B Case 2 tutorial - Health & Illness Behaviour 2
Links: tutorial Date of tutorial: 2025/03/28
Prep for this tutorial/IDL from last tutorial:
find the underlying physiological basis of vomiting in the following presentations:
- A patient who is receiving morphine
activation of the mu opioid receptors in the CTZ by morphine leads to activation of the emesis reflex
- A patient who is in cardiogenic shock
stimulation by STEMI of vagal afferent nerve causes activation of the emetic lack of flow to tissues and organs especially gut vagus nerve stimulation decrease gastric secretions and motility causing emetic reflex
- A patient receiving cytotoxic chemotherapeutic drugs
drugs stimulate the CTZ to trigger vomiting
- A person who has just witnessed a horrifying event
higher conscious centres effect the emetic centre causing vomiting Vasovagal attack?
- A woman in the first trimester of pregnancy
unknown pathophysiology potentially multifactorial hormonal etc
- Find out what an anti-emetic is.
a drug which inhibits the receptors in neurons associated with the emetic reflex and therefore inhibits the emetic reflex
- Give two examples of anti-emetic drugs and for both, briefly outline their mechanism of action.
Cyclizine inhibits histamine H1 receptors as well as acetylcholine receptors which specifically can block the autonomic system and by extension the activation of the emetic reflex and is theorised to also act on the CTZ. Metoclopramide inhibiting the dopamine d2 and serotonin 5ht3 receptors in the CTZ inhibiting emetic reflex
vomiting
Principal Causes of Nausea and Vomiting From Feldman M, Friedman LS, Brandt LJ: Sleisenger and Fortran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.
Abdominal Causes
Mechanical obstruction Gastric outlet obstruction Small bowel obstruction Motility disorders Chronic intestinal pseudo-obstruction Functional dyspepsia Gastroparesis
Other intraabdominal causes
Acute appendicitis Acute cholecystitis Acute hepatitis Acute mesenteric ischemia Crohn disease Gastric and duodenal ulcer disease Pancreatitis and pancreatic neoplasms Peritonitis and peritoneal carcinomatosis Retroperitoneal and mesenteric pathology
Drugs (Partial List) Aspirin and other NSAIDs Antidiabetic agents Antigout drugs Antimicrobial agents Acyclovir Antituberculosis drugs Erythromycin Sulfonamides Tetracycline Cancer chemotherapy Cisplatin Cytarabine Dacarbazine Etoposide 5-Fluorouracil Methotrexate Nitrogen mustard Tamoxifen Vinblastine
Cardiovascular drugs Antiarrhythmics Antihypertensives Beta blockers Calcium channel blockers Digoxin Diuretics
Central nervous system drugs Antiparkinsonian drugs (levodopa and other dopamine agonists) Anticonvulsants
• GI medications Azathioprine Sulfasalazine Narcotics OraL contraceptives Theophylline
Infectious Causes Acute gastroenteritis Viral Bacterial
Nongastrointestinal (systemic) infections
Metabolic and Endocrine Causes
Acute intermittent porphyria Addison disease Diabetic ketoacidosis Diabetes mellitus Hyperparathyroidism and other causes of hypercalcemia Hyperthyroidism Hyponatremia Hypoparathyroidism Pregnancy
Nervous System Causes Demyelinating disorders Disorders of the autonomic nervous system Hydrocephalus Congenital malformations Increased intracranial pressure Low-pressure hydrocephalus Intracerebral lesions with edema Abscess Hemorrhage Infarction Neoplasm Labyrinthine disorders Labyrinthitis Ménière disease Motion sickness Meningitis Migraine headaches Otitis media Seizure disorders Visceral neuropathy
Other Causes Anxiety and depression Cannabinoid hyperemesis syndrome Cardiac disease Heart failure Myocardial infarction, ischemia Radiofrequency ablation for arrhythmias Collagen vascular disorders Scleroderma Systemic lupus erythematosus Cyclic vomiting syndrome Eating disorders Ethanol abuse Functional disorders Hypervitaminosis A Intense pain Paraneoplastic syndrome Postoperative state Postvagotomy Radiation therapy Starvation
Content:
task 3
5 Rs of Motivational interviewing ethics of patient choice
task 4
Understand the patients background and how it may relate to their current position and situation
Task 5
freds morphine caused vomiting and nausea
freds antibiotics caused diarrhoea and some nausea
he needs the antibiotics for his osteomyelitis
and then he has pancreatitis he may change his life style because he has more concrete evidence and consequences
Summary of Case 2 Health and Illness Behaviour
- There may be many possible reasons for a patient’s presenting signs and symptoms.
- Until you have had more experience in discerning such causes, you should have a structure or template that will help you consider all possibilities [see A VINDICATED PI as an example of a pathophysiological sieve].
- Not considering all possibilities may mean you miss something when making a diagnosis.
- Consideration also should be given to the fact that what is common occurs commonly.
- It is important you have a structured approach to obtaining a full history from a patient who presents with undifferentiated signs and symptoms [see Calgary–Cambridge approach to consultation].
- There will always be elements of uncertainty in medical practice and you should recognise these and develop strategies to deal with uncertainty.
- You and your patient are two different people. Finding out what are the best options for any individual patient involves first your recognition of your own attitudes, beliefs and opinions, and secondly that of your patient’s - then acting in a professional manner to try to achieve the best possible outcome for that individual with the knowledge and resources available to you.