Systemic Infectious

A 65-year-old man is brought to the emergency department from a residential aged care facility with a 2-day history of dysuria and increasing lethargy. On arrival his temperature is 39.2°C, heart rate 120 beats/min, blood pressure 80/50 mmHg, respiratory rate 26 breaths/min, and SpO2 94% on room air. He is confused (GCS 13) and his skin is warm and flushed with a capillary refill of 2 seconds. An indwelling urinary catheter drains cloudy, foul-smelling urine. Point-of-care lactate is 4.0 mmol/L. Two sets of blood cultures and a venous blood gas are obtained. Which of the following represents the most appropriate initial management within the first hour?

A 52-year-old man presents to the emergency department with a 24-hour history of severe pain in his right calf out of proportion to examination findings, following a minor scratch while gardening two days earlier. He is drowsy but rousable, temperature 39.4°C, heart rate 138 bpm, blood pressure 78/42 mmHg, and respiratory rate 28/min. The calf is tensely swollen, exquisitely tender, with patchy dusky erythema and early bullae; a diffuse macular erythroderma is also noted over his trunk. Bloods show WCC 3.2 x 10^9/L, platelets 68 x 10^9/L, creatinine 210 µmol/L and lactate 4.8 mmol/L. Blood cultures are taken and Gram-positive cocci in chains are seen on urgent Gram stain, raising suspicion of invasive group A streptococcal infection with streptococcal toxic shock syndrome. Surgical review has been requested for likely necrotising fasciitis. In addition to aggressive fluid resuscitation, vasopressor support and urgent surgical debridement, which antimicrobial regimen is most appropriate?

A 5-week-old male infant, born at term and not yet due for his first vaccination, is brought to the emergency department with a 12-day history of coughing spells. His mother describes bouts of rapid, forceful coughing followed by vomiting, and reports that during the worst episodes he turns dusky around the lips and makes a high-pitched inspiratory sound afterwards. He has had no fever and is breastfeeding well between episodes. On examination he is afebrile, HR 150 bpm, RR 44/min, SpO2 99% on room air at rest but observed to desaturate to 88% during a witnessed coughing paroxysm with associated cyanosis; chest is clear between episodes and there is no increased work of breathing at baseline. A nasopharyngeal PCR swab returns positive for Bordetella pertussis. Which of the following is the most appropriate management?

A 28-year-old intensive care nurse sustains a percutaneous injury to her gloved left index finger from an 18-gauge hollow-bore needle while recapping after venepuncture on a patient with known HIV infection who is on antiretroviral therapy but has a detectable viral load (12,000 copies/mL). The needle had been in a vein and visible blood was present on the device. There was brief bleeding from the puncture site, which she expressed and washed under running water before presenting to the emergency department 15 minutes later. She is haemodynamically stable (BP 118/76 mmHg, HR 88 bpm), has no known drug allergies, is not currently pregnant, and her last HIV test 12 months ago was negative. She is anxious and asks what should be done now.

A 29-year-old emergency nurse sustains a needlestick injury from a hollow-bore cannula needle after use on a patient with a history of injecting drug use and unknown hepatitis B status. She presents to the ED occupational exposure clinic within an hour of the injury. She reports completing the hepatitis B vaccination course as a nursing student and had post-vaccination serology performed three years ago, which is documented in her employee health record as anti-HBs 150 IU/L. She is asymptomatic and systemically well; observations are normal. Examination reveals a small puncture wound to the left index finger with no active bleeding. What is the most appropriate management of this healthcare worker with respect to hepatitis B post-exposure prophylaxis?

A 58-year-old retired teacher presents to the emergency department with a slowly enlarging skin lesion on her right calf that has been present for six weeks. She lives on the Bellarine Peninsula in Victoria and recalls minor trauma to the area while gardening. She reports no pain despite the size of the lesion and denies fever, chills or systemic upset. On examination there is a 4 cm nodule that has ulcerated centrally, with a necrotic base and characteristically undermined, violaceous edges. There is no surrounding cellulitis, and regional lymph nodes are not palpable. Vital signs are normal. PCR of a swab from the ulcer edge confirms Mycobacterium ulcerans. What is the most appropriate management?