Saturday, January 9, 2021

Modes of infectious disease transmission

 Modes of infectious disease transmission

An infectious agent may be transmitted from its natural reservoir to a susceptible host in different ways.

There are different classifications for modes of transmission. 

Here is one classification:

A.   General transmission

B.   Human-to-human transmission:


  • Direct
    • Direct contact
    • Droplet spread
  • Indirect
    • Airborne
    • Vehicleborne
    • Vectorborne (mechanical or biologic)

 more in this file


Monday, December 28, 2020

Growing pains in children

Growing pains in children

Episodes of generalized pain in the lower limbs, referred to as ‘growing pains’ or nocturnal idiopathic pain, are common in preschool and school-aged children.

The pain often wakes the child from sleep and settles with massage or comforting.

The condition is poorly understood. Features to be fulfilled for this diagnosis are often referred to as the ‘Rules of Growing Pains’, which are:

- Age: range 3–12 years

- Pains symmetrical in lower limbs and not limited to joints.

- Pain often follows a day with exercise or other physical activities.

- pains never present at the start of the day after waking up

- physical activities not limited; no limp

- Physical examination normal (including pGALS), with the exception of joint hypermobility in some, and otherwise well.

Monday, December 21, 2020

OMPHALOMESENTERIC (VITELLINE) REMNANT

 

OMPHALOMESENTERIC (VITELLINE) REMNANT

Partial or complete failure of involution of the omphalomesenteric duct can lead to a spectrum of anomalies in the newborn infant due to varying degrees and location of duct patency:

A.   An umbilical cyst containing intestinal tissue.

B.   Umbilical sinus with a band.

C.   A persistent omphalomesenteric duct at the umbilicus with no intestinal connection results in an umbilical polyp.

D.   Patent mid-duct with closure at both the umbilical and ileal ends of the omphalomesenteric duct results in an omphalomesenteric duct cyst. Because the two ends are fixed, this can lead to small bowel obstruction if loops of bowel twist around the cyst.

E.   Persistent tissue at the ileum, with no connection to the umbilicus results in Meckel's diverticulum.

F.   Complete patency results in the omphalomesenteric duct directly connecting the umbilicus to the terminal ileum. This can lead to intermittent drainage from the umbilicus " omphalomesenteric fistula". These infants will often appear to have a "stoma" in the umbilicus after cord separation.

G.  Persistent fibrous cord (band)  between the umbilicus and the ileum, which can lead to small bowel obstruction.


Saturday, December 19, 2020

OMPHALITIS


OMPHALITIS

 Def : Infection of the umbilicus and/or surrounding tissues.
Incidence : approximately 1 in 1,000 infants in developed countries where aseptic delivery and hygienic dry cord care are practiced.

The risk factors associated with the development of omphalitis include:

  • prolonged rupture of membranes
  • maternal infection
  • nonsterile delivery practices
  • home delivery
  • umbilical catheterization
  • low birth weight
  • improper cord care or cultural practices of cord care (such as application of cow dung, charcoal dust, or products such as cooking oil and baby powder to the cord stump, and lotus births)
  • delayed cord separation
  • immunologic conditions such as defects in leukocyte adhesion, neutrophil or natural killer lymphocyte function, and interferon production.

Clinical features:
Mild discharge from the umbilical stump in the absence of inflammatory signs may be a normal occurrence, even when accompanied by some odor.


Unhealthy, discolored, and craggy-appearing umbilical stump; purulent drainage; periumbilical erythema; and induration.


Umbilical stump bleeding may occur with omphalitis because the infection delays thrombosis of the umbilical vessels.


Systemic signs, including lethargy, fever, irritability, temperature instability and poor feeding are suggestive of more severe infection or complication. The most common complication of omphalitis is sepsis.


Other complications include septic umbilical arteritis, portal vein thrombosis, liver abscess, peritonitis, intestinal gangrene, small bowel evisceration, necrotizing fasciitis, and death (Mortality rate is estimated between 7 and 15 percent)
 

Omphalitis is a polymicrobial infection. Historically, the predominant pathogens included Staphylococcus aureus, Streptococcus pyogenes, and Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. However, with the routine use of antistaphylococcal cord care regimens, Gram-negative infections of the umbilicus have increased . In addition, anaerobic bacteria such as Bacteroides fragilis, Clostridium perfringens, and Clostridium tetani can contribute to umbilical infections, especially in infants born to mothers with chorioamnionitis . In these infants, foul smelling umbilical drainage is a typical finding.

Friday, January 3, 2020

Meckel's diverticulum

 

Meckel's diverticulum

Meckel diverticulum is the most common congenital anomaly of the GI tract and is caused by the incomplete obliteration of the omphalomesenteric duct during the 7th wk of gestation.

Meckel diverticulum has been conveniently referred to by the “rule of 2s,”:

  • Occurs in 2% of the population.
  • Appears within 2 feet (50-75 cm) of the ileocecal valve.
  • approximately 2 inches in length
  • Approximately 2% to 4% of patients develop complications over the course of their lives.
  • Typically presents before age 2 years.
  • Two-thirds of patients with MD have 2 types of heterotopic mucosa (gastric and pancreatic), although colonic heterotopic mucosa has also been reported.
  •  Is twice as likely to be symptomatic in boys than girls

Meckel diverticulum is typically lined by ileal mucosa.

Clinical presentations:

The majority are asymptomatic.

It is often found incidentally on imaging studies.

Hematochezia:

  • Cause of bleeding is ectopic gastric mucosa (acid-secreting mucosa)
  • Intermittent painless rectal bleeding (hematochezia) occurs suddenly and tends to be massive in younger patients.
  • Bleeding occurs without prior warning and usually spontaneously subsides.
  • The color of the stool is typically described as brick colored or currant jelly colored.
  • Bleeding can cause significant anemia but is usually self-limited (resolves without intervention) because of contraction of the splanchnic vessels, as patients become hypovolemic.
  • Bleeding from a Meckel diverticulum can also be less dramatic, with melanotic stools.

It should be suspected in children with recurrent or atypical intussusception, a patient with symptoms of appendicitis after their appendix has been removed, and patients with an unclear source of GI bleeding.