What Is an Ask-Upmark Kidney?
Renal segmental hypoplasia or Ask-Upmark kidney is a condition in which a segment of the kidneys, mainly the renal cortex, has failed to develop or is incompletely developed. The kidneys consist of the renal cortex, renal medulla, and renal pelvis. These structures work as the filtration units of the kidneys and also form urine. However, the problem arises when a particular segment of the kidneys has failed to develop or is absent. This condition is known as renal segmental hypoplasia. It must not be confused with renal hypoplasia because, in renal hypoplasia, the entire kidney has not developed properly and is small in size. In renal segmental hypoplasia, mainly the renal cortex is incompletely developed.
What Are the Causes of Ask-Upmark Kidney?
Renal segmental hypoplasia was named Ask-Upmark kidney because Dr. Eric Ask-Upmark discovered the condition. There is no definite cause of this disorder, but researchers believe it is caused by genetic mutations, vesicoureteral reflux, and pyelonephritis. The causes of Ask-Upmark kidney are listed below:
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Genetic Defects - Genetic defects or mutations are one of the causes of renal segmental hypoplasia. The genes responsible for the disease are still unknown. However, some researchers believe that the condition might be present congenitally.
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Chronic Pyelonephritis - The inflammation of the kidneys that occurs due to bacterial infection is known as pyelonephritis. Chronic pyelonephritis is a common disorder among females. The patient can have permanent kidney damage if the condition is left untreated for prolonged periods. Scarring of the kidneys might occur in patients suffering from pyelonephritis for a prolonged period, resulting in renal hypoplasia.
What Are the Signs and Symptoms of Ask-Upmark Kidney?
The Ask-Upmark kidney is a rare disorder; only 175 cases have been reported in the medical literature. The signs and symptoms of renal segmental hypoplasia or Ask-Upmark kidney are listed below:
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Hypertensive Encephalopathy - Hypertensive encephalopathy is one of the most common symptoms of Ask-Upmark kidney. It is a type of hypertensive emergency in which the patient's mental status gets altered due to increased blood pressure. It is a life-threatening condition and requires immediate medical care and attention to save the organs from getting damaged. This condition mainly arises when the heart or the kidneys cannot carry out their activities.
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Hypertensive Retinopathy - As the name suggests, this condition is characterized by retinal damage due to hypertension. The retina is a layer of tissue located in the back of the eye. It converts light into nerve signals that are sent to the brain for interpretation. When the blood pressure is too high, the retina's blood vessels become thick and narrow. As a result, the retina does not receive sufficient blood, and the patient experiences problems related to vision.
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Pain - Sometimes, the patient presents with pain in the lower back and the sides. A lump or a mass might be felt in the abdomen, but it is not painful.
What Methods Are Used to Diagnose Ask-Upmark Kidney?
Ask-Upmark kidneys are diagnosed based on medical history, physical examination, laboratory tests, and imaging tests. The diagnostic methods have been summarized below:
1. Medical History - The medical history explains the general health of the patient. The medical history comprises questions related to the symptoms of the condition, the time of their onset and progression, the family history, the drug history, and the medical conditions experienced by the patient in the past.
2. Physical Examination - The doctor examines the patient to check the physical signs of renal segmental hypoplasia. Usually, the patient presents with the problem of abdominal pain, so a mass might be felt when the abdomen is palpated. Also, the blood pressure and weight are checked because patients suffering from renal segmental hypoplasia usually have high blood pressure.
3. Laboratory Tests -
- Blood Tests - The doctor might ask the patient to undergo a blood test to check urea and creatinine levels. Urea is formed as a waste product after the cells break down proteins. Creatinine is formed as a waste product of muscle activity. Normally, these substances are removed by the kidneys, but their levels may be high in patients suffering from Ask-Upmark kidneys.
- Urinalysis - The patient needs to collect the urine in a container or a sterile bag provided by the hospital. This test helps to check the urine output, white blood cells, and bacteria in the urine.
4. Imaging Tests -
- Ultrasound - It is a type of imaging test in which sound waves are sent to the body organs with the help of a device known as a transducer. The doctor moves the transducer over the abdomen at different angles to obtain images of the internal organs. The affected kidney usually appears smaller than the normal kidney.
- Voiding Cystourethrogram - It is a simple procedure wherein the doctor checks whether the patient urinates normally or presents with backflow of urine. In this procedure, a solution is injected into the bladder through a tube. X-rays are then taken from different angulations to monitor the functioning of the bladder. This test does not give any idea about renal segmental hypoplasia, but it is done to check if the patient is suffering from vesicoureteral reflux.
- Diethylene Triamine Penta Acetate (DTPA) Scan - It is the "gold standard" for diagnosing kidney infections. This procedure is mainly done by injecting a special liquid or a contrast medium into the patient’s body, and the images are obtained with the help of a gamma camera. It detects infection, scars, renal hypoplasia, and renovascular hypertension.
- Renal Angiogram - An imaging test in which a contrast material is injected into the artery that supplies blood to the kidneys. The X-ray images help to visualize the blood vessels. Patients suffering from Ask-Upmark kidney usually show blockage in the blood vessels. Also, the affected kidney appears small compared to the normal one.
- Intravenous Pyelography - Intravenous urography is one of the imaging tests that help to detect the problems of the kidneys, ureters, and urinary bladder. A contrast material is injected into the body’s veins to examine the urinary tract organs. The X-ray images obtained after the procedure helps to compare the size of the kidneys. The affected kidney appears irregular, and the hyperplastic tissue can be easily demarcated from the normal one.
5. Renal Biopsy - In this procedure, the doctor inserts a needle into the body to obtain a tissue sample. Next, the sample is examined in the laboratory under a microscope to detect the cancer cells or changes in the tissues that led to renal hypoplasia.
How to Manage Renal Segmental Hypoplasia or Ask-Upmark Kidney?
The management of renal segmental hypoplasia is based on the severity and the cause. If only one kidney is affected, a nephrectomy is usually indicated. If both kidneys are affected, medical treatment for hypertension and renal insufficiency must be done. The treatment options have been described below:
1. Nephrectomy - Nephrectomy is a surgical procedure in which all or parts of the kidney are removed. It might be done to remove the tumor of the kidneys and the surrounding structures. The affected kidney is usually removed by nephrectomy, and the patient is kept on follow-ups for a few weeks.
2. Medical Management - If both kidneys have got damaged due to renal segmental hypoplasia, the doctor might recommend medications to treat hypertension and renal insufficiency. A nephrectomy will be done only when the medications fail to control the blood pressure. The following drugs are usually recommended to treat hypertension:
- Angiotensin-Converting Enzyme (ACE) Inhibitors - Captopril, Lisinopril, and Benazepril.
- Angiotensin II Receptor Blockers (ARBs) - Candesartan, Losartan, and Valsartan.
What Are the Complications of Ask-Upmark Kidney?
Ask-Upmark kidney or renal segmental hypoplasia is a condition in which some of the kidneys fail to develop completely. It has been seen that patients suffering from renal segmental hypoplasia also face problems in passing urine. It is because the urine flows back to the kidneys and does not flow outside the body. This increases the risk of urinary tract infections because the bacteria can easily grow in the urine. Recurrent urinary tract infections are the most common complications of Ask-Upmark kidneys.
Conclusion
The Ask-Upmark kidney is a type of renal hypoplasia in which a segment of the kidneys has failed to develop. As a result, the kidney appears smaller than normal and shows an indentation that demarcates the normal and hyperplastic tissue. It is a rare condition, and only a few cases have been reported in the medical literature. Some researchers believe that the condition is mainly caused by vesicoureteral reflux and pyelonephritis, while some consider it a congenital condition. The treatment depends on the number of kidneys affected. A nephrectomy or surgical kidney removal is usually done if one of the kidneys is affected. However, if both kidneys are affected, the doctor recommends antihypertensive medications. It is because the blood pressure is too high, and a nephrectomy cannot be carried out in such situations. Consult the doctor to know more about Ask-Upmark kidney and its treatment options.
