Warning Signs Of Senior Loken Syndrome

June 17, 2023

Senior Loken syndrome is a rare inherited condition that causes severe eye and kidney problems. Doctors estimate it impacts approximately one in one million individuals worldwide, and patients typically begin to display symptoms shortly after birth or during their early childhood. Genetic testing can be used to diagnose this syndrome, and doctors will also perform detailed visual, renal, and neurological examinations.

For example, patients will have a visual acuity test and a test of their color vision, and fundoscopy exams and an electroretinogram might be necessary. Refraction tests and eye movement studies are generally performed as well. To evaluate renal symptoms, an abdominal ultrasound is used to properly examine the kidneys, and the liver will be checked during this procedure to detect liver fibrosis.

Excessive Thirst And Urine Production

The renal issues associated with Senior Loken syndrome often result in excessive thirst and urine production. These symptoms usually begin in the early stages of the syndrome, and both thirst and urine production could increase as the disease progresses. Excessive urine production is generally defined as passing more than three liters of urine per day, and this may be accompanied by an increase in urinary frequency.

The typical urinary frequency for healthy individuals is between four to six times per day, and clinicians classify urinary frequency as excessive if a patient urinates more than eight times in a day. Patients with Senior Loken syndrome will need to have their kidney health monitored by a pediatric nephrologist, and they should measure the concentration of the patient's urinary output. The specialist will also need to monitor whether sodium is being properly excreted in the urine.

Retinal Dystrophy

Retinal dystrophy is a gradual and progressive breakdown of the retina, the part of the eye that senses light and color. Some children with Senior Loken syndrome are born with a particularly severe type of retinal dystrophy known as Leber congenital amaurosis, a condition that causes vision issues from birth. Infants with this condition may experience sensitivity to light, and they typically have nystagmus, which are involuntary and rapid movements of the eyes that could result in temporarily blurred vision. These patients often have severe farsightedness.

The patients who have retinal dystrophy without Leber congenital amaurosis may not have their vision issues begin until their early childhood, and the symptoms displayed are those of a form of retinal dystrophy known as retinitis pigmentosa. This eye condition usually begins with night blindness, and it gradually progresses first to a loss of peripheral vision and then to a loss of central vision, eventually resulting in total vision loss. Although there is currently no cure for retinal dystrophy and no way of slowing down its progression, aids for individuals with low vision may help patients with daily activities.

Short Stature

Patients with Senior Loken syndrome are typically short in stature. Doctors define short stature as a height that falls within the lowest two percentiles of the patient's peer group. To properly assess a child's height and determine if they meet the criteria for short stature, doctors must take accurate, detailed measurements at multiple appointments over a period of at least three to six months. Ideally, the patient should have their growth checked regularly over a span of six months to one year.

If the patient is under two years old, their body length will be recorded with a horizontal rule, and children aged two years old and above will have their height measured with a stadiometer (a wall-mounted measuring device). Weight will be recorded for all patients, and young children may also have their head size measured. Where appropriate, doctors may calculate an older child's body mass index. These measurements will be plotted on a growth chart at every appointment, and doctors will use these charts to determine whether a child is at a healthy growth percentile.

Hypertension

Hypertension in patients with Senior Loken syndrome is generally related to the renal issues that occur with this condition. High blood pressure is defined as equal to or greater than 130/80. To diagnose hypertension, the doctor will take at least three blood pressure measurements on three different days. Readings may be taken in both arms, and patients may also be asked to use an at-home monitoring device for a few days to provide more information. The majority of patients with this syndrome will have high blood pressure in childhood, and it is normally necessary to take medications for proper management.

Calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor blockers are among the most commonly prescribed medications for reducing blood pressure. Patients with renal issues, including individuals with Senior Loken syndrome, may especially benefit from using ACE inhibitors or angiotensin II receptor blockers. During treatment with these medications, patients will have regular appointments to monitor their blood pressure and check the medications are effectively reducing it. Occasionally, patients may need to add other medications such as beta blockers, alpha blockers, or vasodilators to their treatment plan to sufficiently lower their blood pressure.

Kidney Damage And Impaired Function

Kidney damage and impaired function are among the most serious symptoms associated with Senior Loken syndrome. This syndrome triggers a condition known as nephronophthisis, which causes the kidneys to become inflamed, and both cysts and heavy scarring are usually present on these organs. Extreme fatigue and weakness may also occur. Over time, nephronophthisis generally leads to end-stage kidney disease, and most patients with Senior Loken syndrome reach this point by the time they are adolescents. While appropriate monitoring and treatment can delay the onset of end-stage kidney disease, it is generally considered life-threatening, and patients will need dialysis or a kidney transplant.

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