A Clinical Approach to Jaundice
This is a presentation on the clinical approach to jaundice. And these are the learning objectives you should achieve by the end of this presentation. Jaundice, also known as icterus, is derived from the French word jaune, which means yellow. Essentially, it refers to the yellow discoloration of the sclera followed by the skin and the presence of hyperbilirubinemia. In fact, the degree of hyperbilirubinemia can be estimated by the extent of jaundice observed.
With sclera icterus presenting when serum bilirubin exceeds 51 micromoles per liter. In order to undertake a systematic approach you jaundice, a good understanding of bilirubin metabolism is key. Briefly, heme derived from the breakdown of red blood cells forms bilirubin, which is then reduced to form unconjugated bilirubin. This is transported to the liver and taken out by hepatocytes in which it undergoes glucuronic acid conjugation to form conjugated bilirubin. Conjugated bilirubin is subsequently secreted out into the biliary system and enters the gastrointestinal tract, where they undergo hydrolysis by gut bacteria and urobilinogen. About 80% to 90% of urobilinogen is excreted in the feces while the remainder is reabsorbed and enters the enterohepatic circulation. With the pathway of bilirubin metabolism in mind, causes of hyperbilirubinemia can be categorized based on anatomical site into pre-hepatic, intra-hepatic, and post-hepatic causes, with further subdivision into unconjugated and conjugated states. Pre-hepatic causes refer to hyperbilirubinemia costs prior to hepatocyte uptake.
As such, it represents a predominantly unconjugated hyperbilirubinemia picture. Causes include hemolytic anemia, which can be inherited or acquired, as well as ineffective erythropoiesis. Intra-hepatic causes can lead to both unconjugated or conjugated hyperbilirubinemia.
For instance, impaired hepatocyte uptake of bilirubin due to drugs or inherited defects in conjugation enzymes can lead to a predominantly unconjugated picture. Conversely, impaired biliary excretion from transporter defects can present as a predominantly conjugated state. However, the most clinically important intra-hepatic cause for hyperbilirubinemia is that of hepatocellular injury, which is usually due to hepatitis resulting from a wide range of etiologies and must be investigated for in any patient presenting with jaundice. The last group of causes belong under the post-hepatic category.
In this instance, jaundice results from the blockage of bile duct along the biliary system up till its outlet at the ampulla of Vater. Causes of obstruction can be intraluminal or extraluminal, and the most common causes of biliary obstruction are as follows. One, stones in the common bile duct. Two, carcinoma of the head or pancreas. And three, cholanglocarcinoma.
Now that we have covered the different causes of hyperbilirubinemia, we can proceed with a targeted history taking. Herein, key information that should be obtained is presented. Age itself is more useful than it seems for instance, a young patient with a first episode of jaundice should raise a suspicion for inherited disorders as opposed to an elderly patient. The temporal pattern of jaundice can also provide clues whereby an acute onset of jaundice with fluctuating presentation can point to cholangitis. Whereas a chronic, gradual progression of jaundice may point to what's carcinoma at the head of pancreas.
Associated symptoms, such as the presence of abdominal pain, symptoms due to anemia, viral prodromal symptoms, can help in the differential diagnosis. In addition, signs of obstructive jaundice such as pale stools and tea colored urine are also useful. Risk factors for different etiologies should also be gathered through a comprehensive past medical, drug, family, and social history. For example, risk factors for viral hepatitis B and C include IV drug abuse, tattoos, and unprotected sexual intercourse. In the physical examination of a patient with jaundice, it is important to first assess for right hypochondrium tenderness or a positive Murphy's Sign. These point to what's cholecystitis, or cholangitis and should trigger a surgical assessment.
Adult patients with acute hepatitis may sometimes have a right hypochondrial tenderness. They do not associate with abdominal guarding. Signs of chronic liver disease should always be examined for in a patient with jaundice. Do also remember to palpate the abdomen for hepatosplenomegaly, which can result from decompensated liver cirrhosis or suggest myelo or lympho proliferative disorders. After a systematic history and physical exam, appropriate blood tests can help to verify our differentials. Beginning with the liver function test, we can determine if there is any hepatocellular injury, demonstrated by a rise in the ALT and AST, or biliary duct disease, as seen by a rise in ALP, GGT.
More importantly, the bilirubin composition will direct us towards investigations for unconjugated or conjugated hyperbilirubinemia. If it is predominantly unconjugated, we can proceed to investigate for hemolysis or ineffective erythropoiesis. In conjugated hyperbilirubinemia, the severity and chronicity can be demonstrated for by a high PT/aPTT and low Albumin level. Lastly, based on the likely differentials obtained from the history and physical exam, a screen for viral hepatitis, autoimmune hepatitis, or Wilson's disease can be done. Radiological imaging can assist in diagnosis and its usefulness varies depending on the differentials considered.
Abdominal ultrasound is the first line modality used in assessing of stores, biliary dilatation, and abscesses. Subsequently, an abdominal CT is usually ordered to determine the presence of hepatic, biliary, or pancreatic malignancy. If further evaluation of the biliary system is required, an endoscopic ultrasound or MRCP can be undertaken. Once the diagnosis points to what's obstruction in the biliary system, an ERCP can be performed for therapeutic purposes.
Finally, a liver biopsy can be done to sample tissue for histology if required. This has been a brief overview on the clinical approach to a patient presenting with jaundice. Important take home messages are as follows.
First of all, jaundice is a clinical sign of hyperbilirubinemia. As there are many causes that can result in jaundice, is important to understand the pathogenesis behind hyperbilirubinemia in order to direct a relevant and targeted approach towards jaundice. To avoid missing important clues, key information must be consciously asked for in the history and inspected and determined during physical exam. Differentiating an obstructive from a hepatic cause of jaundice is of great clinical significance in tailoring management plans. Once we have a few differentials, relevant blood and radiological investigations can help to support and to confirm the final cause of hyperbilirubinemia.
These are the references which has been used in the creation of this presentation. Thank you for your kind attention.
This is a presentation on the clinical approach to jaundice. And these are the learning objectives you should achieve by the end of this presentation. Jaundice, also known as icterus,…By: Learning in 10
My baby was born healthy. My baby was born healthy. My baby was born healthy. My baby was born healthy. My baby was born healthy. My baby was born healthy. My baby was born healthy.My…By: Newbornjaundice
Jaundice, a yellowing of the skin and conjunctiva, is common in newborns, and usually is benign. However, some instances of neonatal jaundice are early signs of a serious underlying…By: Medskl.com