We've been over this before - I don't make stuff up and pass it off as "expertise" - I wouldn't dare take that away from you. I did, however, use the word "suddenly", when the correct word is "spontaneously". I apologize for that mistake.
Per Wikipedia (
http://en.wikipedia.org/wiki/Idiopathic):
"Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios (one's own) + πάθος, pathos (suffering), it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease. For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause may not be readily apparent or characterized. In these cases, the origin of the condition is said to be idiopathic.
With some medical conditions, the medical community cannot establish a root cause for a large percentage of all cases (for example, focal segmental glomerulosclerosis, the majority of which are idiopathic);[1] with other conditions, however, idiopathic cases account for a small percentage (for example, pulmonary fibrosis).[2] As medical and scientific advances are made with relation to a particular condition or disease, more root causes are discovered, and the percentage of cases designated as idiopathic shrinks."
You are correct that
one cause of toe walking is a shortened tendon; but that is only one cause. No, I don't have time to find an ortho doc to lecture me on the issue, so I hope the National Institutes of Health are reputable enough to satisfy you. According to them:
"Idiopathic toe-walking is a diagnosis of exclusion when a child presents with bilateral toe-to-toe gait. Although toe-walking is considered part of the normal gait spectrum in development, it is abnormal when persisting past the age of two. Toe-walking may be caused by cerebral palsy, congenital contracture of the Achilles tendon or paralytic muscular disorders such as Duchenne Muscular Dystrophy. Idiopathic toe-walking may be associated with developmental disorders such as autism or other myopathic or neuropathic disorders. The majority of disorders causing toe-walking can be ruled out through the history and physical examination, resulting in a diagnosis of idiopathic toe-walking. However, it may be difficult to differentiate mild forms of cerebral palsy, specifically mild spastic diplegia, and idiopathic toe-walking. The treatment options for idiopathic toe-walking include observation, conservative methods and surgical methods. Most children can be treated in the primary care setting with either observation or conservative treatment. Patients with severe contracture of the Achilles tendon, or persistent toe-walking, may need surgical intervention. The prognosis of idiopathic toe-walking is favorable with both conservative and surgical treatment allowing children to attain normal function and range of plantarflexion. The following article provides an overview of the background information, differential diagnosis and treatment options for idiopathic toe-walking."
http://www.ncbi.nlm.nih.gov/pubmed/18432151