Causes and pathogenesis of epistaxis

Depending on the causes of the occurrence of nasal bleeding are divided into post-traumatic (including surgical trauma) and spontaneous. Spontaneous nasal bleeding is a symptom of various pathological conditions and diseases, which can have both a local and a general nature.

Etiological factors of a general nature leading to the occurrence of nasal bleeding can be divided into four groups, taking into account possible violations of three interacting functionally structural components of hemostasis: vascular, platelet and coagulation.

• Changes in the vascular wall of the nasal mucosa (violation of the vascular link of the hemostasis):
  • dystrophic processes in the mucosa of the nasal cavity (atrophic rhinitis, dry anterior rhinitis, curvature of the nasal septum, ozona, perforation of the septum of the nose);
  • chronic specific inflammation (tuberculosis, syphilis);
  • tumors of the nose and paranasal sinuses (benign, angiomatous polyp, hemangioma capillary, cavernous, malignant: cancer, sarcoma, borderline: angiofibroma of the nasopharynx, inverted papilloma of the nose)
  • abnormalities of the vascular wall (microangiomatosis, varicose veins, hereditary hemorrhagic telangiectasia):
  • Wegener's granulomatosis,
• Violation of coagulation hemostasis:
  • hereditary coagulopathies (hemophilia, von Willebrand's disease, deficiency of IIV, VII, X, XIII factors, a / hypo- and dysfibrinogenemia, deficiency of protein Z);
  • Acquired coagulopathies (deficiency of vitamin K-dependent factors of blood clotting due to autoimmune myeloproliferative diseases, liver pathology, abnormal therapy with acenocumarol, acetylsalicylic acid, nonsteroidal anti-inflammatory drugs, sulfonamides, antibiotics, barbiturates, etc., DIC syndrome; acquired von Willebrand syndrome against systemic red lupus erythematosus, scleroderma, myelo- and lymphoproliferative diseases, dislobulinaemia, solid tumors, acquired deficiency Plasma factors which determine the intrinsic pathway of blood coagulation, against infectious and autoimmune diseases; peredoeirovka anticoagulants direct and indirect action; overdose protamine sulfate, etc.).
• Violation of platelet hemostasis:
  • thrombocytopathy (congenital, hereditary and acquired);
  • thrombocytopenia (congenital, hereditary and acquired).
• Combined disorder of various hemostatic links:
  • diseases accompanied by an increase in arterial pressure and damage to the vascular endothelium (hypertension, transient and symptomatic hypertension, atherosclerosis);
  • liver diseases (toxic, infectious, parasitic, autoimmune, cirrhosis) and mechanical jaundice;
  • diseases of the nights (acute nephritis, exacerbation of chronic glomerulonephritis, uremia);
  • blood diseases (acute and chronic hemoblastoses, polycythemia, etc.)
  • infectious diseases (measles, scarlet fever, malaria, rickettsiosis, adenovirus infection, etc.).

Among the local causes of epistaxis, an important place belongs to vascular tumors. Hemangiomas (capillary and cavernous) are observed in the nasal cavity on the septum (mainly in the cartilaginous region), in the lower and middle shells, much less often in the region of the khohans, paranasal sinuses. Most of the hemangiomas are regarded as a "bleeding polyp" of the septum of the nose.

Hereditary hemorrhagic telangiectasia (Randyu-Osler's disease) is one of the causes of recurrent nasal bleeding, which is a kind of marker of this disease. They most often start at the age of up to 20 years, arise for no apparent reason or when blowing.

The morphological substratum of ebolevania is dysplasia of the vascular wall with a sharp thinning or lack of a muscle layer and elastic fibers.

With age, the dysplasia of the mesenchyme increases, which contributes to the progressive development of vascular ectasias. Such morphological changes disrupt the contractile capacity of the vascular wall and lead to the appearance of spontaneous recurrent bleeding of the angiomatous type.

Teleangiectasia on the skin and mucous membranes is one of the most striking symptoms of Rundu-Osler's disease. Macroscopically they look like dark red patches the size of millet grain to pea, slightly protruding above the surface, dense to the touch. Telangiectasias are localized on the hands and hands (on the palms, in the nail phalanx), on the mucous membrane of the nasal cavity, tongue, lips.

Quite typical is the absence of changes in the coagulating system of blood, although in a number of patients it is possible to identify local fibrinolysis in the telangiectasia zone and signs of chronic hypochromic anemia.

Diseases characterized by hereditary, congenital or acquired disorders of systemic hemostasis constitute a group of hemorrhagic diathesis.

Among the hereditary coagulopathies, 83-90% of cases occur in different types of deficiency of the VIII factor (haemophilia A - 68-78%, von Willebrand disease - 9-18%) and 6-13% of cases - deficiency of IX factor (hemophilia B). Thus, the deficit of the two coagulation factors (VIII and IX) accounts for 94-96% of all hereditary coagulopathies. The deficiency of other factors (XI, II, VII, X), hypo- and afibrinogenemia accounts for only 4-6% of observations, so they are grouped in the "other" subgroup.

In the group of acquired coagulopathy, secondary forms predominate, differing from the hereditary by a more complex pathogenesis. A number of diseases and syndromes are characterized by the development of two, three or more independent or pathogenetically related disorders of hemostasis. Such polysyndrome disorders are inherent in diseases of the liver, kidneys, leukemias. These diseases are identified by us in a separate subgroup of combined hemostasis disorders. At the same time, with some coagulopathies, hemorrhagic manifestations are caused by absolutely certain mechanisms. For example, nasal bleeding with enteropathy and intestinal dysbacteriosis of drug origin is due to the inadequacy of the formation of vitamin K in the intestine, leading to a disruption in the synthesis of VII, X, II, IX coagulation factors. Similar disorders are observed when competitive exclusion from the metabolism of vitamin K by its functional antagonists - acenocoumarol, phenyldione and other anticoagulants of indirect action,

Complex deficiency of K-vitamin-dependent factors of coagulation is found in two pathogenetic variants: with mechanical jaundice (violation of absorption of fat-soluble vitamin K due to lack of bile in the intestine) and in lesion of liver parenchyma (disruption of synthesis of VII, X, P and IX factors in hepatocytes ). However, other mechanisms (DVS-syndrome, violation of factors V, IX, I and inhibitors of fibrinolysis, the appearance of pathological proteins) also participate in the development of nasal bleeding, therefore they belong to the subgroup of combined hemostasis disorders.

DIC-syndrome - one of the frequent and severe forms of pathology of hemostasis. According to the summary statistics of large multidisciplinary clinical centers, generalized infections (bacterial and viral), including septicemia, proceeding according to the type of acute septic shock, occupy the first place among the causes of DIC syndrome. In addition to sepsis, the DIC syndrome, which has many triggers, can complicate the course of acute renal failure, acute intravascular hemolysis, malignant tumors (most often lung and prostate cancer), pregnancy and childbirth pathology and other pathological conditions and diseases.

In the classification of nasal bleeding reasons, there are four subgroups of medical disorders of hemostasis. Some authors do not consider it possible to combine them, since the pathogenesis of coagulopathies caused by various drugs is fundamentally different. For example, an overdose of an anticoagulant of spicy action (heparin sodium) blocks almost all the coagulation factors belonging to serine proteins (XIIa, XIa, IXa, Xa): medicines having the properties of haptens (quinidine, sulfanilamides, aminosalicylic acid, digitoxin, rifampicin, hydrochlorothiazide, preparations gold, etc.) cause immune thrombocytopenia: salicylates, pyrozolone derivatives and similar drugs induce the development of thrombocytopathies; anticoagulants of indirect action competitively supersede vitamin K. From the metabolism, it is not possible to neglect essential differences in the pathogenesis of drug coagulopathies, since this is determined by the need for differentiated pathogenetic treatment.

Thrombocytopathy is of particular interest in the group of platelet hemostasis disorders, in which nosebleeds are the dominant type of bleeding, and in some cases - the only symptom of the disease. In the latter variant, the diagnosis of the disease is particularly difficult because there are no changes in traditional blood and coagulogram analyzes, and most nasal bleeding of unclear etiology is in fact a manifestation of thrombocytopathy.

Thrombocytopathy is divided into congenital, hereditary and acquired. Hereditary forms are grouped according to the types of dysfunction, morphological and biochemical disorders of platelets. Acquired thrombocytopathy is observed in hypothyroidism, developing both spontaneously and after a strukemectomy, with hypoestrogenia. Secondary thrombocytopathy can be caused by hemoblastoses, myeloproliferative diseases, vitamin B12 deficiency, progressive renal or hepatic insufficiency, paraproteinemic hemoblastoses, massive blood transfusions, DIC syndrome. In these cases, a decrease is observed primarily in the aggregation function of platelets, which is manifested in some patients by petechial hemorrhages on the skin and mucous membranes, nasal and gingival bleeding,

Most of the acquired forms of platelet pathology is complicated by the genesis, heterogeneity of functional disorders, a combination with other hemostatic disorders, and therefore they are included in the group of associated disorders. Thus, thrombocytopenia of the hyporegenerative type, combined with a qualitative inferiority of thrombocytes, is a "background" disorder of hemostasis in acute leukemia, but at any stage of the development of these diseases, a DVS syndrome may join,

Nasal bleeding with uremia is due to the qualitative inferiority of platelets, thrombocytopenia and dystrophic changes in the mucous membrane of the nasal cavity, resulting from the release of the product nitrogen metabolism. In nephritic syndrome, nasal bleeding is caused by DIC syndrome, deficiency of IX, VII or II coagulation factors due to a greater loss of them in the urine, as well as renal arterial hypertension, entailing endothelial dysfunction and increased "fragility" of small vessels.

The definition of the cause of nosebleeds creates a basis for the formation of a detailed diagnosis, which determines a differentiated approach to the treatment of this pathology.

[1], [2], [3], [4], [5], [6]

Pathogenesis of epistaxis

The most common cause of nasal bleeding is hypertension. Although nasal bleeding in this group of patients is observed mainly periods of elevation of blood pressure, the immediate cause is not mechanical vascular rupture, but disorders of microcirculation and coagulation properties of blood, leading to the development of localized intravascular coagulation. Chronic subcompensated DIC syndrome and endothelial dysfunction are an integral part of the pathogenesis of arterial hypertension. Until a certain time, the system of regulation of the aggregate state of the blood in this group of patients is in a state of delicate balance, which can be disturbed by a minimal stimulus (blood loss, therapeutic manipulation, stress, exercise, taking certain medications). If there are one or more local "resolving" factors (damage to the endothelium, dilatation of pathologically altered vessels, slowing of blood flow or stasis in the microcirculatory bed, opening of arterio-venous shunts, increase of blood viscosity). Localized intravascular coagulation of blood with necrosis of the vascular wall and hemorrhagic syndrome, manifested hemorrhagic stroke, hemorrhagic myocardial infarction or epistaxis develops.

With thrombocytopenia and thrombocytopathy, the occurrence of nasal bleeding is due to impaired vascular-platelet hemostasis. Angiototropic function of platelets provides normal permeability and resistance of microvessel walls. Deficiency of platelets leads to endothelial dystrophy, disturbance of its atrombogenicity, increased vascular wall permeability for plasma and red blood cells, which is manifested by petechiae. With severe thrombocytopenia, hemorrhagic syndrome develops. Hemorrhages in the violation of vascular-platelet hemostasis tend to recur. Because quantitative to qualitative platelet deficiency violates both primary hemostasis (violation of adhesion and aggregation of platelets, delivery of plasma coagulation factors and biologically active substances to the site of bleeding), and retraction of the blood clot, necessary for the formation of a full thrombus.

Thus, in the pathogenesis of spontaneous nasal bleeding, an important place belongs to systemic disorders of coagulation and platelet hemostasis, to microcirculation in the mucous membrane of the nasal cavity, to changes in the endothelium atrombogenicity, to reduce the contractile properties of the vessels, to increase vascular permeability.