Thursday, December 9, 2010

268. A very painful encapsulated abscess in the neck

CHUBBY – DOG – Shih Tzu
9 Y/O Male

CBC interpretation:
Haematology Profile:
Description:
The CBC is commonly performed on an automated haematology analyzer using well mixed whole blood that is added to a chemical (EDTA – Ethylenediaminetetraacetic Acid) to prevent clotting. A CBC is a group of tests used to quantify the number of RBCs, WBCs and platelets, provide information about their size and shape, measure the haemoglobin content of RBCs, determine the percentage and absolute number of the five white blood cell types, and identify early and abnormal blood cells. These tests are performed simultaneously.
Analysis (Haematology):
Haematology Result Unit Ref. Range
Haemoglobin 18.4 g/dL 12.0 – 18.0
Red Cell Count 7.7 X10^12 / L 5.5-8.5
Total White cell count 8.3 X10^9 / L 6.0 – 17.0
Differential Count % Absolute V. Unit
Neutrophils 68.19 5.66 X10^9 / L
Lymphocytes 21.08 1.75 X10^9 / L
Monocytes 6.14 0.51 X10^9 / L
Eosinophils 3.49 0.29 X10^9 / L
Basophils 0.96 0.08 X10^9 / L
PCV 0.48 0.37 – 0.55
MCV 63 fL 60 – 77
MCH 24 Pg 20 – 25
MCHC 38 g / dL 32 - 36
RDW 15.7 %
Platelets 491 X10^9 / L 200 - 500

Haemoglobin: 18.4 g/dL
• This value is lightly above reference range but it should not be of much significance as the red blood cell count, PCV, MCV, MCH, RDW are all within normal limits.
• Haemoglobin concentration is normally used to diagnose anaemia, which can be caused by microcytic RBCs, which are smaller than usual in size and unable to carry sufficient Oxygen. Macrocytic anaemia usually occurs when the division of RBC precursor cells in the bone marrow is impaired. The most common cause of macrocytic anaemia are vitamin B12 deficiency, folate deficiency and liver disease.
Normocytic anaemia may be caused by decreased production of RBCs (any cause of bone marrow failure), increased destruction of RBCs (haemolytic anaemia) or loss of blood.
Total White Cell Count: 8.3 x 10^9 / L (within normal limits)
• Normal white cell count usually indicates that the animal is not in any threat of infectious diseases and foreign bodies.
• An elevated white cell count usually occurs in infection, allergy, systemic illness, inflammation, tissue injury and leukemia.
• A depressed white cell count may occur in some viral infections, immunodeficiency states and bone marrow failure.
• The white blood cell differential count will reveal which WBCs are affected the most
• Neutrophils are the most abundant granulocytic cells and are phagocytic cells that aid in the removal of bacteria and antibody-coated antigens
• Lymphocytes are the 2nd most abundant monocytic WBCs and originate from the lymphoid tissues and are NOT phagocytic. They are responsible for initiating and regulating the immune response by the production of antibodies and cytokines.
• Monocytes are the largest monocytic WBCs and are phagocytic cells that process and present antigens to lymphocytes, an event required for lymphocyte activation
• Eosinophils are granulocytic WBCs that have cytoplasms filled with granules that contain peroxidise, hydrolases and basic proteins that aid in the destruction of phagocytised cells. They are increased in allergic and parasitic infections
• Basophils are granulocytic WBCs that contain large amounts of histamine, heparin and acid mucopolysaccharides. They mediate the allergic response by releasing histamine.
Platelets: 149 x 10^9 / L (Below reference range of 200-500)
• Platelets are disc-shaped structures formed from the detachment of cytoplasm from megakaryocytes. They aid in the coagulation process by attaching or adhering to the walls of injured blood vessels, where they stick together to form the initial platelet plug.
• A low platelet count may occur in patients with viral infections, lymphoma or animals taking certain drugs such as quinine and quinidine.
• Decreased platelet production is also a cause of thrombocytopenia, and may be due to aplastic anaemia, leukemia, lymphoma or bone marrow fibrosis.
• A low platelet count can occur due to increased destruction and can result in antibody production that is often drug-induced (heparin treatment being a prominent cause)
• In relation to this case, Chubby’s decreased platelet count might be auto-immune, resulting in platelet destruction and decreasing his ability to clot blood and predisposing him to conditions such as TTP (Thrombotic thrombocytopenic purpura) and DIC (Disseminated intravascular coagulation).





BIOCHEMISTRY RESULTS:
BIOCHEMISTRY RESULT UNIT REF. RANGE
Total Cholesterol 4.75 Mmol / L
HDL Cholesterol 3.72 Mmol / L
LDL Cholesterol 0.20 Mmol / L
Cholesterol / HDL Ratio 1.28 Mmol / L
Triglycerides 1.83 Mmol / L
Glucose 4.1 Mmol / L 3.9 – 6.0
SGPT / ALT 59 U / L < 59
SGOT / AST 41 U / L < 81
Calcium 2.06 Mmol / L 1.50 – 3.60
Uric acid 0.01 Mmol / L <0.13
Urea 11.6 Mmol / L 4.2 – 6.3
Creatinine 77 Mmol / L 89 - 177

Result Interpretation:
Glucose 4.1 mmol / L (within normal limits):
• Serum glucose tests are generally used to diagnose diabetes mellitus and monitor its treatment. It can also diagnose hypoglycaemia.
ALT / AST (within normal limits):
• In Chubby’s case, the results are not too diagnostic of liver disease as serum ALT is at a border line 59 while AST is well within the reference range. However this is not definitive as in liver disease, ALT and AST levels generally rise and plateau for a period of time before decreasing back to normal values. Therefore DO NOT RULE OUT liver failure or complete cirrhosis if ALT / AST values are within normal limits. I would not fret too much about the ALT values in this case but it is best to take an x-ray or ultrasound of the liver to check if the size has been altered.
• ALT (Alanine Aminotransferase) is found in large amounts in the liver, and small amounf os this enzyme are also found in the heart, muscle and kidney. When the liver is injured or inflamed, the levels of ALT in the blood usually rise (a few fold). Therefore this test is performed to check for signs of liver disease
• AST (Aspartate Aminotransferase) is found in many body tissues including the heart, muscle, kidney, brain and lung. When body tissue or an organ such as the heart or liver is damaged, additional AST is released into the bloodstream. The amount of AST in the blood is directly related to the extent of the tissue damage.
Calcium and Uric Acid (within normal limits):
• In Chubby’s case, calcium and uric acid levels are within normal limits, thus indicating a low probability in bone / joint function or diseases such as osteomyelitis, osteoarthritis.

Urea (11.6 mmol / L) Mildly elevated:
• Urea is produced as a break down product of protein and it is usually completely filtered by the kidney while some of it is reabsorbed.
• It is important to note that the amount of urea reabsorbed increases with dehydration, therefore, in Chubby’s case, it is important to assess the hydration state of Chubby first to ensure that he was not dehydration prior to the blood test.
• Mildly elevated BUN may also be a result of an increased protein diet, resulting in increase urea formation.
• It may also result a physiological response to a relative decrease of blood flow to the kidney as seen in heart failure along with dehydration.

Creatinine (77 umol / L) Slightly below reference range:
• Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body.
• A marked increase in serum creatinine levels (normally with a marked increase in BUN – termed azotemia) generally indicates kidney disease.
• In Chubby’s case, his creatinine levels is decreased slightly below reference range which I wouldn’t be too worried about. It is probably due to a decrease in muscle mass due to low protein diets or lack of exercise.
• Rise in blood creatinine levels is generally observed only with marked damage to functioning nephrons



Above report written by a 4th year Murdoch Univ vet student during internship. He saw the encapsulated abscess being operated. Old dog is OK. It was surprising that the abscess erupted like a volcano as it "swelled and subsidied" over the past 2 years and the lady owner thought it was normal. Till 2 weeks ago. The dog just couldn't stop scratching till he got a bloodied bruised neck. (Picture in www.toapayohvets.com).

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