Miscellaneous rare causes of stroke
Stroke complicates pregnancy and the puerperium in about 10 per 100 000 deliveries in developed countries, about twice the background rate (Grosset et al. 1995; Sharshar et al. 1995; Kittner et al. 1996; Mas and Lamy 1998). Causes and mechanisms particularly relevant to pregnancy, rather than to young stroke in general, have not been well studied but include intracranial venous thrombosis; cervical arterial dissection during labour; acute middle cerebral or other large artery occlusion, perhaps due to paradoxical embolism from the leg or pelvic veins; low-flow infarction and disseminated intravascular coagulation complicating eclampsia and other obstetric disasters; puerperal angiopathy, perhaps due to ergot-type and other vasoconstricting drugs or dopaminergic agonists such as bromocriptine; infective endocarditis; peripartum cardiomyopathy; sickle-cell crisis; and intracranial haemorrhage(s) due to eclampsia, anticoagulants, rupture of a pre-existing aneurysm or vascular malformation (Wiebers 1985; Wiebers and Mokri 1985; Cantu and Barinagarrementeria 1993; Dyken and Biller 1994; Comabella et al. 1996; Drislane and Wang 1997). Metastases of choriocarcinoma can present with stroke-like episodes, and on CT look remarkably like primary intracerebral haemorrhages. The risk of recurrent stroke in any future pregnancy is of crucial interest, but unknown. Presumably if no underlying cause is found for the first stroke, the risk of recurrence is low. An ever-increasing number of strokes caused by drug abuse are being reported, at least from the USA where the problem has been recognized for some years (Caplan et al. 1982; McEvoy et al. 1998). At present the most commonly implicated drug is cocaine (and its ‘crack’ form) which causes cerebral infarction, intracerebral and subarachnoid haemorrhage, usually within hours of use. Although a ‘vasculitis’ has been described, more likely explanations are an acute rise in blood pressure and intracranial haemorrhage; an underlying vascular malformation or aneurysm; cardiac arrhythmia, cardiomyopathy and cerebral embolism; and cerebral vasoconstriction (Cregler and Mark 1986; Krendel et al. 1990; Levine et al. 1990; Fredericks et al. 1991; Daras et al. 1991; Kaufman et al. 1998).
Amphetamines can cause a small vessel vasculopathy, leading to intracerebral haemorrhage or infarction. Acute hypertension, perhaps with a pre-existing vascular anomaly, is a likely mechanism of intracerebral haemorrhage (Harrington et al. 1983; Rothrock et al. 1988; Heye and Hankey 1996). Other sympathomimetic drugs such as ephedrine, phenylpropanolamine, fenfluramine and phentermine may cause stroke by similar mechanisms, as may ‘Ecstasy’ (Glick et al. 1987; Kase et al. 1987; Harries and De Silva 1992; Henry et al. 1992; Bruno et al. 1993; Wen et al. 1997).
Other causes of stroke in drug abusers should not, of course, be forgotten (infective endocarditis and HIV infection) and nor should the frequent complications of head injury and alcohol abuse. Stroke in cancer patients can easily be a coincidence, but causal possibilities include embolism of non-infected heart valve vegetations (non-bacterial thrombotic—or marantic—endocarditis;); infection (fungi, herpes zoster, bacterial endocarditis); tumour emboli, sometimes with secondary aneurysm formation and then rupture; haemorrhage into primary tumours (malignant astrocytoma, oligodendroglioma, medulloblastoma, haemangioblastoma) and metastases (melanoma, germ cell tumours, choriocarcinoma, lung, hypernephroma); haemostatic failure (leukaemia, etc.); hyperviscosity syndrome; "hypercoagulability"; disseminated intravascular coagulation; and intracranial venous thrombosis (Hickey et al. 1982; Graus et al. 1985). Irradiation damage or neoplastic compression or invasion of neck arteries are both most unusual causes of ischaemic stroke.
Perioperative stroke complicates well under 5 per cent of non-cardiac surgical procedures (for cardiac surgery, see Section 27.4.5). It can be due to hypotension and boundary zone infarction, trauma to and dissection of neck arteries, paradoxical embolism, fat embolism, infective endocarditis, myocardial infarction, atrial fibrillation, and a haemostatic defect caused by antithrombotic drugs or disseminated intravascular coagulation (Hart and Hindman 1982; Tettenborn et al. 1993). It is more common in patients with previous strokes, other manifestations of vascular disease, and chronic obstructive lung disease (Limburg et al. 1998).
The relationship between migraine and stroke is difficult to disentangle (Olesen et al. 1993). For some reason stroke is probably rather more frequent in migraineurs, particularly young women, than in the normal population (Chang et al. 1999). However, a ‘normal’ stroke (with an obvious cause such as carotid atherothromboembolism) may precipitate a migrainous episode of a type previously experienced, or be followed by typically migrainous attacks which have never been experienced before. Or sometimes symptomatic migraine with aura seems to be precipitated by severe carotid stenosis. Also, a ‘normal’ stroke may start in the midst of a typical migrainous episode for that patient and so appear to be provoked by it. The term ‘migrainous stroke’ should be reserved for a persisting focal neurological deficit which starts during a typical migrainous aura (with or without headache), clearly mimicking the symptomatology of previously experienced auras, and for which there is no better, or even other, explanation (Bousser et al. 1985a).
Such migrainous strokes usually cause a homonymous hemianopia or focal sensory deficit, seldom persisting disability, and do not appear to recur very often (Henrich et al. 1986; Broderick and Swanson 1987; Hoekstra-van Dalen et al. 1996). Sometimes arterial occlusion is demonstrated by angiography and the cause is postulated as ‘vasospastic’. No provoking factors are known. Naturally other possible causes of stroke in the context of migraine-like headache must be seriously considered (i.e. carotid dissection, antiphospholipid antibody syndrome, mitochondrial cytopathy, ruptured vascular malformation, CADASIL). When diagnostic mistakes are made, the strokes are seldom truly migrainous in the sense described above (Shuaib 1991; Tietjen 1995). Migraine auras without headache may be confused with TIAs.
Chronic meningitis may involve the arteries at the base of the brain, or the perforating arteries, and so be complicated by ischaemic stroke and intracranial haemorrhage. This has been well described in tuberculous, syphilitic, and fungal infections (Dalal and Dalal 1989; Landi et al. 1990; Saez de Ocariz et al. 1996). Very occasionally acute infection can cause inflammation of, and secondary thrombosis in, the carotid artery in the neck (e.g. tonsillitis, pharyngitis, lymphadenitis; Bickerstaff 1964); in the dural sinuses (otitis media, etc.); and in the cerebral arteries and veins: bacterial meningitis (Igarashi et al. 1984), ophthalmic herpes zoster and chicken pox (Bourdette et al. 1983; Leopold 1993; Melanson et al. 1996), cysticercosis (del Brutto 1992; Bang et al. 1997), leptospirosis (Lessa and Cortes 1981), mycoplasma (Mulder and Spierings 1987), AIDS (Park et al. 1990; Qureshi et al. 1997), cat scratch disease (Selby and Walker 1979), neurotrichinosis (Fourestie et al. 1993), and possibly borreliosis (Reik 1993).
Inflammatory bowel disease
Inflammatory bowel disease, both ulcerative and Crohn's colitis, may occasionally be complicated by intracranial venous thrombosis or arterial occlusion (Johns 1991; Jorens et al. 1991; M. Jackson et al. 1993; Lossos et al. 1995). The bowel disease is not necessarily severe at the time. This association has been related to thrombocytosis, hypercoagulability, immobility and paradoxical embolism from the legs, vasculitis and dehydration, but with no very good evidence. Coeliac disease can also be complicated by a cerebral vasculitis, but this presents more with an encephalopathy than with stroke (Mumford et al. 1996).
Homocystinuria, an autosomal recessive inborn error of metabolism, is complicated by cerebral arterial or venous thrombosis (Schimke et al. 1965; Visy et al. 1991; Rubba et al. 1994). Heterozygotes may have an increased risk of vascular disease.
Fabry's disease is occasionally complicated by ischaemic stroke, particularly in the vertebrobasilar territory, but usually not until after other more common features are well established (Mitsias and Levine 1996) (Section 12.8.5).
Mitochondrial cytopathy may present with stroke-like episodes with hypodensity on CT scan, particularly in the occipital regions, and complicated by epilepsy. There are often other clinical features, such as calcification of the basal ganglia, migraine, episodic vomiting, short stature, sensorineural deafness, diabetes, and learning disability. A particular syndrome is known as MELAS (mitochondrial encephalopathy, lactic acidosis, and strokes). The blood and CSF lactate are usually raised and most patients have an abnormal muscle biopsy (Hasuo et al. 1987; Ciafaloni et al. 1992; Gilchrist et al. 1996).
Hypoglycaemia, almost always as a result of hypoglycaemic drugs rather than an insulinoma, is a well-recognized, but rare, cause of transient focal neurological episodes, particularly right hemiplegia and aphasia masquerading as TIAs. Consciousness is normal and there is a striking absence of the usual systemic manifestations of hypoglycaemia. The episodes tend to occur on waking in the morning, or after exercise. By the time the patient is seen, the blood glucose may well have returned to normal. Persisting focal deficits seem to be unusual (Malouf and Brust 1985; Wallis et al. 1985; Service 1995; Shanmugam et al. 1997).
Hypercalcaemia (Longo and Witherspoon 1980) and, less convincingly, hyponatraemia (Ruby and Burton 1977; Berkovic et al. 1984) have been reported to cause TIA-like episodes.
Fibrocartilaginous embolism is a rare and curious disorder where fibrocartilaginous emboli, presumably from degenerative intervertebral disc material, are found in various organs—the spinal cord more often than the brain (Toro-Gonzales et al. 1993).
Snake bite with injection of venom may cause intracranial haemorrhage, as a consequence of defibrination and other haemostatic defects, and rarely ischaemic stroke (Bashir and Jinkins 1985).
Fat embolism, which occurs following long bone fracture or surgery, usually causes a global encephalopathy, but on occasion there may be focal features, presumably reflecting focal ischaemia (Jacobson et al. 1986; van Oostenbrugge et al. 1996).
Epidermal naevus syndrome
Epidermal naevus syndrome, a sporadic neurocutaneous disorder, can be complicated by stroke (Dobyns and Garg 1991).
Susac's syndrome is a rare triad of branch retinal artery occlusions, hearing loss, and microangiopathy of the brain, causing a subacute encephalopathy, almost only in women (Ballard et al. 1996).