KAWASAKI DISEASE

Source: TimesOfIndia

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Context

• Two baby girls diagnosed with kawasaki disease, a condition causing inflammation of blood vessels, were successfully treated at Coimbatore Medical College and Hospital (CMCH) very recently.

 Details

• Kawasaki disease, also known as mucocutaneous lymph node syndrome, is an autoimmune condition characterized by inflammation of blood vessels.
• It involves inflammation of the blood vessels throughout the body, commonly affecting the coronary arteries, which supply blood to the heart muscle.
• It predominantly affects children, with the majority of cases occurring in those under the age of 5. It is more common in boys than girls and is most prevalent in East Asian populations.
• The exact cause of Kawasaki disease remains unknown, but it is believed to involve a combination of genetic predisposition and environmental triggers, such as infections.

 Symptoms

• Persistent high fever, typically lasting for at least five days, is a hallmark symptom of Kawasaki disease.
• Mucocutaneous Symptoms: These include redness and swelling of the hands and feet (often referred to as "strawberry tongue"), rash, redness of the eyes (conjunctivitis), and swollen lymph nodes.
• Kawasaki disease can lead to inflammation of the coronary arteries, which may result in coronary artery aneurysms and increase the risk of heart complications such as myocarditis and arrhythmias.
• Children with Kawasaki disease may also experience irritability, joint pain, abdominal pain, diarrhea, and vomiting.

 Treatment and Management

• Intravenous Immunoglobulin (IVIG): The primary treatment for Kawasaki disease is high-dose IVIG, which helps reduce inflammation and decrease the risk of coronary artery complications.
• Aspirin Therapy: High-dose aspirin is often administered along with IVIG to reduce fever and inflammation. After the acute phase, aspirin is typically continued in lower doses to prevent blood clot formation.
• Monitoring: Regular follow-up visits and cardiac evaluations, including echocardiograms, are essential to monitor for coronary artery abnormalities and other complications.
• Since the exact cause of Kawasaki disease is unknown, there are no specific preventive measures. However, early recognition and treatment can help reduce the risk of complications.

 About Blood Vessels

• Blood vessels are tubular structures that form a network throughout the body, transporting blood to and from various tissues and organs.

 Types of Blood Vessels:

• Arteries: Arteries are thick-walled blood vessels that carry oxygen-rich blood away from the heart to the body's tissues and organs. They typically have a pulsatile flow due to the pumping action of the heart.
• Veins: Veins are blood vessels that return deoxygenated blood from the body's tissues back to the heart. They have thinner walls than arteries and often contain valves to prevent backflow of blood.
• Capillaries: Capillaries are small, thin-walled blood vessels that connect arterioles and venules, facilitating the exchange of gases, nutrients, and waste products between the blood and tissues.

 

Structure of Blood Vessels:

• Blood vessel walls consist of three layers:
  • Tunica Intima: The innermost layer composed of endothelial cells that form a smooth surface to facilitate blood flow.
  • Tunica Media: The middle layer composed of smooth muscle cells and elastic fibers that regulate vessel diameter and blood pressure.
  • Tunica Adventitia: The outermost layer composed of connective tissue that provides structural support and flexibility to the vessel.

 Functions of Blood Vessels:

• Transportation: Blood vessels transport oxygen, nutrients, hormones, and waste products throughout the body to maintain cellular function and homeostasis.
• Regulation of Blood Pressure: Arteries and arterioles help regulate blood pressure by adjusting their diameter in response to changes in blood flow and systemic demand.
• Thermoregulation: Blood vessels play a role in thermoregulation by dilating or constricting in response to changes in body temperature, thereby regulating heat exchange with the environment.
• Immune Response: Blood vessels facilitate immune responses by transporting immune cells to sites of infection or injury and facilitating the removal of pathogens and debris from tissues.

 Disorders and Diseases of Blood Vessels:

• Atherosclerosis: Atherosclerosis is a condition characterized by the buildup of plaque (fatty deposits) in the walls of arteries, leading to narrowing and hardening of the vessels, which can restrict blood flow and increase the risk of heart attack and stroke.
• Hypertension: Hypertension, or high blood pressure, is a common condition that can damage blood vessel walls and increase the risk of cardiovascular disease, stroke, and kidney failure.
• Varicose Veins: Varicose veins are enlarged, twisted veins that occur most commonly in the legs and feet due to weakened or damaged vein valves, resulting in poor blood circulation and discomfort.
• Peripheral Artery Disease (PAD): PAD is a condition in which narrowed arteries reduce blood flow to the limbs, leading to symptoms such as leg pain, cramping, and reduced mobility.

 About Heart

• The heart is a muscular organ located in the chest cavity, responsible for pumping blood throughout the body via the circulatory system.
• The primary function of the heart is to circulate oxygen-rich blood to all tissues and organs, ensuring their proper functioning and removing waste products from the body.

 Structure:

• Chambers: The heart has four chambers:
  • Atria (Upper Chambers): Receive blood returning to the heart.
  • Ventricles (Lower Chambers): Pump blood out of the heart to the rest of the body.
• Valves: Valves located between the chambers and major blood vessels prevent backward flow of blood and ensure unidirectional blood flow.
• Coronary Arteries: Blood vessels that supply oxygenated blood to the heart muscle (myocardium) to support its metabolic needs.

 Circulation of Blood Through the Heart:

• Pulmonary Circulation: Deoxygenated blood from the body enters the right atrium, is pumped to the right ventricle, and then to the lungs for oxygenation before returning to the left atrium.
• Systemic Circulation: Oxygenated blood from the lungs enters the left atrium, is pumped to the left ventricle, and then distributed to the rest of the body through the systemic arteries.

 Cardiac Cycle:

• Systole: Contraction phase during which the heart pumps blood out of the chambers.
• Diastole: Relaxation phase during which the heart fills with blood.

 Electrical Conduction System:

• Sinoatrial (SA) Node: Pacemaker of the heart located in the right atrium, initiating electrical impulses that stimulate heart contractions.
• Atrioventricular (AV) Node: Located between the atria and ventricles, delaying the electrical impulse to allow for complete atrial contraction before ventricular contraction.
• Bundle of His and Purkinje Fibers: Transmit electrical impulses from the AV node to the ventricles, causing them to contract.

 Cardiac Cycle and Regulation:

• Autonomic Nervous System: Sympathetic and parasympathetic branches of the autonomic nervous system regulate heart rate and contractility.
• Hormonal Regulation: Hormones such as adrenaline (epinephrine) and noradrenaline (norepinephrine) released in response to stress or exercise can increase heart rate and contractility.

 Common Heart Disorders and Diseases:

• Coronary Artery Disease (CAD): Narrowing or blockage of coronary arteries due to atherosclerosis, leading to angina, heart attack, or heart failure.
• Arrhythmias: Abnormal heart rhythms, including tachycardia (fast heart rate) and bradycardia (slow heart rate), caused by electrical conduction abnormalities.
• Heart Failure: Inability of the heart to pump sufficient blood to meet the body's needs, resulting in fatigue, shortness of breath, and fluid retention.
• Valvular Heart Disease: Malfunction or damage to heart valves, impairing blood flow and causing symptoms such as chest pain, fatigue, and shortness of breath.

 Sources:

 TimesOfIndia

PRACTICE QUESTION Q.  The heart is a vital organ responsible for maintaining blood circulation and delivering oxygen and nutrients to all tissues and organs. Elaborate. (150 words)