Every house officer should know what a stroke is, what are the types and how to manage it? In this blog we are going to cover all the aspects of CVA. Stroke effects approximately 15 million people worldwide in one year. Of the 15 million, 5 million people suffer from permanent damage. Even though age is a significant factor for stroke it does not make it a disease of elderly. It can also happen in children and young. One out of every four stroke is seen in people below 65 years of age.
Stroke:
Stroke is lack of blood supply to a specific part of brain which leads to sudden onset of focal neurological deficit. Stroke last for more than 24 hours. It can lead to death if not managed properly and in time.
Transient Ischemic Stroke:
Abbreviated as TIA is sudden onset of neurological deficit for less than 24 hours with complete recovery. TIA can sometimes last for more than 24 hours and is then said to be stroke.
Stroke in Evolution:
Stroke is said to be in evolution when the focal neurological deficit worsens gradually. The symptoms of the patient are aggravated with the passage of time.
Complete Stroke:
When the focal neurological deficit persist. The presenting symptoms of the patient neither increase nor decrease with the passage of time it is said to be a complete stroke.
Classification of Stroke:
A stroke can be classified into one of the two major categories. It could either be ischemic or hemorrhagic stroke. Ischemic strokes are more common comprising 85% of the total cases, ischemic strokes are due to lack of blood supply to brain tissue leading to irreversible damage. The other type is hemorrhagic. It is less common and is due to rupture of blood vessels due to any reason. It constitutes 15% of the total cases.
Hemorrhagic stroke is further divided into two types. One is Intra-parenchymal hemorrhage (IPH) which is leaking of blood into the brain. The other one is Subarachnoid hemorrhage (SAH) which is leaking of blood into the meningeal lining.
Risk Factors:
Risk factors are divided into modifiable and non-modifiable.
Non Modifiable:
Age.
Gender (makes are more affected than females).
Race (Africans than Asians than European).
Previous vascular events such as myocardial infraction or stroke.
Modifiable:
Hypertension.
Diabetes mellitus.
Hyperlipidemia.
Heart diseases such as Arterial fibrillation, congested heart failure or infective endocarditis.
Smoking.
Alcohol.
Polycythemia.
Estrogen containing drugs such as oral contraceptive pills or hormone replacement therapy.
Transient Ischemic Attack (TIA):
Cerebral ischemia that leads to sudden onset of focal neurological deficit. On imaging there will be no stroke and the symptoms revolve within 24 hours. Most of the symptoms resolve in less than one hour. A mnemonic ABCD² is used for finding risk of subsequent stroke.
A for Age more than 60 years (+1).
B for Blood Pressure more than 140/90 mm hg (+1).
C for Clinical Features unilateral weakness (+2), speech impairment (+1).
D for Duration more than 60 minutes (+1).
D for Diabetes (+1).
Ischemic Stroke:
Inadequate blood supply to any part of the brain due to occlusion of the cerebral arteries is called ischemic stroke.
Pathophysiology:
Ischemia to any part of the brain leads to hypoxia (lack of oxygen). This causes depletion of cellular Adenosine Triphosphate (ATP). This lack of ATP results into lack of energy required for maintaining ionic gradient across the cell membrane required for cellular depolarization. When the ionic gradient disrupts cytotoxic edema follows and is due to influx of sodium and calcium into the cell which promotes passive flow of water into the cell.
Causes:
Stroke may be due to thrombotic diseases, embolic diseases or lacunar stroke.
Thrombotic Causes: The major cause of stroke is thrombus. Thrombus account for 55% of the total cases. It is usually secondary to atherosclerosis in major cranial arteries or carotid arteries or aortic arch.
Embolic Causes: Cardiogenic embolisms such as Valvular thrombi (MS, Endocarditis, and Prosthetic valve), Mural thrombi (MI, Arterial fibrillation, Congestive heart failure, Dilated cardiac myopathy) and atrial myxoma.
Emboli from Extra cranial arteries such as aortic arch. Paradoxical embolism (PDE) may originate from a venous thrombus, most common source is deep vein thrombosis of the lower extremities. This thrombus enters the arterial circulation through an intra cardiac communication such as Patent Foramen Ovale (PFO), ASD, VSD, PDA and Ebstein anomaly. Patent foramen ovale is the most common of all.
Lacunar Stroke:
When the deep penetrating branches of cerebral artery gets occluded it results into lacunar strokes. It accounts for 20 percent of all the cases and is mostly seen in patients with hypertension. The word “lacunes” mean small subcortical infarcts that are less than 15 mm in area supplied by deep penetration branches. Some of the common causes of lacunar strokes are micro thrombi, lipohyalinosis, hyaline arteriosclerosis, amyloid angiopathy and micro emboli.
Presentation of Patient with Stroke:
Presenting symptoms of patient depends upon which artery is involved and also the size of lesion. For different cerebral arteries the clinical features will be as follow.
1. Anterior Cerebral Artery ACA:
Confusion with behavioral disturbances, urinary incontinence, contralateral weakness and sensory loss in legs more than in arms. Usually the face is spared in infarct of anterior cerebral artery.
2. Middle Cerebral Artery MCA:
Contralateral hemiplegia, Contralateral hemi-sensory loss mainly of face and arms, Visual field defect (contralateral homonymous hemianopia),
If dominant hemisphere (left MCA) = Aphasia, this aphasia can either be
Broca’s aphasia = If the problem is in speech production or Wernicke’s aphasia= If the problem is in speech comprehension. If non-dominant hemisphere (right MCA) is involved then there will be visuospatial disturbances for example: patient cannot dress or gets lost.
3. Posterior Cerebral Artery (Posterior Circulation):
This artery supplies the occipital lobe of the brain, ischemia of this artery leads to contralateral homonymous hemianopia with macular sparing, visual hallucination and inability to recognize or discriminate. It is called Visual Agnosia.
4. Vertebro-Basilar Circulation:
It is also part of Posterior circulation If there is ischemia of the vertebral artery. The patient will suffer from Wallenberg syndrome
There is sensory loss of ipsilateral face and contralateral limbs with diplopia, dysarthria and ipsilateral Horner’s syndrome.
If there is involvement of the basilar artery, there will be change in the size of the pupil that is dilated if the lesion is in midbrain or the pupils will be pinpointed if the lesion is in pons, quadriplegia, sensory loss, cranial nerve palsies and locked-in syndrome.
If there is involvement of cerebellar artery the patient will complain of vertigo, nausea, vomiting, diplopia, nystagmus and ipsilateral limb ataxia. Lacunar strokes are associated with 5 major syndromes that are pure Hemiplegia, pure Hemeanesthesia, Clumsy hand syndrome or Dysarthria, Ataxic hemiparesis and Mixed-sensimotor.
Conclusion:
It is important for every house officer to understand stroke from all the aspects. As stroke affect millions of people yearly it is not an uncommon disease to encounter. Stroke can lead to permanent disabilities. It is important to diagnose it in time and manage it properly to minimize complications. A house officer should be able to differentiate between different types of stroke as it plays a crucial role in what type of treatment should be given to the patient. The set of symptoms the patient comes up with gives the house officer clue about the artery that is affected.
Our community need trained professionals that knows how to manage stroke patient so that the burden of cerebrovascular diseases can be reduced. If you liked this blog and want to know more about the human body go to my website Medrizz.com.
FAQs:
What is a stroke?
A stroke occurs when there is a sudden loss of blood supply to a part of the brain, leading to focal neurological deficits that can last for more than 24 hours.
What are the types of strokes?
Strokes are mainly categorized into ischemic and hemorrhagic types. Ischemic strokes, caused by lack of blood flow, are the most common, comprising 85% of cases. Hemorrhagic strokes, resulting from ruptured blood vessels, account for 15%.
What is a Transient Ischemic Attack (TIA)?
A TIA is a temporary blockage of blood flow to the brain, leading to sudden neurological deficits that resolve within 24 hours. It is often a warning sign for a potential future stroke.
What are the risk factors for stroke?
Risk factors are divided into modifiable (e.g., hypertension, diabetes, smoking, alcohol use) and non-modifiable (e.g., age, gender, previous vascular events). Understanding these helps in identifying individuals at higher risk.
What is the ABCD² score?
The ABCD² score is a tool used to assess the risk of a stroke after a Transient Ischemic Attack (TIA). It takes into account Age, Blood Pressure, Clinical Features, Duration, and Diabetes.
How can house officers help in managing stroke patients?
A house officer should be familiar with the symptoms, types, and risk factors of stroke. Timely diagnosis, appropriate referral, and treatment can significantly reduce the burden of stroke-related disabilities.