Documentation:PATH417archive:2020W2/Case 2
| Path 417 Cases | |
|---|---|
| |
| Instructors | |
| Nimah Kelly | |
| Case Projects | |
Case 2
A Stiff Neck
18-year-old Mary has just moved into the dormitory at her university. One day, her roommate finds her lying in bed under her sheets. She is complaining of fever, chills, bad headache and a stiff neck. She is staying under the covers because the light is hurting her eyes. Her roommate calls 911 and an ambulance takes Mary to the local hospital.
The emergency room physician asks Mary about her recent vaccinations and she reports that she has not had any since she was in elementary school. The physician documents a fever of 39.2°C and low blood pressure. He sends blood and cerebral spinal fluid to the Microbiology Laboratory. She is started immediately on intravenous antibiotics. Mary’s blood and cerebral spinal fluid grow Neisseria meningitidis and she is diagnosed with meningococcal meningitis.
1. The Body System
(i) Describe the signs (objective characteristics usually detected by a healthcare professional) and symptoms (subjective characteristics experienced by the patient). Also make note of any key history findings, what samples are taken (and why) and the meaning of any laboratory results reported. (There is no need to describe the laboratory testing as this is the basis of another question).
(ii) Which body system is affected? In what way has the normal physiological functioning of this area of the body been disturbed by the infection (without going into detail on the cause of this disturbance as this will be dealt with in questions 3 and/or 4). Representing this diagrammatically is always helpful.
(iii) What antibiotics might have been in the intravenous drip i.e. what is the antibacterial treatment of choice and how do the(se) antibiotic(s) work to rid the body of the organism?
(iv) Why did the doctor ask about Mary’s vaccination history? Is this a reportable communicable disease?
2. The Microbiology Laboratory
(i) Other than the stated bacterial cause, what are the most common bacterial pathogens associated with this type of infectious scenario.
(ii) What samples are taken for laboratory testing and how important is the Microbiology Laboratory in the diagnosis of this particular infectious disease?
(iii) Explain the tests that will be performed on the samples in order to detect any of the potential bacterial pathogens causing this disease.
(iv) What are the results expected from these tests allowing for the identification of the bacteria named in this case.
3. Bacterial Pathogenesis
Using the following pathogenic steps outline the pathogenesis of the bacteria named as being responsible for this infection.
i. Encounter: where does the organism normally reside, geographically and host wise, and what are the bacterial characteristics that leave it suited to these places of residence. How would our patient have come in contact with this bacteria
ii. Entry: what facilitates the entry of the bacteria into the human host? What are the molecular, cellular and/or physiological factors at play in the initial entry/adherence step from the point of view of the organism and the host.
iii. Multiplication and Spread: does the organism remain extracellular or do they enter into cells and what are the molecular and cellular determinants of these events. Do the bacteria remain at the entry site or do they spread beyond the initial site i.e. are there secondary sites of infection and why do the bacteria hone in on these particular secondary sites.
iv. Bacterial Damage: do the bacteria cause any direct damage to the host (or is the damage fully attributable to the host response, as indicated below) and, if so, what is the nature of the bacterial damage. Can it be linked to any of the signs and symptoms in this case?
4. The Immune Response
i. Host response: what elements of the innate and adaptive (humoral and cellular) immune response are involved in this infection.
ii. Host damage: what damage ensues to the host from the immune response?
iii. Bacterial evasion: how does the bacteria attempt to evade these host response elements.
iv. Outcome: is the bacteria completely removed, does the patient recover fully and is there immunity to future infections from this particular bacteria ?