Oct 222010
 
Arm and leg fractures usually result from trauma and commonly cause substantial muscle, nerve, and other soft-tissue damage. The prognosis varies with the extent of disablement or deformity, the amount of tissue and vascular damage, the adequacy of reduction and immobilization, and the patient’s age, health, and nutritional status.
Children’s bones usually heal rapidly and without deformity. Bones of adults in poor health and with impaired circulation may never heal properly. Severe open fractures, especially of the femoral shaft, may cause substantial blood loss and life-threatening hypovolemic shock.
Causes
Most arm and leg fractures result from major trauma—for example, a fall on an outstretched arm, a skiing accident, or child abuse (shown by multiple or repeated episodes of fractures). However, in a person with a pathologic bone-weakening condition, such as osteoporosis, bone tumors, or metabolic disease, a mere cough or sneeze can also produce a fracture. Prolonged standing, walking, or running can cause stress fractures of the foot and ankle—usually in nurses, postal workers, soldiers, and joggers.
Signs and symptoms
Arm and leg fractures may produce any or all of the five Ps: pain and point tenderness, pallor, pulse loss, paresthesia, and paralysis. (The last three are distal to the fracture site.) Other signs include deformity, swelling, discoloration, crepitus, and loss of limb function. Numbness and tingling, mottled cyanosis, cool skin at the end of the extremity, and loss of pulses distal to the injury may indicate arterial compromise or nerve damage. Open fractures also produce an obvious skin wound.

Complications of arm and leg fractures include:
  • hypovolemic shock as a result of blood vessel damage (This is especially likely to develop in patients with a fractured femur.)
  • permanent deformity and dysfunction if bones fail to heal (nonunion) or heal improperly (malunion)
  • aseptic necrosis of bone segments from impaired circulation Continue reading »
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Oct 202010
 
Consisting of at least eight distinct errors of metabolism—all inherited—glycogen storage disease alters the synthesis or degradation of glycogen, the form in which glucose is stored in the body.
Normally, muscle and liver cells store glycogen. Muscle glycogen is used in muscle contraction; liver glycogen can be converted into free glucose, which can then diffuse out of the liver cells to increase blood glucose levels.
Glycogen storage disease manifests as a dysfunction of the liver, heart, or musculoskeletal system. Symptoms vary from mild and easily controlled hypoglycemia to severe organ involvement that may lead to cardiac and respiratory failure.
Causes
Almost all glycogen storage disease (types I through V and type VII) is transmitted as autosomal recessive traits. (See Types of glycogen storage disease.) The mode of transmission of type VI is unknown; type VIII may be an X-linked trait.
The most common type of glycogen storage disease is type I, glucose-6-phosphatase deficiency, or von Gierke’s disease, which results from a deficiency of the liver enzyme glucose-6-phosphatase. It occurs in about 1 in 200,000 births, but the incidence may be higher in some populations. This enzyme converts glucose-6-phosphate into free glucose and is necessary for the release of stored glycogen and glucose into the bloodstream to relieve hypoglycemia.
Infants may die of acidosis before age 2; if they survive past this age, with proper treatment, they may grow normally and live to adulthood with only minimal hepatomegaly. Brief periods of fasting Continue reading »
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Oct 152010
 
In hypovolemic shock, reduced intravascular blood volume causes circulatory dysfunction and inadequate tissue perfusion. Without sufficient blood or fluid replacement, hypovolemic shock syndrome may lead to irreversible cerebral and renal damage, cardiac arrest and, ultimately, death.  Hypovolemic shock requires early recognition of signs and symptoms and prompt, aggressive treatment to improve the prognosis.
Causes
Hypovolemic shock usually results from acute blood loss—about one-fifth of the total volume. Such massive blood loss may result from GI bleeding, internal hemorrhage (hemothorax and hemoperitoneum), or external hemorrhage (accidental or surgical trauma) or from any condition that reduces circulating intravascular plasma volume or other body fluids such as in severe burns. Other underlying causes of hypovolemic shock include intestinal obstruction, peritonitis, acute pancreatitis, ascites and dehydration from excessive perspiration, severe diarrhea or protracted vomiting, diabetes insipidus, diuresis, and inadequate fluid intake.
Signs and symptoms
Hypovolemic shock produces a syndrome of hypotension with narrowing pulse pressure; decreased sensorium; tachycardia; rapid, shallow respirations; reduced urine output; and cold, pale, clammy skin. Metabolic acidosis with an accumulation of lactic acid develops as a result of tissue anoxia as cellular metabolism shifts from aerobic to anaerobic pathways. Disseminated intravascular coagulation (DIC) is a possible complication of hypovolemic shock.
Diagnosis
No single symptom or diagnostic test establishes the diagnosis or severity of shock. Characteristic Continue reading »
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