ID ~ Short Answer

Question 1.

A 24 year old woman presents to your emergency department two weeks following a backpacking holiday in South-East Asia. She now has had three days of fevers, as well as generalised weakness, anorexia and nausea.

A.) What travel-specific aspects of history are you going to ask?

Show Answer

  • Specific travel history
    • Regions/itinerary
    • Area types e.g. city vs country
    • Time spent in each place
    • Season of travel
    • Habitat/type of accommodation
    • Illness contacts/illness of fellow travellers
  • High risk activity/incidents
    • sexual activity
    • IVDU
    • High risk foods e.g. street vendors
    • Animal bites
    • Assault/trauma
  • Prophylaxis
    • Vaccinations prior to travel
    • Malarial/other prophylaxis and adherence
    • Precautions taken e.g. mosquito nets, repellent

(10 marks)

B.) What is your differential diagnosis of the exotic causes of fever in this patient?

Show Answer

  • Malaria
  • Typhoid fever
  • Meningiococcus
  • Dengue/Dengue Haemorrhagic Fever
  • Hep A, D, E
  • Rickettsial diseases
  • Leishamaniasis
  • Schistosomiasis
  • Yellow Fever
  • Japanese encephalitis

(5 marks)

C.) How do these diseases usually present and what (if any) are the classical physical and investigation findings?

Show Answer

i. Malaria

  • High fevers with rigors becoming periodic
  • Headache, myalgias, malaise and other non-specific Sx too
  • classic triad of fever, splenomegaly and thrombocytopaenia
  • splenomegaly, jaundice
  • altered mental status if cerebral malaria

ii. Dengue fever

  • Sudden high fever, headache, nausea, vomiting myalgias
  • Fine morbilliform rash starting on trunk and spreads to limbs and face
  • Can present with petechiae like meningococcal
  • If haemorrhagic fever will get signs of haemorrhage/DIC and shock
  • Leukopaenia, thrombocytopaenia, hepatic dysfunction

iii. Typhoid fever

  • High fever, headache, cough, abdominal distention, myalgia, constipation, prostration
  • Can present with diarrhoea and vomiting but usually constipation
  • Bradycardia relative to fever
  • Pale macular rash on trunk “rose spots”
  • Splenomegaly
  • Leukopaenia and hepatic derangement

(6 marks)

D.) What investigations are needed for the diagnosis of:

Show Answer

i. Malaria

  • Thick and thin film
  • Rapid antigen detection test

ii. Dengue fever

  • serology

iii. Typhoid fever

  • Cultures – blood, urine, stool, rose spots

(3marks)

E.) What is the initial IV drug recommended for treatment of severe or cerebral malaria?

Show Answer

  • Artesunate (or artemesinin derivative; needs to be followed by long-acting anti-malarial e.g. doxycycline, atovaquone-proguanil, clindamycin, mefloquine)
  • Quinidine
  • Quinine

(1 mark; any of above)

Author: J Haire

Ref: Tintinalli p.1056-62 & 1080-84


 

Question 2.

A 45 year old mildly intellectually impaired man is brought in to the emergency department by his carers. He has been complaining of abdominal pain for the last 24 hours. Last night he had a fever and was shaking and this morning he is drowsy. He has no other significant past medical history and no allergies.

His vitals are:

  • HR 148 bpm
  • BP 78/46 mmHg
  • RR 36 bpm
  • O2 sats 92% on 15L NRB
  • Temp 38.8°C
  • GCS 12 (E3, M5, V4)

On examination he cries out in pain when you palpate the right upper quadrant of his abdomen.

A.) What are the abnormalities this man is presenting with?

Show Answer

  • Shock – tachycardic and hypotensive
  • Tachypnoea and hypoxia – pulmonary compromise
  • Febrile
  • Altered level of consciousness
  • Meets SIRS criteria

(4marks)

 B.) What is the likely diagnosis and possible sources?

Show Answer

  • Sepsis
  • Source
    • ascending cholangitis
    • cholecystitis
    • pneumonia
    • subphrenic abscess

(2 marks)

 C.) Define:

Show Answer

i. Systemic Inflammatory Response Syndrome

  •    Need 2 of the 4 criteria in adults; in children one must be abnormal temp or WCC
  •    SIRS Criteria:
  1. Core temp > 38.3°c in adults, > 38.5°C in children or < 36.0°C
  2. Tachycardia (in absence of other cause) > 90 bpm adults; children > 2 SD above average or < 1 yr of age bradycardia < 10th centile for that age
  3. RR > 20 bpm or PaCO2 < 32 mmHg adults; children RR > 2 SD above normal for age or mechanical ventilation of an acute process not related to underling neuromuscular disease
  4. WCC > 12, 000 mm3 or < 4,000 mm3 or > 10% immature (band) neutrophils in adults; in children elevated or depressed level for age not due to chemotherapy

ii. Sepsis

  • SIRS secondary to infection

iii. Severe sepsis

  • Sepsis plus one of CVS organ dysfunction or ARD or dysfunction or 2 or more other organs

a.) Septic shock

  • Sepsis + acute circulatory failure characterised by persistent refractory hypotension not due to other causes

(6 marks)

 D.) What are the management priorities in this man?

Show Answer

  • Treat septic shock
  • Intubate and ventilate to treat hypoxia
  • Early antibiotics
  • Get rid of source of infection with drainage/surgery as required

(4 marks) 

E.) How would you manage this patients’ shock?

Show Answer

  • 2 large bore IVCs
  • Fluid resuscitation
    • 2 x 1L NSaline boluses
  • Inadequate response then move onto vasopressors
  • Central venous access and invasive arterial monitoring
  • Start Noradrenaline infusion
    • 05-0.3 mcg/kg/min
    • 60 mg in 100 mls NSaline run at 3-20 ml/hr
    • Aims
      • MAP > 65 mmHg
      • HR < 90 bpm
    • Continue fluid resuscitation with aims:
      • CVP 8-12 mmHg OR adequate volume resuscitation as seen on IVC ultrasound
      • UO > 0.5 ml/kg/hr

(6 marks)

 F.) What simple investigation can be used to monitor response to therapy and how?

Show Answer

  • Lactate clearance
  • 10% clearance indicates response
  • Non-inferior to ScVO2 by Jones trial

(2 marks)

 G.) You successfully intubate him. What initial ventilation parameters will you start him on assuming 80 kg body weight?

Show Answer

  • Low TV strategy to prevent ARDS
  • TV 6 ml/kg = 480 ml; RR 18; PEEP 5 mmHg; FIO2 100% initially but lower asap

(2 marks; as long as low TV ventilation strategy)

H.) What specific infection management is essential in this patient?

Show Answer

  • Early antibiotics
  • Within 1 hour
  • Broad spectrum covering gram negatives as well i.e. GIT source e.g. Ampicillin + gentamicin OR Ceftriaxone OR Ticarcillin/clavulanate OR piparcillin/tazobactam +/- metronidazole
  • Source control
    • Depends on diagnosis e.g. surgery, ERCP if needed

(3 marks)

Author: J Haire

Ref: Tintinalli 1003-14


 

Question 3.

A 45 year old female gardener presented with a 5 day history of painful left middle finger. It is her dominant hand.

 Infectious Disease Photo 6 Short Answer

A.) What are the main abnormalities seen in this picture?

Show Answer

  • Pustular lesions along middle finger
  • Necrotic distal finger
  • Swollen hand and other fingers
  • Erythematous areas spreading up arm/lymphadenitis

(3 marks)

 B.) What are the potential organisms involved?

Show Answer

  • Cellulitis – Staph aureus + Strep pyogenes
  • Gas gangrene – Clostridium
  • Other anaerobes
  • Gram negative organisms (manure, soil)
  • Fungal

(3 marks)

C.) Which antibiotics would you initiate?

Show Answer

  • Broad-spectrum to cover gram +ve, gram –ve and anaerobes
  • Flucloxacillin + Ceftriaxone or Ticarcillin/clavulanate or Piperacillin/tazobactam + metronidazole
  • Consult with ID

(2 marks; reasonable choices)

 D.) What is the definitive management and disposition plan?

Show Answer

  • Admission, antibiotics, surgical exploration, debridement and wash-out
  • By hand specialist

(2 marks)

 E.) List 3 potential complications.

Show Answer

  • Compartment syndrome
  • Finger necrosis – Loss of finger/hand/arm
  • osteomyelitis
  • Sepsis

(3 marks)

Author: J Haire

Ref: Tintinalli p. 1014-20 & Therapeutic guidelines


 

 Question 4.

An 18 year old woman, who is 26 weeks pregnant, presents with a two week history of malaise, cough and shortness of breath. She has a history of poorly controlled asthma.

Her pleural aspirate shows:

 Infectious Disease Table 1 Short Answer

A.) Is this likely to be a transudate or exudate and why?

Show Answer

  • Exudate
  • High protein

(2 marks)

 B.) What criteria can be used to determine this? What are the criteria?

Show Answer

  • Light’s criteria:
    • One or more of the following
      • Pleural fluid/serum protein ratio > 0.5
      • Pleural fluid/serum LDH ratio > 0.6
      • Pleural fluid LDH greater than 2/3 the upper limit of serum LDH

(4 marks)

C.) What is your differential diagnosis?

Show Answer

  • Cancer primary or metastatic
  • Bacterial pneumonia with parapneumonic effusion
  • PE
  • Systemic Rheumatological conditions e.g. SLE, RA
  • Uraemia
  • Pancreatitis
  • Drug-related e.g. amiodarone

(4 marks)

D.) Comment on the cell differential

Show Answer

  • Preponderance of lymphocytes and monocytes
  • Indicates not a bacterial infection
  • Maybe atypical organism e.g. fungal or other cause e.g. PE

(2 marks)

 E.) What further investigations on the pleural fluid could be done to help differentiate the cause?

Show Answer

  • Culture – bacterial, fungal and mycobacterial
  • Cytology – for malignant cells
  • Pleural fluid amylase – pancreatitis or oesophogeal rupture
  • TB pleural fluid markers – PCR, adenosine deaminase, ? interferon

(3 marks)

Author: J Haire

Ref: Tintinalli p 471-73


 

 

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