Hemorrhages - types, pathogenesis; denomination according to organ site
There are multiple ways of classifying hemorrhages, we’ll look at two of the easiest.
Firstly, what is a hemorrhage, simply put, hemorrhage is an escape of blood from a ruptured blood vessel.
Remember: by mechanism – per rhexin (rupture of the vessel wall: trauma, ruptured aneurysm), per diabrosin (erosion of the wall from outside: peptic ulcer, tumour, tuberculous cavity) and per diapedesin (red cells pass through an intact but damaged capillary wall: hypoxia, toxins, infections, vitamin C deficiency).
The neatest way to classify hemorrhages is based on the vessel that the blood has escaped from:
- Arterial
- Bright red blood, pouring as a jet which rises and falls in time with pulse
- Protracted bleeding
- Venous
- Darker red, steady copious flow, blood loss is rapid when large veins opened
- Capillary
- Bright red, often rapid, but reduced volume, blood oozes
Petechiae on the lower leg in severe thrombocytopenia (ITP): pinpoint (1–2 mm) red-purple bleeds that do not blanch on pressure; a few larger purpuric spots.
Image: “Petechia lower leg” by James Heilman, MD, CC BY-SA 4.0, via Wikimedia Commons.
Remember: small bleeds into skin, mucosa or serosa are named by size – petechiae (1–2 mm, typical of thrombocytopenia), purpura (≥3 mm) and ecchymoses (1–2 cm, bruises). A hematoma is blood collected within a tissue; blood in a cavity is hemothorax, hemopericardium, hemoperitoneum or hemarthrosis.
We can also classify the type of hemorrhage based on blood loss:
- Class I
- Up to 15% of blood volume, no change to vital signs
- Class II
- 15-30% of blood volume, patient tachycardic, skin may look pale and cool to touch
- Class III
- 30-40% of blood volume, patients BP drops, HR increases, enters shock, capillary refill worsens
- Class IV
- >40% of blood volume, limit of body’s compensation reached, death follows without treatment
Where hemorrhage continues for too long, the body can go into hypovolemic shock, leading to death. This is known as exsanguination.
Classifications of hemorrhage according to organ site are as follows:
- Mouth
- Tooth eruption or loss of a tooth
- Hematemesis - vomiting fresh blood
- Hemoptysis - coughing up blood from the lungs
- Anus
- Melena - upper GI bleeding
- Hematochezia - lower GI bleeding
- Urinary tract
- Hematuria - blood in urine
- Head
- Intracranial hemorrhage - bleeding in skull
- Cerebral hemorrhage - bleeding in brain (subcat of ICH)
- Intracerebral hemorrhage - rupture of blood vessel within the brain tissue
- Subarachnoid hemorrhage - blood in subarachnoid space
- Lungs
- Pulmonary hemorrhage