Platelets and WBCs Flashcards
What is the smallest element in the blood?
Platelets (thrombocytes)
Where are platelets formed?
Bone marrow
What is the lifespan of a platelet?
7-9 days
What is the main role of platelets?
Vascular integrity, blood clotting
What does a platelet count tell us?
Number of circulating platelets (NOT if they are adequately functioning or not)
What is the normal range for platelet count for adults?
140,000-400,000 mm^3
150-450 x 10^3
What are critical values for platelet levels?
< 20,000 = spontaneous bleeding
> 1,000,000 = increased viscosity and inappropriate clotting
What can interfere with the number of platelets we have?
- High altitudes
- Strenuous exercise (increased levels)
- Menses (decreased levels prior)
- Drugs (estrogens, oral contraceptives will increase levels, chemotherapy, H2 blockers will decrease levels)
What is the term for too many platelets?
Thrombocytosis
-Examples: polycythemia vera, post splenectomy syndrome (the spleen is responsible for killing off thrombocytes so if you don’t have a spleen you will have a high amount of them), iron deficiency anemia, rheumatoid arthritis
What is the term for too few platelets?
Thrombocytopenia
-Examples: hypersplenism, hermorrhage, leukemia
What should you do if a pt has a platelet count of <30,000?
Requires urgent referral (because <20,000 is spontaneous bleeding)
What should you do if a pt has a platelet count of 30,000-100,000?
Judgement depending on context. Urgent referral if bleeding. Watch pts levels, did it drop drastically? Has it been slowly dropping over a period of time or did it all of a sudden drop?
What should you do if a pt has a platelet count of 100,000-145,000?
Keep an eye on their count. Run follow up counts. Refer if progressive without obvious cause
What does Mean Platelet Volume (MPV) measure?
- Volume of a large number of platelets
- Indicates the uniformity of size of the platelet population
- Similar to MCV for RBCs
- SIZE
What do petechiae result from?
Bleeding under the skin
What is the key description of petechiae?
Flat to the touch, non-blanching, pinpoint round spots
How do purpura differ from petechiae?
Purpura are bigger than petechiae
What are the three i’s of WBC’s?
Infections, inflammation and immune responses
What is a CBC with differential?
WBC count with a percentage of each type
What is the normal range of WBCs in an adult?
5,000-10,000 mm^3
What WBC count identifies a patient as VERY sick?
> 15,000
What WBC count signifies a infection?
12,000-15,000
What WBC count is an inflammatory/immune rxn?
10,000-12,000
Do older adults (70-80+) mount larger (high WBC count) or smaller (lower WBC count) immune responses when sick?
Smaller. If you have an older adult, think 10-12 WBC count is VERY sick
-This is why many older people didn’t get as sick from the COVID vaccine as we did, because they don’t mount as high of an immune response
What factors can effect a WBC count?
- Time of day (lower in morning, later afternoon peak)
- Age, gender
- Smoke, 30% increase in total WBC
What is a high WBC count called?
Leukocytosis
-Examples: infection, hemorrhage, trauma, leukemia
What is a low WBC count called?
Leukopenia
-Examples: viral infections, bone marrow disorders, spleen disorders, immune problems (MS meds tell immune system to “settle down” = lower WBC count), AIDS
All infections cause ______, but not all ______ is a infection
Inflammation, inflammation
The inflammatory process is triggered by ___ ______
Cell injury
What are the two subdivisions of Leukocytes?
- Phagocytes
- Granulocytes - Immunocytes
- Agranulocytes
What are the 3 types of granulocytes?
- Neutrophils
- Eosinophils
- Basophils
* Contain a multilobed nucleus
What are the two types of agranulocytes?
- Monocytes
- Lymphocytes
* Non lobular nuclei
What is the most numerous and most important leukocyte?
Neutrophils
What is the main role of neutrophils?
- Highly motile - first to arrive in response to acute inflammation or infection
- Primary defense against microbial invasion through phagocytosis
What are immature neutrophils called?
Bands (nucleus is not multi segmented)
Are bands typically found in circulating blood?
NO. They are seen in the blood when a big infection is present and help is needed
What is the normal range for Neutrophils?
3,000-7,000 mm^3
60-70% of total WBC (0-3% are band cells)
What does a left shift indicate?
Abnormal number of immature cells are being released into peripheral blood prematurely (bands are being pushed out) - sign of infection
We must have a ______ immune system in order to release bands
Healthy (no bands means poor immune system)
What are some causes of a left shift?
- Infections
- Intoxications
- Tissue necrosis
- Leukemia
- Pernicious anemia
- Hyposplenism
What does the Absolute Neutrophil count measure?
Infection fighting cells in the body
number of WBC x %(segs + bands)
If ANC <1000 = increased risk of infx
if ANC <150 = increased risk of serious infx
What does a high eosinophil count alert us to?
Parasitic disease or allergies
What is a normal eosinophil count?
0-0.7 x 10/L
0-3% of total WBC count
What does a high basophil count alert us to?
Chronic inflammation
What is a normal basophil count?
.15-.50
0-1% of total WBC count (least amount)
When is the only time we should expect to see blast cells?
Leukemia (blast cells are so immature that they are not found in peripheral blood)
What two things do you know if you see Auer Rods?
- The population of cells you’re looking at are malignant
- The malignancy involves the neutrophil series
* See Auer Rods = think cancer!
What are the largest WBC?
Monocytes
What is the role of monocytes?
Body’s second line of defense against infection
-Produce the antiviral agent called interferon
What is a normal monocyte count?
1.0-5.0
3-7% of total WBC
What is the second most numerous WBC?
Lymphocytes
What is the role of lymphocytes?
Important role in immune system
- B and T lymphocytes
- B = memory
- T = master immune cells
What is a normal lymphocyte count?
1500-4000 cells/mm^3
20-30% of total WBC count
