Neural Images

23 Neural Images Raymond Tak-Fai Cheung Case 23.1 Leading question A 55-year-old woman with a history of hypertension presents with sudden onset of unilateral weakness.

354 Problem-Based Medical Case Management Case 23.1 Questions 1. 2. 3. 4. Describe two CT abnormalities. ‘What is the CT diagnosis? Name two neurological deficits likely present. ‘What is the most likely underlying aetiology? Answers 1. 2. Left subcortical/lenticular/basal ganglial hyperdense lesion; mass effect/obliteration of left lateral ventricle/midline shift. Acute left intracerebral haemorrhage/subcortical haematoma/ lentiform haematoma. Right hemiparesis/hemiplegia, right-sided facial weakness of upper motor neurone pattern, dysarthria, right hemisensory loss. Hypertension. Description Hyperdense lesions in plain CT of the head are due to haemor- rhage or calcification. Calcification is typically symmetrical and not space-occupying. Haematoma is space-occupying and leads to obliteration of ventricles, effacement of sulcal spaces, and midline shift. Intracerebral haemorrhage typically produces contralateral weakness of limbs and face, contralateral sensory loss over limbs and face, and dysarthria. Discussion About 20-25% of strokes are due to intracerebral haemorrhage. Common causes include hypertension, bleeding tendency, and - cerebral amyloid angiopathy. Less common causes include arteriovenous malformation, cav- ernoma, thrombolysis, aneurysm, Moyamoya disease, tumour, vasculitis, and drug abuse. .

Case 23.2 Neural Images 355 + Typical locations of hypertensive intracerebral haemorrhage include lentiform nucleus, thalamus, brainstem, and cerebellum. « Medical or conservative management is usually adopted for deep-seated haemorrhage. Neurosurgical evacuation may be life-saving, but does not improve the quality of life. Case 23.2 Leading question A 53-year-old man with a history of hypertension, diabetes mel- litus, hypercholesterolaemia, and atrial fibrillation presents with sudden onset of unilateral weakness and language deficits.

356 Problem-Based Medical Case Management Case 23.2 Questions 1. Describe the CT abnormalities. 2. What is the CT diagnosis? 3. Name three neurological deficits likely present. 4. What preventive measures should be considered? Answers 1. Left cortical and subcortical hypodense lesion involving the lentiform nucleus, caudate nucleus, frontal and temporal cortex (left middle cerebral artery territory); presence of some isodense areas within the hypodense lesion due to petechial haemorrhagic transformation. . Recent left middle cerebral artery territory ischaemic infarc- tion/stroke with petechial haemorrhagic transformation of infarction. Right hemiparesis/hemiplegia, right-sided facial weakness of upper motor neurone pattern, aphasia, dysarthria, right hemi- sensory loss. Optimal control of hypertension and diabetes mellitus, use of aspirin or another antiplatelet agent, use of a statin, consider- ing long-term anti-coagulation with warfarin or a new oral anti-coagulant. Description Hypodense lesions in plain CT of the head are due to infarction or oedema. Oedema mainly involves the subcortical white matter, produc- ing a finger-like pattern. Infarction involves both grey and white matter unless it is small. Haemorrhagic transformation occurs upon spontaneous Or therapeutic reperfusion, leading to petechial haemorrhage or frank haematoma.

Case 23.3 Neural Images 357 Left middle cerebral artery infarction produces right-sided weakness over limbs and face, right-sided sensory loss over limbs and face, aphasia, dysarthria. Discussion About 70-75% of strokes are due to cerebral infarction (ischae- mic stroke). Common causes include atherothrombosis, thromboembolism, cardioembolism, and small vessel arteriolosclerosis. Less common causes include dissection, hypercoagulopathy, Moyamoya disease, vasospasm, vasculitis, drug abuse, and migraine. Common risk factors are hypertension, diabetes mellitus, hyper- cholesterolaemia, extra- or intracranial stenosis, atrial fibril- lation, valvular heart disease, ischaemic heart disease, other cardioembolic conditions, smoking, alcohol abuse, obesity, advanced age, and male gender. Preventive measures include identification and optimal con- trol of all modifiable risk factors, use of aspirin or another antiplatelet agent, surgical or intervention for severe extracra- nial stenosis, considering anti-coagulation for cardioembolic strokes, cessation of smoking, moderation of drinking, regular exercise, and weight reduction. Case 23.3 Leading question A 75-year-old woman with good past health presents with sudden onset of unilateral weakness. (See p. 358.)

358 Problem-Based Medical Case Management Case 23.3 Questions 1. Describe the CT abnormalities. 2. What is the CT diagnosis? 3. Please name two neurological deficits likely present. 4. What is the most likely underlying aetiology? Answers 1. Right frontoparietal hyperdense lesion with surrounding hypodense rim; sulcal effacement from mass effect. 2. Acute right lobar intracerebral haemorrhage. 3. Left hemiparesis/hemiplegia, left-sided facial weakness of upper motor neurone pattern, dysarthria, left-sided cortical sensory loss. 4. Cerebral amyloid angiopathy.

Case 23.4 Neural Images 359 Description . Hyperdense lesions in plain CT of the head are due to haemor- rhage or calcification. Calcification is typically symmetrical and not space-occupying. Haematoma is space-occupying and leads to obliteration of ventricles, effacement of sulcal spaces, and midline shift. Intracerebral haemorrhage typically produces contralateral weakness of limbs and face, contralateral sensory loss over limbs and face and dysarthria. Involvement of parietal cortex may cause contralateral cortical sensory loss. Discussion About 20-25% of strokes are due to intracerebral haemorrhage. Common causes include hypertension, bleeding tendency, and cerebral amyloid angiopathy. Patients with cerebral amyloid angiopathy are usually 70 years or older. Less common causes include arteriovenous malformation, cav- ernoma, thrombolysis, aneurysm, Moyamoya disease, tumour, vasculitis, and drug abuse. Typical locations of intracerebral haemorrhage from cerebral amyloid angiopathy are lobar, subarachnoid, and mutifocal. Recurrent haemorrhage is common. Medical or conservative management is usually adopted. Neurosurgical biopsy may confirm amyloid angiopathy, but haemostasis is a concern. Case 23.4 Leading question A 45-year-old man with good past health presents with sudden onset of unilateral facial numbness and limb ataxia, contralateral numbness, dysphagia, and vertigo. He receivad vigorous massage over his neck 3 days ago. (See p. 360.)

360 Problem-Based Medical Case Management Case 23.4 Questions 1. Describe the abnormalities. 2. What is the diagnosis? 3. Describe the neurological deficits. 4. What is the most likely underlying aetiology? Answers 1. Hyperintense signal over right lateral medulla; right vertebral artery occlusion. 2. Right lateral medullary syndrome/infarction or Wallenberg’s syndrome. 3. Spinothalamic sensory loss over right face and left arm and leg, right-sided cerebellar ataxia, right Horner’s syndrome, dyspha- gia, nystagmus, vertigo. 4. Right vertebral artery dissection, leading to thrombosis.

Case 23.4 Neural Images 361 Description Diffusion-weighted imaging reveals the acute infarction in the form of a hyperintense signal. Magnetic resonance angiography shows the luminal anatomy of cerebral arteries. Lateral medullary infarction can result from thrombosis of ver- tebral artery, basilar artery, posterior inferior cerebellar artery, anterior inferior cerebellar artery or superior cerebellar artery. There is involvement of trigeminal nucleus and tract, spinocer- ebellar tract, spinothalamic tract, nucleus solitarius, nucleus ambiguus, ninth and tenth nuclei, and sympathetic fibres. Discussion Arterial dissection should be considered in young stroke patients without vascular risk factors especially if there is a history of recent trauma or manipulation of the neck. Tears occur in a major neck artery with bleeding into the arterial wall, leading to stenosis, occlusion, and/or aneurismal dilata- tion. Spontaneous dissection also oceurs, especially in patients with Ehlers-Danlos syndrome, Marfan syndrome, polycystic kidney disease, osteogenesis imperfecta type I, fibromuscular dysplasia, and cystic medial necrosis. Dissection can be asymptomatic. Characteristic features include unilateral headache, facial or neck pain, Horner’s syndrome, recurrent transient ischaemic attacks, cranial nerve palsies, pul- satile tinnitus, and audible bruit. Dissection can be confirmed by digital subtraction angiography, magnetic resonance angiography, and CT angiography. Anti-coagulation for 3-6 months is considered. Aspirin is an alternative and also for long-term use if luminal irregulari- ties persist. Endovascular or surgical treatment is reserved for patients with persistent symptoms despite anti-coagulation.

362 Problem-Based Medical Case Management Case 23.5 Case 23.5 Leading question A 36-year-old man with good past health presents with confused speech, poor memory, and disorientation. He has had flu-like illness for 3 days. Questions 1. Describe the magnetic resonance imaging abnormalities. 2. What is the diagnosis? 3. Name the possible complications. 4. Outline the specific treatment.

Case 23.5 Neural Images 363 Answers 1. Hyperintense signal over right mesiotemporal region with mildly thickened cortices over the right temporal lobe in the T2-weighted and FLAIR images; abnormal gadolinium enhancement over the right mesiotemporal region in the T1-weighted image. Herpes simplex encephalitis (viral encephalitis with temporal lobe involvement). 3. Epileptic seizures, aphasia, hemiparesis, amnesia, coma. 4. Acyclovir, anticonvulsant, corticosteroids. IS Description * Hyperintense signal on T2-weighted and FLAIR images indi- cates increased water content. Abnormal enhancement with gadolinium indicates break-down of the blood-brain barrier. * Predominant involvement of cortex suggests encephalitis. * Herpes simplex encephalitis has a predilection for the temporal and frontal lobes. Discussion * Encephalitis refers to inflammation of brain tissue. Grey matter is predominately involved in acute viral encephalitis; coexisting viral meningitis is common. Post-infectious encephalitis typi- cally causes white matter demyelination. * Features include non-specific symptoms of infection, altered mental state, seizures, focal deficits, aphasia, amnesia, and myoclonus. * CT may be normal. Useful investigations include magnetic res- onance imaging, cerebrospinal fluid analyses, polymerase chain reaction, paired sera for viral titre, and electroencephalogram. Brain biopsy is seldom performed nowadays. * Herpes simplex type 1 is the most common cause of sporadic encephalitis worldwide. There is a predilection for the temporal and frontal lobes.

364 Problem-Based Medical Case Management Case 23.6 * Specific treatment includes acyclovir, anticonvulsant, and corti- costeroids. Mortality and disability are high if left untreated or treatment is delayed. Case 23.6 Leading question A 19-year-old college student with good past health presents with low-grade fever, headache, nausea, vomiting, and ataxia. Cerebrospinal fluid examination shows a total cell count of 120 per puL (86% lymphocytes), protein concentration of 2.6 g/L, and glucose concentration of 1.8 mmol/L (plasma glucose level = 5.8). Questions 1. Describe the CT abnormality. 2. Explain the cerebrospinal fluid findings. 3. What is the most likely diagnosis? 4. Outline the management.

Case 23.6 Neural Images 365 Answers 1. Dilated lateral and third ventricles with sulcal effacement indicative of obstructive hydrocephalus. Lymphocytic pleocytosis with low glucose level and high protein level indicative of chronic bacterial meningitis (e.g., tuberculosis) or fungal meningitis. Tuberculous meningitis with obstructive hydrocephalus. . Multiple anti-tuberculous drugs for 9-12 months, shunting of hydrocephalus, a course of corticosteroids, monitoring of response with clinical and radiological assessment, and repeated lumbar puncture. Description Ventricles are slit-like in young subjects. Dilated ventricles with sulcal effacement suggest obstructive hydrocephalus. Although lymphocytic pleocytosis is consistent with viral men- ingitis, low glucose level is against this possibility. High protein level indicates a chronic type of infection. Urgent external ventricular drainage and/or ventriculo-perito- neal shunting should be considered in obstructive hydrocepha- lus. Lumbar puncture is contra-indicated. Extra-pulmonary tuberculosis requires a longer duration of standard anti-tuberculous chemotherapy. A course of corti- costeroids is indicated in stage II or I tuberculous meningitis (lethargy, prominent meningeal irritation, cranial nerve palsies, hydrocephalus, convulsion, paralysis, stupor or coma). Discussion . Acute rather than chronic presentation of tuberculous meningi- tis is common in Hong Kong. Possible complications include hydrocephalus, cranial nerve palsies, tuberculoma, spinal block, stroke, tuberculous brain abscess, and myeloradiculopathy.

366 Problem-Based Medical Case Management Case 23.7 » Delayed treatment is associated with a high mortality and disability. * Anti-tuberculous chemotherapy carries a high risk of adverse effects: isoniazid (hepatitis, peripheral neuropathy); rifampicin (drug interactions, hepatitis, fever and vasculitis, nausea and vomiting); ethambutol (optic neuritis, hepatitis, peripheral neu- ropathy); pyrazinamide (hepatitis, gout). Case 23.7 Leading question A 52-year-old man presents with gradual onset of headache, nausea, and vomiting. He also has several episodes of involuntary twitching of his right leg. His serum and urine osmolality are 250 and 500 milliosmole/kg, respectively. He is a chronic smoker.

Case 23.7 Neural Images 367 Questions W — . Describe the abnormalities. . What is the most likely diagnosis? . What complications have developed? . Outline the management for his neurological condition and the above complications. Answers L. Hypodense lesions in the form of finger-like projections over the left frontal and parietal regions as well as the right frontal and parieto-occipital regions; contrast-enhancing nodules over the right fronto-parietal regions; sulcal effacement, obliteration of lateral ventricle, and right-to-left midline shift indicative of mass effects. . Cerebral metastases (likely to have underlying carcinoma of lung). Focal motor epileptic seizures, raised intracranial pressure, syn- drome of inappropriate antidiuretic hormone secretion. High-dose corticosteroids for vasogenic oedema and raised intracranial pressure, prophylactic anti-convulsant for focal seizures, palliative whole brain irradiation for cerebral metas- tases and fluid restriction plus sodium chloride supplement for syndrome of inappropriate antidiuretic hormone secretion. Description Hypodensity on CT indicates cytotoxic or vasogenic oedema. Vasogenic oedema predominately affects the white matter, leading to a finger-like projection pattern. Sulcal effacement, obliteration of ventricles, and midline shift indicate mass effect.

368 Problem-Based Medical Case Management Case 23.8 Contrast-enhancement indicates breakdown of blood-brain barrier, e.g., metastasis, inflammation, infection, infarction. Low serum osmolality and high urine osmolality indicate inap- propriate secretion of antidiuretic hormone. Episodic involuntary contractions of a limb suggest focal motor seizures. Discussion Cerebral metastasis commonly arises from carcinomas of lung, breast, kidney, and colon as well as from choriocarcinoma and malignant melanoma. Secondaries to the brain are more common than primary brain tumours. Focal features of insidious onset and gradual progression are typical. Focal seizures and raised intracranial pressure are common. CT or magnetic resonance imaging of the brain with and without contrast, electroencephalogram, and screening of the primary are appropriate. Lumbar puncture is contra-indicated. Case 23.8 Leading question A 62-year-old man with hypertension, diabetes mellitus, and hypercholesterolaemia presents with an episode of transient blind- ness of his left eye. He is a chronic smoker and a heavy drinker. Neck bruits are present.

Case 23.8 Neural Images 369 Questions 1. Describe the abnormality. 2. What is the diagnosis of his transient neurological symptom? 3. What complication is he at risk of developing? 4. Qutline the treatment options. Answers 1. Severe stenosis (narrowing) of his proximal left internal carotid artery. 2. Left amaurosis fugax (transient monocular blindness). . Left middle cerebral artery territory ischaemic stroke. 4. Control of risk factors, use of an antiplatelet agent, carotid endarterectomy or percutaneous transluminal angioplasty and stenting, cessation of smoking, and moderation of drinking. W

370 Problem-Based Medical Case Management Case 23.8 Description Digital subtraction angiography is the gold-standard examina- tion for suspected arterial lesions. Severe stenosis of the internal carotid artery is associated with a higher risk of ipsilateral transient ischaemic attacks or strokes. Mechanisms include thromboembolism and haemodynamic compromise. The ophthalmic artery is a branch of the internal carotid artery. The internal carotid artery terminates into the middle cerebral artery. Discussion Internal carotid artery stenosis is an important cause of ischae- mic stroke, especially in Caucasians. The actual risk of stroke is increased by the following factors: occurrence of symptoms, higher degree of stenosis, presence of ulceration, contralateral occlusion, inadequate collaterals, coexistence of multiple risk factors, and cerebral infarction on CT. Use of aspirin or another antiplatelet agent and control of risk factors should be adopted in all patients. Carotid endarterectomy carries a risk of stroke, death, cranial nerve palsy, hoarseness of voice, and wound complications. Carotid endarterectomy is indicated in patients with severe symptomatic stenosis of the internal carotid artery if the risk of surgery is less than 6%. Percutaneous transluminal angioplasty and stenting are alternatives.

Case 23.9 Neural Images 371 Case 23.9 Leading question A 60-year-old woman with good past health presents with sudden onset of severe occipital headache, neck stiffness, and vomiting. Questions 1. Describe the abnormality. 2. What is the diagnosis? 3. What are the useful investigations? 4. What other neurological features are possible? 5. Outline the management.

372 Problem-Based Medical Case Management Case 23.9 Answers 1. . Subarachnoid haemorrhage from leakage of the giant aneurysm. . CT of the head, lumbar puncture, and cerebrospinal fluid A giant fusiform aneurysm of the basilar artery. analysis. . Features of brainstem compression, thromboembolic events to brainstem and posterior cerebral artery territory (homonymous hemianopia, thalamic sensory symptoms). Neurosurgical clipping and decompression or endovascular coiling of the aneurysm, prophylactic anti-convulsant, close neuro-observation, surveillance of complications, a course of calcium antagonist (e.g., nimodipine). Description Digital subtraction angiography is the gold-standard examina- tion for suspected arterial lesions. Abnormal dilatation of an artery is termed aneurysm. The shape can be fusiform or saccular. An aneurysm may rupture into subarachnoid space to cause subarachnoid haemorrhage or into brain parenchyma to cause intracerebral haemorrhage. A large aneurysm has a greater risk of rupture and may com- press onto the neighboring structures. Turbulent flow inside may lead to thromboembolic events. Discussion Typical features of subarachnoid haemorrhage are severe head- ache of sudden onset, neck stiffness, and symptoms of raised intracranial pressure. Impaired consciousness is common. CT shows hyperdense signal of the blood in the subarachnoid space, ventricles, and/or cisterns in 95% of patients. Presence of blood in cerebrospinal fluid is also diagnostic. Lumbar puncture is usually reserved for CT-negative cases. Examination for xanthochromia is crucial when there is a

Case 23.10 Neural Images 373 relatively long interval between the suspected bleeding and [umbar puncture. » Complications include rebleeding, vasospasm, hydrocephalus, cerebral oedema, seizure, syndrome of inappropriate anti- diuretic hormone secretion, cardiac arrhythmias, and other complications. Case 23.10 Leading question A 55-year-old man with hypertension and diabetes mellitus pre- sents with a 2-year history of episodic neck pain with radiation down to the arms, a 6-month history of bilateral arm weakness and a 3-month history of difficulty in walking.

374 Problem-Based Medical Case Management Case 23.10 Questions 1. Describe the abnormalities. 2. What is the diagnosis? 3. Describe the neurological deficits. 4. Outline the treatment options. Answers 1. Spondylotic changes of the cervical spine; obliteration of the cerebrospinal space anterior and posterior to the cervical spinal cord from herniating intervertebral discs; osteophytes, ossified posterior longitudinal ligament, and hypertrophied ligamentum flavam; compression of the cervical spinal cord at multiple levels. Cervical spondylotic radiculomyelopathy. . Cervical radiculopathy with sensory symptoms and lower- motor-neurone pattern of weakness over multiple cervical roots, spastic paraparesis, and dorsal column sensory deficits from cervical myelopathy due to compression of the lateral and dorsal columns. Conservative management with traction, physiotherapy, neck collar, and analgesics; surgical decompression with anterior spinal fusion. Description Water is hyperintense on T2-weighted magnetic resonance imaging. Presence of ample cerebrospinal fluid-filled space both anterior and posterior to the cord is normal. Hyperintense signal within the cord may be present to indicate cord oedema.

Case 23.10 Neural Images 375 Discussion Degenerative tissues of the spine may compress the spinal cord and roots. These tissues include osteophytes, herniating discs, ossified posterior longitudinal ligament, and hypertrophied ligamentum flavum. Cervical spondylosis is a very common radiological diagnosis, and cervical spondylotic radiculomyelopathy is a common cause of cervical cord and root lesion in people aged 50 or older. Pain over the neck with radiation down the upper limb dermato- mes is common. Compression of cervical roots leads to lower- motor-neurone motor deficits and sensory symptoms over the arms. Cervical cord compression leads to upper-motor-neurone motor deficits over the legs. Dorsal column sensory loss over the legs may be present. Magnetic resonance imaging and somatosensory evoked poten- tial study are useful investigations. Conservative management is indicated in patients with mild stable symptoms. Surgical treatment is indicated in patients with significant symptoms or progression and for those who fail conservative treatment.