Infectious diseases

Question 1

Symptoms of bacterial menigitis

Answer 1

• fever
• headache
• photophobia
• nausea and vomiting
• drowsiness

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Question 2

Signs of bacterial meningitis

Answer 2

• neck stiffness
• non-blanching purpuric rash
• Kernig’s sign

Question 3

What is Kernig’s sign?

Answer 3

• knee flexed to 90 degrees
• further extension of the knee is painful: indicates subarachnoid haemorrghage or meningitis

Question 4

Bacterial vs viral meningitis

Answer 4

Bacterial: acute onset (hours)

Viral: more gradual onset

Question 5

Investigations for meningitis

Answer 5

1. Lumbar puncture: CSF microscopy, culture and sensitivity (MC & S) - CT head if raised ICP suspected
2. Blood cultures: septiciaemia

Question 6

Drugs used to treat meningitis

Answer 6

Community: benzylpenicillin

Hospital: cefuroxime, cefotaxime or ceftriaxone

Question 7

2 main organisms causing gastroenteritis

Answer 7

1. Salmonella
2. Camylobacter

Question 8

Clues for salmonella infection

Answer 8

• 8 hours
• diarrhoea and vomiting together
• uncooked eggs/chicken etc

Question 9

Clues for campylobacter infection

Answer 9

• 7 days!
• blood in stool
• crampy abdominal pain: severe. women describe it as being like labour

Question 10

Questions to ask when patient presents with fever

Answer 10

Fever itself

• how long
• pattern eg constant vs on and off (malaria)
• rigors (shivers)

associated symptoms

• headache (due to high temp causing vasodilation)
• mylagia
• rash (eg rubella)
• sore throat/cough/dyspnoea
• urinary symptoms
• GI symptoms

Other clues

• travel- last 2 years (eg malaria usually has incubation period of a week but can go up to a year)
• pets
• hobbies
• dietary
• others eg conferences (eg syphyllis)

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Question 11

Organisms causing malaria

Answer 11

Plasmodium Falciparum

Plasmodium ovale

Plasmodium vivax

Plasmodium malariae

Question 12

Diagnosis of malaria

Answer 12

Thick blood film

Subtyping of organism: thin blood film

Question 13

What causes viral haemorrghagic fever

Answer 13

Ebola

Lassa

Marburg

Importance of travel history+isolation

Question 14

Key facts about dengue

Answer 14

Tropics: SEA, Africa, India, Central and South America

Incubation period: 1-2 days

Symptoms: severe headache, fever, rash

Can be haemorrghagic

Question 15

What type of rash can occur in dengue fever?

Answer 15

Scarlitiniform

Maculopapular

Haemorrghagic

Question 16

Occupations that increase risk of infectious diseases

Answer 16

Question 17

Key questions about PMH to ask in infectious diseases

Answer 17

Similar episodes: eg recurrent fevers could be familial mediterranean syndrome

Immune status

Question 18

What things would you suspect if someone had fever and relative bradycardia?

Answer 18

Typhoid, brucellosis

Question 19

Things to look for on examination for infectious diseases

Answer 19

• pulse, temperature, BP, respiratory rate (pneumonia)
• Lymph nodes
• Skin: rashes
• ENT: eg otitis media causing the fever

Systems

CVS: murmurs (endocarditis)

Resp: Added sounds (pneumonia)

GIT: liver, spleen (eg enlarged), tenderness, PR

GU exam

CNS: neck stiffness

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Question 20

Tests to do for fever

Answer 20

Urine: dipstick, MSU

Bloods: FBC, blood film, blood culture- specific request for malaria, U&E, LFT, TSH (thryotoxicosis can cause a fever)

CXR (to look for pneumonia, hilar lymphadenopathy eg in TB)

Throat and other swabs

Stool specimen

LP- if suspicious of meningitis

Specific serological tests- eg HIV antibodies

Ultrasound- eg if you suspect liver abscess

CT and other imaging (esp in elderly, with no localising symptoms or signs)

Question 21

What is FUO/PUO?

Answer 21

Pyrexia of unknown origin

Definition: illness more than 3 weeks. Above 38.3 C fever on several occasions. Patient goes more than 1 week without diagnosis as an in-patient