26. Clinical approach to patients with icterus (jaundice) Flashcards
What is jaundice?
Jaundice is the yellow staining of serum or tissues by an excessive amount of bile pigment or bilirubin
Jaundice in general
Origins: Pre-hepatic; Hepatic; Post-hepatic
Because the liver is able to excrete bilirubin, for jaundice to occur,
there needs to be a large, persistent increase in bile pigment
production or a major impairment of its excretion
↑ Br → Detectable by lab tests
↑↑ Br → Plasma appears yellow
↑↑↑↑ Br → Jaundice
Prehepatic Jaundice ?
PREHEPATIC JAUNDICE (HAEMOLYTIC CRISIS)
Haemolysis → ↑ Hb degradation → ↑ Br
Haemolysis → ↓ RBCs → Hypoxia → Necrosis → Cholestasis
Causes:
§ Babesia
§ IMHA
§ Toxicosis: Snake bite; Onion/garlic; Paracetamol; Zn
§ Bacteria: Mycoplasma haemofelis
CSx: Hypercholic faeces (due to stercobilin)
Lab. D
§ ↓ PCV
§ ↑ Hb (due to haemolysis)
§ ↑ Reticulocytes (immature RBCs)
§ ↑ Bilirubin I in serum → Icteric serum
§ ↑ Bilirubin II & UBG in urine
Tests: PCV; TP; Icteric serum; Spherocytes; Agglutination
Hepatic/ Hepatocellular jaundice?
HEPATIC/HEPATOCELLULAR JAUNDICE
↓ Uptake & conjugation due to hepatic disease;↓ Hepatic excretion
Hepatocyte damage/structural damage → Leakage between
sinusoids & biliary vessel
Causes:
§ Severe/acute hepatitis § Plants
§ Abnormal conjugation § Neoplasia
§ Abnormal excretion § Bacteria
§ Intrahepatic cholestasis § Parasites
§ Extrahepatic infection § Sepsis
§ Cholangiohepatitis § Mycotoxins
CSx: Hypercholic faeces
Lab. D: ↑ Br; ↑ ALT; ↑ ALP; ↑GGT; ↑ AST
Imaging: Ultrasound
Posthepatic Jaundice?
POSTHEPATIC JAUNDICE
Obstruction of the biliary duct
Cause
Biliary tract obstruction: Stones/mucocele
§ Duodenal foreign body: Blocking of papillae
§ Pancreatitis
CSx: Grey faeces
Lab. D
§ ↑ Br; ↑ ALP; ↑ GGT; ↑/- AST
§ Ø Urinary UBG
§ Ø Faecal stercobilin
Imaging: Ultrasound (stones; biliary tract congestion; pancreatitis)
Note: Cholestasis → ↑ BBA (blood bile acid) → RBC destruction →
Haemolysis
Clinical approach to jaundice?
Clinical Approach To Jaundice
Normal serum total bilirubin
§ Dogs: <0.6mg/dl
§ Cats: <0.3mg/dl
Canine renal tubules have a low resorptive threshold for bilirubin &
and process Br to a limited extent ∴ bilirubinuria may be normal for
dogs
As for cats, they do not have this ability.
Bilirubinuria = Hyperbilirubinaemia = Pathologic!
Lab D in general?
Treatment?
TREATMENT
Treat the cause!
§ Supportive therapy: IVFT; Electrolytes; Antiemetics;
§ Antibiotics (cause dependent): Metronidazole; Ampicillin
§ Coagulopathy: Plasma; Vit. K injection
§ Adjunctive therapy
Antioxidants: Vit. E; Vit. C; SAMe
Choleretic: UDCA
N-acetylcysteine in paracetamol toxicosis cases
