PBA is generally associated with later stages of the disease (chronic progressive phase). PBA in MS patients is associated with more severe intellectual deterioration, physical disability, and neurological disability. Amyotrophic lateral sclerosis
A study designed specifically to survey for prevalence found that 49% of patients with amyotrophic lateral sclerosis (ALS) also had PBA. PBA does not appear to be associated with duration of ALS. It is a symptom of ALS that many patients are unaware of and do not receive information about from their physician. Traumatic brain injury
One study of 301 consecutive cases in a clinic setting reported a 5% prevalence. PBA occurred in patients with more severe head injury, and coincided with other neurological features suggestive of pseudobulbar palsy.The Brain Injury Association of America (BIAA) indicates that approximately 80% of survey respondents experience symptoms of PBA. Results from a recent investigation estimate the prevalence of PBA associated with traumatic brain injury to exceed more than 55% of survivors. Treatment
Education of patients, families, and caregivers is an important component of the appropriate treatment of PBA. Crying associated with PBA may be incorrectly interpreted as depression; laughter may be embarrassing, anger can be debilitating. It is therefore critical for families and caregivers to recognize the pathological nature of PBA and the reassurance that this is an involuntary syndrome that is manageable. Traditionally, antidepressants such as sertraline, fluoxetine, citalopram, nortriptyline and amitriptyline have been prescribed with some efficacy. Medication
Dextromethorphan hydrobromide affects the signals in the brain that trigger the cough reflex.
HCL-V differs from classic HCL principally in these respects:

Higher white blood cell counts, sometimes exceeding 100,000 cells per microliter
A more aggressive course of disease requiring more frequent treatment
Hairy cells with an unusually large nucleolus for their size
Production of little excess fibronectin produced by classic hairy cells to interfere with bone marrow biopsies
Low or no cell-surface expression of CD25 (interleukin-2 [IL-2] receptor alpha chain, or p55).Low levels of CD25, a part of the receptor for a key immunoregulating hormone, may explain why HCL-V cases are generally much more resistant to treatment by immune-system hormones.HCL-V, which usually features a high proportion of hairy cells without a functional p53 tumor suppressor gene, is somewhat more likely to transform into a higher-grade malignancy. A typical transformation rate of 5-6% has been postulated in the UK, similar to the Richters transformation rate for splenic lymphoma with villous lymphocytes (SLVL) and CLL. Among HCL-V patients, the most aggressive cases normally have the least amount of p53 gene activity. Hairy cells without the p53 gene tend, over time, to displace the less aggressive p53(+) hairy cells. Some evidence suggests that a rearrangement of the immunoglobulin gene VH4-34, which is found in about 40% of HCL-V patients and 10% of classic HCL patients, may be a more important poor prognostic factor than variant status, with HCL-V patients without the VH4-34 rearrangement responding about as well as classic HCL patients. Hairy cell leukemia-Japanese variant
The variant called hairy cell leukemia-Japanese variant, or HCL-J, is more easily treated. Treatment with cladribine has been reported.