mottling of skin with bullae can be sign of necrotizing infection

The patient has evidence of severe shock with lactic acidosis, impaired consciousness, and cutaneous mottling. His chest radiograph is compatible with pneumonia as a possible cause. However, the most likely cause of shock in this case is necrotizing skin and soft-tissue infection of the right arm. The general mottling of the skin may complicate the physical examination somewhat, but the presence of vesicles or bullae in a background of purpura is extremely suggestive of necrotizing skin and soft-tissue infection. In the setting of shock and purpura with vesicles or bullae, the probability of necrotizing infection is >90%. In addition to the conventional administration of clindamycin (on the basis of a theoretical Eagle effect, whereby a ribosomal toxin decreases production of toxins used by bacteria that cause necrotizing infection) and perhaps IV immunoglobulin (on the basis of small randomized controlled trials suggesting benefit), urgent consultation with a surgeon for invasive exploration of the affected extremity is indicated (choice B is correct).

The two possible approaches are a diagnostic surgical exploration or immediate debridement. If the initial exploration confirms the suspected diagnosis of necrotizing infection, urgent debridement is indicated. Imaging modalities are insensitive for the diagnosis; CT scans, as in this case, may be of limited use. Doxycycline is a critical therapy for patients with leptospirosis and rickettsial diseases, in which doxycycline is lifesaving. Although these diseases can manifest with shock and multiorgan system failure, they are not causes of necrotizing skin and soft-tissue infection (choice A is incorrect).

Septic shock may be complicated by multiple forms of cardiac dysfunction, often termed septic cardiomyopathy, and a moderate decrease in left ventricular ejection fraction is noted in a substantial minority of patients. However, randomized controlled trials to date have not suggested that inotrope therapy changes outcomes in patients with mild to moderate decreases in cardiac contractility (choice C is incorrect). Although the patient may also have pneumonia (or, more likely, early ARDS) on the basis of the chest radiographic results, CT scanning of the thorax is not indicated even if pneumonia or ARDS were present (choice D is incorrect).

Some clinical scores have been proposed (eg, the Laboratory Risk Indicator for Necrotizing Fasciitis [LRINEC] score), but they are largely measures of overall severity of illness. Given that necrotizing infections tend to be more severe than nonnecrotizing infections, it is not surprising that higher scores are associated with necrotizing infection. Early in the disease course, scores like LRINEC may provide false reassurance. When typical cutaneous findings are present in the right clinical context, surgical exploration is likely indicated regardless of the LRINEC score.123

A 65-year-old man presents to the ED with altered mental status and hypoxemia. On initial evaluation, his Glasgow Coma Scale score is 8, SpO2 while breathing ambient air is 72%, and a plain chest radiograph depicts bibasilar opacities. His BP is 115/70 mm Hg, with a heart rate of 125/min. His core temperature is 35.8°C. Sampling of blood reveals a pH of 7.01, PaCO2 of 35 mm Hg, and PaO2 of 52 mm Hg. His arterial lactate level is 108.11 mg/dL (12 mmol/L). Given the hypoxemia and impaired consciousness, he undergoes intubation and mechanical ventilation. An ECG is normal, and point-of-care ultrasonography reveals a left ventricular ejection fraction of 40% without pericardial effusion; the right ventricle exhibits mild dilation and hypofunction. On physical examination, his abdomen is not distended; palpation of the abdomen elicits no grimace or other evidence of tenderness. He has diffuse purplish mottling of the skin. His right upper extremity is more purple than the left; both are mottled. The right upper extremity is also larger than the left; there is no obvious difference in temperature between the two extremities. Five vesicles are present on the right upper extremity; the fluid is purplish but not obviously hemorrhagic. A CT scan of the right upper extremity reveals edema consistent with cellulitis without evidence of gas or fasciitis. IV vancomycin and piperacillin/tazobactam are administered, and a request for ICU admission is made.

What is the most appropriate next step in management?

Footnotes

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  2. Goh T, Goh LG, Ang CH, et al. Early diagnosis of necrotizing fasciitis. Br J Surg. 2014;101(1):e119-e125. PubMed ↩

  3. Wong CH, Khin LW, Heng KS, et al. The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Crit Care Med. 2004;32(7):1535-1541. PubMed ↩