Pseudohypoparathyroidism
Pseudohypoparathyroidism (PHP) is a condition where there is end-organ resistance to parathyroid hormone (PTH).
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Epidemiology
Pseudohypoparathyroidism has an estimated prevalence of 1.1 per 100,000 people 6.
Clinical Presentation
- Hypocalcemia and tetany
- Short stature
- Developmental delay
Pathology
Subtypes
There are several recognized subtypes which include:
-
type I: abnormal cAMP response to PTH stimulation
- type Ia (Albright hereditary osteodystrophy (AHO)): has characteristic phenotypical features
- type Ib: lacks phenotypical features
- type II: normal cAMP response to PTH stimulation
Markers
- parathyroid hormone level: high
- serum phosphate level: high
- serum calcium level: low
Radiographic features
Musculoskeletal manifestations
- short stature and obesity
-
brachydactyly
- short metacarpals (inclusive of short 4th/5th metacarpals)
- short metatarsals
- soft tissue calcification
- exostoses: short metaphyseal or more central and perpendicular to long axis of a bone
- broad bones with coned epiphyses
CNS / head and neck manifestations
Related Radiopaedia articles
Metabolic bone disease
- bone mineralization
- liver-related
- osteosclerosis (differential diagnosis / mnemonic)
- parathyroid-related
- pituitary gland-related
- thyroid gland-related