Lead Poisoning

Lead poisoning can occur when lead builds up within the body, usually over a long period of time. Young children are vulnerable to lead poisoning and it is important to be aware of this due to lead poisoning being a factor in mental and physical development. Lead poisoning is a medical condition caused by increased levels of lead within the body that interferes with the normal processes of the body and is particularly toxic to children. This occurs because lead and calcium compete for the protein that is important for body functions, especially the nervous system. The lead can displace the calcium from that protein so the calcium will not be able to function properly.

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When simplifying the signs and symptoms of lead poisoning, we use the acronym “LEAD”. L represents the lines on the gingiva and long bones; E stands for Encephalopathy and erythrocyte (RBC) basophilic stippling (disease, damage, or malfunction of the brain), A signifies abdominal colic and anemia, and D which stands for drop foot and drop wrist.

Lead inhibits the enzymes that are needed to make Heme—preventing the production of hemoglobin. This causes basophilic stippling of the cells due to lead inhibiting the ribosomal RNA degradation. The red blood cells (RBC) will retain aggregates of ribosomal RNA that causes the stippling of the cells.

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Lead poisoning will present itself with a “lead line” in the gingiva (gums) called the Burton’s line. This gray-blue line is visible at the margin of the gum at the base of the teeth. The long bones will also have lead lines in the metaphysis that appear like white bands on an x-ray because the lead is collected within these white bands. The width and density of these lines reflects chronic exposure.

 

At the RBC level, you will find anemia and basophilic stippling of the red blood cells.

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The patient will also have encephalopathy associated with headache and memory loss. Lead poisoning may also cause abdominal colic—pain, cramps, and constipation. Another condition that may occur due to lead poisoning is “foot drop”. The patient may experience permanent damage to the central nervous system and the peripheral nerves.

 

This condition usually occurs from exposure to lead based paint, typically used in much older homes. Particles from the lead based paint can be inhaled through the air or from contaminated drinking water, as we have seen recently. Extended exposure can cause serious problems, with children being the most vulnerable. They will commonly show signs of: irritability, fatigue, lower IQ, and lack of attentiveness. The child may show signs of encephalopathy, nausea, vomiting, gait disturbances, and seizures. Exposure in adults is usually occupational related. Adults will experience personality changes, headaches, neuropathy, weakness, foot and wrist drop, and stomach aches. Both children and adults will experience pale skin due to anemia because lead interferes with the normal formation of hemoglobin.

When diagnosing lead poisoning, you have to take into consideration the history of exposure, cm lead levels are usually greater than 5—however, some people use higher numbers. If a complete blood count (CBC) test is done, microcytic anemia will be found and in a peripheral blood smear, you will find basophilic stippling (ribosomes). The serum iron will be normal.

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When treating lead poisoning, the first step will be to eliminate the source of lead contamination. Next, a chelating agent will be used. During this step, various drugs may be used to help remove lead from the body. A chelating agent will bind the lead into a form that the body can excrete. It is used if lead levels are higher than 45µg/dL in children, and more than 70µg/dL in adults. Dimercaprol (oral chelating agent) is used in cases where patients present with encephalopathy. Succimer is used when there aren’t any signs of encephalopathy.

It is also possible to be contaminated by lead due to a bullet penetrating a joint or if it is introduced into the cerebral spinal fluid. This may cause severe synovitis and low grade lead poisoning. This condition is rare, however it can occur. Lead toxicity can also occur due to contamination of the ground water and soil. Lead poisoning can occur due to ingesting food grown in contaminated soil.

Salter-Harris Fracture Classifications

The Salter-Harris fracture is a common injury in children, involving the growth plates of the long bones. Approximately 15% to 30% of all childhood fractures are growth plate fractures and are common in the lower leg bones (tibia and fibula). It is important to detect these fractures as they may affect the growth of the bone if not treated properly.

There are five types of Salter-Harris fractures. The higher the type number, the more complications associated with the fracture.

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Type I

Type I

Only 5% of fractures are Type I. It may be difficult to diagnose unless there is obvious displacement and sometimes the diagnosis is a clinical one. Type I fractures occur though the weak zone of the provisional calcification and are known for their fast healing and rare complication rate.

Type II:

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Type II

Approximately 75% of fractures are type II. These fractures occur at the physis (growth plate) and metaphysis – and when the corner of the metaphysis separates (Thurston-Holland Sign). The fragment usually stays with the epiphysis while the rest of the metaphysis will displace. Typically, healing is fast and growth is usually okay; however, distal femur fractures may result in growth deformity.

 

Type III:

10% of fractures are Type III, which are defined as fractures of the growth plate and epiphysis, or even a split of the epiphysis. The fractures extend into the articular surface of the bone and will require reduction of the joint. In distal femur fractures it may result in a growth deformity.

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Type III

Type IV:

About 10% of fractures are Type IV fractures—which pass through the epiphysis, physis (growth plate), and the metaphysis. Type IV fractures can cause complications such as growth disturbance and angular deformity.

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Type IV

Type V:

Type V fractures are uncommon, only occurring about 5% of the time. In type V fractures, compression or a crush injury of the growth plate takes place. This fracture has no association with the epiphysis or metaphysis and an initial diagnosis may be difficult. Despite being uncommon, these fractures have the highest incidence of growth deformity and disturbance.

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Type V

Sever’s Disease

Sever’s disease is a common cause of heel pain in children between the ages of 9 and 12 years. The pain is due to calcaneal apophysitis occurring due to repetitive and continuous traction on the calcaneus from the Achilles tendon. The apophysis is not part of a joint and has muscle or tendon attachments. This traction apophysitis may lead to stress fractures, pain and tenderness over the heel.

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Sever’s disease is similar to Osgood-schlatter disease of the tibial tubercle.

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Patients are usually young athletes presenting with heel pain that increases with activities. Upon examination there could be swelling, tenderness, warmth and/or redness on the back of the heel where the Achilles tendon inserts.

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Plain lateral X-rays may show sclerosis or fragmentation of the calcaneal tuberosity. Sclerosis is not specific for this condition.

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Fragmentation of the calcaneal tuberosity on the other hand, is more common in patients with Sever’s disease relative to the general population.

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Remember that Sever’s disease is a clinical diagnosis. X-rays may show other causes of pain such as tumors, fractures, infections or cysts. MRI is not commonly used, but can help rule out calcaneal stress fractures or osteomyelitis.

Sever’s disease is a self-limiting condition that usually resolves with time. Treatment usually consists of NSAID, Achilles tendon stretching exercises, and activity modifications and in severe condition a short leg walking cast can be used.

Pediatric Cervical Spine Injuries

Cervical spine injuries are generally not common in children. Blow 8 years of age, cervical spine injuries usually occur in the upper cervical region. Above 8 years of age, cervical spine injuries occur in the lower cervical region. The prevertebral soft tissue shadow may appear widened on lateral x-ray of a crying child with no injury. Cervical spine injuries should be suspected in multiple trauma patients. Rule out cervical injuries in all patients with head or facial trauma.

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Spinal cord injury without radiological abnormality (SCIWORA) is due to ligamentous elasticity and flexibility of the pediatric vertebral column which can withstand injuries without the evidence of deformity, however the spinal cord will be damaged. It should be suspected in a child with neck injury and neurological symptoms with no radiological bony abnormalities. Common in spinal cord injuries below 8 years of age and usually occurs in the cervical or thoracic spine. SCIWORA usually resolves with no neurological deficiencies but there is high risk of reoccurrence. Investigation of choice is MRI and treatment is cervical immobilization.

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Atlanto-occipital dislocation

It is a fatal injury due to major trauma. It is more common in children than adults due to:

Increased head-body ratio in children.

The occipital condyles of children are smaller than those of adults.

There are three classifications for Atlanto-occipital injuries:

  1. Anterior displacement of the occiput
  2. Longitudinal distraction of the occiput from the atlas ( avoid traction)
  3. Posterior displacement of the occiput.

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Diagnosis is by x-ray. CT scan and MRI that shows ligamentous injury.

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Treatment: reduction should be urgently done with early immobilization by halo vest. Avoid traction in type II. Post reduction radiograph should be obtained to ensure adequate reduction. Cervical spine x-ray should be done daily to ensure maintained reduction.  Atlanto-occipital dislocation is a ligamentous injury that is usually unstable and may need atlanto-occipital fusion.

Os odontoid

Os odontoid is due to congenital or unrecognized fracture of the odontoid. It is accidently discovered on radiological investigation. It should be differentiated from acute odontoid fractures.

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Treatment is conservative if no pain, no neurological deficiency and no cervical spine instability. Surgical treatment is done in patients with progressive symptoms as neck pain, neurological deficiency or cervical spine instability. In young children without progressive deficits, it is better to delay surgical treatment until six to seven years of age. By that time the child will have sufficient bony development of the cervical spine.

Odontoid fracture

Odontoid fractures occur in young children usually around 4 years of age. Treatment includes reduction and immobilization in extension. Complete reduction is usually obtained but it is not necessary, 50% reduction is satisfactory. Growth disturbances are rare.

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Persistence of the basilar odontoid synchondrosis is seen in one half of children up to age eleven and may mimic an odontoid fracture. This line appears sclerotic unlike acute fractures and is located well below the base of the odontoid where most adult fractures occur.

Atlanto- Axial rotatory subluxation

Child with rotatory subluxation of C1 on C2 is marked by the direction of head tilt and rotation of the neck.

Atlanto- Axial rotatory subluxation is classified as following:

Type I: unilateral rotatory subluxation with intact transverse ligament.

Type II: unilateral rotatory subluxation with torn transverse ligament

Type III: bilateral rotatory subluxation

Type VI: posterior rotatory subluxation.

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Most common causes of Atlanto-Axial Rotatory Subluxation are:

  • Neck trauma
  • Inflammatory condition as upper respiratory tract infection.
  • Children with congenital anomalies and ligamentous laxity such as Down syndrome.

This injury may be missed due to mild symptoms and signs. The child usually presents with neck pain and torticollis (cock-robin sign). Physician must rule out any neurological deficiencies.

Lateral X-ray shows anterior displacement of C1 over C2. Open mouth view X-ray shows asymmetrical lateral masses of C1. Dynamic CT scan is diagnostic.

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Treatment depends on the duration of injury. For injuries less than 1 week, immobilization by neck collar should be attempted. Halter traction is used in injuries of more than 1 week in duration. Surgical reduction in C1-C2 fusion is used to treat fixed deformities or used in patients with neurological deficits.

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Sub-axial injuries are rare in children and usually occur in adults. These include:

Posterior ligamentous disruption

It is due to flexion or distraction injuries. It may be missed on radiological evaluation due to normal loss of cervical lordosis in children. MRI is diagnostic for the ligamentous injury and treatment by immobilization in extension or posterior arthrodesis if signs of instability are present.

Compression fractures

They occur due to flexion and axial loading injuries. It leads to loss of the vertebral height and usually diagnosed on lateral view x-ray. In children under 8 years of age vertebral height will be regained during growth and kyphosis will be corrected but if kyphosis is more than 20 degrees it might not be corrected with growth.

Burst fractures

It is due to axial loading injuries. Treatment is by traction followed by halo immobilization if there is no neurological deficiency. Surgical fusion is done when neurological deficiencies are present. Anterior fusion leads to kyphotic deformity due to suppression of the anterior growth potential.

Unilateral or bilateral facet dislocation

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Scoliosis in children

Scoliosis is lateral curving of the spine. Pediatric spinal cord trauma will almost always result in scoliosis.

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