Pharmacy Infection Flashcards
SBA
What is the primary mechanism of action for PPIs in GORD management?
Irreversible inhibition of H/K-ATPase.
EMQ
Select the most appropriate therapy for a patient with GORD who responds poorly to PPIs.
H2 Receptor Antagonist.
SAQ
Outline a stepwise management plan for GORD, including lifestyle and pharmacological interventions.
Lifestyle changes (e.g., weight loss, smaller meals, avoid eating before bedtime).
Start antacids for immediate symptom relief.
Prescribe a PPI (e.g., Omeprazole 20 mg daily for 4 weeks).
For recurring symptoms, consider a step-down approach or H2RAs.
SBA: What is the correct timing for taking a PPI for maximum efficacy in GORD?
Answer: 30 minutes to 1 hour before meals.
SBA: What is the primary non-pharmacological management recommendation for patients with nighttime GORD symptoms?
Answer: Elevate the head of the bed.
SBA: Why are gastro-resistant capsules used for omeprazole?
Answer: To protect the drug from degradation in the acidic stomach environment.
SBA: What is the most common risk associated with long-term PPI use in older patients?
Answer: Chronic kidney disease.
EMQ: Select the most appropriate treatment for a patient with mild GORD symptoms who has not improved with lifestyle changes.
Answer: Prescribe a PPI for 4 weeks.
EMQ: Select the next step for a patient with GORD who has recurrent symptoms after 4 weeks of PPI therapy.
Answer: Continue PPI at the lowest effective dose.
EMQ: Choose the best alternative treatment for a patient who responds poorly to PPIs.
Answer: Prescribe an H2 receptor antagonist.
EMQ: Select the appropriate management for a patient presenting with water brash and regurgitation due to GORD.
Answer: Start antacids for immediate symptom relief.
EMQ: For a patient with severe reflux symptoms persisting despite treatment, what is the appropriate next step?
Answer: Refer to a GP for further investigation.
SAQ: Explain the mechanism of action of omeprazole and how it achieves long-term acid suppression.
Answer: Omeprazole irreversibly inhibits the H/K-ATPase proton pump in gastric parietal cells, blocking ~90% of acid secretion. This effect lasts beyond the plasma half-life because it requires new proton pumps to be synthesized.
SAQ: Describe the risks and monitoring recommendations for long-term PPI use.
Answer: Risks include hypomagnesemia, chronic kidney disease, and possible acid rebound after discontinuation. Monitor serum magnesium in patients on long-term PPI therapy, especially those on ACE inhibitors or diuretics.
SBA: What is the most common side effect associated with GORD?
Answer: Heartburn.
SBA: Why are gastro-resistant capsules used for omeprazole?
Answer: To protect the drug from degradation in the acidic stomach environment.
BA: What is the effect of antacids when taken on an empty stomach?
Answer: Effects last no longer than an hour due to rapid gastric emptying.
SBA: What is the initial treatment duration for GORD using omeprazole 20 mg daily?
Answer: 4 weeks.
SBA: What is a potential long-term risk of PPI therapy in older adults?
Answer: Chronic kidney disease.
SBA: What should be monitored in long-term PPI use according to the BNF?
Answer: Serum magnesium.
EMQ: Select the most appropriate non-pharmacological advice for a patient presenting with mild, intermittent GORD symptoms.
Answer: Advise smaller, more frequent meals and avoidance of eating 2–3 hours before bed.
EMQ: Choose the most suitable therapy for a patient with uninvestigated dyspepsia and GORD symptoms.
Answer: Omeprazole 20 mg daily for 4 weeks.
EMQ: Identify the best alternative therapy for a patient with GORD who does not respond to PPI therapy.
Answer: H2 receptor antagonist.
EMQ: Select the best management for a patient reporting mild symptoms of acid reflux despite lifestyle changes.
Answer: Start antacids for immediate symptom relief.
EMQ: What is the next step for a patient whose symptoms return after stopping PPI therapy?
Answer: Initiate a step-down approach with the lowest effective PPI dose.
EMQ: Which pharmacological therapy is appropriate for a patient concerned about long-term PPI side effects but still requiring symptom control?
Answer: When-needed PPI therapy.
EMQ: Select the most suitable management for a patient with alarm symptoms (e.g., dysphagia or weight loss) after initial PPI therapy.
Answer: Refer to a GP for further investigation.
SAQ 1:
Describe pharmacological and non-pharmacological treatments for GORD. (10 marks)
Non-Pharmacological (2 marks):
Advise lifestyle changes: weight loss, smaller meals, avoid eating before bed.
Elevate the head of the bed for nighttime symptoms.
Pharmacological (8 marks):
Antacids for immediate relief (e.g., Gaviscon).
PPI (e.g., omeprazole 20 mg daily for 4 weeks) as first-line therapy.
H2 receptor antagonist (e.g., ranitidine) if PPI response is inadequate.
Step-down approach or on-demand PPI for long-term management.
SAQ 2:
Explain the role of gastro-resistant capsules in PPI therapy. (10 marks)
Prevents degradation of the drug in the stomach (2 marks).
Ensures release in the small intestine, where absorption is optimal (2 marks).
Helps maintain the biological effect of the PPI despite its short plasma half-life (2 marks).
Allows for sustained acid suppression by irreversibly inactivating proton pumps (4 marks).
Describe how to manage a patient with recurrent GORD symptoms after successful initial treatment with PPIs. (10 marks)
Restart PPI therapy at the lowest effective dose (2 marks).
Offer on-demand therapy as an alternative for intermittent symptoms (2 marks).
Address lifestyle factors and adherence to non-pharmacological measures (2 marks).
Consider H2 receptor antagonist if symptoms persist despite PPI (2 marks).
Refer to a GP if alarm symptoms (e.g., weight loss, dysphagia) appear (2 marks).
SBA: Which structure prevents food from entering the trachea?
Answer: Epiglottis.
SBA: Which layer of the alimentary canal is responsible for mucous secretion?
Answer: Mucosa.
SBA: Which vitamin requires intrinsic factor for absorption?
Answer: Vitamin B12.
SBA: What is the primary function of bile salts?
Answer: Emulsification of fats.
SBA: In what form are proteins absorbed into the bloodstream?
Answer: Amino acids.
SBA: What is the main function of the large intestine?
Answer: Absorption of water.
SBA: What hormone stimulates gastric juice secretion during the gastric phase?
Answer: Gastrin.
SBA: Where is vitamin B12 absorbed in the GI tract?
Answer: Terminal ileum.
SBA: What is the primary pharmacological target for reducing gastric acid secretion?
Answer: H+/K+ ATPase pump.
SBA: What is the first-line treatment for H. pylori-associated peptic ulcer disease?
Answer: Triple therapy with PPI, amoxicillin, and clarithromycin/metronidazole.
SBA: What is the main diagnostic test for H. pylori infection?
Answer: Urea breath test.
SBA: What is the pharmacological treatment for mild Crohn’s disease?
Answer: Budesonide (oral corticosteroid).
SBA: Which condition primarily involves inflammation of the rectum and colon?
Answer: Ulcerative colitis.
SBA: What supplementation is required after ileal resection in Crohn’s disease?
Answer: Vitamin B12.
SBA: What is the appropriate treatment for diarrhea in IBS?
Answer: Loperamide.
SBA: What is the most common risk associated with long-term PPI use in older adults?
Answer: Chronic kidney disease.
SBA: What side effect is commonly monitored during long-term PPI use?
Answer: Hypomagnesemia.
SBA: What is the primary action of alginates in GORD treatment?
Answer: Form a physical barrier to prevent reflux.
SBA: What red flag symptom requires urgent referral for further investigation in GORD?
Answer: Dysphagia.
SBA: What is the correct timing for taking a PPI for maximum efficacy?
Answer: 30 minutes to 1 hour before meals.
SBA: Why are gastro-resistant capsules used for omeprazole?
Answer: To protect the drug from degradation in the acidic stomach environment.
SBA: What non-pharmacological measure is most appropriate for patients with nighttime GORD symptoms?
Answer: Elevate the head of the bed.
SBA: How should GORD symptoms recurring after stopping PPI therapy be managed?
Answer: Restart PPI therapy at the lowest effective dose.
SBA: Which diagnostic tool is most appropriate for suspected esophageal cancer in a patient with alarm symptoms?
Answer: Endoscopy.
SBA: What condition is associated with long-term bile duct obstruction?
Answer: Steatorrhea.
SBA: What is the role of bile salts in fat digestion?
Answer: Facilitate the formation of micelles for fat absorption.
SBA: Which vitamin absorption would be impaired due to bile salt deficiency?
Answer: Vitamin A.
SBA: What is the primary role of the enteric nervous system in digestion?
Answer: Control of motility, secretion, and blood flow within the GI tract.
List the main features of GORD, peptic ulcers and H. pylori infection
Gastro-oesophageal reflux disease
* Usually caused by weakening/relaxation in lower oesophageal sphincter
* Acid from stomach leaks up into oesophagus, causing symptoms:
* Heartburn
* Acid reflux
* Bad breath
* Bloating / belching
* Nausea / vomiting
State how GORD, peptic ulcers and H. pylori infections are diagnosed
Diagnosis usually made solely on symptoms
* Should take a full drug history to identify any possible drug causes
* Calcium antagonists, nitrates, theophyllines, bisphosphonates, corticosteroids and
non-steroidal anti-inflammatory drugs
* Will unlikely perform any other tests to confirm GORD diagnosis
* May perform other tests to investigate other causes of symptoms
* Urea breath test for H. pylori infection
* Endoscopy for gastric cancers
Outline the pharmacological management of GORD, peptic ulcers and H. pylori
infection
Antacid: Pepto-Bismol®, Rennie®
* Alignate: Gaviscon Advance®
* Dual Product: Gaviscon Dual Action®, Peptac®
* PPI or H2 receptor antagonists
* Longer acting, but take longer to work than antacids
* Do not take both at same time, one or the other
* Quite strict criteria of who you can supply PPI to (recent POM to P switch)
* Max 2-4 weeks treatment, then refer to GP
What if any red flags exist for GORD referral?
Patients over 55 years with new onset symptoms
* Patients over 55 years with unexplained dyspepsia that hasn’t responded to 2 weeks of
treatment
* Patients who have continuously taken remedies for 4 weeks (risk of rebound indigestion)
* Pregnant or breastfeeding
* Not responded to OTC treatment
* Red flag symptoms:
* Unintentional weight loss
* Epigastric mass
* Stomach pain, pain/difficulty when swallowing
* Persistent vomiting
* Jaundice
* Signs suggestive of GI bleed
Sarah’s Pub Lunch Route:
Mouth → Pharynx → Esophagus → Stomach → Small Intestine (duodenum → jejunum → ileum) → Large Intestine (cecum → colon → rectum) → Anus.
Accessory Organs:
Liver, pancreas, gallbladder, salivary glands.
Four Layers of the GI Tract:
Mucosa → Submucosa → Muscularis externa → Serosa.
Location of the Oblique Muscle:
Found in the stomach’s muscularis externa, aiding in mechanical digestion.
Role of Mucus in the GI Tract:
Protects the lining from acidic and enzymatic damage.
Lubricates food passage.
Vomiting Center and Receptor Types:
Role: Coordinates emesis by activating GI and diaphragm muscles.
Receptors: Dopamine (D2), Serotonin (5-HT3), Histamine (H1), Acetylcholine (muscarinic), and Neurokinin-1 (NK1).
Pain Timing in Ulcers:
Duodenal Ulcers: Pain improves with eating.
Gastric Ulcers: Pain worsens with eating.
Gastroparesis Definition:
Partial paralysis of the stomach, delaying gastric emptying.
Symptoms and Treatment of Gastroparesis:
Symptoms: Nausea, vomiting, bloating, early satiety.
Treatment: Dietary changes, prokinetic agents (e.g., metoclopramide), and antiemetics.
Pathology of GORD:
Dysfunction of the lower esophageal sphincter (LES) → Acid reflux damages esophageal mucosa.
Features of GORD, Peptic Ulcers, H. pylori:
GORD: Heartburn, regurgitation, dysphagia.
Peptic Ulcers: Epigastric pain, hematemesis, melena.
H. pylori: Chronic gastritis, ulcer formation.
Diagnosis of GORD, Peptic Ulcers, H. pylori:
GORD: Clinical diagnosis, endoscopy if severe.
Peptic Ulcers: Endoscopy, urea breath test.
H. pylori: Urea breath test, stool antigen test, biopsy.
Pharmacological Management:
GORD: Antacids, PPIs, H2RAs.
Peptic Ulcers: PPIs + H. pylori eradication therapy.
H. pylori: Triple therapy (PPI, amoxicillin, clarithromycin/metronidazole).
Red Flags for GORD Referral:
Dysphagia, unintentional weight loss, GI bleeding, epigastric mass.
First-Line Treatment for GORD:
PPIs (e.g., omeprazole).
Sites of Action: Omeprazole vs. Ranitidine:
Omeprazole: Inhibits H+/K+ ATPase in parietal cells.
Ranitidine: Blocks H2 receptors in parietal cells.
PPI Drug Interactions:
PPIs inhibit CYP enzymes (e.g., CYP2C19), reducing metabolism of drugs like clopidogrel.
Role of H. pylori in Ulcers:
Produces urease, neutralizing stomach acid → Mucosal damage → Ulcer formation.
Treatment for H. pylori-Associated Ulcers:
Triple therapy: PPI + amoxicillin + clarithromycin/metronidazole.
Ulcers Without H. pylori:
Possible causes: NSAIDs, stress ulcers, Zollinger-Ellison syndrome.
Zollinger-Ellison Syndrome:
Gastrin-secreting tumor → Excess acid production → Refractory peptic ulcers.
IBD Symptoms:
Diarrhea (bloody in UC), abdominal pain, weight loss, fatigue, extraintestinal symptoms (e.g., joint pain).
Differential Diagnosis of UC:
Differentiated from Crohn’s by UC’s limitation to the colon/rectum and lack of skip lesions.
Term for UC + Crohn’s:
nflammatory Bowel Disease (IBD).
Recommended Treatment for Diarrhea:
Loperamide or oral rehydration therapy.
Role of Enteric Nervous System in IBS Treatment:
Regulates motility, secretion, and pain perception; targeted by antispasmodics (e.g., hyoscine).
Role and Types of PPI Drugs:
Block H+/K+ ATPase to reduce acid secretion (e.g., omeprazole, lansoprazole).
TPMT Analysis:
Required prior to azathioprine/mercaptopurine therapy to assess risk of myelosuppression.
SBA: What step in the viral lifecycle do HIV integrase inhibitors target?
Answer: HIV genome integration.
SBA: What is the primary mechanism of action of nucleoside reverse transcriptase inhibitors (NRTIs)?
Answer: Inhibition of genome replication via DNA chain termination.
SBA: Which class of drugs prevents HIV viral fusion with host cells?
Answer: HIV gp41 inhibitors.
SBA: What step in the influenza virus lifecycle do neuraminidase inhibitors block?
Answer: Viral release/exit.
SBA: What step in the influenza lifecycle do M2 blockers inhibit?
Answer: Viral uncoating.
SBA: Why are host proteins targeted in some antiviral drugs?
Answer: Host proteins mutate less frequently, reducing resistance risk.
SBA: What antiviral drug targets the CCR5 receptor to prevent HIV entry?
Answer: Maraviroc.
SBA: What is the oral prodrug of penciclovir?
Answer: Famciclovir.
SBA: How does acyclovir selectively target HSV-infected cells?
Answer: It requires phosphorylation by viral thymidine kinase for activation.
SBA: What makes cidofovir more stable than Antiviral A?
Answer: Cidofovir has a phosphonate bond (P-C), which is more stable than a phosphate bond (P-O).
SBA: What viral polymerase does remdesivir inhibit?
Answer: SARS-CoV-2 RNA-dependent RNA polymerase.
SBA: What technology is used to deliver monophosphate nucleotide inhibitors like remdesivir?
Answer: ProTide technology.
SBA: What is the key feature of tenofovir disoproxil that increases its absorption?
Answer: Masking of the phosphonate group with disoproxil groups.
SBA: Why is monotherapy ineffective for treating HIV?
Answer: High mutation rate leads to rapid emergence of resistance.
SBA: What is the active form of adefovir dipivoxil?
Answer: Adefovir diphosphate.
SBA: What is the role of NNRTIs in HIV therapy?
Answer: Allosteric inhibition of reverse transcriptase.
SBA: Which HIV drug class does not require intracellular activation?
Answer: NNRTIs (e.g., rilpivirine).
SBA: How does adefovir cause DNA chain termination?
Answer: It lacks a 3’-OH group required for DNA elongation.
SBA: Which viral infection can be cured with current antiviral therapies?
Answer: Hepatitis C virus (HCV).
SBA: What structural feature of remdesivir aids in intracellular delivery?
Answer: Masking of the negatively charged phosphate group.
EMQ: Match the drug class to its inhibited viral step in HIV replication.
Answer:
NRTIs: Genome replication.
NNRTIs: Reverse transcriptase allosteric inhibition.
Integrase inhibitors: HIV genome integration.
EMQ: Select the antiviral mechanism of acyclovir.
Answer: Inhibition of viral DNA polymerase by chain termination.
EMQ: Identify the correct antiviral therapy for influenza targeting viral uncoating.
Answer: M2 blockers.
EMQ: Choose the treatment targeting HSV that requires intracellular activation.
Answer: Acyclovir.
EMQ: Select the drug preventing HIV entry into host cells.
Answer: Maraviroc.
EMQ: Match the drug to its use: Famciclovir or Acyclovir for cold sores.
Answer: Acyclovir cream for cold sores (HSV-1).
EMQ: Choose the prodrug that enhances absorption of tenofovir.
Answer: Tenofovir disoproxil.
EMQ: Select the correct antiviral for HCV with a high mutation barrier.
Answer: Combination therapy with direct-acting antivirals (DAAs).
EMQ: Match ProTide technology to its role in remdesivir.
Answer: Facilitates intracellular delivery of monophosphate nucleosides.
EMQ: Identify the drug causing selective toxicity by viral thymidine kinase activation.
Answer: Acyclovir.
SAQ 1:
Explain the mechanism of action of acyclovir and its selective activity against HSV-infected cells.
Acyclovir is a nucleoside analog that inhibits viral DNA polymerase by causing chain termination. (3 marks)
It is phosphorylated into the active triphosphate form by viral thymidine kinase, ensuring activation only in infected cells. (4 marks)
It binds viral DNA polymerase with >100-fold affinity compared to human DNA polymerase, minimizing toxicity. (3 marks)
SAQ 2:
Describe the rationale for using combination therapy in HIV treatment.
Prevents resistance by targeting multiple steps of the viral lifecycle. (3 marks)
Provides a synergistic effect, improving antiviral efficacy. (2 marks)
Reduces drug toxicity by lowering individual drug dosages. (2 marks)
Addresses HIV’s high mutation and replication rates. (3 marks)
SAQ 3:
Outline the advantages of ProTide technology used in remdesivir.
Masks negatively charged phosphate group, enhancing membrane permeability. (3 marks)
Circumvents inefficient first phosphorylation step in nucleoside activation. (3 marks)
Protects the drug from hydrolysis until inside the target cell. (2 marks)
Increases delivery efficiency and antiviral potency. (2 marks)
SBA: What is the target of sulfonamides in bacterial cells?
Answer: Dihydropteroate synthetase (DHPS).
SBA: What family does ceftazidime belong to?
Answer: Cephalosporins.
SBA: What is the antibacterial effect of clavulanic acid?
Answer: No direct antibacterial effect (β-lactamase inhibitor).
SBA: Which bacterial target do fluoroquinolones inhibit?
Answer: Topoisomerases.
SBA: What is the key structural feature of methicillin responsible for β-lactamase resistance?
Answer: Bulky side chain on the acylamino group.
SBA: Which antibiotic is active against Mycoplasma pneumoniae?
Answer: Macrolides (e.g., erythromycin).
SBA: What is the mechanism of resistance in Mycoplasma pneumoniae to β-lactams?
Answer: Intrinsic resistance due to the absence of a cell wall.
SBA: Which family does doxycycline belong to?
Answer: Tetracyclines.
SBA: What is the minimum inhibitory concentration (MIC)?
Answer: The lowest concentration of an antibiotic that inhibits bacterial growth.
SBA: What family does levofloxacin belong to?
Answer: Fluoroquinolones.
SBA: What is the mode of action of aminoglycosides?
Answer: Inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit.
SBA: Which penicillin has the narrowest spectrum of activity?
Answer: Penicillin G.
SBA: What is the mechanism of sulfonamide activity reduction by procaine?
Answer: Procaine hydrolyzes to release PABA, which competes with sulfonamides for binding to DHPS.
SBA: What is the effect of β-lactamase on penicillin?
Answer: Hydrolyzes the β-lactam ring, rendering the antibiotic inactive.
SBA: Which bacterial mechanism involves physical contact for horizontal gene transfer?
Answer: Conjugation.
SBA: What is the antibacterial effect of tetracyclines?
Answer: Bacteriostatic.
SBA: Why are bactericidal antibiotics preferred for immunocompromised patients?
Answer: They kill bacteria directly without relying on the immune system.
SBA: What is the role of β-lactamase inhibitors like clavulanic acid?
Answer: Prevent β-lactamase from hydrolyzing β-lactam antibiotics.
SBA: What family does piperacillin/tazobactam belong to?
Answer: Antipseudomonal penicillins combined with a β-lactamase inhibitor.
SBA: Which antibiotic family targets nucleic acid synthesis?
Answer: Fluoroquinolones.
EMQ: Match the bacterial target to the drug family.
Protein synthesis (50S ribosomal subunit): Macrolides.
Cell wall synthesis: Penicillins.
Nucleic acid synthesis: Fluoroquinolones.
EMQ: Select the appropriate drug for atypical pneumonia caused by Mycoplasma pneumoniae.
Answer: Azithromycin (Macrolides).
EMQ: Match the penicillins in order of spectrum of activity from narrowest to broadest.
Penicillin G → Flucloxacillin → Amoxicillin → Piperacillin-tazobactam.
EMQ: Choose the best treatment for a patient with Staphylococcus aureus producing β-lactamase.
Answer: Flucloxacillin.
EMQ: Select the antibiotic active against Pseudomonas aeruginosa.
Answer: Piperacillin-tazobactam.
EMQ: Choose the correct effect of sulfonamides on bacterial metabolism.
Answer: Inhibit folic acid synthesis.
EMQ: Match the β-lactamase inhibitor to its use.
Clavulanic acid: Used with amoxicillin.
EMQ: Select the drug that inhibits protein synthesis at the 30S ribosomal subunit.
Answer: Doxycycline (Tetracyclines).
EMQ: Choose the drug family requiring intracellular activation.
Answer: Nitroimidazoles (e.g., metronidazole).
EMQ: Match the antibacterial effect to the drug.
Amoxicillin: Bactericidal.
Sulfamethoxazole: Bacteriostatic.
SAQ 1:
Explain the mechanism of β-lactam resistance in bacteria.
β-lactamase production: Hydrolyzes the β-lactam ring, rendering the antibiotic inactive (4 marks).
Alteration of target site: Mutation in penicillin-binding proteins (PBPs) reduces drug binding (4 marks).
Efflux pumps: Bacteria actively pump out the antibiotic (2 marks).
SAQ 2:
Describe the role of clavulanic acid in combination therapy.
Prevents β-lactam hydrolysis by inhibiting β-lactamase enzymes (4 marks).
Extends the spectrum of β-lactam antibiotics (3 marks).
No direct antibacterial activity but enhances drug efficacy (3 marks).
SAQ 3:
Outline the difference between bacteriostatic and bactericidal antibiotics.
Bacteriostatic: Inhibit bacterial growth, rely on immune system for clearance (e.g., tetracyclines) (4 marks).
Bactericidal: Directly kill bacteria, preferred in immunocompromised patients (e.g., β-lactams) (4 marks).
Clinical Use: Choice depends on patient’s immune status and infection severity (2 marks).
SBA: What is the definition of epidemiology?
Answer: The study of how often diseases occur in different groups of people and why.
SBA: What is the role of epidemiology in healthcare?
Answer: To plan and evaluate strategies for disease prevention and guide patient management.
SBA: What is a biological agent of disease?
Answer: Bacteria, viruses, or fungi.
SBA: What is the primary transmission route of tuberculosis?
Answer: Airborne transmission.
SBA: What are fomites in the context of infection?
Answer: Objects that can facilitate pathogen transmission, such as handrails or utensils.
SBA: What is the natural reservoir for Clostridium tetani?
Answer: Soil.
SBA: Which pathogens are commonly transmitted through the faecal-oral route?
Answer: Cholera and hepatitis A.
SBA: What is a key feature of robust pathogens?
Answer: Ability to survive for long periods outside the host.
SBA: Which transmission route involves pathogens being carried by vectors?
Answer: Vector-borne transmission (e.g., malaria via mosquitoes).
SBA: What does the antimicrobial spectrum of activity describe?
Answer: The range of organisms targeted by an antimicrobial.
EMQ: Match the transmission route to the example of infection.
Airborne transmission: Tuberculosis.
Faecal-oral transmission: Cholera.
Vector-borne transmission: Malaria.
Direct contact transmission: Cold sores (HSV-1).
EMQ: Select the most appropriate prevention method for waterborne diseases.
Answer: Adequate sanitation and safe water supply.
EMQ: Match the pathogen to its primary reservoir.
Clostridium tetani: Soil.
Legionella pneumophila: Water.
Rabies virus: Infected animals.
EMQ: Identify the most likely mode of influenza transmission in an office setting.
Answer: Indirect contact via shared surfaces.
EMQ: Match the pathogen to its antimicrobial susceptibility.
Gram-positive bacteria: Penicillin V.
Gram-negative bacteria: Ceftriaxone.
Define epidemiology and its importance.
Answer: The study of disease occurrence and distribution in populations, used for prevention and management.
List three major modes of pathogen transmission.
Answer: Airborne, faecal-oral, and vector-borne.
Explain the term “fomites” and provide two examples.
Answer: Objects that facilitate transmission, e.g., handrails, used tissues.
What is the difference between droplet and airborne transmission?
Answer: Droplet transmission requires close contact, airborne pathogens remain infective for long periods in the air.
What factors make a pathogen “robust”?
Answer: Ability to survive outside a host, resistance to environmental changes, high transmissibility.
SBA: What is the definition of pathophysiology?
Answer: The study of disordered physiological processes associated with disease or injury.
SBA: What is the role of prostaglandin E2 (PGE2) in fever development?
Answer: Alters the hypothalamic set-point, leading to an elevated body temperature.
SBA: What is the systemic inflammatory response syndrome (SIRS) criterion for tachypnea?
Answer: Respiratory rate >20 breaths per minute.
SBA: Which immune cells are responsible for killing virus-infected cells?
Answer: Natural killer (NK) cells.
SBA: What defines sepsis in the context of infection?
Answer: SIRS caused by an infection.
SBA: What is the most common cause of bacterial sepsis in the hospital setting?
Answer: Staphylococcus aureus.
SBA: What type of molecular pattern triggers the inflammatory response in infection?
Answer: Pathogen-associated molecular patterns (PAMPs).
SBA: What is the hallmark cytokine associated with sepsis-induced organ dysfunction?
Answer: Tumor necrosis factor-alpha (TNF-α).
SBA: What is the primary diagnostic marker for sepsis?
Answer: Elevated lactate levels (>2 mmol/L).
SBA: Which organ dysfunction is commonly associated with severe sepsis?
Answer: Acute kidney injury.
EMQ: Match the pathogen to its disease association.
Staphylococcus aureus: Toxic shock syndrome.
Escherichia coli O157: Haemolytic uraemic syndrome.
Listeria monocytogenes: Meningitis in immunocompromised patients.
EMQ: Select the most likely systemic effect of infection in sepsis.
Answer: Vasodilation leading to hypotension.
EMQ: Identify the appropriate cytokine associated with systemic inflammation in infection.
Answer: Interleukin-1 (IL-1).
EMQ: Match the clinical sign to its systemic cause in infection.
Fever: Elevated hypothalamic set-point.
Hypotension: Systemic vasodilation.
Tachypnea: Increased metabolic demand.
EMQ: Match the infection to its primary mode of transmission.
Staphylococcus aureus: Direct contact.
Listeria monocytogenes: Ingestion of contaminated food.
Escherichia coli O157: Faecal-oral transmission.
SAQ: Explain the systemic effects of infection and their clinical markers. (10 marks)
Define sepsis and its progression to severe sepsis.
Answer: Sepsis is SIRS due to infection, characterized by dysregulated immune response. Severe sepsis includes organ dysfunction.
List the three major systemic effects of infection.
Answer: Fever, sepsis, and organ dysfunction
Describe the role of PGE2 in fever development.
nswer: PGE2 stimulates endogenous pyrogens (IL-1, IL-6, TNF-α), resetting the hypothalamic temperature set-point.
What is the clinical definition of septic shock?
Answer: Sepsis-induced hypotension persisting despite fluid resuscitation. (1 mark)
Explain the significance of lactate levels in sepsis diagnosis.
Answer: Elevated lactate (>2 mmol/L) indicates tissue hypoperfusion and metabolic dysfunction.
SBA: What is the definition of pneumonia?
Answer: Inflammation of the lungs caused by bacterial or viral infection, with pus-filled air sacs.
SBA: Which bacterial pathogen is the most common cause of community-acquired pneumonia (CAP)?
Answer: Streptococcus pneumoniae.
SBA: What scoring system is used to assess the severity of CAP in the hospital setting?
Answer: CURB-65.
SBA: What is the first-line antibiotic treatment for low-severity CAP in a non-penicillin-allergic patient?
Answer: Amoxicillin 500 mg TDS for 5 days.
SBA: What symptom in CAP is commonly associated with confusion in elderly patients?
Answer: Delirium.
SBA: What is a hallmark radiological finding in CAP?
Answer: New consolidation on chest X-ray.
SBA: What CRB-65 score suggests that a CAP patient can be managed at home?
Answer: CRB-65 score = 0.
SBA: Which risk factor increases susceptibility to CAP?
Answer: Smoking (active or passive).
SBA: What is the most common side effect of doxycycline?
Answer: Gastrointestinal upset (nausea, vomiting).
SBA: What antibiotic class does levofloxacin belong to?
Answer: Quinolones.
MQ: Match the antibiotic to the associated CAP severity and allergy status.
Amoxicillin: Low-severity CAP, non-penicillin-allergic.
Doxycycline: Low-severity CAP, penicillin-allergic.
Co-amoxiclav + Clarithromycin: High-severity CAP.
Levofloxacin: High-severity CAP, penicillin-allergic.
EMQ: Match the CURB-65 parameters to their thresholds.
Confusion: Abbreviated Mental Test (AMT) score ≤8.
Urea: >7 mmol/L.
Respiratory rate: >30 breaths/min.
Blood pressure: Systolic <90 mmHg or diastolic ≤60 mmHg.
EMQ: Match the pathogen to its associated CAP context.
Legionella spp.: Immunocompromised patients.
Haemophilus influenzae: Smokers or COPD patients.
Staphylococcus aureus: Post-influenza pneumonia.
EMQ: Identify the expected timeline for symptom resolution in CAP.
1 week: Fever resolution.
4 weeks: Reduction in chest pain and sputum production.
6 months: Return to normal energy levels.
EMQ: Match the diagnosis method to the relevant symptom or finding in CAP.
Chest X-ray: Consolidation.
CRP and WCC: Inflammatory markers.
Oxygen saturation: Hypoxia detection.
What are the common symptoms of CAP?
Answer: Fever, cough (productive with yellow/green sputum), dyspnea, chest pain, fatigue, confusion (in elderly).
Outline the CURB-65 parameters for severity classification.
Confusion (AMT ≤8).
Urea >7 mmol/L.
Respiratory rate >30 breaths/min.
Blood pressure (systolic <90 mmHg or diastolic ≤60 mmHg).
Age ≥65 years. (3 marks)
List first-line antibiotic options for low-severity CAP in non-penicillin-allergic and penicillin-allergic patients.
nswer:
Non-penicillin-allergic: Amoxicillin.
Penicillin-allergic: Doxycycline or Clarithromycin.
What investigations confirm the diagnosis of CAP?
Answer:
Chest X-ray (consolidation).
Blood tests: CRP, WCC.
Oxygen saturation. (2 marks)
How should CAP patients be counselled about symptom resolution?
Answer:
1 week: Fever resolves.
4 weeks: Chest pain and sputum reduce.
6 weeks: Cough and breathlessness improve.
3 months: Most symptoms resolve, fatigue may persist.
6 months: Full recovery expected.
SBA: What is the primary goal of antibiotic therapy?
Answer: To kill pathogenic bacteria while causing no harm to human tissue.
SBA: Which bacterial group is commonly associated with community-acquired pneumonia?
Answer: Streptococcus pneumoniae (Gram-positive).
SBA: What is the mechanism of action of penicillins?
Answer: Inhibition of bacterial cell wall synthesis.
SBA: Which antibiotic is contraindicated in children under 12 due to its effects on teeth and bone?
Answer: Tetracycline.
SBA: What is the definition of antimicrobial resistance (AMR)?
Answer: Loss of effectiveness of any anti-infective medicine.
SBA: What is the principal adverse effect of fluoroquinolones?
Answer: Tendon damage (e.g., tendinitis or tendon rupture).
SBA: Which parameter determines the efficacy of time-dependent antibiotics?
Answer: Time above the minimum inhibitory concentration (MIC).
SBA: What is the main side effect of aminoglycosides like gentamicin?
Answer: Nephrotoxicity and ototoxicity.
SBA: What is the role of beta-lactamase inhibitors like clavulanic acid?
Answer: Protect beta-lactam antibiotics from hydrolysis by beta-lactamases.
SBA: What is the primary benefit of using narrow-spectrum antibiotics over broad-spectrum antibiotics?
Answer: Reduced risk of Clostridium difficile infection and antimicrobial resistance.
EMQ: Match the antibiotic class to its mechanism of action.
Penicillins: Inhibit bacterial cell wall synthesis.
Macrolides: Inhibit protein synthesis at the 50S ribosomal subunit.
Fluoroquinolones: Inhibit bacterial DNA synthesis by targeting DNA gyrase.
EMQ: Match the bacterial infection with the likely causative pathogen.
Community-acquired pneumonia: Streptococcus pneumoniae.
Post-influenza pneumonia: Staphylococcus aureus.
Urinary tract infection: Escherichia coli.
EMQ: Match the patient scenario to the appropriate antibiotic choice.
Penicillin-allergic patient with mild CAP: Doxycycline.
Severe CAP requiring IV antibiotics: Co-amoxiclav + clarithromycin.
Skin infection caused by MRSA: Vancomycin.
EMQ: Match the mechanism of resistance to the bacterial adaptation.
Efflux pumps: Expels antibiotics from the cell.
Hydrolysis: Breaks down beta-lactam antibiotics.
Mutation of binding site: Prevents antibiotic binding.
EMQ: Select the principle of antimicrobial stewardship applied in these cases.
Avoiding broad-spectrum antibiotics in mild infections: Reduce AMR risk.
Reviewing IV antibiotics after 48 hours: Promote stepping down to oral therapy.
Counseling on completing the course: Prevent relapse and resistance.
What factors should be considered before starting antibiotic therapy?
Answer: History of allergy, renal/hepatic function, site of infection, likely pathogen, antibacterial sensitivity, patient age, comorbidities, and prior antibiotic use. (2 marks)
Explain the significance of reviewing IV antibiotics within 48 hours.
Answer: Ensures appropriateness of therapy, promotes stepping down to oral therapy, and reduces hospital-acquired infections. (2 marks)
List three common mechanisms of bacterial resistance to antibiotics.
Answer: Efflux pumps, beta-lactamase production, and target site mutations. (3 marks)
Why is it important to minimize broad-spectrum antibiotic use in community settings?
Answer: Broad-spectrum antibiotics increase the risk of resistant pathogens like MRSA and Clostridium difficile.
What advice should be given to patients prescribed antibiotics?
Answer: Complete the full course, avoid skipping doses, avoid alcohol if contraindicated (e.g., metronidazole), and report any adverse reactions immediately. (1 mark)
SBA: What is the primary function of the innate immune system?
Answer: Non-specific defense against pathogens, providing the first line of protection.
SBA: What is the key difference between innate and adaptive immunity?
Answer: Adaptive immunity involves specific antigen recognition and immunological memory.
SBA: Which component of the immune system is responsible for opsonization?
Answer: Complement system (e.g., C3).
SBA: What is the role of cytotoxic T cells in viral infections?
Answer: Induce apoptosis in virus-infected host cells.
SBA: Which immune cells produce antibodies?
Answer: B cells (Plasma cells).
SBA: What does the complement cascade form to induce microbial cell lysis?
Answer: Membrane attack complex (MAC).
SBA: What is the main immune response to extracellular bacterial infections?
Answer: Activation of phagocytes and complement-mediated opsonization.
SBA: Which type of T cell helps B cells differentiate into plasma cells?
Answer: Helper T cells (Th2 subtype).
SBA: How do NK cells recognize and target infected host cells?
Answer: Detect the absence of MHC-I molecules on the cell surface.
SBA: What cytokine is secreted by macrophages to induce antiviral states in neighboring cells?
Answer: Interferon (e.g., IFN-α/β).
MQ: Match the immune system component to its function.
Complement: Opsonization and lysis of pathogens.
Cytotoxic T cells: Induce apoptosis in infected cells.
Antibodies: Neutralization of extracellular pathogens.
EMQ: Match the pathogen type to the predominant immune response.
Extracellular bacteria: Phagocytosis and antibody response.
Viruses: T-cell-mediated immunity.
EMQ: Select the immune cells involved in each infection phase.
Early bacterial infection: Neutrophils.
Viral-infected host cells: Cytotoxic T cells and NK cells.
EMQ: Identify the stage of immune response from the description.
First exposure to an antigen: Primary response.
Faster and more robust response: Secondary response (memory cells).
EMQ: Match the complement function to the mechanism.
Opsonization: Binding of C3 to microbes.
Inflammation: C3a and C5a attract leukocytes.
Lysis: MAC formation by C5-C9.
What are the primary innate defenses against bacteria?
Answer: Complement activation, phagocytosis by macrophages and neutrophils, and inflammation. (2 marks)
Describe the adaptive immune response to extracellular bacteria.
Answer: Antigen-presenting cells activate helper T cells, which stimulate B cells to produce antibodies. Opsonization enhances phagocytosis.
How does the immune system respond to viruses during the extracellular phase?
nswer: Antibodies neutralize viral particles and promote phagocytosis. (2 marks)
What role do cytotoxic T cells play in intracellular viral infections?
Answer: Recognize viral antigens presented on MHC-I molecules and induce apoptosis in infected cells.
Explain the role of interferons in antiviral defense.
Answer: Induce antiviral states in neighboring cells, inhibiting viral replication. (2 marks)
SBA: What are the three necessary factors for an infection to occur?
Answer: Source, susceptible person, and transmission route.
SBA: What is the most effective method for preventing the spread of infection in healthcare?
Answer: Handwashing with soap and water.
SBA: Why is handwashing with soap preferred over alcohol gel for C. difficile?
Answer: Alcohol gel does not kill C. difficile spores.
SBA: What is the primary goal of personal protective equipment (PPE)?
Answer: To protect both healthcare workers and patients from cross-infection.
SBA: Which microorganism commonly causes healthcare-associated infections (HCAIs) via contact transmission?
Answer: Methicillin-resistant Staphylococcus aureus (MRSA).
SBA: What type of transmission is most associated with tuberculosis?
Answer: Airborne transmission.
SBA: What is the main objective of antibiotic prophylaxis in surgery?
Answer: To prevent surgical site infections.
SBA: Which patients are at the highest risk of Clostridium difficile infections?
Answer: Patients who have recently taken broad-spectrum antibiotics.
SBA: What does the term “bare below the elbow” refer to in infection control?
Answer: A policy to improve hand hygiene and reduce cross-infection.
SBA: What is the purpose of MRSA decolonization therapy?
Answer: To reduce colonization and prevent active infections and transmission.
EMQ: Match the transmission route to the infection example.
Contact transmission: C. difficile.
Droplet transmission: COVID-19.
Airborne transmission: Tuberculosis.
EMQ: Match the infection prevention measure to the purpose.
Handwashing: Remove microorganisms from hands.
Isolation: Prevent spread of infectious diseases.
PPE: Protect healthcare workers and patients.
EMQ: Match the HCAI pathogen to the clinical context.
MRSA: Contact transmission via healthcare worker hands.
C. difficile: Disruption of gut flora from broad-spectrum antibiotics.
Carbapenemase-producing organisms: Hospital admission abroad.
EMQ: Match the infection control procedure to its function.
Cleaning and decontamination: Reduce surface microorganisms.
Screening: Identify colonized patients before procedures.
Decolonization: Reduce MRSA colonization.
EMQ: Match the vaccination program to its primary goal.
Pneumococcal vaccine: Prevent invasive infections like sepsis and meningitis.
Influenza vaccine: Protect against seasonal flu strains.
MMR vaccine: Provide lifetime immunity against measles, mumps, and rubella.
Define healthcare-associated infections (HCAIs) and give examples.
Answer: Infections acquired during healthcare delivery (e.g., MRSA, C. difficile). (2 marks)
Describe the three components required for infection to occur.
Source: Place where microorganisms reside (e.g., surfaces, human skin).
Susceptible person: Individual with weakened immunity or entry points (e.g., IV lines).
Transmission route: Contact, droplet, airborne, or via medical equipment. (3 marks)
What are the key elements of standard precautions?
Answer:
Hand hygiene.
PPE use.
Respiratory hygiene/cough etiquette.
Cleaning and disinfecting surfaces. (2 marks)
How is Clostridium difficile prevented and managed in hospitals?
Answer:
Use soap and water for handwashing.
Avoid unnecessary antibiotics.
Isolate infected patients. (2 marks)
What is the role of vaccinations in infection prevention?
Answer: Prevent infections by inducing immunity (e.g., pneumococcal vaccine for sepsis, meningitis).
SBA: What is antimicrobial resistance (AMR)?
Answer: The ability of microorganisms to survive exposure to antimicrobial agents intended to kill or inhibit them.
SBA: What is the main goal of antimicrobial stewardship (AMS)?
Answer: To promote judicious use of antimicrobials to preserve their future effectiveness.
