Ch 17 Systemic Diseases 5 Flashcards
Hypophosphatasia is a rare metabolic bone disease that is characterized by a deficiency of tissue nonspecific __________
alkaline phosphatase
What is one of the first signs of hypophosphatasia?
premature loss of the primary teeth, presumably caused by a lack of cementum on the root surfaces
(childhood) hypophosphatasia
What are three common factors in all types of hypophosphatasia?
- decreased bone, liver, kidney isozyme of alk phos
- increased blood/uriniary phosphoethanolamine
- bone abdnormalities that resemle rickets
Name that type of hypophosphatasia: It is usually diagnosed at birth, and the infant rarely survives for more than a few hours. Death is due to respiratory
failure. Marked hypocalcification of the skeletal structures
is observed.
perinatal lethal
Name that type of hypophosphatasia: clinical course similar to infantile hypophosphatasia…skeletal calcification may be detected
in some of these fetuses during the third trimester of pregnancy,
in contrast to the lethal form.
perinatal benign
Name that type of hypophosphatasia: may appear
normal up to 6 months of age; after this time, they
begin to show a failure to grow
Vomiting and hypotonia
may develop as well. Skeletal malformations that suggest
rickets are typically observed; these malformations include
shortened, bowed limbs.
If these infants
survive, premature shedding of the deciduous teeth is
often seen.
infantile hypophosphatasia
Name that type of hypophosphatasia:
usually detected at a later age and
has a wide range of clinical expression’
premature loss of the primary teeth
without evidence of a significant inflammatory response
deciduous incisor teeth are
usually affected first and may be the only teeth involved
open
fontanelles with premature fusion of cranial sutures.
Affected patients typically
have a short stature, bowed legs, and a waddling gait.
childhood hypophosphatasia
Name that type of hypophosphatasia:
typically mild
history of premature loss of their primary or permanent
dentition, and many of these patients are edentulous
Stress
fractures that involve the metatarsal bones of the feet may
be a presenting sign of the condition, or an increased
number of fractures associated with relatively minor trauma
adult hypophosphatasia
Name that type of hypophosphatasia:
the most controversial
premature loss of the
incisor teeth as the only clinical sign of disease
serologic studies will be consistent with hypophosphatasia
Odontohypophosphatasia
Name that type of hypophosphatasia:
Radiographically, the skull of more severely affected individuals
may show uniformly spaced, poorly defined, small
radiolucencies, a pattern that has been described as resembling
“beaten copper.”
Childhood hypophosphatasia
how is hypophosphatasia diagnosed?
decreased serum alk phos, increased phosphoethanolamine in both urine and blood (serum alk phos may approach normal with age)
What is the histologic difference between infintile and childhood/adult hypophosphatasia?
Infantile: abundant poorly mineralized osteoid
Childhood/adult: relatively normal bone or increased woven bone (less mature osteoid)
Why do the primary teeth exfoliate early in a patient with hypophosphatasia?
reduced cementum = inability of PDL fibers to attach to the tooth
What is the treatment for hypophosphatasia?
Treating symptoms only - administering alk phos has no effect due to its function within a cell, not the extracellular environment