Block 8 Week 9
Gastrointestinal bleeding and intestinal parasites
Tutor : Prof DF Wittenberg MD FCP(SA) dwittenb@medic.up.ac.za
Objectives:
To be able to
 list the causes and discuss the investigation and management of patients presenting with
bleeding from the gut;
 discuss the clinical features, investigation and management of patients presenting with
dysentery
 discuss the clinical features, diagnosis and management of patients suffering from
diseases caused by intestinal parasites;
Illustrative case report 3, page 101:
A 7 year old boy is admitted via Casualty, having presented with a story of vomiting up more than 1 cup full of
bright red blood.
His parents report that he has been feeling unwell over the last couple of days, with a mild fever and
abdominal discomfort. Today, he ate his breakfast toast and then vomited. Soon afterwards, he vomited up
blood on repeated occasions. Subsequently, he has felt faint and appears pale and sweaty.
The family has recently moved to this area from the Lowveld. Mother cannot remember any serious illnesses.
In the newborn period, he was given a drip through his umbilicus, but she cannot supply further details.
Apart from the fact that he has had a rather prominent abdomen and is not growing too well, he has been
fairly well. More recently, he appears to have been quite tired and looking a little pale.
Introduction
A patient vomiting up blood does not always have to have been bleeding from the gut.
Consider swallowed blood from bleeding in the nose or mouth.
Once that has been excluded, bright red blood indicates that the bleeding is from the
oesophagus or stomach with little time for contact with gastric or duodenal digestive juices
which change the appearance of blood to dark brown/black (coffee ground).
The principles of management and diagnosis of GIT bleeding include the following:
 Assess the severity of bleeding: does the patient require resuscitation?
 Identify the site of bleeding and stop it: This often requires endoscopy.
 Identify and manage the aetiology (eg find the predisposing cause of a gastric or
duodenal ulcer, identify portal hypertension etc)
Task
Review the presentation, differential diagnosis and management of GIT bleeding
Case Analysis
The patient’s history suggests that he may have had an intercurrent infection with mild fever. This is a
common precipitant of bleeding episodes due to the fact that the infection increases cardiac output and
circulation and fever causes vasodilatation.
The patient ate food which might have irritated a sore throat, and when he vomited, this increased pressure in
the intravascular compartment.
He has felt faint and is pale and sweaty. While his fright at vomiting up blood may have caused pallor
(vasoconstriction due to catecholamine release), one has to be concerned that this is a manifestation of shock
from blood loss. His pulse rate and blood pressure must be estimated urgently with a view to putting up a
drip and deciding on the need for resuscitation.
There are 2 possible lines of evidence about his underlying disease. If he has lived in the Lowveld, there may
be the environmental risk posed by geographic or climatic conditions: eg Bilharzia is common in the Lowveld,
he may have had a liver condition due to environmental factors (eg Senecio, aflatoxin). The other evidence
concerns the history of neonatal umbilical venous drip with its association with portal vein thrombophlebitis
and subsequent obstruction and portal hypertension.
He has not been growing too well. This may point to a chronic health problem including the possibility of
chronic liver disease.
This patient therefore needs to be assessed very carefully to identify hepatosplenomegaly, possibility of
chronic liver disease and any evidence of portal hypertension.
Portal hypertension
The venous pressure in the portal vein system is increased because of one or more of the
following:
1. Obstruction to the portal vein before it reaches the liver. This may happen with a
congenitally abnormal vein, thrombosis or malformation. Even if secondary channels
open up, the “flow through” is impeded. Babies who have catheters or other
instrumentation of the umbilical vein after birth are liable to this complication due to
thrombosis or septic thrombophlebitis of the duuctus venosus involving the portal
vein
2. Obstruction to flow at or near the portal triads within the liver. This happens with
hepatic schistosomiasis in which the ova lodge in the portal triads and there cause
the so-called “Pipe stem” fibrosis. This is a narrowing effect on flow still before the
portal blood flows past the sinusoids of the liver ie presinusoidal obstruction
3. Sinusoidal obstruction: blood flowing through disorganised or damaged sinusoids of
the liver lobule (eg cirrhosis, chronic liver disease) : Sinusoidal obstruction.
4. Obstruction of hepatic vein outflow from the liver starting at the central veins of liver
lobules: Veno-occlusive disease of liver, hepatic vein obstruction, inferior vena cave
obstruction above the hepatic vein opening, constrictive pericarditis (Post-sinusoidal
obstruction).
Effects of portal hypertension
The effects depend to a degree on the site of obstruction: A patient with portal vein
obstruction (pre-hepatic) does not usually develop hepatomegaly. In the patient with
hepatic vein obstruction or veno-occlusive disease, hepatomegaly may be very marked
indeed, but there does not have to be any liver dysfunction in these cases, as the only
reason for hepatomegaly is the damming up of blood within the liver sinusoids.
The main effects of portal hypertension are :
1. Increased hydrostatic pressure in the portal system. This predisposes to the
development of ascites
2. Enlargement of the spleen. It is however, possible to have portal hypertension
without a large spleen.
3. Development of collateral circulation between the portal and the systemic venous
systems of inferior and superior venae cava.
The enlargement of the spleen also has consequences:
 Hypersplenism: “Overactivity “ of the spleen leading to increased breakdown of blood
cells. This leads to pancytopaenia in the full-blown case (Decreased red cells : anaemia;
diminished white cells : leukopenia; Reduced platelets : thrombocytopaenia). Each of the
above may have unwanted effects on its own, eg thrombocytopaenia : purpura, bleeding
tendency ; leukopenia : infections etc.
Anaemia in a case of portal hypertension may be caused by
 Chronic bleeding from oesophageal varices : Iron deficiency picture, any patient with big
spleen must have stool examined for occult blood
 Sequestration and breakdown of red cells ( look for other evidence of hyperplenism)
Task
Study portal hypertension (C&W p 590 – 591)
Intestinal parasites
A large number of human diseases are caused by parasites. These are acquired by several
means:
Ingestion of cysts, oocysts, ova
Predominant intestinal parasites
Intestinal worms:
ascaris lumbricoides
trichuris trichiuria
taenia saginata
enterobius vermicularis
Intestinal protozoans
giardia lamblia
cryptosporidium parvum
entamoeba histolytica
Intestinal entry, disease elsewhere
(Larval stage leaves the gut)
acquired toxoplasmosis
hydatid disease (echinococcus)
cysticercosis (taenia solium)
visceral larva migrans (Toxocara canis)
trichinosis (trichinella spiralis)
Skin penetration by larvae
Skin entry, gut manifestations
(Mature stage enters the gut)
Hookworm
Strongyloides
Schistosoma mansoni
Skin entry, localized disease
(Dissemination or failure to complete life cycle)
Leishmaniasis
Filariasis
Skin entry, disease by dissemination
Malaria
Trypanosomiasis
Schistosomiasis
Symptoms caused by intestinal parasites




General symptoms
Anaemia
From blood loss, malabsorption, malnutrition
Abdominal symptoms
Abdominal pain and distension
Diarrhoea with or without malabsorption
Diarrhoea with blood loss
Tenesmus, Rectal prolapse
Respiratory Symptoms
Cough and wheeze
Skin rashes
Hypersensitivity
Skin invasion
Abdominal Symptoms and parasites causing them
Abdominal pain and distension
Giardia
Cryptosporidium
Amoebiasis
Ascaris, hookworm, taenia
Diarrhoea +/- malabsorption
Giardia
Cryptosporidium
Strongyloides
Diarrhoea with blood loss
Amoebiasis
Trichuris
Hookworm
Trichuris
Tenesmus, prolapsed rectum
Surgical disorders caused by intestinal parasites
Intestinal obstruction
Worm bolus
Ascaris
Appendicitis
Obstruction
Ascaris
Jaundice, biliary colic
Biliary obstruction
Ascaris
Prolapsed rectum
Tenesmus, weight loss
Trichuris
Intestinal perforation and peritonitis
Transmural necrosis
Amoebiasis
General symptoms caused by intestinal parasites
Anaemia
Blood loss
Amoebiasis
Hookworm
Trichuris
S mansoni
Malabsorption
Giardia
Diphyllobothrium
Malnutrition
Heavy infestation
Skin rash
Papulovesicular
Creeping eruption
Peri-anal rash and pruritus
Hookworm
Strongyloides
Enterobius
Respiratory symptoms
Pulmonary migration
Ascaris
Hookworm
Strongyloides
Toxocara
Task
Review the diseases caused by parasites and their treatment C & W (5th ed) pp 286 – 290, 294 – 303, 322 324