Hypertensive Syndrome

Manifestations in hypercatecholaminemia

Excess catecholamines, such as in pheochromocytoma, cause a pronounced hypertensive syndrome. Blood pressure elevation may be constant or occur in paroxysms.

This condition is characterized by severe hypertensive crises, which can be followed by dangerous acute hypotensive reactions—the "rebound" syndrome or orthostatic collapse.

In addition to cardiovascular disorders (including arrhythmias), the syndrome is accompanied by:

• Metabolic shifts: hyperglycemia, hyperlipidemia, and weight loss due to a catabolic effect.
• Autonomic symptoms: marked sweating (hyperhidrosis) and tremor.
• Ophthalmological problems: development of retinopathy secondary to high blood pressure.

To confirm the diagnosis, laboratory tests reveal elevated concentrations of catecholamine metabolites in the urine.

Arterial hypertension in children

In pediatric practice, blood pressure norms are strictly adjusted for the child's age: threshold values increase from the neonatal period through adolescence.

The clinical presentation depends on the degree of blood pressure elevation:

1. Mild hypertension. Often asymptomatic. Children may complain of nonspecific fatigue, irritability, or rare headaches. Objectively, excess weight or signs of autonomic dysfunction are frequently identified.
2. Moderate to severe hypertension. Corresponds to stage II hypertension in adults. Manifests as persistent headaches, cardialgia, dizziness, and memory impairment. Instrumental diagnostics reveal signs of left ventricular hypertrophy and retinal angiopathy.
3. Malignant hypertension. Typically of secondary renal origin, extremely resistant to therapy, and carries a high risk of mortality.

Crises in children pose a threat of acute left ventricular failure (up to pulmonary edema), hypertensive encephalopathy with seizures, and acute kidney injury.

Differential diagnosis of secondary forms

When searching for the causes of hypertensive syndrome, secondary pathologies must be excluded. The following options are ruled out during the workup:

• Renoparenchymal hypertension: excluded by normal renal ultrasound findings, absence of abnormalities in urinalysis, and a normal glomerular filtration rate.
• Thyrotoxicosis: ruled out by normal TSH levels, absence of resting tachycardia, and no weight loss.
• Cushing's syndrome: unconfirmed in the absence of a specific phenotype (purple striae, moon face) and normal glucose levels.
• Coarctation of the aorta: excluded if blood pressure in the upper and lower extremities is symmetrical, femoral pulses are normal, and chest radiography shows no rib notching.
• Obstructive sleep apnea syndrome (OSAS): unlikely in the absence of snoring, daytime sleepiness, and a low STOP-BANG score.
• Drug-induced hypertension: ruled out by a negative history of glucocorticoid or decongestant use.

Kidney damage and CKD progression

In hypertension, the kidneys are one of the three main target organs (along with the heart and brain). Constantly high blood pressure activates the renin-angiotensin-aldosterone system (RAAS) and the sympathoadrenal system, leading to progressive nephron loss, bilateral nephroangiosclerosis, and the formation of a primary shrunken kidney.

Decreased renal function is classified as chronic kidney disease (CKD). Both modifiable factors (diabetes mellitus, dyslipidemia, obesity, smoking) and non-modifiable factors (advanced age, low birth weight) play an important role in the development of this pathology.

To slow the progression of CKD, combination therapy must be used:

• ACE inhibitors or ARBs to target the RAAS.
• Calcium channel blockers and beta-blockers to reduce vascular tone.
• Diuretics and SGLT2 inhibitors (e.g., empagliflozin) for nephroprotection.

The mandatory triple drug combination helps reduce circulating blood volume, dilate the vascular bed, and protect target organs from complications (myocardial infarction and stroke).

Class and exam questions

What else to study on this topic

• Catecholamine metabolism and diagnosis of pheochromocytoma via urine tests
• Mechanisms of myocardial remodeling and left ventricular hypertrophy
• Application of percentile charts for blood pressure assessment in pediatrics
• The role of SGLT2 inhibitors in nephroprotection in chronic kidney disease
• Pathogenesis of malignant renoparenchymal hypertension

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.