590116
research-article2015
CPJXXX10.1177/0009922815590116Clinical PediatricsWampole et al
Brief Report
A Case of Postinfectious Protein S Deficiency Masquerading as Henoch– Schönlein Purpura
Clinical Pediatrics 1–4 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0009922815590116 cpj.sagepub.com
Anthony J. Wampole, MD1, Halie M. Anderson, MD1, and Ellen R. Wald, MD1
Case Report (Presentation) The patient is a previously healthy 4-year-old male who is admitted for a purpuric rash. Ten days before admission he experienced mild, transient cold symptoms. Four days before admission he developed hives on his lower abdomen and mild swelling of his feet; symptoms improved with diphenhydramine. Two days later the primary care provider (PCP) was informed of slight periorbital puffiness and ongoing swelling (with a slight “bluish-hue”) on the dorsum of his feet bilaterally. He was otherwise well, without fever or discomfort, except for mild itching between doses of diphenhydramine. Family was instructed to seek medical care if he developed joint pain or swelling, difficulty with mobility, blue-purple rash, or fever. Twelve hours later, a dark purple rash evolved over his legs. He was taken to a local emergency department (ED) where he was afebrile with normal vital signs. He was documented to have purpuric lesions on his lower extremities and scattered hives on his torso. Laboratory studies were remarkable for a low normal platelet count and prothrombin time (PT)/international normalized ratio (INR) = 1.4 (see Table 1 for timeline of presentation, including vital signs, pertinent labs, and physical exam findings). He was discharged home with a presumptive diagnosis of Henoch–Schönlein purpura (HSP). His PCP saw him the following day; his vital signs were normal and he was noted to have swelling and redness of his penis, as well as “deep bruising” of the posterior thighs and buttock. Urinalysis did not show hematuria. The PCP agreed with the diagnosis of HSP; the patient was sent home with anticipatory guidance. That night, he developed worsening bruising and swelling and progressive penile pain that inhibited his ability to void. The escalation of pain prompted a second visit to his local ED. He remained afebrile without vital sign changes. His exam was notable for progressive ecchymoses of the lower extremities and buttocks. His penile shaft was described as “moderately to severely edematous and ecchymotic.” No laboratory studies were obtained. He was started on oral prednisone and discharged. Unremitting pain and
inability to urinate brought him back to the ED. His exam was notable for tachycardia; he had scattered petechiae on chest and arms and diffuse “nonpalpable” purpura on legs, buttocks, perineum, and penis with surrounding edema. His scrotum was purpuric and grossly edematous, with overlying bullae. Urine was grossly bloody. Repeat laboratory studies were notable for leukocytosis, anemia, and thrombocytopenia. Complete metabolic panel, including electrolytes, kidney function, and transaminases, was notable for a mildly low CO2 (21 mEq/L) and albumin (2.8 g/L). Coagulation studies were grossly abnormal with PT/ INR = 8.0, partial thromboplastin time (PTT) = 70.2, fibrinogen 10 000. Blood cultures were obtained; he was given a dose of ceftriaxone, normal saline bolus, and fresh frozen plasma and transferred to our critical care unit. On arrival he was hemodynamically stable but showed ongoing, severe coagulopathy. He had deep purple plaques over thighs and lower extremities, including lateral hips and penis. Feet were relatively spared with some purple discoloration of toes. There were no petechiae or purpura above the waistline. His penis and scrotum were extremely swollen and deeply ecchymotic, with overlying bullae (see Figure 1). He had a normal blood gas, with a lactate of 2.1 mEq/l. He was diagnosed with purpura fulminans (PF) and disseminated intravascular coagulation of uncertain etiology. Further diagnostic workup was undertaken to determine the etiology of the PF. Blood drawn on the day of admission (before receiving any blood products) was retrospectively found to have suppressed protein S activity (49%; reference range = 75% to 140%). After the initiation of plasmapheresis, the DIC stabilized and 1
University of Wisconsin School of Medicine and Public Health, Madison, WI, USA Corresponding Author: Anthony J. Wampole, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Box 4108, 600 Highland Avenue, Madison, WI 53792, USA. Email: [email protected]
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
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Clinical Pediatrics
Table 1. Timeline and Associated Laboratory Findings. First ED Visit (2 days PTA) Vital signs Examination
WBC (K/µL)
PCP Office (1.5 days PTA)
Second ED Visit (1 day PTA)
Afebrile; HR 139; BP Afebrile; HR 128; BP Afebrile; HR 121; BP 108/59; RR 24 104/50; RR 24 106/68; RR 26 Purpuric lesions on Swelling and redness of Ecchymoses of the lower extremities his penis, as well as lower extremities; “deep bruising” of the and buttocks; penile scattered hives on shaft was described posterior thighs and torso as “moderately to buttock severely edematous and ecchymotic”
10.3; 70% PMNs, 24% lymphs Hgb (g/dL)/Hct (%) 12.5/35.6 Platelets (K/µL) 152 CO2 (mEq/L) 22 BUN (mg/dL) 13 Creatinine (mg/dL) 0.35 Urinalysis Unable to be obtained PT/INR 1.4 Diagnosis HSP Intervention Anticipatory guidance
—
—
— — — — — (+) ketones; 2-5 WBCs
— — — — — —
— HSP Anticipatory guidance
— HSP Prednisone (1 mg/kg, BID)
Third ED Visit
Admission to PICU
Afebrile; HR 154; BP Afebrile; HR 145; BP 106/73; RR 28 114/68; RR 22 Deep purple plaques Scattered petechiae over thighs and on chest and arms; lower extremities. diffuse “nonpalpable” Feet relatively spared purpura on legs, with some purple buttocks, perineum, discoloration of and penis with toes. No petechiae surrounding edema; scrotum purpuric and or purpura above the waistline. grossly edematous, Penis and scrotum with overlying bullae were extremely swollen and deeply ecchymotic, with overlying bullae. 16.7; 87% PMNs; 11% 10.5; 81% PMNs; 16 lymphs lymphs 9.5/27.9 5.3/15 41 17 21 23 18 20 0.47 0.43 Grossly bloody — 8 DIC Blood products, fluids, transfer to PICU
1.3 Purpura fulminans
Abbreviations: ED, emergency department; PTA, prior to admission; PCP, primary care physician; PICU, pediatric intensive care unit; HR, heart rate; BP, blood pressure; RR, respiratory rate; WBC, white blood cell count; PMN, neutrophils; lymphs, lymphocytes; Hgb, hemoglobin; Hct, hematocrit; BUN, blood urea nitrogen; PT, prothrombin time; INR, international normalized ratio; HSP, Henoch–Schönlein purpura; DIC, disseminated intravascular dissemination.
the protein S activity normalized rapidly, supporting the diagnosis of a postinfectious acquired antibody to protein. He underwent a series of debridements and cadaveric skin grafts, but ultimately required bilateral below-knee amputations. His scrotum re-epithelialized; a urinary catheter was placed for urethral patency and he had suprapubic catheter placement for urinary diversion. Pain and agitation were management issues throughout his hospitalization. He experienced several skin and urinary tract infections. He will ultimately require penile reconstruction and bladder augmentation procedures. His total hospital stay was 84 days.
Discussion The patient’s initial presentation seemed most consistent with HSP; however, his clinical trajectory diverged substantially from the expected course. He was diagnosed to have postinfectious PF, which ultimately threatened his life and compromised his limbs.
Henoch–Schönlein Purpura HSP is the most common small vessel vasculitis in childhood, affecting approximately 20/100 000 children annually.1 It is the most common cause of petechiae and purpura in children (more common than idiopathic thrombocytopenic purpura [ITP] and childhood leukemias). HSP can occur anytime in childhood with a peak incidence at 4 to 5 years. It is preceded by a viral upper respiratory tract infection in more than half of cases. The hallmark of HSP is palpable purpura, classically involving pressure-dependent areas of the lower extremities and buttocks. The rash can initially appear as urticariallike lesions and often progresses to varying-sized petechiae and coalesced, raised purpura. Other commonly associated findings include edema, abdominal pain (75%), migratory arthralgias/arthritis affecting joints of lower extremities (80%), renal involvement (30% to 50%), and, more rarely, scrotal involvement and intussusception. HSP is generally a self-limited illness. Most children have complete resolution of symptoms within
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
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Wampole et al
Figure 1. Physical exam findings.
Exam findings on presentation (top photo and left photo) and evolution over first 12 hours of inpatient admission (right photo). He had purple plaques over thighs and lower extremities, including lateral hips and penis. Feet were relatively spared with some purple discoloration of toes. There were no petechiae or purpura above the waistline. His penis and scrotum were extremely swollen and deeply ecchymotic, with overlying bullae.
4 to 6 weeks with about one third of patients experiencing relapse of symptoms within the first year. Renal involvement and risk for hypertension and chronic kidney disease are the most significant long-term sequelae that require ongoing monitoring and management. HSP is diagnosed clinically without specific or confirmatory laboratory studies with the exception of a skin biopsy (rarely performed). None of the major pediatric textbooks provide strong recommendations regarding the initial evaluation of a patient with a new diagnosis of HSP.2-5 Most pediatric resources only recommend urinalysis to determine whether hematuria is present. However, some recent articles have recommended more extensive preliminary testing, including complete blood count, erythrocyte sedimentation rate, prothrombin time or INR, basic metabolic panel, antistreptolysin antibody testing, urine dipstick with protein/creatinine ratio, and blood culture.6 This testing evaluates for diagnoses that may be masquerading as HSP. Based on the lack of recommendations from classic textbooks and our experience with this case, we polled
general pediatricians in our community to determine their typical diagnostic evaluation for patients presenting with presumed HSP. Responses of 36 pediatricians demonstrated that urinalysis was the most frequently obtained laboratory test obtained by providers (97%). A complete blood count and basic metabolic panel were the next most popular tests, 63% and 29%, respectively; only 10% to 13% obtained an INR or PTT.
Purpura Fulminans PF is a descriptive term that encompasses a variety of disorders that culminate in the rapid development of progressive skin lesions that may ultimately lead to extensive skin necrosis and gangrene, all in the context of a consumptive coagulopathy.7 In children, PF most often occurs as a component of overwhelming sepsis, usually caused by Neisseria meningitidis or Streptococcus pneumoniae.8 Rarely, PF is caused by inherited deficiencies of coagulation factors (protein C or S deficiencies) or is deemed idiopathic. It has recently
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
4
Clinical Pediatrics
been recognized that a preceding illness was present in 90% of pediatric patients who have been categorized as having idiopathic PF. Based on these observations, some propose that the term “idiopathic” is better characterized as “postinfectious” and may be immune-mediated. A small case series, in which patients with postinfectious PF have absent protein S levels, has substantiated this claim.7 Absent protein S levels may be mediated by the development of an autoantibody against protein S (ie, an acquired protein S deficiency). Interestingly, the patients in this series with PF, thought to be secondary to an anti– protein S antibody, first developed erythematous macules, which rapidly progressed to sharply defined purpura, primarily affecting the buttocks and lower extremities. Distinguishing HSP and postinfectious PF may be difficult. In both entities, the distribution of purpuric lesions is similar. Unfortunately, there is no description in the literature about the precise appearance of the purpuric skin demarcation in HSP versus postinfectious PF, with the exception that HSP is typically described as palpable purpura and is generally nonscarring. Multiple features appear distinctive in our patient, including (a) presentation with ecchymoses involving his penis and scrotum, which is atypical for HSP; (b) complaints of severe leg pain, which were qualitatively different than the arthralgias experienced more frequently in HSP; and (c) flat, cutaneous lesions that became deep purple and sharply demarcated from the surrounding normal skin. In our case an abnormal INR was documented nearly 48 hours before admission but was not further evaluated. A low-normal platelet count on presentation might also have been unexpected in the context of illness and/or inflammation. Recognition of the prolonged INR may have altered his disease course. Although laboratory studies in patients suspected to have HSP are generally of low yield, the benefit of identifying a case of postinfectious PF, with abnormal coagulation studies as the distinguishing factor, seems compelling. Accordingly, we recommend the performance of screening blood counts and an INR in children presenting with presumed HSP.
Author Contributions Each author contributed to the writing, research and editing of this article.
Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Reid-Adam J. Henoch–Schönlein purpura. Pediatr Rev. 2014;35:447-449. 2. Miller ML, Pachman LM. Vasculitis syndromes: Henoch– Schönlein purpura. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. Philadelphia, PA: Saunders; 2007:1043-1045. 3. Higuchi LM, Sundel RP. Henoch–Schönlein syndrome. In: McMilllan JA, Feigin RD, DeAngelis CD, Jones MD, eds. Oski’s Pediatrics: Principles and Practice. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:2559-2562. 4. Barron KS. Vasculitides: Henoch–Schönlein purpura (anaphylactoid purpura). In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. New York, NY: McGraw-Hill; 2011:810-812. 5. Adrogué HE, Flores FX. Henoch–Schönlein purpura. In: McInerny TK, Adam HM, Campbell DE, Kamat DM, Kelleher KJ, eds. American Academy of Pediatrics Textbook of Pediatric Care. Elk Grove Village, IL: American Academy of Pediatrics; 2009:2112-2115. 6. McCarthy HJ, Tizard EJ. Clinical practice: diagnosis and management of Henoch–Schönlein purpura. Eur J Pediatr. 2010;169:643-650. 7. Levin M, Eley BS, Louis J, Cohen H, Young L, Heyderman RS. Postinfectious purpura fulminans caused by an autoantibody directed against protein S. J Pediatr. 1995;127: 355-363. 8. Chalmers E, Cooper P, Forman K, et al. Purpura fulminans: recognition, diagnosis and management. Arch Dis Child. 2011;96:1066-1071.
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
research-article2015
CPJXXX10.1177/0009922815590116Clinical PediatricsWampole et al
Brief Report
A Case of Postinfectious Protein S Deficiency Masquerading as Henoch– Schönlein Purpura
Clinical Pediatrics 1–4 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0009922815590116 cpj.sagepub.com
Anthony J. Wampole, MD1, Halie M. Anderson, MD1, and Ellen R. Wald, MD1
Case Report (Presentation) The patient is a previously healthy 4-year-old male who is admitted for a purpuric rash. Ten days before admission he experienced mild, transient cold symptoms. Four days before admission he developed hives on his lower abdomen and mild swelling of his feet; symptoms improved with diphenhydramine. Two days later the primary care provider (PCP) was informed of slight periorbital puffiness and ongoing swelling (with a slight “bluish-hue”) on the dorsum of his feet bilaterally. He was otherwise well, without fever or discomfort, except for mild itching between doses of diphenhydramine. Family was instructed to seek medical care if he developed joint pain or swelling, difficulty with mobility, blue-purple rash, or fever. Twelve hours later, a dark purple rash evolved over his legs. He was taken to a local emergency department (ED) where he was afebrile with normal vital signs. He was documented to have purpuric lesions on his lower extremities and scattered hives on his torso. Laboratory studies were remarkable for a low normal platelet count and prothrombin time (PT)/international normalized ratio (INR) = 1.4 (see Table 1 for timeline of presentation, including vital signs, pertinent labs, and physical exam findings). He was discharged home with a presumptive diagnosis of Henoch–Schönlein purpura (HSP). His PCP saw him the following day; his vital signs were normal and he was noted to have swelling and redness of his penis, as well as “deep bruising” of the posterior thighs and buttock. Urinalysis did not show hematuria. The PCP agreed with the diagnosis of HSP; the patient was sent home with anticipatory guidance. That night, he developed worsening bruising and swelling and progressive penile pain that inhibited his ability to void. The escalation of pain prompted a second visit to his local ED. He remained afebrile without vital sign changes. His exam was notable for progressive ecchymoses of the lower extremities and buttocks. His penile shaft was described as “moderately to severely edematous and ecchymotic.” No laboratory studies were obtained. He was started on oral prednisone and discharged. Unremitting pain and
inability to urinate brought him back to the ED. His exam was notable for tachycardia; he had scattered petechiae on chest and arms and diffuse “nonpalpable” purpura on legs, buttocks, perineum, and penis with surrounding edema. His scrotum was purpuric and grossly edematous, with overlying bullae. Urine was grossly bloody. Repeat laboratory studies were notable for leukocytosis, anemia, and thrombocytopenia. Complete metabolic panel, including electrolytes, kidney function, and transaminases, was notable for a mildly low CO2 (21 mEq/L) and albumin (2.8 g/L). Coagulation studies were grossly abnormal with PT/ INR = 8.0, partial thromboplastin time (PTT) = 70.2, fibrinogen 10 000. Blood cultures were obtained; he was given a dose of ceftriaxone, normal saline bolus, and fresh frozen plasma and transferred to our critical care unit. On arrival he was hemodynamically stable but showed ongoing, severe coagulopathy. He had deep purple plaques over thighs and lower extremities, including lateral hips and penis. Feet were relatively spared with some purple discoloration of toes. There were no petechiae or purpura above the waistline. His penis and scrotum were extremely swollen and deeply ecchymotic, with overlying bullae (see Figure 1). He had a normal blood gas, with a lactate of 2.1 mEq/l. He was diagnosed with purpura fulminans (PF) and disseminated intravascular coagulation of uncertain etiology. Further diagnostic workup was undertaken to determine the etiology of the PF. Blood drawn on the day of admission (before receiving any blood products) was retrospectively found to have suppressed protein S activity (49%; reference range = 75% to 140%). After the initiation of plasmapheresis, the DIC stabilized and 1
University of Wisconsin School of Medicine and Public Health, Madison, WI, USA Corresponding Author: Anthony J. Wampole, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Box 4108, 600 Highland Avenue, Madison, WI 53792, USA. Email: [email protected]
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
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Clinical Pediatrics
Table 1. Timeline and Associated Laboratory Findings. First ED Visit (2 days PTA) Vital signs Examination
WBC (K/µL)
PCP Office (1.5 days PTA)
Second ED Visit (1 day PTA)
Afebrile; HR 139; BP Afebrile; HR 128; BP Afebrile; HR 121; BP 108/59; RR 24 104/50; RR 24 106/68; RR 26 Purpuric lesions on Swelling and redness of Ecchymoses of the lower extremities his penis, as well as lower extremities; “deep bruising” of the and buttocks; penile scattered hives on shaft was described posterior thighs and torso as “moderately to buttock severely edematous and ecchymotic”
10.3; 70% PMNs, 24% lymphs Hgb (g/dL)/Hct (%) 12.5/35.6 Platelets (K/µL) 152 CO2 (mEq/L) 22 BUN (mg/dL) 13 Creatinine (mg/dL) 0.35 Urinalysis Unable to be obtained PT/INR 1.4 Diagnosis HSP Intervention Anticipatory guidance
—
—
— — — — — (+) ketones; 2-5 WBCs
— — — — — —
— HSP Anticipatory guidance
— HSP Prednisone (1 mg/kg, BID)
Third ED Visit
Admission to PICU
Afebrile; HR 154; BP Afebrile; HR 145; BP 106/73; RR 28 114/68; RR 22 Deep purple plaques Scattered petechiae over thighs and on chest and arms; lower extremities. diffuse “nonpalpable” Feet relatively spared purpura on legs, with some purple buttocks, perineum, discoloration of and penis with toes. No petechiae surrounding edema; scrotum purpuric and or purpura above the waistline. grossly edematous, Penis and scrotum with overlying bullae were extremely swollen and deeply ecchymotic, with overlying bullae. 16.7; 87% PMNs; 11% 10.5; 81% PMNs; 16 lymphs lymphs 9.5/27.9 5.3/15 41 17 21 23 18 20 0.47 0.43 Grossly bloody — 8 DIC Blood products, fluids, transfer to PICU
1.3 Purpura fulminans
Abbreviations: ED, emergency department; PTA, prior to admission; PCP, primary care physician; PICU, pediatric intensive care unit; HR, heart rate; BP, blood pressure; RR, respiratory rate; WBC, white blood cell count; PMN, neutrophils; lymphs, lymphocytes; Hgb, hemoglobin; Hct, hematocrit; BUN, blood urea nitrogen; PT, prothrombin time; INR, international normalized ratio; HSP, Henoch–Schönlein purpura; DIC, disseminated intravascular dissemination.
the protein S activity normalized rapidly, supporting the diagnosis of a postinfectious acquired antibody to protein. He underwent a series of debridements and cadaveric skin grafts, but ultimately required bilateral below-knee amputations. His scrotum re-epithelialized; a urinary catheter was placed for urethral patency and he had suprapubic catheter placement for urinary diversion. Pain and agitation were management issues throughout his hospitalization. He experienced several skin and urinary tract infections. He will ultimately require penile reconstruction and bladder augmentation procedures. His total hospital stay was 84 days.
Discussion The patient’s initial presentation seemed most consistent with HSP; however, his clinical trajectory diverged substantially from the expected course. He was diagnosed to have postinfectious PF, which ultimately threatened his life and compromised his limbs.
Henoch–Schönlein Purpura HSP is the most common small vessel vasculitis in childhood, affecting approximately 20/100 000 children annually.1 It is the most common cause of petechiae and purpura in children (more common than idiopathic thrombocytopenic purpura [ITP] and childhood leukemias). HSP can occur anytime in childhood with a peak incidence at 4 to 5 years. It is preceded by a viral upper respiratory tract infection in more than half of cases. The hallmark of HSP is palpable purpura, classically involving pressure-dependent areas of the lower extremities and buttocks. The rash can initially appear as urticariallike lesions and often progresses to varying-sized petechiae and coalesced, raised purpura. Other commonly associated findings include edema, abdominal pain (75%), migratory arthralgias/arthritis affecting joints of lower extremities (80%), renal involvement (30% to 50%), and, more rarely, scrotal involvement and intussusception. HSP is generally a self-limited illness. Most children have complete resolution of symptoms within
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
3
Wampole et al
Figure 1. Physical exam findings.
Exam findings on presentation (top photo and left photo) and evolution over first 12 hours of inpatient admission (right photo). He had purple plaques over thighs and lower extremities, including lateral hips and penis. Feet were relatively spared with some purple discoloration of toes. There were no petechiae or purpura above the waistline. His penis and scrotum were extremely swollen and deeply ecchymotic, with overlying bullae.
4 to 6 weeks with about one third of patients experiencing relapse of symptoms within the first year. Renal involvement and risk for hypertension and chronic kidney disease are the most significant long-term sequelae that require ongoing monitoring and management. HSP is diagnosed clinically without specific or confirmatory laboratory studies with the exception of a skin biopsy (rarely performed). None of the major pediatric textbooks provide strong recommendations regarding the initial evaluation of a patient with a new diagnosis of HSP.2-5 Most pediatric resources only recommend urinalysis to determine whether hematuria is present. However, some recent articles have recommended more extensive preliminary testing, including complete blood count, erythrocyte sedimentation rate, prothrombin time or INR, basic metabolic panel, antistreptolysin antibody testing, urine dipstick with protein/creatinine ratio, and blood culture.6 This testing evaluates for diagnoses that may be masquerading as HSP. Based on the lack of recommendations from classic textbooks and our experience with this case, we polled
general pediatricians in our community to determine their typical diagnostic evaluation for patients presenting with presumed HSP. Responses of 36 pediatricians demonstrated that urinalysis was the most frequently obtained laboratory test obtained by providers (97%). A complete blood count and basic metabolic panel were the next most popular tests, 63% and 29%, respectively; only 10% to 13% obtained an INR or PTT.
Purpura Fulminans PF is a descriptive term that encompasses a variety of disorders that culminate in the rapid development of progressive skin lesions that may ultimately lead to extensive skin necrosis and gangrene, all in the context of a consumptive coagulopathy.7 In children, PF most often occurs as a component of overwhelming sepsis, usually caused by Neisseria meningitidis or Streptococcus pneumoniae.8 Rarely, PF is caused by inherited deficiencies of coagulation factors (protein C or S deficiencies) or is deemed idiopathic. It has recently
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
4
Clinical Pediatrics
been recognized that a preceding illness was present in 90% of pediatric patients who have been categorized as having idiopathic PF. Based on these observations, some propose that the term “idiopathic” is better characterized as “postinfectious” and may be immune-mediated. A small case series, in which patients with postinfectious PF have absent protein S levels, has substantiated this claim.7 Absent protein S levels may be mediated by the development of an autoantibody against protein S (ie, an acquired protein S deficiency). Interestingly, the patients in this series with PF, thought to be secondary to an anti– protein S antibody, first developed erythematous macules, which rapidly progressed to sharply defined purpura, primarily affecting the buttocks and lower extremities. Distinguishing HSP and postinfectious PF may be difficult. In both entities, the distribution of purpuric lesions is similar. Unfortunately, there is no description in the literature about the precise appearance of the purpuric skin demarcation in HSP versus postinfectious PF, with the exception that HSP is typically described as palpable purpura and is generally nonscarring. Multiple features appear distinctive in our patient, including (a) presentation with ecchymoses involving his penis and scrotum, which is atypical for HSP; (b) complaints of severe leg pain, which were qualitatively different than the arthralgias experienced more frequently in HSP; and (c) flat, cutaneous lesions that became deep purple and sharply demarcated from the surrounding normal skin. In our case an abnormal INR was documented nearly 48 hours before admission but was not further evaluated. A low-normal platelet count on presentation might also have been unexpected in the context of illness and/or inflammation. Recognition of the prolonged INR may have altered his disease course. Although laboratory studies in patients suspected to have HSP are generally of low yield, the benefit of identifying a case of postinfectious PF, with abnormal coagulation studies as the distinguishing factor, seems compelling. Accordingly, we recommend the performance of screening blood counts and an INR in children presenting with presumed HSP.
Author Contributions Each author contributed to the writing, research and editing of this article.
Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Reid-Adam J. Henoch–Schönlein purpura. Pediatr Rev. 2014;35:447-449. 2. Miller ML, Pachman LM. Vasculitis syndromes: Henoch– Schönlein purpura. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. Philadelphia, PA: Saunders; 2007:1043-1045. 3. Higuchi LM, Sundel RP. Henoch–Schönlein syndrome. In: McMilllan JA, Feigin RD, DeAngelis CD, Jones MD, eds. Oski’s Pediatrics: Principles and Practice. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:2559-2562. 4. Barron KS. Vasculitides: Henoch–Schönlein purpura (anaphylactoid purpura). In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA, eds. Rudolph’s Pediatrics. New York, NY: McGraw-Hill; 2011:810-812. 5. Adrogué HE, Flores FX. Henoch–Schönlein purpura. In: McInerny TK, Adam HM, Campbell DE, Kamat DM, Kelleher KJ, eds. American Academy of Pediatrics Textbook of Pediatric Care. Elk Grove Village, IL: American Academy of Pediatrics; 2009:2112-2115. 6. McCarthy HJ, Tizard EJ. Clinical practice: diagnosis and management of Henoch–Schönlein purpura. Eur J Pediatr. 2010;169:643-650. 7. Levin M, Eley BS, Louis J, Cohen H, Young L, Heyderman RS. Postinfectious purpura fulminans caused by an autoantibody directed against protein S. J Pediatr. 1995;127: 355-363. 8. Chalmers E, Cooper P, Forman K, et al. Purpura fulminans: recognition, diagnosis and management. Arch Dis Child. 2011;96:1066-1071.
Downloaded from cpj.sagepub.com at UQ Library on July 26, 2015
