Summary about Disease
Yashar syndrome, also known as cutaneous syndrome with osteomalacia, is a very rare disorder characterized by chronic skin lesions (typically hyperpigmentation and thickening, sometimes resembling lichen planus) in conjunction with osteomalacia (softening of the bones due to impaired mineralization). It is primarily due to phosphate wasting by abnormal levels of phosphatonins.
Symptoms
Skin lesions: Hyperpigmentation (darkening of the skin), thickened skin, pruritus (itching), lesions resembling lichen planus. Lesions can occur anywhere on the body but are frequently found on the extremities and trunk.
Bone pain: Pain in the bones, especially in the legs, back, and hips.
Muscle weakness: Difficulty walking, climbing stairs, or performing other physical activities.
Fatigue: Persistent tiredness and lack of energy.
Fractures: Increased susceptibility to bone fractures, even with minor trauma.
Height loss: Due to vertebral compression fractures.
Dental problems: Tooth enamel defects can sometimes occur.
Causes
Yashar syndrome is primarily caused by tumors, usually benign, that secrete fibroblast growth factor 23 (FGF23) or other phosphatonins, such as matrix extracellular phosphoglycoprotein (MEPE). These substances lead to increased phosphate excretion in the kidneys, resulting in hypophosphatemia (low phosphate levels in the blood). The low phosphate levels interfere with bone mineralization, leading to osteomalacia. The tumor(s) may be small and difficult to locate. Occasionally, no tumor can be found (tumor-induced osteomalacia of unknown origin).
Medicine Used
Phosphate supplements: Oral phosphate supplements are prescribed to increase phosphate levels in the blood.
Calcitriol (active form of vitamin D): Calcitriol helps increase phosphate absorption from the gut and reduce phosphate excretion by the kidneys.
Surgery: If a tumor is found, surgical removal is the primary treatment to address the underlying cause.
Burosumab: A monoclonal antibody that blocks the activity of FGF23 and can be effective in treating tumor-induced osteomalacia if the tumor cannot be located or completely removed.
Is Communicable
No, Yashar syndrome is not a communicable disease. It is not caused by an infectious agent and cannot be transmitted from person to person.
Precautions
Adherence to medication: Strictly follow the prescribed medication regimen, including phosphate supplements and calcitriol.
Regular monitoring: Frequent blood tests are necessary to monitor phosphate, calcium, vitamin D, and other relevant levels.
Fall prevention: Take measures to prevent falls, such as using assistive devices (e.g., canes, walkers) and removing hazards from the home.
Diet: Maintain a balanced diet rich in calcium and vitamin D.
Sun exposure: Get adequate sun exposure to promote vitamin D synthesis (with appropriate sun protection to avoid skin damage).
How long does an outbreak last?
Since Yashar Syndrome is not an infectious disease, the term "outbreak" is not applicable. The symptoms and the disease itself can persist for a prolonged period if left untreated, and the duration depends on the underlying cause (e.g., tumor presence) and the effectiveness of treatment.
How is it diagnosed?
Clinical evaluation: A thorough physical examination and review of the patient's symptoms, including skin lesions, bone pain, and muscle weakness.
Blood tests: Measurement of serum phosphate, calcium, alkaline phosphatase, vitamin D levels, parathyroid hormone (PTH), and FGF23 levels. Low phosphate levels are a key indicator.
Urine tests: Measurement of phosphate excretion in the urine.
Bone X-rays: To assess for osteomalacia and fractures.
Bone scan: To identify areas of increased bone turnover.
Bone biopsy: In some cases, a bone biopsy may be necessary to confirm the diagnosis of osteomalacia.
Imaging studies: CT scans, MRI, or PET scans may be used to locate tumors that could be causing the phosphate wasting.
Timeline of Symptoms
The timeline of symptoms can vary considerably from person to person. It often begins insidiously, with subtle symptoms that worsen over time.
Early stages: Skin lesions may appear gradually, accompanied by mild bone pain and fatigue.
Progression: As the disease progresses, bone pain becomes more severe, muscle weakness develops, and the risk of fractures increases.
Advanced stages: Untreated Yashar syndrome can lead to significant disability, including difficulty walking, chronic pain, and impaired quality of life.
With treatment: Appropriate medical management, including phosphate supplementation, calcitriol, and tumor removal (if applicable), can improve symptoms and slow disease progression.
Important Considerations
Early diagnosis: Prompt diagnosis and treatment are essential to prevent long-term complications of osteomalacia.
Multidisciplinary approach: Management of Yashar syndrome often requires a multidisciplinary approach involving dermatologists, endocrinologists, nephrologists, orthopedists, and radiologists.
Tumor localization: Locating the tumor responsible for phosphate wasting can be challenging, and advanced imaging techniques may be necessary.
Treatment response: Monitoring treatment response is crucial to adjust medication dosages and ensure optimal outcomes.
Long-term follow-up: Regular follow-up is necessary to monitor for recurrence of tumors and to manage any long-term complications of the disease.