Neurological disorders
- Multiple sclerosis
- Parkinson's disease
- Chronic idiopathic intestinal pseudo-obstruction
- Stroke
- Spinal cord injuries
Metabolic and endocrine conditions
- Diabetes
- Uremia
- Hypercalcemia
- Hypothyroidism
- Poor glycemic control
Systemic disorders
- Amyloidosis
- Lupus
- Scleroderma