Common neurological conditions seen in the long case are stroke, multiple sclerosis, epilepsy and myasthenia gravis. Any one of these conditions can be the main problem of the case. But many other neurological conditions, such as Parkinson’s disease, other movement disorders, peripheral neuropathy, migraine, vertigo, tinnitus and myelopathy, can be present as an associated problem. It is important to look at the case as a whole when encountering these features, because another medical condition or a medication may be the causative factor of the neurological deficit. In such situations, treating the possible precipitating condition or changing the medication may resolve the neurological problem. An example is a patient with a background history of hepatitis C presenting with peripheral neuropathy. The neuropathy is sometimes caused by hepatitis C-associated cryoglobulinaemia. So it is important to contextualise the neurological symptoms and signs, in the interplay of multiple diseases and medications in the long case.
COGNITIVE IMPAIRMENT
It is unusual to encounter a significantly demented patient in the long case examination. However, there have been instances where patients with progressive dementia, but who could still hold a reasonably rational conversation, have been presented at the examination. The objective of such long cases is to assess the candidate’s ability to identify the problem of progressive intellectual deterioration and the candidate’s knowledge and skills in handling the issues involved, such as remedying any correctable causes, attempting to slow down the deterioration where possible, and preparing for the optimal care of the patient medically and socially in anticipation of the inevitable total dementia.
The candidate should try to identify the broad pattern of cognitive impairment and the type of dementia. The following is a very basic introduction to such classification:
Approach to the patient
Candidates should be able to perform a very quick assessment of the patient’s cognitive function, and a formal ‘mini mental’ test is a useful tool for this. Because this is a standardised and quantitative test, it can provide an objective assessment (though not always very accurate) that would be acceptable to the examiners. A good method to employ here is to memorise the mnemonic, which incorporates the important components of the mini mental test:
O R A — R L C
O Orientation—year/season/month/date/day, country/state/city/hospital/floor (10 points)
R Registration—three words: window, basketball, tree (4 points)
A Attention—serial sevens, or counting backwards from 100 by sevens, or spelling WORLD backwards (5 points)
R Recall—the three words above (3 points)
L Language skills—repeating a phrase such as West Register Street, naming two objects, reading a sentence, writing a sentence and obeying a three-stage command (8 points)
C Construction—copying two intersecting pentagons (1 point).
The maximum score is 30. A score of < 25 may suggest dementia.
In addition to the above assessment, look for features that may give clues to possible intellectual impairment. General demeanor, the response to your initial introduction, smell of urine and extrapyramidal facies are some such important clues. Check for the frontal reflexes.
Investigations
In patients with suspected dementia, a standard dementia screen is warranted. This battery of tests includes:
1. CT or MRI of the head
2. Full blood count with vitamin B12 and folate levels
3. Thyroid function tests
4. Midstream urine for microscopy and culture
5. Venereal disease research laboratory test for syphilis
6. Vasculitic and connective tissue disease screen
7. Electroencephalogram (EEG)
8. HIV serology in the young demented.
STROKE AND TRANSIENT ISCHAEMIC ATTACK
Approach to the patient
When approaching a stroke patient, the candidate should be well versed in the basic principles of stroke management.
History
The history must be very detailed and accurately describe the neurological symptoms. Ask about:
• how the patient manages with the neurological deficit
• any history of atrial fibrillation, palpitations, migraine, manipulation of the neck (a precipitating cause for dissection of the carotid or vertebral artery)
• any recent cardiac investigations such as coronary angiography
• recent cessation of anticoagulant therapy for some reason in patients with atrial fibrillation.
In the young stroke patient, consider the possibility of patent foramen ovale and paradoxical embolus.
Also obtain history regarding other thrombotic events (DVT, PE, miscarriages) in the patient or first-degree family members. Ask about alcohol consumption and recent falls that may have caused an intracranial haemorrhage.
Enquire about premorbid as well as the current level of independence and mobility. If the patient is incapacitated, ask about the social support available at home. Ask about the patient’s mood.
Examination
Never forget to look for poorly controlled hypertension, fundoscopic changes of hypertension and diabetes, carotid bruits, orbital bruits (commonly heard in the side opposite the carotid occlusion, due to increased contralateral flow), atrial fibrillation, cardiac murmurs and evidence of peripheral vascular disease.
Check the blood pressure in both arms (a difference of more than 20 mmHg systolic may suggest subclavian stenosis and a steal phenomenon). Look for complications such as pressure sores, limb contractures and disuse atrophy of the weak limbs.
See whether the patient has a percutaneous gastrostomy (PEG) feeding tube inserted and, if present, inspect for cellulitis or pus around the insertion site. Check the patient’s temperature and look at the temperature chart for any evidence of fevers. Check for DVT in the lower limbs if a peripheral embolic cause is suspected, especially in the younger patient.
With the history and the physical examination, the candidate should be able to accurately characterise the exact neurological deficit and localise the area of the brain involved.
Management
Depending on the type and severity, transient ischaemic attack may be managed at home if timely investigation and adequate treatment can be arranged. Stroke with residual neurological deficit needs to be managed in hospital. Essential therapeutic goals in a stroke patient are early rehabilitation, the prevention of secondary complications such as DVT, aspiration pneumonia, urinary tract infections, limb contractures and pressure sores, prevention of recurrent stroke, and identifying/treating stroke risk factors. Rehabilitation should be planned according to the deficits identified on the examination.
Younger stroke patients (aged under 40 years) should be screened for unusual causes, such as illicit drug use (cocaine), vasculitic disorders, subacute bacterial endocarditis, patent foramen ovale or cardiac septal defects with a right-to-left shunt, paroxysmal atrial fibrillation or atrial flutter, thrombophilia, and inherited disorders such as CADASIL (see box) and homocystinuria. Some patients can develop a ‘post-stroke dementia’, and therefore the patient’s cognitive function should be assessed.
Conditions associated with stroke (ischaemic and haemorrhagic)
• Atherosclerosis of the carotid or vertebrobasilar arterial systems
• Hypertension (lacunar infarcts due to arteriosclerosis of small penetrating arteries of the brain)
• Atrial fibrillation leading to thromboembolism
• Left ventricular aneurysm with mural thrombus
• Spontaneous/traumatic intracranial haemorrhage
• Amyloid angiopathy
• Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL)
• Vasculitis
• Connective tissue disorders (e.g. systemic lupus erythmatosus (SLE))
• Narcotic use (e.g. cocaine, amphetamines)
• Bacterial endocarditis (septic emboli/mycotic aneurysm rupture)
• Thrombophilia (e.g. factor C/S deficiency, factor V gene mutation)
• Hypercoagulable states (e.g. polycythaemia, thrombotic thrombocytopenic purpura)
• Cerebral venous thrombosis
• Dissection of extracranial arteries
• Intracranial neoplasms (primary/secondary)
• Cerebral vascular malformations
• Subclavian steal syndrome
Investigations
The following investigations should be considered for the stroke patient, as guided by the clinical assessment:
1. Urine analysis and blood sugar levels—to exclude diabetes mellitus or a precipitating urinary tract infection
2. Full blood count—looking at haemoglobin levels (to exclude polycythaemia), white cell count (to exclude sepsis as a precipitating cause) and platelet count (rarely, essential thrombocythaemia can contribute to stroke)
3. Coagulation profile
4. ESR—to exclude any inflammatory arteritic/vasculitic process
5. Chest X-ray—for cardiomegaly/neoplasms/aspiration
7. Fasting blood lipid profile
8. CT or MRI of the head—looking for ischaemic infarcts, haemorrhage or mass lesions
9. Doppler scan of the carotid arteries—and, if the duplex ultrasonography suggests significant carotid stenosis, consider obtaining another confirmatory imaging study such as carotid CT angiography, carotid digital subtraction angiography or MR angiography. If the diagnosis is confirmed, discuss possibility of interventions such as carotid endarterectomy or stent placement in suitable patients.
10. If the patient is in AF, ask for the results of the transoesophageal echocardiogram (TOE)—looking for thrombus or spontaneous echo contrast in the left atrial appendage. This may also show up any atheromatous plaques in the ascending aorta and the arch of aorta that may have contributed to the stroke.
11. In the younger stroke patient, consider also the following investigations:
• drug screen—looking for narcotic agents
• vasculitic screen—if there are features of vasculitis
• blood cultures and cardiac imaging—if endocarditis is suspected
• cardiac event monitor—looking for paroxysmal AF
• thrombophilic screen, and transthoracic echocardiogram with bubble study—looking for patent foramen ovale (PFO) (Fig 5.1) or septal defect.
If there is evidence of right-to-left shunt, particularly when right-sided pressures become high (as in Valsalva manoeuvre), a follow-up TOE is indicated to better characterise this shunt with a view to closing it (Fig 5.2).
Management: stroke
The goals of stroke management are: 1) to determine and address the causative factors (secondary prevention), and 2) to restore functionality.
1. Control blood pressure—Initial steps are adequate and cautious control of the blood pressure (aggressive lowering of blood pressure in ischaemic stroke can worsen the neurological damage) and serum glucose level, and-antiplatelet therapy in the form of aspirin, clopidogrel or aspirin/sustained-release dipyridamole combination. Dipyridamole can cause side effects of headache, which may complicate the initial stroke symptoms. The popular approach is to use aspirin during the first few days post ischaemic stroke. This can later be changed to aspirin/sustained-release dipyridamole combination. Clopidogrel may be used in aspirin-intolerant patients. There is also an important role for ‘statin’ cholesterol-lowering agents and ACE inhibitors in the setting of acute stroke.
2. Anticoagulation
Buy Membership for Internal Medicine Category to continue reading. Learn more here
