Anterior Cord Syndrome

Anterior Cord Syndrome refers to the Anterior Spinal Artery Syndrome. The anterior spinal artery originates from the vertebral arteries and basal artery at the base of the brain. It supplies the anterior two thirds of the spinal cord to the upper thoracic, that is chest, region. Anterior cord syndrome results from injury to the motor and sensory pathways in the anterior cord. Patients suffering from Anterior Cord Syndrome may feel some crude sensations, but their movement and more detailed sensation is lost. In Anterior cord syndrome there is damage primarily in the anterior 2/3 cord. This is related to vascular insufficiency, sparing the posterior columns. Anterior cord syndrome usually results from the compression of the artery that runs in front of the spinal cord. The compression may be from bone fragments or a large disc herniation.

• In Anterior Spinal cord syndrome, there is usually complete loss of strength below the level of the injury. Anterior spinal artery syndrome produces variable loss of motor function and of sensitivity to pinprick and temperature. Thus the patient undergoes complete sensory loss. But the sensitivity to vibration (vibratory sense) and position sense (proprioception) is preserved.
  
• In Anterior Cord syndrome, the anterior section of the spinal cord is injured. This results in loss of movement and sensory perception. In anterior cord syndrome, there is complete motor paralysis.
  
• In Anterior Cord Syndrome, there is sparing of the dorsal column. The patient therefore exhibits greater motor loss in the legs than arms.
  
• It is interesting to note 80% of spinal cord injuries occur in males. Children suffer spinal cord injuries due to sports activities. Adult suffer spinal cord injuries that are work related.

MRI is a most accurate imaging test for spinal disorders. This is because in MRI the spinal cord parenchyma, soft tissue lesions like hematomas, tumors and interverterbral disks, bony lesions like erosion, hypertrophic changes, collapse, fracture and subluxation are revealed. Myelography with a radiopaque agent is used less often. Physicians normally use CT scans to demonstrate bony fragments compressing the anterior spinal cord. X rays may help to detect bony lesions.

Anterior cord syndrome is said to have the worst prognosis of all cord syndromes. The prognosis is usually good if the recovery is evident and progressive in the patient during first 24 hours. However, if there are no signs of sacral sensibility to pinprick or temperature are present after 24 hours, then the prognosis for functional recovery can be said to be poor. There is no standard course of treatment or cure for anterior cord syndrome. Physicians adopt drug therapies and surgery as part of the treatment program. There have been some exceptional cases where sensations that travel along pathways are still intact after the injury. Normally, it is observed that only 10 to 15% of anterior cord syndrome sufferers demonstrate any improvement in functions over a period of time.

Pathologist

Pathology is the study of disease origin and it paves a way for comprehensive diagnosis of medical conditions for effective prognosis. The role of a pathologist offers significant diagnostic approach in the field of clinical laboratory science. It is important position as it requires exceptional interpretational skills associated with anatomical and physiological changes in the cells, tissues and body fluids.

Pathologists have diverse responsibilities ranging from cytology to molecular studies. Studies such as autopsy are essential in the field of forensic medicine, identification of genetic disorders and also the origin of disease. The results are interpreted by a pathologist. Biopsy on the other hand is a routine procedure for many major health complications to detect the presence of inflammatory diseases and cancer. Many important fields such as microbiology, hematology, biochemistry, immunohistochemistry, transfusion medicine come under clinical pathology, which is very important to determine the cause of any disease. Pathologists in clinical research pave the way for the discovery of new drugs and better diagnostic ventures for comprehensive patient care.

Osteogenesis Imperfecta

Osteogenesis imperfecta or OI, also known as brittle bone disease, is a genetic disorder that is characterized by weak and fragile bones that break easily. Osteogenesis imperfecta is caused by a genetic defect that disables the body to make strong bones. A person may experience occasional fractures or may have multiple fractures throughout life depending upon the severity of Osteogenesis imperfecta present. Apart from fragile bones, people with OI suffer from teeth problems - Dentinogenesis Imperfecta, hearing loss, muscle weakness, loose joints (joint laxity) and skeletal malformations.

Causes of OI

Osteogenesis imperfecta is either inherited from a parent who has the defective gene or could be a result of new mutations. Due to the defective gene, an important protein substance called type I collagen is not produced in the body. This protein plays an important role in forming connective tissues in bones and also helps in forming ligaments, teeth and the white outer tissue of the eyeballs (sclera). Due to poor production of the protein, bones become brittle and fragile and tend to break easily. Most of the mutations in OI exist in the two type I collagen genes, COL1A1 and COL1A2 and account for almost all the forms of OI.

Classification of Osteogenesis imperfecta

Depending upon the severity of the Osteogenesis imperfecta, the condition is divided into type 1, type 2, type 3, type 4. These types are classified mostly by fracture frequency and by characteristic features. Recently, research has identified three more additional variations to Osteogenesis imperfecta known as type 5, 6 and 7.

Type 1

Type 1 Osteogenesis imperfecta is the mildest and the most common form of OI. More than 50% patients suffer from Type 1 Osteogenesis imperfecta. In this type, though body produces normal type I collagen but only half the normal quantity. People with Type 1 OI may experience fewer fractures, and most often the condition may go unnoticed for several years after their birth.

Type 2

Type 2 Is the most severe form of Osteogenesis imperfecta often resulting in bone deformities in the child. Type 2 OI normally turns out to be fatal with the production of very little or poor quality collagen being produced in the body. Infants with type 2 OI are born with fragile rib cage and underdeveloped lungs. They usually die either in the womb or soon after birth.

Type 3

Osteogenesis imperfecta type III is severely progressive type associated with symptoms like short stature, a triangular face, severe scoliosis, grayish sclera, and Dentinogenesis imperfecta (impaired and irregular teeth with yellow-blue tinge). Infants with type 3 OI have fractures at the time of birth itself, and few infants reveal a fractured and eventually healed bones in the womb itself.

Type 4

Type 4 Osteogenesis imperfecta can range from very mild to severe form often resulting in growth retardation in children. A child with type 4 OI is short with bow shaped legs. Symptoms like tinted sclerae (white of the eye) and dental deformities may also be present at the time of the birth. Child normally suffers from Long bone fractures, vertebral compression, scoliosis, and ligament laxity with type 4 OI.

Type 4 also has two sub types called type 5 and type 6 OI. Though clinically they resemble type 4, types 5 and 6 have unique patterns to the bones. Type 5 exhibits features like ossification of interosseous membrane of the forearm with radial head dislocation, large callus formation and an abnormal histopathological pattern. Type 6 will have elevated alkaline phosphatase and blue-white sclerae.

Diagnosis

Most severe forms are diagnosed before birth itself. Ultrasound scanning during second trimester may reveal deformity of limbs, abnormally short fetus, irregular skull shape, lack of mineralizations and narrow chest cavity. Few cases are diagnosed soon after the birth and mild type of OI is found out much later in life when such individuals suffer from repeated fractures. However, the following diagnostic methods are used to assess the condition.

• Clinical examination, wherein history of frequent fractures with minimal trauma is noted
  
  
• X-Ray
  
  
• Genetic testing of a blood sample (DNA )
  
  
• Skin biopsy to assess collagen production.

Treatment

Since Osteogenesis imperfecta is a genetic condition, it does not have a cure. Patient will be treated symptomatically and will be aided with external tools to provide maximum possible mobility. Efforts are also taken to improve muscle strength and boost the bone mass in the patient through physical therapy. Professionally designed exercise programmes are highly beneficial and play an important role in treating the patients suffering from OI. Patient may also be prescribed required nutritional supplements like calcium, and vitamin D along with physical therapy. Few suitable candidates are also treated with surgical procedure called intramedullary rod surgery wherein metal rods are inserted through the length of the long bones to support and strengthen them.

Of late, Bisphosphonates drugs are being used in treating Osteogenesis imperfecta. Bisphosphonates are used to decrease the amount of bone resorption. It also helps in preventing fractures and improve person's functional mobility. There is also research being done to understand the role of gene therapy in treating Osteogenesis imperfecta.

Prognosis

Prognosis of Osteogenesis imperfecta depends upon the severity of the conditions. Despite bone deformity, restricted activity, and short stature, often patients with OI lead productive and near to normal lives.

Terminologies :

• Osteogenesis : Growing new bone
  
• Osteocytes : Bone cells
  
• Osteoblasts : Bone cells building new bone structure
  
• Osteoclasts : Bone cells which scavange bone tissue