Hematology · Coagulation Disorders
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Acute syndrome triggered by severe infection (classically meningococcemia) or homozygous Protein C deficiency in neonates.
Hallmark lesion is retiform purpura: branching, star-shaped hemorrhagic plaques rapidly evolving to necrotic eschars with hemodynamic collapse.
This is a clinical diagnosis requiring empiric treatment before labs return; confirmed by DIC labs (low platelets, prolonged PT/aPTT, low fibrinogen, elevated D-dimer).
Mechanism is massive coagulation activation with depletion of Protein C and Protein S, causing dermal microvascular thrombosis and DIC.
Give broad-spectrum IV antibiotics immediately (e.g., ceftriaxone plus vancomycin) for suspected sepsis along with aggressive fluids and vasopressors.
For neonatal or severe acquired forms, emergent Protein C concentrate or fresh frozen plasma (FFP) halts coagulation cascade activation.
Survivors frequently require amputation of necrotic digits or limbs; biopsy shows fibrin thrombi in dermal capillaries without perivascular inflammation.
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A 4-year-old child presents with fever, hypotension, and rapidly spreading dark purple, branching, star-shaped skin lesions over the extremities that are evolving into black eschars. Laboratory studies show thrombocytopenia, prolonged PT and aPTT, low fibrinogen, and elevated D-dimer. Blood cultures are pending. The child appears toxic and is in shock.
Which of the following is the most appropriate next step in management?
Immediate broad-spectrum IV antibiotics (e.g., ceftriaxone) with fluid resuscitation.
Retiform purpura with necrotic eschars, septic shock, and a DIC coagulation profile is purpura fulminans, most often from meningococcemia. This is a clinical diagnosis requiring immediate empiric broad-spectrum antibiotics and resuscitation before culture results return.
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Etiology / Epidemiology
Acute, life-threatening syndrome often triggered by severe infections (e.g., meningococcemia) or homozygous Protein C deficiency in neonates.
Clinical Manifestations
Rapidly progressive retiform purpura and sharply demarcated erythematous lesions evolving to necrotic eschars, accompanied by hemodynamic collapse.
Diagnosis
Clinical diagnosis supported by severe DIC labs (prolonged PT/aPTT, low fibrinogen, elevated D-dimer) and biopsy showing dermal microvascular thrombosis.
Treatment
Immediate resuscitation, broad-spectrum IV antibiotics (e.g., ceftriaxone), and Protein C concentrate or FFP for factor replacement.
Prognosis
Extremely high mortality from septic shock; survivors frequently require amputation of necrotic digits or limbs.
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Epidemiology & Etiology
Three main forms exist: neonatal (homozygous Protein C deficiency or Protein S deficiency), acute infectious (classic meningococcemia, Streptococcus pneumoniae, or post-varicella), and idiopathic. The neonatal form typically presents within the first few days of life. The acute infectious form is a rapidly fatal complication of severe bacterial sepsis seen primarily in pediatric and asplenic populations.
Pertinent Anatomy
The primary site of injury is the dermal microvasculature (capillaries and venules). Thrombosis in these superficial vessels leads to full-thickness epidermal and dermal necrosis, clinically appearing as hemorrhagic, necrotic skin lesions.
Pathophysiology
An initial trigger (bacterial endotoxin or hereditary defect) causes massive activation of the coagulation cascade and profound depletion of Protein C and Protein S. This unchecked microvascular thrombosis simultaneously consumes clotting factors, resulting in severe disseminated intravascular coagulation (DIC). The resulting microthrombi physically occlude dermal vessels, causing the characteristic hemorrhagic infarction known as retiform purpura.
Clinical Manifestations
The disease starts as sharply demarcated, tender, erythematous macules that rapidly evolve into dark purple/black necrotic eschars. The classic hallmark lesion is retiform purpura, appearing as branching, star-shaped hemorrhagic plaques. Patients typically present in extremis with profound shock, high fever, and rapidly progressive multiorgan failure.
Diagnosis
This is a clinical diagnosis requiring immediate empiric intervention before laboratory results return. Laboratory evaluation confirms DIC with decreased platelets, prolonged PT/aPTT, decreased fibrinogen, and elevated D-dimer. Blood cultures are the gold standard for identifying an underlying infectious etiology. If performed, a skin biopsy shows pathognomonic fibrin thrombi in dermal capillaries with a notable absence of perivascular inflammation.
Treatment
Purpura fulminans is a medical emergency requiring aggressive IV fluids and vasopressors to manage profound shock. Providers must administer broad-spectrum IV antibiotics (e.g., ceftriaxone plus vancomycin) immediately for suspected sepsis. For neonatal forms or severe acquired cases, emergent administration of Protein C concentrate or fresh frozen plasma (FFP) is required to halt coagulation cascade activation. Once the patient is stabilized, surgical debridement or amputation is frequently necessary for demarcated necrotic tissue.
Prognosis
The condition carries a very high mortality rate, most often due to refractory septic shock, multiorgan failure, or intracranial hemorrhage. Survivors face severe, life-altering morbidity, frequently requiring skin grafting or extensive limb amputation due to irreversible gangrene.
Differential Diagnosis
1. Warfarin-induced skin necrosis: Occurs days after starting warfarin in patients with underlying Protein C deficiency, lacking the profound sepsis of purpura fulminans.
2. Thrombotic thrombocytopenic purpura (TTP): Presents with a classic pentad including neurologic and renal symptoms, but lacks the severe DIC coagulation profile.
3. Henoch-Schönlein Purpura (IgA Vasculitis): Features palpable purpura typically on buttocks/legs with abdominal pain and arthritis, but patients do not present in profound shock.
4. Calciphylaxis: Seen in ESRD patients, causing painful necrotic skin lesions but lacks acute infectious signs and systemic DIC.