Metabolic Disorders—When Metabolism Is Disrupted and Pathologically Altered

Medical professionals divide human metabolism into several categories:

• Lipid metabolism
• Amino acid and protein metabolism
• Carbohydrate and
• mineral metabolism

The most well-known metabolic disorder is diabetes mellitus, in which the hormone insulin no longer functions properly.

As a result, the cells no longer take up sugar from the blood.

This manifests as:

• Fatigue
• Physical weakness and
• Increased thirst (to excrete sugar through urine)

There are currently around 11 million people with diabetes in Germany, including 8.7 million with a diagnosis of type 2 diabetes @ Kwangmoozaa /AdobeStock

Other examples of metabolic disorders include:

• Phenylketonuria (an amino acid metabolism disorder)
• Cushing’s disease (Cushing’s syndrome: excessive cortisol production due to a brain tumor)
• Cystic fibrosis
• Hypertriglyceridemia (lipid metabolism disorder)
• Addison's disease (adrenal cortex disorder)
• Hashimoto's thyroiditis (inflammation of the thyroid gland)

In Hashimoto's thyroiditis, the thyroid gland is chronically inflamed @ zigres /AdobeStock

Metabolic disorders are usually caused by a genetic defect, meaning the disorder is congenital. However, this does not mean that symptoms are present from birth. Often, congenital metabolic disorders do not develop until later in life or when certain environmental factors act as triggers.

Acquired metabolic disorders, such as type 2 diabetes mellitus, can occur at any age.

Certain risk factors contribute to their development, such as:

• Being overweight
• A sedentary lifestyle, or
• Environmental toxins such as car exhaust or cigarette smoke

Hormone-producing tumors can also cause metabolic disorders.

As we age, the risk that disrupted metabolic processes will affect the entire body also increases. If changes occur in the chemical reactions of metabolism, cardiovascular diseases can develop over the long term.

Gout and diabetes, in particular, promote arterial calcification and thus contribute to atherosclerotic processes, which in turn significantly increase the risk of arterial blockages.

An unhealthy lifestyle can trigger metabolic disorders @ Joaquin Corbalan /AdobeStock

In general, different metabolic disorders are associated with various symptoms. However, there are some key symptoms that indicate metabolic dysfunction.

These include:

• Significant changes in weight without the patient having changed their eating habits
• Fatigue and weakness
• Nervousness and restlessness
• Skin redness or stabbing pains
• Abdominal cramps, nausea, and stomach pain

If metabolic disorders are not treated appropriately, they can lead to serious symptoms, physical and mental developmental disorders, or death.

Every examination begins with a patient interview (medical history).

The doctor uses this to determine:

• Symptoms
• Medications taken
• Lifestyle habits
• Medical history and family history of disease

This is followed by a physical examination. If there are indications or suspicion of a metabolic disorder, the primary care physician will perform the appropriate tests.

The most important diagnostic procedures are blood and urine tests.

These determine:

• Hormone and enzyme levels
• Metabolic byproducts
• Hypothyroidism or hyperthyroidism

Rare and less obvious conditions sometimes require several different blood and urine tests before doctors can identify the cause of the symptoms.

In some cases, imaging procedures are used following the results of blood or urine tests. These often include ultrasound (sonography), but occasionally also computed tomography (CT) or magnetic resonance imaging (MRI).

Newborn screening is a test for certain metabolic disorders in the first few days of life. A typical test is for phenylketonuria, which involves collecting a heel prick blood sample.

During newborn screening, doctors test the newborn’s blood for various metabolic disorders @ sushytska /AdobeStock

In most cases, metabolic disorders are incurable. Therefore, those affected often have to take medication for their entire lives. However, with this medication, they are generally symptom-free.

There are numerous mechanisms by which medications work in the body, such as:

• The medication replaces the substance missing in the body, such as a hormone
• The medication reduces the substance that is accumulating, such as medications to lower blood sugar
• The medication prevents the body from absorbing the substance, such as so-called cholesterol absorption inhibitors

Symptoms can usually be improved through drug therapy. Nevertheless, patients often must follow a diet, as is the case with diabetes mellitus or lipid metabolism disorders. In these cases, the body’s regulatory mechanisms do not respond adequately despite medication.

If no medication is available for treatment, a specific diet can help relieve the affected metabolic pathway. The patient will then at least experience fewer symptoms.

If tumors are the cause of the metabolic or hormonal disorder, surgery is necessary. Nevertheless, lifelong medication is usually required afterward, since the missing gland no longer secretes hormones.

Unfortunately, some metabolic disorders cannot always be successfully treated, even with intensive therapy.

You can often find metabolic specialists in hospitals or specialized clinics. If a metabolic disorder is suspected in a newborn, the pediatric ward is responsible for managing the case.

They are most familiar with the needs and specific characteristics of young children. The pediatrician is also an important point of contact in this regard.

For older patients, endocrinologists and gastroenterologists are the appropriate specialists to consult. Diabetologists are physicians who specialize in diabetes mellitus.

Metabolic specialists therefore often have subspecialty training in internal medicine, endocrinology, and diabetology.

However, they may also have training in other medical specialties, such as:

• Specialist in Internal Medicine
• Specialist in General Practice
• Specialist in Pediatrics and Adolescent Medicine, and
• Additional training in the field of metabolic diseases

Certification as a diabetologist by the German Diabetes Society or advanced training as a neonatologist is also possible.

Specialty training takes five to six years. During this time, the physician must perform a specified number of diagnostic procedures and therapies. This enables the specialist in metabolic diseases to acquire in-depth knowledge in all areas of the diagnosis and treatment of metabolic diseases.

Metabolic disorders can have far-reaching effects on the entire body, as they disrupt key processes involved in energy production, hormone regulation, and nutrient utilization. Persistently elevated cholesterol levels increase the risk of atherosclerosis and can thus lead to a heart attack or stroke. High blood pressure also frequently arises in connection with metabolic disorders and places additional strain on the heart and blood vessels.

Pancreatic disorders, such as type 1 diabetes, directly affect blood sugar levels and can be life-threatening if left untreated. Metabolic disorders also affect the joints—for example, in cases of gout—or impair organ systems such as the thyroid; an overactive thyroid drastically accelerates metabolism and leads to clearly noticeable symptoms. These connections highlight how important early diagnosis and targeted treatment of metabolic disorders are for preventing serious complications.

How is high cholesterol related to metabolic disorders?
Elevated cholesterol levels often indicate a disturbance in fat metabolism and can lead to the deposition of fatty acids in the blood vessels. This significantly increases the risk of atherosclerosis and cardiovascular disease. Many metabolic disorders influence this mechanism and accelerate the development of such vascular damage.

What are the health implications of persistently elevated blood sugar levels?
If blood sugar levels remain constantly elevated, blood vessels and nerves will suffer long-term damage. This affects both people with type 1 diabetes and those with insulin resistance. Early stabilization protects against complications such as kidney disease or nerve damage.

How does type 1 diabetes differ from other forms of diabetes?
In type 1 diabetes, the pancreas can no longer produce its own insulin. This makes lifelong insulin replacement necessary. Other forms of diabetes, especially those that begin with insulin resistance, are initially caused by a reduced effect of the body’s existing insulin.

What role do fatty acids play in metabolic disorders?
Fatty acids are important for energy balance, but an imbalance can significantly disrupt metabolism. An excess promotes inflammation, negatively affects insulin sensitivity, and contributes to lipid metabolism disorders, which further increases the risk of cardiovascular disease.