Case 16 questions 16-29

Question 16

Which of these definitions correctly describes ‘pathogenicity’ of a virus?

1. Characteristics that disease causing viruses possess that allow them to be pathogenic
2. The severity of disease caused by different strains of the same virus
3. The severity of the disease caused by different viruses
4. The initial replication of a virus
5. The immune evasion of a virus

The correct answer is option c,The severity of disease caused by different strains of the same virus

The first option is the definition of pathogenicity factors

The second option is the definition of virulence

Options 4 and 5 are examples of pathogenicity factors

Question 17

Which of these viruses is transmitted via zoonotic transmisison?

1. Hepatitis A
2. Herpes simplex virus
3. Varicella Zoster
4. Dengue fever
5. Norovirus

The correct answer is option d, Dengue virus

Dengue vrus is transmitted to humans via the aedes mosquito

The other options are passed via horizontal transmission

Question 18

Which part of the body does norovirus primarily affect?

1. Respiratory epithelium
2. The liver
3. GI epithelium
4. The central nervous system
5. The skin<

The correct answer is option c, GI epithelium

Norovirus is also known as the winter vomiting disease. It is a localised infection affecting the GI epithelium. It is transmitted via contact with infected individuals, surface contact doors, handles, tables, contaminated food/water, aerosol produced from vomit.

Question 19

Which of these viruses produces a generalised infection?

1. Varicella Zoster Virus
2. Influenza
3. Rhinovirus
4. Norovirus
5. Human papillomavirus

The correct answer is option c, Varicella Zoster Virus

Generalised infections cause infections that spread to target organs or tissues remote from the site of entry (include polio, chickenpox, measles, hepatitis, rabies). Chickenpox is transmitted via the respiratory route but cause manifestations in the skin

The other answers are localised infections which cause infections at tissues at or contiguous with the site of entry, typically epithelia and skin. Influenza and rhinovirus are transmitted via the respiratory route and affect the respiratory epithelium. Norovirus is transmitted via the fecal oral route and affects the GI tract

Question 20

A 79-year-old man has been referred to the ENT clinic on the suspected cancer referral pathway.

He presented with a six-week history of unilateral otalgia, with the pain being worse on swallowing. He has also lost 1 stone in weight over a similar period. On examination, otoscopy is unremarkable, but you note lymphadenopathy in the cervical chain.

The GP is concerned he may have an underlying pharyngeal malignancy.

Which cranial nerve is responsible for the presentation of otalgia in pharyngeal malignancy?

1. Hypoglossal nerve
2. Vestibulocochlear nerve
3. Vagus nerve
4. Glossopharyngeal nerve
5. Accessory nerve

The correct answer is option d, Glossopharyngeal nerve (CN 9)

The glossopharyngeal nerve has both sensory and motor functions. The tympanic nerve (a branch of cranial nerve IX) directly innervates the ear but also has pharyngeal, lingual, and tonsillar branches to supply the posterior one-third portion of the tongue, tonsillar fossa/pillars, pharynx, eustachian tube, parapharyngeal and retropharyngeal spaces. Any pathologic process involving these areas can result in referred otalgia. Oropharyngeal, nasopharyngeal, tonsilar and tongue-base cancers can all present with otalgia. These cancers are all most commonly squamous cell carcinomas and the risk is increased by smoking and excessive alcohol.

The vestibulocochlear nerve is purely sensory but only has a role in hearing and balance.

The accessory nerve and the hypoglossal nerve are purely motor so would not be responsible for pain sensation.

Question 21

You are a GP registrar working in a deprived area. You see James, a 14-month-old child who attends with his mother. For the last three weeks he has been unsettled, and for the last two weeks, he has had a discharging left ear.

You note from his records that he saw your colleague two weeks ago, who diagnosed otitis media with perforation, took swabs for culture and started a course of amoxicillin orally.

Here are the swab results:

• Candida culture: not isolated
• Sample culture: Heavy growth of Pseudomonas species. Sensitivities not yet determined.

Which is the most appropriate action?

1. Start a course of topical ciprofloxacin
2. Start oral clotrimazole
3. Start a course of topical neomycin/dexamethasone
4. Stop treatment
5. Continue amoxicillin while awaiting sensitivities

The correct answer is option a, Start a course of topical ciprofloxacin

P. aeruginosa is a multidrug-resistant intracellular pathogen. In terms of readily available topical options as in this case, you are limited to ciprofloxacin and gentamicin

Co-amoxiclav and neomycin are unlikely to be effective against Pseudomonas.

Clotrimazole is an antifungal, so wouldn’t be appropriate.

Stopping treatment is not appropriate as the infection will not likely self-limit.

Question 22

Which layer is just below the skull?

1. Subarachnoid space
2. Periosteal dura mater
3. Pia mater
4. Arachnoid mater
5. Meningeal dura mater

The correct answer is option b, Periosteal dura mater

The layes under the skull are: Periosteal dura matter -> Meningeal dura matter -> Arachnoid mater -> Pia mater -> Cerebral cortex

Question 23

Which of the ear ossicle is closest to the inner ear structure and is also the smallest bone in the human body?

1. Auditory canal
2. Stapes
3. Malleus
4. Incus
5. Auricle

The correct answer is option b, Stapes

Question 24

A 24-year-old male patient presents to his GP with fever, malaise and a sore throat that started two days ago. He also has a headache but denies any cough, coryza or other significant symptoms.

The patient has no significant past medical history and takes no regular medication. Vital signs reveal a fever of 38.2 degrees, but other parameters are within normal limits.

On examination, there is tender cervical lymphadenopathy and obviously enlarged and inflamed tonsils with a purlent exudate. There are no other abnormalities on systemic examination.

Given the likely diagnosis, which of the following is the most appropriate management option?

1. Paracetamol only
2. Gargles of salt water
3. Phenoxymethylpenicillin
4. Prednisolone
5. Amoxicillin

The correct answer is option b, Phenoxymethylpenicillin

The patient has presented with typical symptoms of tonsilitis including a sore throat, malaise, fever and swollen tonsils.The feverpain score should be used to establish the probibility of streptococcal tonsilitis. Click here to try it out.

We make it 5 points giving a 62-65% probibility of streptococcus isolation.

The recommended treatment is a 10-day course of phenoxymethylpenicillin.

Amoxicillin should be avoided if there is a possibility of glandular fever due to the risk of developing a widespread macular rash (which can then be interpreted as an allergy when in fact it is related to the EBV antibodies).

There is no evidence for gargling salt water, although anecdotal reports from some patients suggest this can provide some symptomatic relief. Prednisolone is only recommended in patients with infectious mononucleosis who require hospital admission and have significant swelling that may threaten their airway.

Question 25

Which of the following is a cause of sensorineural hearing loss?

1. Wax
2. Anatomical abnormalities
3. Ossicle damage
4. Meniere’s disease
5. Having a cut on the pinna

The correct answer is option d, Meniere’s disease

Classic Meniere’s Disease is an inner ear disorder characterized by episodic vertigo attacks (often with nausea and vomiting), sensorineural hearing loss, tinnitus, and pressure or fullness in the involved ear (usually unilateral)

Having a cut on the pinna is unlikley to cause any significant hearing loss

The other 3 options can cause conductive hearing loss

Question 26

Which structure links the lateral ventricles and the 3rd ventricle in the brain?

1. Cisterna magna
2. Aqueduct of Sylvius
3. Foramen of Monro
4. Central canal
5. Cerebral aqueduct

The correct answer is option c, Foramen of Monro

Question 27

An 8-year-old boy has had a 3-day history of left-sided otalgia and purulent aural discharge. In the past 24 hours, he has developed a fever of 38 degrees Celsius and has been complaining of tenderness behind his ear. On examination, his left ear looks more prominent than the right and is pushed downwards and outwards. On palpation there is tenderness behind the ear and otoscopy reveals a left-sided bulging tympanic membrane.

Which of the following is the most appropriate next management step?

1. Refer urgently to ENT
2. Refer routinely to ENT
3. Prescribe a course of oral antibiotics
4. No treatment
5. Prescribe a course of topical antibiotics

The correct answer is option a, Refer urgently to ENT

The history and examination findings fit with a diagnosis of otitis media with secondary mastoiditis.The mastoid air cells are in direct contact with the middle ear, as well as the middle and posterior cranial fossae. Mastoiditis leads to suppuration and bone necrosis, which can progress to intracerebral abscesses and meningitis. If the ear is pushed down and out, suspect that the patient may have a subperiosteal abscess.

Patients with mastoiditis need to be managed in a hospital setting and the most appropriate next management step would be to refer urgently to ENT. They will need treatment with a prolonged course of IV antibiotics. Some patients will require a myringotomy and grommet insertion to drain fluid out of the middle ear. Others may need mastoidectomy and tympanoplasty if they have complications such as an abscess or meningitis.

Question 28

A 65-year-old male presents to the GP complaining of worsening hearing over the last year. He feels otherwise well and has no significant past medical history. Gross assessment reveals reduced hearing on the left. Weber’s test lateralises to the right. Rinne’s test shows air conduction is better than bone conduction in the left ear.

Which of the following is the most likely diagnosis based on these findings?

1. Left sided sensorineural hearing loss
2. Right sided sensorineural hearing loss
3. Right sided conductive hearing loss
4. Left sided conductive hearing loss
5. Bilateral conductive hearing loss

The correct answer is option a, Left sided sensorineural hearing loss

The most likely diagnosis is left-sided sensorineural hearing loss based on the clinical examination findings. Gross hearing assessment confirmed hearing loss on the left side, Weber’s test lateralised to the unaffected side, suggesting that bone conduction was reduced on the left side. Rinne’s test showed air conduction was better than bone conduction (suggesting that both air and bone conduction have been reduced). These findings are all in keeping with a diagnosis of left-sided sensorineural hearing loss.

Weber’s test interpretation

• Normal – sound is heard equally in both ears
• Sensorineural deafness – sound is heard louder on the side of the intact ear
• Conductive deafness – sound is heard louder on the side of the affected ear

Rinne’s test interpretation

• Normal – Air conduction > Bone conduction (Rinne’s positive)
• Sensorineural deafness – Air conduction > Bone conduction (both air and bone conduction reduced equally)
• Conductive deafness – Bone conduction > Air conduction (Rinne’s negative)

Question 29

A 2-year-old child is brought to the GP by his father who feels the child is generally more irritable and has been pulling at their right ear. The child is still eating and drinking. The father reports that the child was unwell with a runny nose and cough a week ago.

On assessment, the child is irritable but interactive, with normal vital signs and no evidence of a rash. The child’s chest is clear and examination of the throat and external ear is unremarkable. Otoscopy is performed, which shows a normal ear canal, but an absence of the cone of light on the right side.

1. Perforated tympanic membrane
2. Otitis externa
3. Otitis media
4. Cholesteatoma
5. Normal tympanic membrane

The correct answer is option c, Otitis media

The most likely diagnosis is otitis media, given the history of a recent viral upper respiratory tract infection, irritability, some localisation (pulling at ear), and the loss of the cone of light (implying increased middle ear pressure). The usual course of acute otitis media is about 3 days, but can be up to 1 week, with it typically resolving spontaneously. In this case, underlying aetiology is likely to be viral, and therefore an antibiotic prescription would not be appropriate at this time, given the child is otherwise well.