EMG tests in patients who do have PMA usually show denervation (neuron death) in most affected body parts, and in some unaffected parts too.It typically takes longer to be diagnosed with PMA than ALS, an average of 20 months for PMA vs 15 months in ALS. Differential diagnosis
In contrast to amyotrophic lateral sclerosis or primary lateral sclerosis, PMA is distinguished by the absence of:
brisk reflexes
spasticity
Babinskis sign
emotional labilityThe importance of correctly recognizing progressive muscular atrophy as opposed to ALS is important for several reasons. The prognosis is a little better. A recent study found the 5-year survival rate in PMA to be 33% (vs 20% in ALS) and the 10-year survival rate to be 12% (vs 6% in ALS). Patients with PMA do not have the cognitive change identified in certain groups of patients with MND. Because PMA patients do not have UMN signs, they usually do not meet the World Federation of Neurology El Escorial Research Criteria for "Definite" or "Probable" ALS and so are ineligible to participate in the majority of clinical trials conducted in ALS. Because of its rarity (even compared to ALS) and confusion about the condition, some insurance policies or local healthcare policies may not recognize PMA as being the life-changing illness that it is.
The Canadian data in some areas may be confounded or explained by the tendency to establish indigenous communities in wooded, riparian, northern areas corresponding to the core habitat of B. dermatitidis, often with known B. dermatitidis habitats such as woodpiles and beaver constructions in the near vicinity. Communicability
Blastomycosis is not considered contagious, either among humans or between animals and humans. However, there are a very small number of cases of human-to-human transmission of B. dermatitidis related to dermal contact or sexual transmission of disseminated blastomycosis of the genital tract among spouses. History
The organisms causing blastomycosis have existed for millions of years. The pathogenic group of onygenalean fungi that give rise to conditions including blastomycosis and histoplasmosis emerged approximately 150 million years ago. The most closely related blastomycosis-causing fungi, Blastomyces dermatitidis and Blastomyces gilchristii, diverged during the Pleistocene, approximately 1.9 million years ago.At the Koster Site in Illinois, evidence pointing to possible blastomycosis infections among Late Woodland Native Americans has been identified. At that site, Dr. Jane Buikstra found evidence for what may have been an epidemic of a serious spinal disease in adolescents and young adults. Several of the skeletons showed lesions in the spinal vertebrae in the lower back. There are two modern diseases that produce lesions in the bone similar to the ones Dr. Buikstra found in these prehistoric specimens: spinal TB and blastomycosis. The bony lesions in these two diseases are practically identical.