September 2000
A 6-year-old boy was admitted to the hospital for evaluation and treatment of multiple problems, including the appearance of a rash on both thighs and being tired for no apparent reason.
The rash and fatigue
were first noted at the end of a family camping trip about five days prior to
admission. On the trip, the family slept in a van with minimal to no insect
exposure. No ticks were seen. The next day, he began complaining of abdominal
pain, without fever or nausea. The following day, he was evaluated for the
abdominal pain and anorexia and found to only have some bug bites on his lower
leg area that appeared to be impetiginous, and was started on cephalexin. These
bites preceded the camping trip, and were thought to be a result of chigger
bites from their yard. He also had a urinalysis (UA) that showed microscopic
hematuria and trace protein. He was also somewhat dehydrated.
The
next day, his mother noted that he had some painful swelling of his left knee
with a limp and right wrist and elbow swelling. This also heralded the onset of
diarrhea, which at times was dark black in color. The next day (day of
admission), there was some red blood seen in his stools and he went back to his
physician, who obtained more lab tests including a complete blood count (CBC),
UA, C-reactive protein (CRP), blood urea nitrogen, creatinine and serum
electrolytes, and obtained radiographs of his knee and referred him for
admission. At this point his UA still showed evidence of dehydration, but the
hematuria and proteinuria had cleared. His CBC revealed a white blood count of
15,700 with a normal differential, a platelet count of 140,000 and no anemia.
His CRP was 7.7. The rest, including the X-rays, was normal.
Examination revealed normal vital signs. He was not ill-appearing, but did have the rash shown in figures 1 and 2, and some mild swelling of the knees, right wrist and elbow (figures 3 and 4). The rash, which appeared to be small, nonblanching ecchymotic lesions on the legs and buttocks, mixed in with excoriated bug bites on the lower legs (figure 5), had not significantly changed since the day before. He also had a cold sore on his lower lip (figure 6). The rest of the exam, including his abdomen, was normal.
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This is a case of Henoch-Schönlein purpura (HSP), also called "allergic or anaphylactoid purpura." This is in the small vessel vasculitis category, affecting arterioles and capillaries. The cause is thought to be a reaction to an infectious disease agent or other allergic triggers. Various bacterial and viral infections have been implicated. Perhaps the herpes simplex sore on his lip was the trigger. It tends to occur in prepubertal boys about twice as often as in girls. As demonstrated in this patient, it can involve not only the skin, but also the joints, kidney and gastrointestinal tract. According to Nelson's Textbook of Pediatrics, central nervous system involvement is rare, but with potentially serious sequelae. Fortunately, this patient had a fairly uncomplicated case and resolved without sequelae. This case had a rather gradual onset, but some are acute in nature. The rash can take on a variety of manifestations ranging from maculopapular to urticarial. However, development of petechiae and purpura are classic. The distribution is usually more intense over the thighs and buttocks, but it can be more generalized. In this patient the rash was complicated by being mixed with some impetiginous lesions as shown in figure 5. Arthritis, which occurs to some extent in most patients, is usually transient with a waxing and waning course during the acute stage. In this patient, joint pain was one of the main complaints. The swelling was subtle, but notable to the parents (figures 3 and 4). In the early 1800s, Schönlein described the rash and joint manifestations. A half a century later, Henoch reported on the renal and gastrointestinal manifestations of the disease. The renal involvement in this patient was minimal and very brief. It could have easily gone unnoticed. However, the gastrointestinal involvement, which most patients have, was significant with pain and bleeding.
Few lab tests are needed to diagnose typical HSP. However, one may need to follow blood and urine to monitor blood loss and/or renal involvement once the diagnosis is made. Treatment is supportive and symptomatic. If there is an underlying bacterial infection that triggered the disease, then of course it should be treated as well. Depending on the injury to the gut or kidneys, there could be long-term sequelae, but most patients completely recover, as did this patient.
Rocky Mountain
spotted fever (RMSF), caused by Rickettsia rickettsii, which is spread
by a variety of ticks, is an acute, febrile disease that causes small vessel
inflammation and typically is associated with a maculopapular (spotty) rash,
which begins on the extremities about the wrists, ankles, palms and soles
(figure 7). It then spreads to the trunk and typically becomes petechial,
possibly purpuric with disseminated intravascular coagulation (DIC) (figures 8
and 9). Other symptoms can be indistinguishable from HSP with nausea, vomiting
and abdominal pain, kidney involvement, and central nervous system findings. As
opposed to HSP, headache is a characteristic feature of this infection. When
suspected, treatment should begin as soon as possible with doxycycline. I feel
that this is the drug of choice regardless of the child's age. The dreaded
staining of the teeth is not going to occur with one 10-day course of
doxycycline. Other experts still consider chloramphenicol the drug of choice in
children younger than 8 years of age. However, many pharmacies no longer stock
this excellent antimicrobial agent.
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A single elevated titer one to two weeks after the onset is suggestive, but confirmation of the diagnosis is with paired serology showing a fourfold rise. Obviously, treatment cannot be delayed that long.
Meningococcemia is of course bacteremia with Neisseria
meningitidis but has come to be synonymous with being septic with this
organism. It is in the differential in this case primarily because of the rash,
which is present in most infected patients, along with fever or sometimes
hypothermia. However, fever is not a big part of HSP. It is usually low-grade
if seen at all. At its worst, meningococcemia is rapidly progressive with
septic shock and purpura fulminans, with DIC and mortality rate approaching
90%. Overall, the mortality appears to be about 8% to 10%, depending on their
presentation and access to intensive care. At its best, it may just be an
occult bacteremia that readily clears with or without antimicrobials. The rash
may look exactly like that for RMSF or HSP. It typically begins on the
posterior thighs and buttocks (figure 10), and may rapidly spread to the rest
of the body (figure 11). It often involves the distal extremities. The
circulatory insufficiency may result in areas of necrosis as shown in figures
12 and 13, which were taken three days apart. The diagnosis is usually
confirmed with blood and/or cerebrospinal fluid cultures. The treatment is with
antibiotics and intensive care support as needed. There are isolation
precautions and antimicrobial prophylaxis recommendations, for which I will
refer you to the references below for details. In some cases, it may be
necessary to treat for both RMSF and meningococcemia pending clarification of
the diagnosis. A very nice review of meningococcemia can be found in the 1996
issue of Infectious Disease Clinics of North America by Mark B.
Salzman and Lorry G. Rubin, on pages 709-725.
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Enteroviral infections can present with a wide variety of clinical pictures, including rashes, fever and multiorgan involvement mimicking bacterial sepsis. However, it is unlikely that classic presentations of the above conditions would be confused with enteroviral infections. The trouble is, they are not always classic. For a more in-depth discussion of enteroviral diseases and treatment, I would refer you to the supplemental monograph to July's issue of Infectious Diseases in Children called Advances in Antiviral Medications. You might also look into the SLACK Web site for more information (www.slackinc.com).
Lastly, acute glomerulonephritis (AGN) was thrown in because of the infected insect bites and renal involvement. AGN is caused by nephritogenic strains of group A streptococcus causing impetigo. However, the urine would be dark with hemoglobin (figure 14) and the rash and other manifestations noted in this case would not be likely.
This seems like a good time to plug some new references. All the information in this discussion can be found in the new (2000), 16th edition of Nelson's Textbook of Pediatrics, edited by Richard E. Behrman, Robert M. Kliegman and Hal B. Jenson, and, in my opinion, still the best single pediatric reference. Also the new Red Book 2000, published by the Committee on Infectious Diseases of the American Academy of Pediatrics, is now out.
I think ownership of this book is a must for any practitioner seeing children. The answers to many of the questions I receive as a pediatric infectious disease consultant can be found in the Red Book.
Lastly, John Nelson's millennium (14th) edition of his Pocketbook of Pediatric Antimicrobial Therapy is out, co-edited by John Bradley. This is the only book I carry in my white coat, and I use it almost every day. When I first began carrying this pocketbook around, it was because I just did not know that much about antimicrobial therapy. Now I carry it because of age-related short-term memory loss. The ginkgo biloba just does not seem to be working as well as I had hoped.
To see how some of your colleagues manage children with fever and petechial rashes, I would recommend you read an excellent paper from the December 1998 issue of The Pediatric Infectious Disease Journal. The title is "Evaluation of febrile children with petechial rashes: Is there consensus among pediatricians?" by David Nelson, John Leake, John Bradley (mentioned above as co-editor of Nelson's Pocketbook of Antimicrobial Therapy, and Nathan Kuppermann. I would also recommend Greenes and Harper's paper, "Low risk of bacteremia in febrile children with recognizable viral syndromes" in the March 1999 issue of the same journal.
To finish on an unrelated note, remember that influenza season will be here soon, and vaccine should be out next month, so start reminding your high-risk patients to come in as soon as it is available. Also remember that influenza can be seen year-round. There was an outbreak of influenza A in a summer camp here in central Texas at the beginning of August, with 15 culture-confirmed cases and over 80 more suspected. Try to imagine having a highly febrile disease, in an unairconditioned environment, in weather where the daily temperature exceeds 100° F. As of this writing it is unknown whether the strain in the outbreak was in the vaccine or not. But my guess is, very few of those campers got vaccinated last season anyway. I am one of those who thinks all children should be immunized against influenza, and perhaps when the nasal spray version is licensed, it will be more acceptable. Look for a report on this outbreak to appear in one of the September issues of the Morbidity and Mortality Weekly Report from the Centers for Disease Control and Prevention.
I wonder if doubling the dose of ginkgo biloba will do any good? Give me your thoughts at jhbrien@aol.com. Hopefully I'll remember how to boot-up my computer.
Acknowledgements: I would like to thank Mike Weir, MD, head of the Pediatric Hospital Service at Scott & White, for his assistance with this case. I would also like to thank Dr. Jim Bass in Honolulu, for the use of figures 7, 8 and 9.
For more information:
- James H. Brien, DO, Pediatric Infectious Disease, Scott and White's Children's Health Center and Texas A&M University, College of Medicine, Temple, Texas; E-mail:jhbrien@aol.com.
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