Anemia syndromes

Peripheral blood pathology and posthemorrhagic anemia

At the initial stages of the development of a number of hemorrhagic syndromes, the main red blood parameters (red blood cell count and hemoglobin level), as well as the total leukocyte count, may remain within normal limits. The leading early change in the peripheral blood in such cases is a marked decrease in the platelet count.

A characteristic morphological feature is a change in the size of the blood platelets themselves — platelet anisocytosis develops, in which both a pathological increase and a significant decrease are possible. An important differential diagnostic criterion is the fact that in the immunogenic nature of thrombocytopenia, the size of the platelets often remains unchanged.

Posthemorrhagic anemia does not occur instantly by itself. Its clinical and laboratory manifestation is observed exclusively with the development of a prolonged and/or extremely pronounced hemorrhagic syndrome, when the natural compensatory mechanisms of hematopoiesis are completely exhausted.

Hemolytic anemia in chronic rheumatic heart disease

Chronic rheumatic heart disease (CRHD) is a predictable outcome of acute rheumatic fever (ARF). The transition of the disease from the acute phase to the chronic stage is characterized by the formation of persistent morphological changes in the cardiac apparatus.

The main pathological substrate of CRHD is the development of acquired valvular heart defects. This pathology is recorded in 20–25% of patients who have undergone ARF. Associated syndromes and complications develop against the background of established defects:

• Hemolytic anemia. Its pathogenesis is caused by direct mechanical damage (destruction) of erythrocytes as they pass through deformed, sclerosed valves.
• Thromboembolic syndrome. Arises as a direct consequence of pronounced disorders of intracardiac hemodynamics.
• Atrial arrhythmias. Formed due to chronic overload and atrial dilatation against the background of an existing valvular defect.

Thrombotic microangiopathy and complement dysregulation

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a heterogeneous group of severe diseases. The leading clinical and laboratory manifestation here is microangiopathic hemolytic anemia combined with consumptive thrombocytopenia. The latter develops as a result of massive microthrombus formation, which ultimately leads to systemic ischemic damage to internal organs.

The pathogenetic cascade includes the following consecutive stages:

1. Initial damage to the vascular endothelium.
2. Pronounced activation of the inflammatory and procoagulant cascades.
3. Persistent capillary occlusion by microthrombi.

A key difference between HSCT-TMA and many other endothelial syndromes is complement system dysregulation. This immunological failure leads to pathological overproduction of the C4d complement fraction and the C5b-9 membrane attack complex.

Among the provoking risk factors for the development of HSCT-TMA are:

• Use of calcineurin inhibitors.
• Viral infections (specifically cytomegalovirus, adenovirus, BK virus).
• Fungal infections.
• Graft-versus-host disease (GVHD).

Syndromic therapy, as well as mandatory dose reduction or complete withdrawal of calcineurin inhibitors, is used as first-line baseline therapy.

Diagnostics of comorbid conditions in aplastic anemia (AA)

Diagnostics of the aplastic form of anemia requires an integrated approach due to the high risk of developing specific complications. Patients are strictly indicated for initial examinations and consultations by related subspecialists:

• Ophthalmologist is involved if the patient has clinical signs of hemorrhagic syndrome.
• Otolaryngologist is necessary in the event of infectious, hemorrhagic, and any other complications from the ENT organs.
• Neurologist consults patients with hemorrhagic, infectious, or other specific damage to the nervous system.

Note: The recommendation grading level for all listed consultations is C (with a level of evidence certainty of 5).

Class and exam questions

What else to study on this topic

• Pathogenetic mechanisms of the development of immunogenic thrombocytopenia
• Hemodynamic disorders and thromboembolic syndrome in CRHD
• The role of viral infections (CMV, BK virus) in the development of endothelial dysfunction
• Graft-versus-host disease (GVHD) as an inducer of microangiopathies
• Principles of syndromic therapy in thrombotic microangiopathy

Other topics in the "Additional Topics" section

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