Case Study 9 - Infection Flashcards
A 75 year old man is sent to hospital by his GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
What is cephalexin and what is it prescribed for?
cell wall synthesis inhibitor that binds to PBP & inhibits peptidoglycan synthesis. It’s used for middle ear infection, cellulitis, UTI, pharyngitis
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
What is the mechanism of action of cephalexin?
Cephalexin is a beta-lactam antibiotic, specifically a first-generation cephalosporin. Its mechanism of action involves inhibiting bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). This interference with peptidoglycan synthesis weakens the bacterial cell wall, leading to cell lysis and death. As a result, cephalexin is effective against a wide range of bacteria that have a cell wall, including those causing middle ear infections, respiratory tract infections, skin and soft tissue infections, and urinary tract infections.
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
What are the risks associated with prescribing cephalexin?
antibiotic resistance, allergic reactions, nausea, vomiting, diarrhoea, pseudomembraneouscolitis causes by clostridium bacteria replace the normal flora of bacteria
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
What are the potential causes for our patient’s diarrhoea?
bacterial infection (pseudomembraneouscolitis), norovirus which can cause noro gastroenteritis, salmonella, e.coli, IBD
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
Why is our patient tachycardic?
decrease in blood pressure due to dehydration (compensatory mechanism), also can be caused by sepsis (infection → cytokines leading to vasodilation due to nitric oxide synthase responsible for synthesis for nitric oxide
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
What is lomotil and how does it work?
Lomotil is a medication used to treat diarrhea. It contains two active ingredients: diphenoxylate and atropine. Diphenoxylate is an opioid agonist, meaning it binds to opioid receptors in the gut. Atropine is included to discourage intentional misuse of the medication.
The mechanism of action of diphenoxylate involves its binding to opioid receptors, specifically the mu-opioid receptors, in the gastrointestinal tract. When diphenoxylate binds to these receptors, it inhibits the release of acetylcholine, a neurotransmitter that plays a role in stimulating smooth muscle contractions in the intestine.
The inhibition of acetylcholine release results in decreased peristalsis (the wave-like contractions that move contents through the intestines). This reduction in intestinal motility helps to slow down the movement of stool through the gut, allowing for increased water absorption and ultimately leading to firmer stools.
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription
Why has the lomotil been stopped?
infection is one of its contraindication as you want evacuation of the infection, allows the diarrhoea to remove the bacteria so not retaining bacteria in the gut
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription
What is clostridium difficile, and what is its pathogenesis?
gram-positive bacteria, it’s a normal component of the colon in 2-5% of the population, the toxins released by the bacteria cause ribosylation of small GTPa’s which leads to inactivation of GTP which leads to disruption of the cytoskeleton, this then leads to increased permeability of lumen to toxins and infectious spore-forming molecules. This leads to mucosal immune activation which then leads to cytokine release and inflammation which leads to apoptosis to the membranous colitis
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription
Describe the mechanism of how our patient has developed clostridium difficile.
The development of Clostridium difficile infection (CDI) in this patient can be attributed to the disruption of the normal gut flora, a condition known as antibiotic-associated colitis. Here’s a step-by-step explanation:
Antibiotic Use (Cephalexin): The patient has been taking cephalexin for a middle ear infection. Cephalexin is an antibiotic that is effective against a variety of bacterial infections. However, antibiotics do not selectively target only harmful bacteria; they also affect the normal, beneficial bacteria that reside in the gut.
Disruption of Normal Gut Flora: Antibiotics like cephalexin can alter the balance of the microbial community in the gastrointestinal tract. The normal gut flora, which plays a crucial role in maintaining a healthy and balanced environment in the colon, is disturbed. This disruption provides an opportunity for opportunistic pathogens, such as Clostridium difficile, to proliferate.
Overgrowth of Clostridium difficile: With the normal checks and balances disrupted by antibiotic use, C. difficile, which may have been present in low numbers as part of the normal flora in some individuals, can overgrow and become more dominant in the colon.
Toxin Production: Clostridium difficile produces toxins, primarily toxin A and toxin B. These toxins are responsible for the pathogenic effects of C. difficile infection.
Toxin-Mediated Damage: The toxins released by C. difficile act on the cells lining the colon. They cause cellular damage, disrupt the cytoskeleton, and increase permeability of the colonic epithelium. This results in inflammation, diarrhea, and other symptoms associated with C. difficile infection.
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription
This is a picture of a colon from someone with clostridium difficile infection.
Describe the findings. What is the diagnosis? (1)
Image
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription.
What are the consequences if Pseudomembraneouscolitis is left untreated?
sepsis, protein loss, low albumin levels, hypokalaemia which can cause arrhythmia, renal failure due to dehydration, perforation of colon, toxic megacolon leads to dilated swollen colon as a result of the inflammation
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription.
The patient is first prescribed metronidazole, but then oral vancomycin is added to the chart.
How will metronidazole treat this condition?
done
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription.
The patient is first prescribed metronidazole, but then oral vancomycin is added to the chart.
What is vancomycin and why has it been prescribed?
Vancomycin is an antibiotic that belongs to the glycopeptide class. It is used to treat bacterial infections, particularly those caused by Gram-positive bacteria. Vancomycin acts by inhibiting the synthesis of the bacterial cell wall, making it effective against a variety of bacteria, including certain strains of Clostridium difficile.
Mechanism of Action:
Vancomycin’s primary mechanism of action is the inhibition of bacterial cell wall synthesis. It interferes with the formation of peptidoglycan, a key component of the bacterial cell wall. Peptidoglycan provides structural support to the bacterial cell and is crucial for maintaining cell shape and integrity.
Vancomycin specifically binds to the D-alanyl-D-alanine terminus of the peptidoglycan precursor, preventing the addition of new subunits to the growing peptidoglycan chain. This inhibition disrupts the formation of the cell wall, leading to weakened bacterial cell walls and, eventually, cell death.
Use in Clostridium difficile Infection (CDI):
Vancomycin is one of the antibiotics commonly used to treat Clostridium difficile infection (CDI). CDI occurs when there is overgrowth of C. difficile in the colon, often triggered by the disruption of normal gut flora, such as that caused by antibiotic use.
In the case described, vancomycin is likely prescribed because Clostridium difficile has been identified as the causative agent of the persistent loose stools. Vancomycin is effective against C. difficile, particularly in cases where the infection is severe or when there is a lack of response to other antibiotics like metronidazole.
The decision to add oral vancomycin to the treatment plan may be based on the severity of the infection or the specific circumstances of the patient. In severe cases of C. difficile infection or when metronidazole alone is not sufficient, vancomycin is often preferred due to its effectiveness against this particular bacterium. The combination of metronidazole and vancomycin may be used in certain cases to optimize the treatment approach.
A 75 year old man is sent to hospital by her GP. He presented with a 2 day
history of persistent loose stools. He has been to the toilet 5 times already that
day. He has been feeling
feverish and very tired.
The GP examines him
and notes that he is very
dehydrated. He notes
that he has been taking
cephalexin for a middle
ear infection.
On arrival at the hospital, our patient explains to the doctor the symptoms he has been having, but he forgets to mention that he has been taking cephalexin. He notes that he doesn’t look well and he is tachycardic. He gives him some IV fluid therapy and requests for a stool sample to be sent to the microbiology team. He also prescribes some lomotil for him.
The doctor is looking at the patient’s results a few days later…..he notes that
the culture result is positive for clostridium difficile. He immediately runs to the
ward and crosses out the lomotil prescription.
The patient is first prescribed metronidazole, but then oral vancomycin is added to the chart.
What are the complications of vancomycin therapy?
abdominal pain, fever, rash, hypersensitivity, autotoxicity, nephrotoxicity
A 26 year old woman
attends a clinic to have
her cervical smear. The
sample is sent to the
pathologist for review.
What is the cervical screening programme, and what is the aim?
The cervical screening program, also known as cervical smear or Pap smear, is a preventive healthcare measure aimed at detecting and preventing cervical cancer. The primary goal of cervical screening is to identify pre-cancerous changes in the cervix early on, allowing for intervention and treatment before the development of invasive cervical cancer.
women between 25-49 - 3 yearly, 50-64 - 5 yearly, 64+ only those who haven’t been screened since the age of 50, pre-cancerous
