Test the stability of the small blood vessels to retain the red blood cell in their lumen under conditions of stress or trauma.
capillary fragility test
- assess fragility of BV walls
- determine if the patient has hemorrhagic tendency because there is a problem in platelets or vascular system
[check how strong or weak the small BV are, determines if can hold rbc w/o leaking under stress]
what are the important/ essentials in the maintenance of normal capillary integrity or resistance
- Platelets
– help seal small vessel injuries - Vitamin C (ascorbic acid)
– needed to make collagen - Collagen & elastin
– give strength and structure to vessel walls
*if vitamin C is low, collagen is weak → capillaries become fragile → bleeding/bruising easily, especially on skin and mucous membranes
this occurs when small BV or platelets cannot stop bleeding properly
mucocutaneous hemorrhage
EXAMPLES
Thrombocytopenia (platelet count < 100,000/µL)
Qualitative platelet disorders (platelets don’t work properly)
Vascular disorders (weak or abnormal vessels)
Hereditary or acquired causes
Infections, e.g., Dengue Fever
Why Ecchymoses Change Color
Red-blue → hemoglobin from RBCs
Blue-green → biliverdin (breakdown product of heme)
Golden-brown → hemosiderin (iron from RBCs)
*these changes color as they heal
Dilated superficial blood vessels that create small focal red lesions
Telangiectasias
- goes throughout the body but are more obvious on the face, lips, tongue, conjunctiva, nasal mucosa, fingers, toes, trunks and under the tongue
this is also common in Rendu-Osler Weber
epistaxis or nose bleeding
this provides structure and strength to the connective tissue such as blood vessel and skin
collagen
briefly explain
- cause
- affected tissue
- Scurvy
- Senile Purpura
- Allergic / Anaphylactoid Purpura
- Henoch-Schonlein Purpura
- Dengue Fever
1.
- Vitamin C deficiency
- Weak collagen → fragile capillaries
2.
- Aging, loss of collagen/elastic fibers
- Fragile blood vessels
3.
- Infection, drugs, cold, insect bites
- Small vessel inflammation
4.
- Immune-mediated vasculitis
- Small vessels (skin, joints, GI, kidneys)
5.
- Flavivirus, mosquito-borne
- Virus affects bone marrow & capillaries
Insufficient dietary intake of vitamin C (ascorbic acid)
scurvy
this is due to a lack of collagen support for small blood vessels and loss of subcutaneous fat and elastic fibers.
senile purpura
- commonly in elderly people
- dark blotches are flattened, are about 1 to 10 mm in diameter
- brown stain in the skin (age spots)
- may fade but some are permanent
Onset of the disease is sudden often following an upper respiratory tract infection
allergic purpura
*this may progress to Henoch-Schonlein purpura
what causes mosquito-borne disease
Flavivirus
- transmitted by Aedes aegypti (mosquito)
Dengue rash vs Dengue hemorrhagic fever:
Dengue rash:
- appears when the temperature of the fever goes down or disappears
Shock:
- can be a result in severe cases
Dengue hemorrhagic fever:
- can cause possible internal bleeding that can be cause of death
Always considered a predicative parameter of a patient with dengue fever
Thrombocytopenia
- occurs in dengue fever since some studies have said that dengue fever directly or indirectly affects the bone marrow progenitor cells by inhibiting their function
how can capillary made to rupture in 2 ways
- Positive Pressure Method
- increase pressure inside the veins → blood pushes on capillaries
- technique
apply a blood pressure cuff on the arm
inflate to a certain pressure → veins become congested
observe if small hemorrhages (petechiae) appear
Example: Tourniquet test - Negative Pressure Method
- decrease pressure outside the capillaries → suction causes vessels to burst
- technique:
use a suction cup or petechiometer
reduce air pressure for a fixed time
observe petechiae formation
[Positive pressure: Like squeezing a water balloon → weak spots may burst
Negative pressure: Like sucking on a thin balloon → weak spots pop]
other name of tourniquet test
Rumple-Leede Test
Hess Test
- named after Alfred Fabian Hess
briefly explain the principle of tourniquet Test
partially blocks venous blood → increases capillary pressure → weak vessels leak → petechiae
procedure of Tourniquet Test
Procedure (Simple Steps):
- Determine patient’s BP; mark existing petechiae.
- Place cuff on upper forearm, inflate to midpoint between systolic & diastolic.
- example: 100/70 → midpoint = 85 mmHg - Maintain for 5 minutes → arteries open, veins closed → venous congestion.
- Remove cuff → wait 15 minutes → count petechiae in a 1-inch area.
(reference range in trans)
materials needed for the positive pressure methods
Blood pressure cuff (recommended), pen, timer
procedure and interpretation of Quick’s Method and Gothlin’s Method
Quick’s Method:
- Inflate cuff to 100 mmHg for 5 minutes on upper forearm.
- Release → check petechiae on arm, wrist, hand after 15–30 minutes
*Normal: 0–5 petechiae in a 5 cm circle
Note: Can only reassess after 7 days
Gothlin’s Method:
1. Inflate cuff to 35 mmHg on both arms for 15 minutes.
2. Release → count petechiae on both arms → multiply by 2.
Interpretation:
0–8 petechiae = normal
8–12 petechiae = equivocal
(12 petechiae = increased capillary fragility)
principle of suction cup/ petechiometer method
negative pressure (suction) → capillaries forced to rupture → petechiae
*materials:
petechiometer
timer
procedure in Suction Cup / Petechiometer Method
- Apply suction cup to upper arm.
- Reduce pressure to 200 mmHg for 1 minute.
- Release → inspect for petechiae.
**Normal: < 4 petechiae at 200 mmHg
