Topic 25 - Clinical approach to patients with icterus (jaundice) Flashcards
Icterus
Definition
Yellow staining of serum an tissue in the body due to accumulationof bilirubin, which is produced on the degradation of haemoglobin.
There are different types: Prehepatic, hepatic, posthepatic
What does prehepatic icterus indicate?
Haemolysis
= rupture of red blood cells
What does hepatic icterus indicate?
hepatic injury
What does posthepatic icterus indicate?
Cholestasis
= reduced bile flow
Diagnostic approach of icteric patient
Steps
- Signalement, history
- physical examination
- Diagnosis
Diagnostic approach of icteric patient
Signalement, history:
- Breed: predisposition?
- Age, sex, general status
- Onset and duration
- Vomiting, diarrhoea?
- Exposure to toxins or drugs?
Diagnostic approach of icteric patient
Physical examination
Check for abdominal pain.
- size, shape of liver
- ascites
- hepatomegaly
- splenomegaly
Diagnostic approach of icteric patient
Diagnostics
- PCV
- Ultrasound: check pancreas, bile duct, gallbladder, liver
- Liver enzymes: ALT, AST, ALKP
- Bilirubin
- Cholesterol
- Urinanalysis
- Ascites analysis
Prehepatic icterus
Definition:
Causes:
= accelerated haemolysis
More haemoglobin was broken down to produce more bilirubin on the blood.
Causes:
- Infections: mycplasma, babesia, leptospirosis
- Immune-mediated haemolytic anaemia: stress, tumours
- Hb absorption is increased: internal hamoerrhage
- Chemicals
- Toxins
Hepatic icterus
Definition:
Causes
= the uptake of bilirubin by the liver is decreased, it remains in the blood
Causes:
- Liver diseases: necrosis, inflammation, neoplasia, lipidosis
Posthepatic icterus
= decreased removal of bilirubin by the bile due to bile obstruction or cholestasis
Caused by:
- Trauma
- Neoplasia
- Obstruction
- Cholestasis
Measurements found in Serum for prehepatic, hepatic and posthepatic
Prehepatic: ⭡Hemoglobin, ⭡⭡Bilirubin 1, ⭣Hematocrit
Hepatic: ⭡ALT, ⭡AST, ⭡⭡Bilirubin 1 and 2
Posthepatic: ⭡⭡⭡Bile acid, ⭡⭡⭡Bilirubin2, ⭡bilirubin1, ⭡GGT, ⭡ALP
Measurements found in Urine for prehepatic, hepatic and posthepatic
Prehepatic: ⭡⭡⭡Urobilinogen, presence of Hemoglobin
Hepatic: ⭡Urobilinogen, ⭡biliverdin, no hemoblogin
Posthepatic: ⭡⭡Biliverdin, no hemoglobin, normal to slight ⭣urobilinogen
Measurements found in Faeces for prehepatic, hepatic and posthepatic
Prehepatic: ⭡stercobilinogen = Hypercholic DARK BROWN
Hepatic: ⭣stercobilinogen =Hypocholic
PALE COLOUR
Posthepatic: no stercobilinogen
WHITE COLOUR
Bilirubin metabolism
Bilirubin is the product of hemoglobin breakdown.
bilirubin1 is unconjugated bilirubin, which travels to the liver, where hepatocytes converts it to bilirubin 1, conjugated bilirubin. Conjugated bilirubin will be excreted in urine and feaces
How to diagnose icterus
- Evaluate the animal for jaundice discolouration
- Signalement and history
- Abdominal palpation
- Rectal palpation
- Neurological exam
Treatment for icterus
Icterus is not a disease, it is a sign that disease is present.
Therefore, there is not a specific treatment for icterus. Icterus will resolve when the disease that causes it is cured.
The basis for resolving icterus is to diagnose and treat the underlying disease
