in a fairly desultory fashion, we have carried out psychometric testing on selected APS patients—and the results have often been surprising. Even more so, given the striking improvement seen in memory tests when anticoagulation is commenced.23
In view of the prominence of neurological features, including visual disturbance and fluctuating myelopathy, seen in APS, it is not surprising that a number of cases are diagnosed as MS.24,25
The subject is far from straightforward. Some in neurology declare that positive aPL tests are, in fact, sometimes seen in classical MS. I would prefer to turn the picture around. Such patients, at least some, may be APS first and MS second. Although anecdotally a number of such cases respond to anticoagulation, in others the response is, at best, borderline. Uthman has recently reviewed the fairly substantial literature on APS vs. MS.26
Other Neurological Features
These include balance problems (a number of cases presenting as Meniere’s), chorea (sometimes severe),27,28 anosmia, sleep disturbance (including cataplexy and narcolepsy) and, recently, autonomic disturbance with a series of cases of POTS (postural orthostatic tachycardia syndrome).29
One of the questions on which there is debate is the prevalence of psychiatric manifestations.
It has been my view that acute psychosis has been more a feature of lupus than APS, but in this I may be wrong. One of my patients, a woman with APS and OCD (obsessive compulsive disorder), improved with anticoagulation treatment. Interestingly, her teenage son, also a patient with OCD (and aPL positive), found the neuropsychiatric manifestations were far less prominent when aspirin treatment was started.
Not the Brain
Bone & joints—Have you suffered any fractures? A question not perhaps part of the routine history taking in APS patients. And yet, spontaneous bone fracture is becoming well recognized following the report of 27 spontaneous metatarsal fractures by Dr. Shirish Sangle in APS patients.30
Anecdotal reports suggest that (ischemic) bone fractures may be an important manifestation of the disease: My colleague, Professor Munther Khamashta, has a Hughes syndrome patient with normal DEXA and parathyroid studies who has had 57 spontaneous fractures. Clearly, this is an important area for clinical research.
Likewise, avascular necrosis (AVN) hip pain is not uncommon in our APS patients. MRI has shown early AVN in some cases with no other risk factors, such as steroids. My clinical impression is that the hip pain often improves when heparin or warfarin is started.
Heart—A major concern is the presence of angina and other cardiac symptoms in APS. Despite a few early reports of myocardial ischemia and coronary thrombosis, it’s only in recent years that publications revealing a high frequency of these complications have increased in frequency.
Two examples are the research of Greco et al showing a relatively high prevalence of positive aPL tests in patients with cardiac ischemia, and the striking observation that women smokers on the pill who were aPL positive had a relative risk of 22 times for the development of myocardial infarction.31,32
The cardiac links are increased by the reporting of an association with cardiac syndrome X, angina with normal coronary angiographs.33 It’s a fair bet that aPL testing will become a standard in the cardiology clinic, especially in symptomatic women under 40.
Like migraine, stroke is one of the recognized complications of APS/Hughes syndrome. Figures as high as 1 in 5 young strokes (under 45) having positive aPL tests have been reported.
GI tract & liver—Since we made our observations on focal stenotic lesions in various arteries, including celiac and mesenteric arteries, we have focused more on symptoms of abdominal angina in patients with aPL/APS.34 This is a difficult condition to quantify, but we have seen a number of cases in whom clopidogrel or heparin has resulted in improvement (sometimes marked) in post-prandial pain.
Although liver involvement in lupus is rare, abnormal liver function tests in APS are seen frequently. Although these can presage serious liver thrombosis, such as Budd-Chiari syndrome or the HELLP syndrome in pregnancy warning of impending catastrophic APS, more commonly, they have a more benign prognosis.35,36
One very positive case history: Back in the early 1980s, I saw a teenage girl with a DVT, positive aPL and Budd-Chiari syndrome.
Thirty-plus years on, she remains well—on careful lifelong warfarin managed by her physicians in Portugal.
Goldblatt’s disease, the kidney & APS—Renal artery stenosis, seen on a clear background of otherwise normal arteries, can mimic Goldblatt’s early observations on the development of hypertension in animals with experimentally occluded renal arteries. The discovery of renal artery stenosis localized lesions by Sangle led to similar findings in other vessels, leading to theories about localized thrombotic/endothelial pathology.37
Skin: livedo reticularis, an enigma—Although skin ulcers, dilated veins and subungual splinter hemorrhages are well-known sequelae of skin thrombosis in APS, livedo reticularis has an aura of mystery.38,39
Diagnostically, its presence is an important clue in patients suspected of having Hughes syndrome—including seronegative APS.
Looking back over some of the conditions mentioned in this article—MS, migraine, multiple fractures, memory problems—for example, one wonders whether careful noting of the presence or absence of livedo might prove significant in the differential diagnosis of these conditions.
One thing is certain: The presence of livedo adds an extra dimension to the severity of the clinical picture.
Of course, the headline story of the syndrome is in pregnancy, where the success rate of healthy deliveries in aPL-positive pregnancies has soared from under 15% to over 90%. Without a doubt, diagnosis and treatment of these cases has been a significant advance in the world of obstetrics.40
Sadly, all of us working with APS have looked after aPL-positive patients (some of whom had suffered early miscarriages) who lost a baby late in the pregnancy. Stillbirth.
Two years ago, The Times of London published a lead article titled, “The Stillbirth Scandal,” highlighting the poor stillbirth figures in the U.K.41 Yet some cases of stillbirth in the aPL-positive women could have been prevented. For example, a recent study from Utah found that aPL pregnancies had a three- to fivefold increased odds of stillbirth.42
Would more routine aPL testing in pregnancy help? Cost considerations apply. Miscarriage is common, and there are numerous causes. Thus, the current recommendation is to reserve testing for those women with three or more miscarriages. This does seem harsh. Perhaps a simple screening process might help.
I have suggested that part of the initial midwife or obstetrician’s screening should include a simple three-part questionnaire:
- Have you had a thrombosis?
- Are you a migraine sufferer?
- Do you have a family history of autoimmune disease (i.e., lupus, RA, multiple sclerosis, thyroid disease)?
I am sure that such a simple questionnaire might help identify a small at-risk group.
In most centers, once the mother and baby are safely sent home, there is no long-term follow-up. Yet often, APS patients presenting at, say, the age of 40 with a thrombotic problem, give a past history of miscarriage 20 years earlier. In an ideal world, women with recurrent miscarriage deserve regular long-term follow-up. But the world is far from ideal.
Lupus & APS
The early clinical studies of APS were carried out in lupus clinics, and could well have included “lupus features.” Perhaps surprisingly, time has shown little difference between primary APS and the APS associated with lupus. There are, undoubtedly, some classical features of lupus (e.g., Libman Sachs endocarditis, stroke, seizures) that are more likely to be aPL related. It also appears likely that aPL positivity in lupus confers a higher chronicity index.
The passage of time has also revealed one positive finding: It’s very unusual for patients with primary APS to develop lupus in later years.
The Big 3
The association between Hughes syndrome, Sjögren’s and hypothyroidism is so common that I have taken to calling them the big 3. Clinically, it’s an important association because the clinical symptoms of the three conditions—fatigue, cold circulation, aches and pains, and balance and memory problems—are common to all three. Similarly, many of these patients are burdened with the label fibromyalgia.
Each of the three interconnecting syndromes can respond well to treatment—for example, the clinical Sjögren’s to hydroxychloroquine and so on. Many of these patients are on my two trees treatment—willow (aspirin) and cinchona (quinine).
I believe that one of the benefits of a trainee clinician’s time spent in the lab is the recognition that many laboratory tests are open to variation. Many, many studies have attempted to assess the importance of titer, immunoglobulin class, triple or double positivity, relevance of “other” aPL such as anti-phosphatidyl-serine etc.43,44
Broadly, all of these have relevance, but in the clinic, some don’t fit, such as those patients with all of the clinical features of APS whose aPL tests remain doggedly negative.
Some years ago, we wrote a paper introducing the term seronegative APS, calling attention to patients with strong clinical features of APS but with negative tests.45 The concept goes back to the early days of seronegative RA and seronegative lupus—both of which labels, although based on clinical observation alone, had important therapeutic and prognostic consequences.
Three possible explanations for seronegative APS are: 1) The diagnosis is incorrect (unlikely in all cases); 2) the previously positive tests have become negative over time (uncommon in my experience); or 3) new tests are needed.46
Perhaps the most potent reason for open-mindedness about seronegative APS comes from family studies. Some weeks ago, I saw a pair of identical twins—the first with classical seropositive APS, who later brought along her (absolutely) identical twin sister. The second twin had identical sets of symptoms, but unlike the first twin, she had negative aPL tests. Both patients responded to treatment.
Once a year, we hold a patients meeting at our hospital. At the last meeting, we arranged a simple anonymous questionnaire with two questions: Are you a patient with APS or a friend/spouse? Have you any close female relative (sister, mother, aunt) with autoimmune disease (i.e., lupus, RA, thyroid, multiple sclerosis, APS)? The result: Sixty percent of patients had a positive history of autoimmune illnesses in close relatives. Less than 20% of friends/spouses answered positive.
It may be that my own experience is skewed by referral bias from families of APS patients—but seropositive or not, most patients with seronegative APS respond just as well to treatment.
If some of these individuals in the family study did, in fact, have seronegative APS yet were potentially responsive to treatment, then the possibilities are intriguing. Perhaps a higher percentage of our migraine, young stroke, young angina patients might benefit from a closer look for more of the clues to APS—the dry Schirmer’s, the livedo, the family history of autoimmune disease—for example.
In many ways, it’s disappointing to confess that 30 years on, there are few new treatments. Introduction of the new oral anticoagulants in the treatment of APS has been predictably cautious, and it is too early to generalize.47
Statins, IVIG and hydroxychlorquine have been thrown into the mix and, of course, anti-B cell therapy has received favorable anecdotes. A recent study from Paris suggested that sirolimus, used in renal transplantation, might have a protective effect on aPL-induced vasculopathy.48
So in 2016, the current treatment of APS is still largely confined to aspirin, clopidogrel, heparin and warfarin.
Low-dose aspirin, despite its detractors, is, of course, first choice in many APS patients. However, clopidogrel remains a useful alternative in patients with gastritis or in asthmatics. But there is a third role for clopidogrel—important in the real world of practical medicine—that is, in those patients who, for whatever reason, have tried aspirin, without clear benefit.
Heparin—Low molecular weight heparin has, in most countries, largely replaced old heparin, and with it, fears of thrombocytopenia and osteoporosis have largely disappeared. This is an important point to make, because many practitioners are reluctant to prolong heparin usage.
Two observations: First, a number of patients improve dramatically on heparin, only to feel less well on warfarin.
Where to go next? When dosage issues, warfarin resistance and compliance are (hopefully) ruled out, one immediate option is a temporary return to heparin. In some cases, temporary has turned into semi-long term. In our APS clinic we have a couple dozen such patients who, by choice, have remained on subcutaneous heparin for two years or more. Yes, they have experienced bruising, but so far, we have not seen worsening DEXA scans.
The second (and very clinical) observation concerns a heparin trial. It is a regular observation that aPL/APS patients on heparin during pregnancy are often headache free for the full eight or nine months. This led us to develop a clinical tool—a therapeutic trial that has stood us in good stead. The trial is a three- or four-week course of LMW heparin.49
Let me give an example of its use: In the aPL/APS patient with increasingly severe headaches despite aspirin/clopidogrel (and with a normal brain MRI), a trial of 10,000 units of dalteparin (or enoxaparin) for three or four weeks can achieve substantial results. First, it can give a surprisingly clear indication of whether anticoagulation is the correct path. Second, in the traumatized patient who has been down the familiar pathway of multiple specialist consultations, with borderline clinical success, it can be a major turning point—the first palpable sign of improvement.
Warfarin—There is little new to say about warfarin. It has been vilified by the media, but it remains one of the most useful drugs in our armamentarium. Warfarin, to put it in simple terms, protects against stroke and heart attack in APS.
Mention has been made of the frequent need for a higher INR in many APS patients—especially those with neurological features. I am a strong believer in the use of self-testing INR machines whenever possible in our patients.
Sadly, some anticoagulant clinics oppose the use of self-testing machines. To me, this is wrong. Look at the freedom self-testing for insulin-dependent diabetics has achieved.
As physicians, I believe we have a duty (until better, newer anticoagulants become established) to support warfarin as a largely safe, effective medicine that has saved many thousands of lives.
In 2015, the current treatment of Hughes syndrome is still largely confined to aspirin, clopidogrel, heparin & warfarin.
The Family—It comes as no surprise that a family history is an important clue in Hughes syndrome. Autoimmune disease (particularly thyroid) crops up regularly as a diagnosis in relatives of our patients. But how often are these family cases diagnosed? Examples could include the 17-year-old daughter of an APS patient suffering from headache and glandular fever, the sibling with multiple sclerosis or the mother and aunt of a newly diagnosed APS patient who suffered a stroke in their early 40s.
It is not inconceivable that APS has changed the course of history, as in the case reported by my friend, Dr. Gerald Weissmann, of Queen Anne of England who had 17 failed pregnancies and died childless, thereby bringing an end to the Stuart reign and the start of the Hanoverians—with George III, American Colony taxes, the revolution and the birth of the U.S.50
The Offspring—To date, most studies have suggested that the offspring of aPL-positive mothers have no major adverse effects (other than, perhaps, the later-developing inherited APS features in some). However, some worrying case reports of fetal and neonatal problems indicate a need for further study. The ongoing studies of Drs. Anne Parke, Angela Tincani, Maria Claire Boffa and others will, in time, provide some of these missing data.51,52
Classification vs. diagnosis—
Dear Doctor, I would be grateful if you could advise on this patient. She developed thrombosis on the oral contraceptive pill. She has had one positive test for aPL, but did not have a repeat test 12 weeks later.
As in the case of lupus, classification criteria do sometimes become mixed up with diagnosis. Many patients don’t come armed with tests “12 weeks apart” (this criterion was introduced to cover the risk that an inter-current infection might have led to a transient positive aPL test—not a major factor in our assessment of this patient).
There are also financial considerations, such as in the following study from Beirut, Lebanon.
“Only 50.5% had both aCL and LA tested. … The cost of each test was around US$50 for the patient. … It remains to be seen whether the test costs might partly explain the very small percentage of patients who did undergo a follow-up confirmatory test.”
The passage of time has also revealed one positive finding: It’s very unusual for patients with primary APS to develop lupus in later years.
The recognition of the many non-thrombotic manifestations of APS has added to the importance of separating diagnosis from classification. Perhaps, laboratory advances in the measurement of potential risk markers will, in time, come to our aid.44
Fear of Flying—This clinical anecdote appears regularly in my clinic. So much so that I believe it needs further study. A number of my APS patients, notably before treatment has been started, suffer badly from prolonged jet lag after a long-haul flight, with fatigue, headache and confusion, sometimes lasting for days.
Interestingly, once heparin or warfarin treatment is successfully commenced, this phenomenon disappears. Whether these symptoms relate to mild cerebral hypoxia second to slightly reduced cabin pressure is not known. Nevertheless, some of my patients with APS will supplement their aspirin treatment prior to a long-haul flight with an injection of LMW heparin. Although the placebo effect may be considerable, I am sufficiently impressed by the clinical experience of these (observant) patients to believe that the phenomenon of prolonged jet lag in many of our patients is very real.
The Future—At the 14th International Congress on Antiphospholipid Antibodies held in Rio de Janeiro in 2013, I was asked for my predictions on the future of APS.23 In summary, I believe:
- aPL testing will become worldwide and routine;
- Over-the-counter aPL testing kits will become available;
- A substantial subset of migraine sufferers will have new hope;
- APS will become recognized as the major link between migraine and stroke;
- Heart attacks in young women (especially those under 45) will be reduced;
- Strokes in those under 45 will be reduced;
- Some cases of accelerated arterial disease will be recognized as being associated with (untreated) aPL;
- Some cases of memory loss are treatable;
- APS will continue to have a profound effect on our clinical assessment and treatment of lupus; and
- Finally, to return to the opening theme, the incidence of stillbirth will be reduced, thanks, in part, to a more proactive approach to aPL testing in pregnancy.
To repeat a sentence taken from the 1983 paper:1
For those of us hardened into nihilism by years of study of various autoantibodies in SLE, there is a rare sense of excitement at the implications of the associations now being reported.
Thirty years on, that clinical excitement remains undimmed.
Graham R.V. Hughes, MD, FRCP, is a consultant rheumatologist and head of the London Lupus Centre. He trained at The London Hospital, and spent two years in New York working on the introduction of the DNA-binding test, under the leadership of Dr. Charles Christian. In 1971, he opened a specialist clinic in London, dealing uniquely with lupus and related diseases. He is founder and editor of the international journal, Lupus. In 1983, he described the antiphospholipid syndrome and in 1991, was awarded the ILAR (world research) prize for this work. Other honors include Doctor Honoris Causa in the Universities of Marseille and Barcelona, and Master of the ACR.
- Hughes GR. Thrombosis, abortion, cerebral disease, and the lupus anticoagulant. Br Med J (Clin Res Ed). 1983 Oct 15;287(6399):1088–1089.
- Harris EN, Gharavi AE, Boey ML, et al. Anticardiolipin in antibodies: Detection by radioimmunoassay and association with thrombosis in SLE. Lancet. 1983 Nov 26;2(8361):1211–1214.
- Boey ML, Colaco CB, Gharavi AE, et al. Thrombosis in SLE: Striking association with the presence of circulating lupus anticoagulant. Br Med J (Clin Res Ed). 1983 Oct 8;287:1021–1023.
- Hughes GR. The Prosser White oration 1983: Connective tissue disease and the skin. Clin Exp Dermatol. 1984 Nov;9(6):535–544.
- Asherson RA, Mackworth-Young CG, Boey ML, Hughes GRV. Pulmonary hypertension in systemic lupus erythematosus.Br Med J (Clin Res Ed). 1983 Oct 8;287(6398):1024–1025.
- Derue GJ, Englert HJ, Harris EN, et al. Fetal loss in systemic lupus: Association with anticardiolipin antibodies. J Obstet Gynaecol. 1985;5(4):207–209.
- Hughes GR, Harris NN, Gharavi AE. The anticardiolipin syndrome. J Rheumatol. 1986 Jun;13(3):486–489.
- Hughes GR. Hughes’ syndrome: The anticardiolipin syndrome. A historical view. Lupus. 1998;7 Suppl 2:S1–S4.
- Carecchio M, Cantello R, Comi C. Revisiting the molecular mechanism in antiphospholipid syndrome: Beyond vascular damage. J Immunol Res. 2014;2014:239398.
- Bluestein HG, Zvaifler NJ. Brain-reactive lymphocytotoxic antibodies in the serum of patients with SLE. J Clin Invest. 1976 Feb;57(2):509–516.
- Bresnihan B, Oliver N, Grigor R, Hughes GR. Brain-reactivity of lymphocytotoxic anitibodies in systemic lupus erythematosus with and without cerebral involvement. Clin Exp Immunol. 1977 Dec;30(3):333–337.
- Bresnihan B, Hohmeister R, Cutting J, et al. The neuropsychiatric disorder in SLE: Evidence for both vascular and immune mechanisms. Ann Rheum Dis. 1979 Aug;38(4):301–306.
- Denburg SD, Behmann SA, Carbotte RM, et al. Lymphocyte antigens in neuropsychiatric systemic lupus erythematosus. Relationship of lymphocyte antibody specificities to clinical disease. Arthritis Rheum. 1994 Mar;37(3):369–375.
- Harris EN, Gharavi AE, Asherson RA, et al. Cerebral infarction in SLE. Association with anticardiolipin antibodies. Clin Exp Rheumatol. 1984 Jan-Mar;2(1):47–51.
- Navarrete MG, Brey RL, Levine SR. “Cerebral disease in the antiphospholipid syndrome” in Hughes Syndrome—Antiphospholipid Syndrome. Khamashta MA, ed. Springer, London: 2000.
- Sanna G, Bertolaccini ML, Cuadrado MJ, et al. Central nervous system involvement in the antiphospholipid (Hughes) syndrome. Rheumatology (Oxford). 2003 Feb;42(2):200–213.
- Etminan M, Takkouche B, Isorna FC, Samii A. Risk of ischaemic stroke in people with migraine: Systemic review and meta-analysis of observational studies. BMJ. 2005 Jan 8;330(7482):63.
- Nencini P, Baruffi MC, Abbate R, et al. Lupus anticoagulant and anticardiolipin antibodies in young adults with cerebral ischaemia. Stroke. 1992 Feb;23(2):189–193.
- Hughes GR. Antiphospholipid syndrome, migraine and stroke. Lupus. 2010 Apr;19(5):555–556.
- Mackworth-Young CG, Hughes GR. Epilepsy: An early symptom of systemic lupus erythematosus. J Neurol Neurosurg Psychiatry. 1985 Feb;48(2):185.
- Cimaz R, Meroni PL, Shoenfeld Y. Epilepsy as part of systemic lupus erythematosus and systemic antiphospholipid syndrome (Hughes syndrome). Lupus. 2006;15(4):191–194.
- Hughes GR. “Diplomatic epilepsy” in Understanding Hughes Syndrome. Springer-Verlag, London: 2009.
- Hughes GR. Hughes syndrome/APS. 30 years on, what have we learnt? Opening talk at the 14th International Congress on antiphospholipid antibodies. Rio de Janeiro, October 2013. Lupus. 2014;23:400–406.
- Cuadrado MJ, Khamashta MA, Ballesteros A, et al. Can neurologic manifestations of Hughes (antiphospholipid) syndrome be distinguished from multiple sclerosis? Analysis of 27 patients and review of the literature. Medicine (Baltimore). 2000 Jan;79(1):57–68.
- Hughes GR. Migraine, memory loss, and “multiple sclerosis.” Neurological features of the antiphospholipid (Hughes’) syndrome. Postgrad Med J. 2003 Feb;79(928):81–83.
- Uthman I, Noureldine MH, Berjawi A, et al. Hughes syndrome and multiple sclerosis. Lupus. 2015 Feb;24(2):115–121.
- Cervera R, Asherson RA, Font J, et al. Chorea in the antiphospholipid syndrome. Clinical, radiologic, and immunologic characteristics of 50 patients from our clinics and the recent literature. Medicine (Baltimore). 1997 May;76(3):203–212.
- Baizabal-Carvallo JF, Bonnet C, Jankovic J. Movement disorders in systemic lupus erythematosus and the antiphospholipid syndrome. J Neural Transm (Vienna). 2013 Nov;120(11):1579–1589.
- Schofield JR, Blitshteyn S, Shoenfeld Y, et al. Postural tachycardia syndrome (POTS) and other autonomic disorders in antiphospholipid (Hughes) syndrome (APS). Lupus. 2014 Jun;23(7):697–702.
- Sangle S, D’Cruz DP, Khamashta MA, et al. Antiphospholipid antibodies, systemic lupus erythematosus, and non-traumatic metatarsal fractures. Ann Rheum Dis. 2004 Oct;63(10):1241–1243.
- Greco TP1, Conti-Kelly AM, Greco T Jr., et al. Newer antiphospholipid antibodies predict adverse outcomes in patients with acute coronary syndrome. Am J Clin Pathol. 2009 Oct;132(4):613–620.
- Urbanus RT, Siegerink B, Roest M, et al. Antiphospholipid antibodies and risk of myocardial infarction and ischaemic stroke in young women in the RATIO study: A case-control study. Lancet Neurol. 2009 Nov;8(11):998–1005.
- Nair S, Khamashta MA, Hughes GR. Syndrome X and Hughes syndrome. Lupus. 2002;11(5):332.
- Sangle SR, Jan W, Lau IS, et al. Coeliac artery stenosis and antiphospholipid (Hughes) syndrome/antiphospholipid antibodies. Clin Exp Rheumatol. 2006 May–Jun;24(3):349.
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