Clinical pathology, SIRS, sepsis & MODS Flashcards
How many days worth of neutrophil reserves are held within the bone marrow?
Approximately 5-days
What are examples of Type A hyperlactataemia?
Hypoperfusion
Severe hypoxaemia
Severe, acute anaemia
Carbon monoxide toxicity
Extreme muscle activity
What are examples of Type B1 hyperlactataemia?
Underlying disease: DM, neoplasia, liver disease, sepsis, pheochromocytoma, thiamine deficiency
What are examples of Type B2 hyperlactataemia?
Drugs/toxins: ethanol, methanol, acetominophen, cyanide, epinephrine, sorbitol, ethylene glycol, xylitol, salicylate, terbutaline
How much ATP is produced during aerobic metabolism per 1 glucose?
32
How is lactate used in anaerobic metabolism?
- transported out of the cell
- oxidised to produce energy
- converted back to glucose via gluconeogenesis
1mmol/L of lactate is equivalent to ____ of H+ ions released and ____ BE difference
1mmol/L, 1mmol/L
What is lactic acidosis?
Combination of hyperlactataemia and metabolic acidosis
The liver consumes/processes _____ lactate.
50-70%
The renal system consumes/processes _____ lactate.
25-30%
Hyperlactataemia is classified as mild, moderate and severe. What are the ranges for each class?
Mild 2-4mmol/L
Moderate 4-6mmol/L
Severe >6mmol/L
Puppies generally have _____ lactate compared to adults due to _______.
Higher, utilise lactate for energy.
Which isoform of lactate is clinically relevant to mammalian species and commonly measured in-house?
L-lactate
How should a sample to be used for lactate measurement be stored if not utilised within 60 minutes and why?
Place on ice or collect fresh sample as continued glycolysis of the sample continues after collection.
Lactate is a late indicator of tissue perfusion due to it being produced after tissue oxygen extraction, true or false?
True
A lactate level above ____ is shown to be significantly associated with mortality (6-fold) within 3 days in septic peritonitis patients.
4mmol/L
Resolution of hyperlactatemia within which time frame has been associated with 79% survival in septic peritonitis patients?
6-12 hours
What are some common abdominal fluid ctyology findings in patients with septic peritonitis?
- toxic neutrophils with/without intracellular bacteria
- high nucleated cell count
- Micro-organisms
- pH <7.2
- pCO2 >55mmHg
- Glucose <5.0
- Lactate >5.5
What are the most common micro-organisms found in patients with septic peritonitis?
1 Escherichia coli
Enterococcus spp.
Enterobacter spp.
Streptococcus spp.
Clostridium spp.
Klebsiella spp.
What is the gold standard for diagnosis of septic peritonitis? What is the limitation?
Bacterial culture and susceptibility but ay take days to weeks to culture and treatment cannot wait to be commenced
What difference in glucose between the peritoneal fluid and blood indicates potential septic peritonitis?
BFG >20mg/dL
What difference in lactate between the peritoneal fluid and blood indicates potential septic peritonitis?
< -2mmol/L
What are neutrophils?
Neutrophils are the most abundant type of WBC and are the hallmark of inflammation due to them being one of the first cells to arrive at an inflamed or injured area during infection or stress.
What are lymphocytes?
Help organisms fight infection by producing antibodies and removing foreign invaders. These cells determine the specificity of the immune response.
What are eosinophils?
Usually linked to allergic diseases and are made in the bone marrow. They curb infection and boost inflammation.
What are monocytes?
Produced in the bone marrow and can turn into macrophagic or dendritic cells which are involved in phagocytosis, antigen presentation, and cytokine production. They are involved in homeostasis, pathogen challenge and clearance, and inflammation.
What are basophils?
Attack micro-organisms seen as foreign in the body. Granules store and release enzyme (i.e. histamine, heparin) to fight infection.
What may cause neutrophilia?
Increased production of neutrophils (appropriate v. inappropriate)
Demargination
Decreased egress from circulation
What is a ‘left shift’?
Increased immature neutrophil production
What is the difference between a regenerative and a non-regenerative left shift?
Regenerative: production of immature neutrophils with adequate number of mature neutrophils. Production = utilisation and the body is coping.
Degenerative: production of immature neutrophils with low number of mature neutrophils indicating utilisation>production. The body is not coping.
Demargination of neutrophils can occur due to..
Corticosteroid administration or epinephrine release/administration
Neutropaenia can result from?
Increased utilisation of neutrophils
Increase destruction of neutrophils
Decreased neutrophil production in bone marrow
How is neutropaenia treated?
Broad-spectrum antimicrobials
Recombinant G-CSF
Aggressive resuscitation if sepsis/septic shock present
Reduced exposure to infection
Consider home management to reduce nosocomial infection risk
+- antifungals
What are characteristics that may be found in toxic changes of neutrophils?
- foamy basophilic cytoplasm
- dohle bodies
- giant neutrophils
- abberant nuclear shapes
What is the normal platelet count?
8-15/hpf or 200,000-800,000 cells/uL
At what platelet count does spontaneous bleeding occur?
20,000-50,000 cells/uL
What are the signs of clinical bleeding associated with a low PLT count?
Petechiae & ecchymoses
Haematuria
Mucosal bleeding
Anaemia
What are the four broad causes of thrombocytopaenia?
Sequestration
Consumption
Increased destruction
Reduced production