Pseudohypoparathyroidism shows the same symptoms as normal hypoparathyroidism without the presence of parathyroid hormone deficiency. Calcium levels in the blood are too low and phosphate levels are too high. Despite a normal or even increased concentration, the parathyroid hormone cannot develop its effect.
What is pseudohypoparathyroidism?
Pseudohypoparathyroidism, also known as Martin-Albright syndrome, is characterized by the same symptoms as hypoparathyroidism. The term hypoparathyroidism can be translated as a lack of parathyroid hormone caused by an underactive parathyroid gland. The prefix “pseudo” means “as if” and indicates a deficient effect of the parathyroid hormone at a normal concentration of this hormone. See whicheverhealth for Leber Congenital Amaurosis Meanings.
The parathyroid hormone regulates the concentration of calcium and phosphate in the blood serum. The action of this hormone releases calcium from the bones when needed while promoting the elimination of phosphate through the kidneys. When the calcium level in the blood falls or the need for it increases, the production of parathyroid hormone from the parathyroid glands is stimulated.
With the release of calcium from the bones, however, the release of phosphate automatically increases, because the main material of the bones consists of calcium phosphate. However, increased phosphate concentrations inhibit further calcium release. Therefore, the parathyroid hormone also ensures the inhibition of phosphate absorption via the kidneys.
This means that phosphate is increasingly excreted in the urine. Balanced calcium and phosphate levels are crucial for the electrolyte balance, which is responsible for the normal transmission of impulses in muscle and nerve cells.
Causes
Pseudohypoparathyroidism is therefore characterized by a reduced effect of sufficient parathyroid hormone. As with classic hypoparathyroidism, this leads to hypocalcaemia (calcium deficiency) and hyperphosphataemia (excess phosphate) in the blood. The consequences are increased stimulus transmission and states of excitement with neurological deficits.
In terms of how the parathyroid hormone works, not only is its correct concentration important, but also the smooth functioning of all intermediate steps in the development of the effect. For a hormone to work, for example, it must dock with a corresponding receptor. This receptor mediates the effect of hormones or other bioactive substances and thus brings them to their expression.
However, if a receptor is not working properly, the hormone, in this case the parathyroid hormone, cannot fulfill its function. The same failures occur as with a real lack of parathyroid hormone. The corresponding defects in the parathyroid hormone receptors are genetically determined. The processes at these switching points are complicated and diverse, so there are four different possibilities for malfunctions.
In type Ia pseudohypoparathyroidism, the proportion of G proteins in the parathyroid receptor complex is reduced. Type Ib is directly characterized by a defect in the PHT receptor. A defect in the catalytic unit of the parathyroid hormone receptor leads to type Ic pseudohypoparathyroidism. Finally, in type II, the receptor is intact. However, the intracellular response is missing here.
Symptoms, Ailments & Signs
In addition to the deformities of the physique, the symptoms of pseudohypoparathyroidism, like hypoparathyroidism, are characterized by hypocalcemia. The physique of the patient is characterized by short stature and shortening of the metacarpal and metatarsal bones. The hypocalcemia produces the symptoms of tetany.
This leads to paraesthesia, pawed-toe position of the hands, pointed foot position of the feet and cramps in the area of the feet and hands. There is also an increased readiness for reflexes (hyperreflexia). This leads to hyperexcitability of the muscle and nerve cells. Chvostek’s sign and Trousseau’s test are positive.
In Chvostek’s sign, the facial muscles contract when the facial nerve is tapped. The Trousseau test is characterized by a spasmodic contraction of the forearm muscles with the hands in a pawed position after a blood pressure cuff has been put on and pumped up on the upper arm. The spasms can also manifest themselves in individual organs.
This then occurs biliary colic, cramps of the heart or lungs. Hair loss, cataracts, a congested papilla or dry skin can also occur as further symptoms. In severe cases, calcium deposits can form in the brain, leading to headaches and increasing dementia.
Diagnosis & course of disease
The clinical picture of pseudohypoparathyroidism usually initially leads to a suspected diagnosis of hypoparathyroidism. The parathyroid hormone concentration is examined via laboratory tests. If this is normal, it is usually pseudohypoparathyroidism.
However, this in turn must be differentiated from the so-called pseudopseudohypoparathyroidism. In pseudopseudohypoparathyroidism, calcium metabolism is normal, but the activity of the Gsa protein is reduced.
Complications
Pseudohypoparathyroidism causes symptoms similar to hypoparathyroidism. The same applies to the complications that occur in both diseases. The main symptoms are hypocalcemia and hyperphosphatemia, which are the main causes of various complications. Hypocalcaemia can be asymptomatic. However, it can also lead to such symptoms as tetany, increased reflex readiness and low heart rate.
In severe cases, cardiac arrhythmias and heart failure occur, which pose a great risk of cardiac arrest with cardiovascular system failure. Tetany is cramps in the hands and feet, which can lead to the paws-paw position of the hands and the feet to the hips. If hypocalcemia persists for a long time, psychological problems often appear, which are manifested by symptoms such as depression, moodiness or anxiety.
Since phosphate is also increasingly formed in addition to calcium, calcium phosphate precipitates in the blood vessels, which ultimately results in a reduced calcium and increased phosphate content in the blood as a result of regulatory mechanisms. The calcium phosphates precipitated in this reaction lead in particular to calcification of the brain.
The calcium deposits in the brain cause severe headaches and, in extreme cases, can also develop dementia. Calcium and phosphate levels can be easily adjusted as part of therapy. However, pseudohypoparathyroidism cannot be cured because it is genetic. The shape anomalies of the joints and the short stature cannot be influenced therapeutically.
When should you go to the doctor?
Pseudohypoparathyroidism should always be treated by a doctor. The disease can lead to various complications, although the affected person does not heal himself. Treatment by a doctor is therefore essential. As a rule, the doctor should be consulted if the person concerned suffers from short stature.
Various limbs are severely shortened, which can lead to severe limitations and complaints in everyday life. Short stature is usually noticed in the course of child development. Pseudohypoparathyroidism must also be treated if the person concerned suffers from various muscle problems. There may be pain in the muscles that occurs without any particular reason.
A visit to a doctor is also necessary if the disease leads to heart problems, dementia or dry skin. If the heart problems are not treated in time, the patient’s life expectancy may be reduced. In most cases, pseudohypoparathyroidism can be diagnosed by a pediatrician or general practitioner. However, further treatment requires the assistance of specialists.
Treatment & Therapy
Since pseudohypoparathyroidism is genetic, this disease cannot be treated causally. Only symptomatic therapies to adjust the calcium metabolism are possible. However, the physical impairments such as short stature and shape anomalies cannot be treated. A normal calcium level can only be adjusted with medication.
This is done by oral administration of calcium supplements in combination with vitamin D. A tetany attack sometimes requires an intravenous injection of calcium. Constant monitoring of the calcium and phosphate levels is required. Long-term administration of calcium can lead to the formation of kidney stones. Administration of a thiazide diuretic may be necessary to avoid increased calcium concentration in the urine. Calcium excretion should also be checked regularly.
Prevention
Pseudohypoparathyroidism is a genetic disease. For this reason, there can be no recommendation for its prevention. In the case of familial accumulation, however, human genetic counseling and examinations can be used to assess the risk for the offspring. However, it should be noted that the genetic basis is not known for all forms of pseudohypoparathyroidism.
Aftercare
Pseudohypoparathyroidism is a genetic disease, which means that the aftercare of the symptoms is only symptomatic and a cure is impossible. Drug treatment helps to adjust calcium metabolism. For this purpose, calcium preparations are taken in combination with vitamin D. In cases of tetany attacks, calcium must be given intravenously at times.
Calcium intake can lead to the formation of kidney stones. To avoid this, it may also be necessary to take diuretic medication. Calcium excretion should always be monitored. Check-ups at regular intervals by a specialist are recommended. These are used to monitor calcium and phosphate levels and adjust medication if necessary.
After diagnosis, a healthy lifestyle should be followed. A healthy diet with calcium-rich foods helps to reduce the deficiency naturally. The intake of vitamin D from foods such as porcini mushrooms, oatmeal or sweet potatoes also has a positive effect on the body. You should also aim for a low-phosphate diet by reducing the amount of protein-containing products, legumes and nuts.
Physical impairments such as short stature or shortened metacarpal or metatarsal bones cannot be treated and can lead to severe limitations in everyday life. Muscle hyperexcitability can be trained through physiotherapy. Relaxation techniques such as yoga or meditation also help to cope better with the disease.
You can do that yourself
The possibilities of self-help are very limited in the case of pseudohypoparathyroidism. The symptoms of the disease are extensive and cannot be sufficiently minimized with your own actions.
Those affected can positively support their organism by optimizing their food intake. Foods that contain calcium should be increased. The aim is to reduce the existing calcium deficiency in a natural way. Various calcium-containing products should therefore be consumed every day throughout the day. At the same time, nutrients containing phosphate should be avoided. Products containing protein, legumes and nuts should therefore be avoided when preparing the menu. Otherwise, the excess phosphate already produced by the body would be amplified. To further improve health, an intake of vitamin Dto recommend. Mushrooms or chanterelles contain the vitamin and should be on the menu regularly.
Dealing with the hyperexcitability of the muscles can be promoted through targeted training or relaxation techniques. In physiotherapy, the affected person learns various exercises that should be pursued independently outside of the therapy appointments. In addition, methods such as yoga, meditation or autogenic training help to strengthen mental strength. In everyday life, this can be helpful in coping with the disease. Well-being is stabilized and stressors are reduced.