Tucker- skin manifestations of disease Flashcards
Causes of purpura, e.g.
HSP (Henoch Schonlein) Purpura Fulminans (meningococcal)
differential of a child with petechiae
Infectious, hematologic, immunologic, and traumatic
Infectious causes: Rocky Mountain Spotted Fever, sepsis with meningococcemia, pneumococcemia in particular, atypical measles.
When they occur as an enanthem, you can see them in Strep (palatal petechiae) or Mono. Coagulation disorders, ITP, TTP, Leukemia. Vasculitis, anaphylactoid purpura, or HSP.
Rocky Mountain Spotted Fever
Most common fatal tick-borne disease in the United States
- Caused by Rickettsia rickettsii
- Multiple tick vectors, incl. American dog tick, the common brown dog tick, and the Rocky Mountain wood tick
A tick must feed for 6 hours before infection transmission occurs, and Rickettsia replicate for an average of 1 week before clinical symptoms begin.
The incidence is highest in individuals aged 5-9 and 60-69 years
Majority of cases occur between April and September in the Southeast and Midwest United States
Most common symptoms are:
- high fever (> 102° F)
- Headache
- rash
petechial rash typically begins on the wrists and ankles but may be found anywhere, including the oral mucosa, as in this child
spotless RMSF occurs in 10%-15% of cases
- myalgias
A high index of suspicion must be maintained, as the mortality rate is 20%-30% for untreated patients and 1%-5% for treated ones
Empiric antibiotic therapy is usually initiated based on the history and physical examination, without waiting for confirmatory serologic testing
- delay between presentation and diagnosis of RMSF
3/4 may require hospitalization
Outpatients must be closely monitored, as rapid deterioration is not uncommon and requires subsequent admission.
Meningococcemia
- gram-negative diplococcus Neisseria meningitidis
- transmission is person-to-person via respiratory droplets, often from an asymptomatic carrier
- Up to 30% of teenagers and 10% of adults carry meningococci in the upper respiratory tract.
Clinical presentation is variable
- 50% of patients developing meningitis only
- 10% developing septicemia only
- 40% developing both
Symptoms:
usually febrile, ill-appearing, lethargy, vomiting, and nuchal rigidity
Septicemia leads to capillary leak, coagulopathy, profound acidosis, and myocardial failure
Septic emboli cause arterial occlusion in the distal extremities
Treatment:
- must be closely monitored for hypotension, shock, pericarditis, organ failure, and coagulopathy, usually in an intensive care unit setting
- Patients with coagulopathy and gangrene may be candidates for anticoagulation therapy.
- In patients with both septicemia and meningitis, a depressed level of consciousness may be from elevated intracranial pressure or hypotension
mortality rate, even with prompt treatment, is 5%-10%
If suspected, antibiotic treatment should be initiated without waiting for confirmatory culture testing
** Important note: Pneumococcus can have a very similar presentation to Meningococcemia
Measles
One of the most contagious infectious diseases, with a secondary infection rate of 90% in susceptible individual
- vaccine introduced in 1963 –> a reduction in annual incidence in the United States of greater than 99%
- it remains one of the leading causes of death in young children worldwide, with an estimated 197,000 deaths yearly
Clinical Presentation:
- After exposure, the incubation period lasts for 7-14 days
- Then prodrome of high fevers, often > 104° F, with the classic triad of cough, coryza, and conjunctivitis
- A couple of days later, Koplik spots develop on the buccal mucosa, appearing as white spots on an erythematous base.
- W/i a couple of days after the Koplik spots appear, an exanthem develops which consists of blanching, erythematous macules and papules, as shown
- – begins on the face at the hairline and coalesces into patches and plaques that spread cephalocaudally to the trunk and extremities
- – this lasts for a week before fading to hyperpigmented patches which desquamate
Treatment:
- Vitamin A deficiency has been associated with a worse prognosis, including blindness, so all children diagnosed with measles receive supplementation
- Care is otherwise supportive with adequate hydration.
- Subacute sclerosing panencephalitis is a late, long-term complication caused by persistent infection
Leukemia
ALL the most common malignancy of childhood
Clinical Presentation:
- Often presents with nonspecific symptoms of anorexia, irritability and lethargy
- may follow a mild respiratory infection
- Subsequently one may see progressive fatigue, weight loss, pallor, bone pain, fever and petechiae
Peak incidence at age 4, more common in whites than blacks, more common in boys than girls.
TTP/ Hemolytic-Uremic Syndrome
Classic presentation is 5-10 days after developing gastroenteritis
Frequently associated with bloody diarrhea (E. coli O-157)
patient develop progressive renal failure, anemia, thrombocytopenia
(HUS may be the childhood version of TTP)
ITP
Most common cause of thrombocytopenic petechiae in childhood
- associated with bleeding and bruising
Most commonly preceeded by an acute viral illness 2-4 before presentation
** Platelet counts often are below 20,000 (antibodies consume every platelet that comes out, as opposed to leukemias)
Most serious complication is intracranial bleed but this is very rare due to etiology of disease
- Autoimmune destruction of platelets resulting in large, new, very effective platelets, although low in numbers, most severe bleeds do not occur
Need to differentiate from infiltrative disease such as Leukemia, neuroblastoma etc.
(many treated with IV IG now)
HSP
vasculitis that can affect the skin, joints, gastrointestinal tract, and kidneys
Clinical Presentation:
- In a well-appearing child, HSP can be managed on an outpatient basis.
- helpful to check blood pressure, urine, and electrolytes to look for a glomerulonephritis
- Urinalysis and blood pressure may be followed for several months to monitor kidney function
- fecal occult blood test can help rule out significant gut involvement, especially in children with pain
- Intussusception is the most serious complication of HSP; if it is suspected, the child should be admitted and monitored.
Labs:
- Platelet count is generally normal in HSP, helping to differentiate it from idiopathic thrombocytopenic purpura (ITP), which has low platelets
- ITP presents with petechiae, bruising (as shown), or bleeding, often in areas of trauma
- If counts are sufficiently low, there is a risk for intracranial bleed
Treatment: A consult with hematology can help determine appropriate management in case of uncertainty.
classic picture: rash, blood in the urine, abdominal pain
HSP
some get chronic renal disease but this is rare
Chicken pox progression
starts as a red macule–> papule–> vesicle–> crust
the vesicle: “dew-drop on a rose petal”
starts on torso and spreads centrifugally– outwards.
lesions come in crops
opthalmic involvement of herpes
take antiviral eye drops to avoid the dreaded herpes keratitis (–> damaged vision/ blindness)
hypothermic baby with vesicles on the scalp. WHat did he have?
neonatal herpes. –> skin manifestations of herpes, encephalitis, etc.
what causes bullae? (in particular, an infectious agent)
staph aureus. Bullous impetigo
floppy pop
staph can also cause scalded skin syndrome
strep throat
is an enanthum
scarlet fever– maculopapular rash, increased in popliteal space, groin, cubital region
–> rheumatic fever if you don’t take ABX