Primary progressive multiple sclerosis (PPMS) is one of the subtypes of multiple sclerosis (MS) distinguished by a slow and irreversible course of myelopathy and overall neurological decline. Contrary to other MS forms, significant female predilection is not observed. Spastic paraparesis and progressive ataxia are principal symptoms in this subset of patients. The diagnosis is made by clinical criteria, findings obtained from magnetic resonance imaging (MRI) of the brain and/or spinal cord, as well as cerebrospinal fluid (CSF) reports.
Primary progressive multiple sclerosis is a well-recognized form of multiple sclerosis that is characterized by progressive damage to the central nervous system (CNS) and subsequent decline in overall functioning and quality of life    . The exact pathogenic mechanism by which neuronal degeneration occurs, however, remains unclear  . It is recognized in about 10-15% of all cases suffering from MS and is one of the rare entity that equally affects both genders     . In fact, some studies propose that males are more frequently affected than females and that MS patients are more likely to develop PPMS at an older age   . Compared to relapsing-remitting multiple sclerosis (RRMS), which encompasses the vast majority of MS patients and presents with optic neuritis and other isolated spinal cord/brainstem abnormalities , the clinical presentation of PPMS is comprised of two main symptoms - spastic paraplegia (often described with an unclear sensory level) and ataxia  . These signs appear due to progressive atrophy of the spinal cord and the cerebellum, whereas the appearance of brainstem abnormalities, visual deficits, sexual dysfunction, cognitive decline, and inability to maintain sphincter control, are less commonly reported in PPMS   . Primary progressive multiple sclerosis has a poor prognosis than other types of MS, mainly because of a delayed diagnosis and an aggressive neurological deterioration  .
Because the various clinical forms of MS might be indistinguishable in their initial stages , particularly the different types of progressive MS, the physician, with his/her ability to obtain a detailed patient history and conduct a thorough physical examination, plays a crucial role in recognizing MS early on. Firstly, key information regarding the presence of symptoms, their duration, as well as progression, should be obtained, followed by a meticulous neurological evaluation. In recent years, diagnostic criteria for identifying PPMS have been designed and consist of the following    :