Hyperinfection syndrome or disseminated strongyloidiasis:

Hyperinfection syndrome or disseminated strongyloidiasis: 

Hyperinfection syndrome and disseminated strongyloidiasis are most frequently associated with subclinical infection in patients receiving high-dose corticosteroids for the treatment of asthma or chronic obstructive pulmonary disease (COPD) exacerbations. Subsequent impaired host immunity leads to accelerated autoinfection and an overwhelming number of migrating larvae. In chronic strongyloidiasis and in hyperinfection syndrome the larvae are limited to the GI tract and the lungs whereas in disseminated strongyloidiasis the larvae invade numerous organs. Left untreated, the mortality rates of hyperinfection syndrome and disseminated strongyloidiasis can approach 90%.

Cause

Strongyloidiasis is caused by the parasitic roundworm S. stercoralis. This worm infects mainly humans. Most humans get the infection by coming into contact with contaminated soil.

It’s most often found in tropical and subtropical climates, but it can occasionally be found in more temperate climates. This may include parts of the southern United States and Appalachia.

Once a person comes into contact with S. stercoralis, the infection follows the lifecycle of the worm. The worm’s lifecycle includes the following stages:

• The tiny worms penetrate your skin and enter your bloodstream.
• The worms then move through your bloodstream and pass through the right side of your heart and into the lungs.
• The parasites travel from the lungs up the windpipe and into your mouth.
• You unknowingly swallow the worms, and they travel into your stomach.
• The worms move into your small intestine.
• The worms lay eggs that hatch and become larvae.
• The larvae are expelled from your body in your feces.
• The larvae can infect your body by penetrating the skin around your anus, or they can develop into mature worms and infect someone else.
• The worms can also live and reproduce in soil, without a host.
• Rarely, the worms can penetrate the intestine of the host as larvae rather than pass out of the body through the feces.

Symptoms 

The following are signs and symptoms that can be seen with hyperinfection syndrome and disseminated strongyloidiasis:

Gastrointestinal manifestations

• Abdominal pain, nausea, vomiting, diarrhea
• Ileus, bowel edema, intestinal obstruction
• Mucosal ulceration, massive hemorrhage, and subsequent peritonitis or bacterial sepsis
• Pulmonary manifestations and findings
• Cough, wheezing, dyspnea, hoarseness
• Pneumonitis
• Hemoptysis
• Respiratory failure
• Diffuse interstitial infiltrates or consolidation on chest radiographs

Neurologic findings

• Aseptic or gram-negative meningitis
• Larvae have been reported in the CSF, meningeal vessels, dura, epidural, subdural, and subarachnoid spaces

Systemic signs and symptoms

• Peripheral edema and ascites secondary to hypoalbuminemia from protein losing enteropathy
• Recurrent gram negative bacteremia or sepsis from larvae carrying bacteria that penetrate mucosal walls
• Syndrome of inappropriate secretion of anti-diuretic hormone (SIADH)
• Peripheral eosinophilia is frequently absent

Cutaneous manifestations

• Recurrent maculopapular or urticarial rash that can be found anywhere on the skin but is most commonly found along the buttocks, perineum, and thighs due to repeated auto-infection
• Larva currens serpiginous or urticarial rash that advances as rapidly as 10cm/hr. 

Diagnosis 

Strongyloidiasis can be difficult to diagnose because examining the stool under a microscope doesn't always show the infection. Examining the stool on five occasions at different times can be more reliable. Strongyloidiasis can sometimes be diagnosed with a blood test. More advanced cases may be diagnosed by testing fluid from your lungs or small intestine.