Achalasia

Achalasia is a neurological disorder of the esophagus and the muscles associated with it. Achalasia is a Greek term which means lack of relaxation. It involves the sphincter muscles of the esophageal region which help in the movement of food in the alimentary by esophageal peristalsis. The upper esophageal sphincter muscle measures about 3- 4 cm and is composed of striated muscles. The lower or the distal esophageal sphincter muscle is smooth. The esophagus is further comprised of circular and longitudinal muscles which help in the peristaltic movement. The muscles of the mesenteric plexus have a significant role in the occurrence of conditions such as achalasia. This is because of the association of the mesenteric plexus with intramural nerve innervations. Studies reveal that the damage of the mesenteric plexus is caused by the immune system.

Clinical manifestations of Achalasia

Classical symptoms associated with achalasia include dysphagia, regurgitation and respiratory complications. The lower esophageal sphincter muscles are impaired in this condition causing distended lower esophagus. In this region, the food is stuck as the muscles of the lower esophageal sphincter do not relax causing disturbance in the peristaltic movements of the esophagus. The patient experiences pain or spasms as a result of the cramped food in the esophagus. Often there is a tendency to vomit followed by heartburn and weakness.

Incidences of chest pain and breathing difficulties due to nocturnal choking are not uncommon. Histological examination of the esophagus reveals the decrease in myenteric neurons which are predominantly responsible for the relaxation of the lower esophageal sphincter muscles. Achalasia is categorized as primary, secondary and pseudoachlasia depending upon the etiology of the disease. The primary cause of achalasia can be hereditary or underlying autoimmune disease. The secondary cause is associated with preexisting infections such as chagas disease. It is usually associated with malignancy.

Diagnosis of Achalasia

Achalasia onset is generally asymptomatic and the severity increases after five years. Patients who are probable suspects of achalasia are diagnosed using radiologic, manometric and endoscopic methods. The manometric analysis determines the esophageal pressure of the lower origin. This enables the peristalsis and relaxation associated with the esophagus. It also indicates the functionality of smooth muscle contraction pertaining to the lower esophageal region. Radiological analysis indicates the abnormalities in structural arrangement of the esophagus. The bird beak appearance of the esophagus is the classical sign for the occurrence of achalasia. A normal chest X-ray does not identify the presence of achalasia, but it gives an anatomical description of the respective changes pertaining to esophagus such as widening of the mediastinum due to esophageal dilation and presence of gastric air bubble which occurs because of lack of relaxation in the lower esophagus.

Treatment of Achalasia

The restoration of the esophagus is difficult. However, many treatment options are available for achalasia. Use of nitrates and calcium blocking drugs help in the prevention of calcification of the esophagus. In some cases, balloon dilation of the lower esophagus is done. Although this method has a short time recovery there is always a risk of perforation during the procedure. Surgical methods such as thoracotomy and myotomy are considered. In addition to these treatment options, endoscopic administration of botulinum toxin has also become a possible option.

Blount Disease

Blount's disease or 'tibia vara,' is a growth disorder in the shin bone that affects the bones of the lower leg causing the lower leg to angle inward. This resembles a bow leg.

Named after the American orthopedic surgeon, Putnam Blount (1900 - 1992), Blount's disease is characterized by progressive lower limb deformity. Though Blount can affect people at any time during the growing process, it is more common in kids younger than four and in teens. A lot of pressure is put on the growth plate on the top of the tibia. This portion is called the physis - made out of cartilage, weaker than bone. The function of the physis is to allow the bone to lengthen and grow.

Due to excess pressure, the bone does not grow normally and instead the lateral outer side of the tibia keeps growing whereas the medial or inner side of the bone does not. Because of uneven bone growth, the tibia tends to bend outward instead of growing straight. Blount is not the same as naturally bowed legs that babies and toddlers have which usually straighten out when they start walking.

Blount is described as two distinct forms, early or infantile and late or adolescent Blount disease.

Infantile Blount disease is diagnosed between age one and three years. The disease presents when a child begins to ambulate. This disease is often bilateral and is less commonly associated with obesity.

Quite unlike the infantile Blount, late onset of Blount disease occurs in older children and is commonly associated with obesity and is often unilateral.

A combination of mechanical and biological factors influences Blount's disease to varying degrees. The mechanical forces contributing to the disease are weight of the child, age at walking, and varus deformity. The compressive forces across the medial femoral physis lead to growth retardation. Adolescent Blount does not appear to be progressive, or as common as the infantile form.

Causes

The cause of Blount disease remains controversial but it is mostly due to a combination of hereditary and developmental factors. There is increased incidence of the disease in overweight children who walk at an early age. Certain theories that mechanical overload of the proximal tibia contribute to Blount disease has been found. This mechanical overload is attributed to obesity and varus deformity. But this alone cannot be a cause as the disease is also noticed in children with normal weight.

Increasingly it is more common in people of African heritage, where kids start walking at an early age and whose family member might have had it. There is a genetic component to the disease as well, though a direct pattern of inheritance has not been clearly revealed. Hence, Blount is multifactorial and may differ in the early or late onset forms of the disease.

Symptoms

It is imperative to understand that Blount disease starts in early childhood or late teen years, the curve can get worse if not treated. Hence early diagnosis is important. The most obvious sign of Blount is bowing of the leg below the knee. While in young kids it is usually not painful, it teens it can be. It can feel like a growing pain in the knee area. The pain may come and go and many teens resort to over-the-counter pain relievers. As the lower leg bears the weight of the body, other problems such as rotation of the tibia are noticed. This causes a condition called in-toeing, wherein the feet point inward instead of straight out. Blount disease, over several years, can lead to arthritis of the knee joint and trouble walking. One leg may become slightly shorter than the other.

Diagnosis

If there is knee pain that seems to be getting worse and cannot be traced to an injury, then the doctor might possibly consider Blount. A complete physical examination will be done, and X-rays of legs taken. The doctor will look for any abnormal growth pattern at the top of the tibia - a tell tale sign of Blount. This will help the doctor measure how severe the bowing is.

Treatment

Treatment for Blount depends on the age of the patient and how far the disease has progressed. Young kids are advised braces, which are long-legged and lock the knee and need to be worn whilst weight bearing. But bracing is usually unsuccessful in girls and those with obesity. Older kids and teens will need surgery. There are different types of surgeries to correct Blount disease. These involve cutting the tibia, realigning it and holding it in place with plate and screws. This procedure is called Osteotomy. Sometimes, the damaged growth plate is removed and a device called external fixator is used to hold bones in place from the outside. In case of a twisted toe, surgeons correct the cause of it. Surgery is done under general anesthesia, and the patient might wear a cast and use crutches for a while. Physical therapy will be needed after surgery.

Ultrasound

Ultrasonography is a medical imaging technique that is also called ultrasound scanning or sonography. High frequency sound waves and their echoes and used in this technique for obtaining images from inside the human body. The echoes of sound waves reflected from the human body are recorded and displayed as a real-time visual image. This technique is similar to the echo location used by bats, whales and dolphins. The sonar used by submarines also operates with the same technique. Ultrasound is useful method to examine many of the body's internal organs like heart, liver, gallbladder, spleen, pancreas, kidneys and bladder.

Ultrasound Scanning

1. Sound Waves: A transducer (a small handheld device) emits high-frequency sound waves.
   
2. Echoes: These sound waves bounce off tissues, organs, and other structures inside the body.
   
3. Image Formation: The transducer detects the echoes and sends this information to a computer, which creates images based on the patterns of the echoes.
   

Types of Ultra sound:

1. Abdominal Ultra sound: Evaluates organs in the abdomen, such as the liver, gallbladder, spleen, pancreas, and kidneys.
   
2. Pelvic Ultra sound: Assesses reproductive organs (uterus, ovaries) and bladder.
   
3. Obstetric Ultra sound: Monitors pregnancy and fetal development, to assess the risk of fetal abnormalities such as neural tube defects or Down's syndrome
   
4. Cardiac Ultrasound (Echocardiogram): Evaluates heart structure and function.
   
5. Doppler Ultra sound: Measures blood flow through vessels.
   
6. Musculoskeletal Ultra sound: Examines muscles, tendons, and joints.
   
7. Thyroid Ultra sound: Evaluates the thyroid gland.
   

Preparation:

• Fasting: May be required for certain abdominal ultrasounds.
  
• Full Bladder: Often necessary for pelvic ultrasounds.
  
• Loose Clothing: Wear comfortable, loose-fitting clothes for easy access to the area being examined.
  

Procedure:

1. Preparation: The patient may be asked to lie on a table and expose the area to be examined.
   
2. Application of Gel: A special gel is applied to the skin to help transmit sound waves.
   
3. Transducer Use: The healthcare provider moves the transducer over the area, capturing images.
   
4. Image Review: The images are reviewed in real-time, and the provider may take multiple images from different angles.
   

Benefits:

• Non-Invasive: No needles or incisions.
  
• Safe: Uses sound waves, not radiation.
  
• Real-Time Imaging: Allows dynamic assessment of moving structures.
  
• Widely Available: Accessible in most healthcare settings.
  

Applications:

• Diagnosis: Identifying and evaluating various medical conditions.
  
• Monitoring: Tracking the progress of diseases or conditions.
  
• Guidance: Assisting in procedures such as biopsies or fluid drainage.
  

Common Uses:

• Pregnancy Monitoring: Checking fetal health and development.
  
• Organ Assessment: Evaluating the liver, kidneys, and other organs.
  
• Cardiac Evaluation: Assessing heart function and detecting abnormalities.
  
• Blood Flow Analysis: Checking for blood clots or poor circulation.
  
• Musculoskeletal Issues: Diagnosing tendonitis, bursitis, or tears.
  

Ultrasound examinations are versatile and essential tools in modern medical diagnostics, providing crucial information for the diagnosis and management of many health conditions.

Carotid Doppler ultrasound scanning is a diagnostic method used to assess blood flow through the carotid arteries, which are the primary vessels supplying the neck and head. This non-invasive modality is employed in the evaluation of various conditions, including:
1. Carotid artery stenosis (narrowing) - a common finding associated with increased risk of stroke. Doppler echocardiography image reveals any narrowing of the arteries or turbu￾lence in blood flow.
Echocardiography is a diagnostic tech￾nique used to evaluate structural and functional abnormalities of the heart including:
1. Heart wall: Detecting changes in thickness, texture or motion.
2. Heart chambers: Assessing size, shape, and function.
3. Heart valves: Evaluating valve leaflet movement, regurgitation and stenosis.
4. Large coronary arteries: Identifying narrowing or obstruction.
In addition to detecting cardiovascular lesions, echocardiography is also employed in the diagnosis of:
1. Congenital heart disease: Abnormalities present at birth.
2. Cardiomyopathy: Heart muscle disorders characterized by impaired function.
3. Aneurysms: Ballooning or dilation of the heart or blood vessel walls.
4. Pericarditis: Inflammation of the pericardial sac surrounding the heart.
5. Blood clots in the heart: Emboli that may have originated from other sources and traveled to the heart.

2. Transient ischemic attacks (TIAs), also known as "mini-strokes" or "warning strokes" - a temporary loss of blood flow to the brain.
3. Stroke - a neurovascular event characterized by permanent disruption of blood flow to the brain.
Doppler echocardiography is a valuable diagnostic tool that enables the measurement of blood flow velocity (speed) within the heart. This modality allows cardiologists to:
1. Assess structural abnormalities: Such as mitral valve prolapse, where the mitral valve leaflets protrude into the left ventricle.
2. Evaluate septal defects: Abnormal openings in the septum that separate the right and left sides of the heart.
By analyzing blood flow velocity, Doppler echocardiography can help diagnose and monitor various cardiovascular conditions, including those affecting the heart valves and septum.

Cataract Surgery: An ultrasound probe is inserted into the lens capsule through a small incision in the cornea. The incision is made using a diamond tipped instrument. The ultrasound probe softens the lens by emitting sound waves. It then sucks out the softened lens tissue. Only the front part of the lens capsule is removed.

Doppler ultrasound is a type of echocardiography that utilizes the principles of Doppler shift to measure the velocity of moving structures. This technique involves transmitting high-frequency ultrasonic waves from an emitter and detecting the frequency changes resulting from the interaction with moving targets, such as blood flowing through a blood vessel.
Doppler ultrasonography has become a widely accepted diagnostic modality for detecting various vascular conditions. Specifically, it is commonly employed to:
1. Identify arterial narrowing or stenosis in the neck, often resulting from atherosclerosis (the accumulation of fatty deposits on artery walls).
2. Detect blood clots (thrombi) within veins, as seen in deep vein thrombosis.
In addition to its vascular applications, Doppler ultrasound is also used for:
1. Fetal monitoring: To non-invasively assess fetal heart rate and detect any potential abnormalities.
2. Dialysis and cardiopulmonary bypass procedures: To monitor for air emboli (air bubbles) that may form during these interventions.
3. Blood pressure measurement: As a non-invasive means to estimate blood pressure, particularly in situations where direct measurement is not possible or practical.
The process begins with the emission of pulses of ultrasound at a specific frequency. As these pulses interact with moving objects, such as red blood cells in a vessel, the frequency of the reflected signals (echoes) shifts due to the Doppler effect. A sensor detects these frequency changes and converts them into meaningful data, providing valuable information about the velocity or flow characteristics of the target structure, for example, blood flow through an artery or vein.

Ancillary term used in ultrasound imaging to describe an anechoic region or structure that does not produce any reflective echoes (sonographic signals) when exposed to ultrasound waves. This is typically seen in structures containing clear fluid, such as:
1. Cysts: Fluid-filled cavities that do not reflect ultrasound signals.
In these cases, the lack of echogenicity allows for better visualization and differentiation from surrounding tissues.
"Echogenic" - A descriptive term used in ultrasound imaging to identify structures that produce reflective echoes or signals when exposed to ultrasound waves. In other words, an echogenic structure is one that generates a strong sonographic signal, allowing it to be visualized and characterized on the ultrasound image.

The frequency of ultrasound waves used in medical imaging varies depending on the type of examination and the depth of the tissue being imaged. Here are some general guidelines:

Common Frequencies:

1. General Diagnostic Ultrasound:
   • Frequencies typically range from 2 MHz to 15 MHz.
     
   
   
2. Abdominal Ultrasound:
   • Lower frequencies around 2 MHz to 5 MHz.
     
   • Lower frequencies provide deeper penetration but lower resolution.
     
   
   
3. Pelvic Ultrasound:
   • Frequencies typically in the range of 3 MHz to 7.5 MHz.
     
   
   
4. Obstetric Ultrasound:
   • Frequencies around 2 MHz to 5 MHz for deeper penetration to view the fetus.
     
   
   
5. Cardiac Ultrasound (Echocardiogram):
   • Frequencies typically range from 2.5 MHz to 5 MHz.
     
   
   
6. Vascular Ultrasound:
   • Frequencies around 5 MHz to 10 MHz.
     
   
   
7. Musculoskeletal Ultrasound:
   • Higher frequencies around 7.5 MHz to 15 MHz.
     
   • Higher frequencies provide better resolution for superficial structures.
     
   
   
8. Small Parts (Thyroid, Breast, Scrotal):
   • Frequencies in the range of 7.5 MHz to 15 MHz.
     
   
   

• Penetration vs. Resolution: Lower frequencies penetrate deeper into the body but produce images with lower resolution. Higher frequencies provide higher resolution images but do not penetrate as deeply.
  
• Tissue Characteristics: Different tissues reflect sound waves differently, so the frequency is chosen based on the specific characteristics and location of the tissue being examined.
  

Specific Frequency Ranges:

1. 2-3.5 MHz: Deep structures like the liver, kidneys, and heart.
   
2. 3.5-5 MHz: General abdominal and obstetric imaging.
   
3. 5-7.5 MHz: Breast, thyroid, and vascular imaging.
   
4. 7.5-10 MHz: Musculoskeletal and superficial structures.
   
5. 10-15 MHz: Very superficial structures and detailed imaging of small parts.
   

Normally the term ultrasound refers to frequencies above 20 kHz (the maximum frequency a human can hear), medical ultrasound utilizes frequencies in the range of several MHz to achieve the necessary balance between resolution and penetration for effective imaging of different tissues and organs.

As you can see from the table above, specific band of frequencies are chosen for optimal imaging.

• Resolution: Higher frequencies provide better resolution, allowing for more detailed images of tissues and structures.
  
• Penetration: The choice of frequency is a trade-off between penetration and resolution. Lower frequencies penetrate deeper but have lower resolution, while higher frequencies provide detailed images of superficial structures.
  

Movement of the internal tissues and organs are captured in ultrasound. Ultrasonography enables the physicians to diagnose a variety of disease conditions and also assess the damage caused to the systems. The ultrasound machine transmits high frequency sound pulses into the human body by using probes. These sound waves that travel into the body hit a boundary between the tissues inside the body and reflect the sound waves to the probe. Some waves travel even further and they reach another boundary and then get reflected back. The waves that are reflected are picked up by the probe and relayed back into the ultrasound machine.

The ultrasound machine in turn calculates the distance from the probe to the tissue or organ by using the speed of sound tissue and the time of each echo's return. The machine displays these distances and intensities of the echoes on the screen. Through the echoes that are produced the sonologist can identify how far away an object is, how large it is, its shape and consistency (fluid, solid or mixed). Two dimensional images are formed and reflected on the screen. Different types of ultrasound are used for different disease conditions. Ultrasound is used in a variety of clinical settings including obstetrics and gynecology, cardiology and cancer detection.