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Ch. 18 - Nervous System Infections
Norman-McKay- Microbiology: Basic and Clinical Principles 2nd Edition
Norman-McKay2nd EditionMicrobiology: Basic and Clinical PrinciplesISBN: 9780137661619Not the one you use?Change textbook
All textbooksNorman-McKay 2nd EditionCh. 18 - Nervous System InfectionsProblem 1
Chapter 18, Problem 1

A patient is admitted who is complaining of headache, disorientation, and numbness in his left arm. He was bitten by a raccoon two days before. The FIRST step taken to help this patient would be
a. retrieving and testing the raccoon’s brain tissues for the rabies virus.
b. collecting a CSF sample from the patient.
c. performing a tissue biopsy on the patient to look for Negri bodies.
d. administering an anti-rabies vaccine as well as anti-rabies antibodies.

Verified step by step guidance
1
Step 1: Recognize the clinical context and urgency. The patient has symptoms (headache, disorientation, numbness) and a history of a raccoon bite, which raises suspicion for rabies infection, a rapidly progressing and fatal disease if untreated.
Step 2: Understand the incubation period and timing. Since the bite occurred two days ago, the virus may still be in the incubation phase, and immediate intervention is critical to prevent disease progression.
Step 3: Evaluate the options for initial management. Testing the raccoon's brain tissue (option a) or collecting CSF (option b) or performing a biopsy (option c) are diagnostic steps but take time and do not provide immediate protection to the patient.
Step 4: Recall that rabies post-exposure prophylaxis (PEP) involves prompt administration of the rabies vaccine and rabies immunoglobulin (antibodies) to neutralize the virus before it reaches the central nervous system.
Step 5: Conclude that the first step should be to administer the anti-rabies vaccine and antibodies (option d) immediately to maximize the chance of preventing the disease, while diagnostic steps can be pursued concurrently or afterward.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Rabies Virus Transmission and Incubation

Rabies is a viral infection transmitted through the saliva of infected animals, commonly via bites. The incubation period varies but symptoms like headache and neurological signs appear after the virus reaches the central nervous system. Early intervention after exposure is critical to prevent disease progression.
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Post-Exposure Prophylaxis (PEP) for Rabies

PEP involves immediate administration of the rabies vaccine and rabies immunoglobulin to neutralize the virus before symptoms develop. This treatment is the first and most effective step after a potential rabies exposure, as once symptoms appear, rabies is almost always fatal.
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Diagnostic Methods for Rabies

Definitive rabies diagnosis can involve testing animal brain tissue for the virus, detecting Negri bodies in patient tissue, or analyzing cerebrospinal fluid. However, these tests are not immediate treatments and are typically used for confirmation rather than initial management.
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Related Practice
Textbook Question

A patient’s lab data report has come back with a positive ELISA for pneumococcal C polysaccharide from CSF samples. The MOST appropriate next step for a health professional to recommend is to

a. culture from the CSF sample to test for antibiotic resistance.

b. administer tetracycline.

c. administer cephalosporin.

d. wait for RT-PCR confirmation before antibiotic treatment.

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Textbook Question

A patient under one year old is vomiting, drowsy, floppy (flaccid), and unresponsive. Both infant botulism and infant meningitis caused by other bacteria are suspected. Which piece of information would best help narrow down the possible diagnosis?

a. The child has spent almost no time outside the home.

b. The child is being breast-fed.

c. The child was born one month ago.

d. The child has a very high fever.

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Textbook Question

Viral meningitis is more common than other forms of meningitis because

a. these infectious agents are all intracellular, evading the immune system.

b. there are more types of viruses than bacteria because they evolve more quickly.

c. the small size of viruses makes them able to pass more easily through the blood–brain barrier.

d. viruses are spread person to person more easily than bacteria, fungi, or protozoans.

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