Sildenafil citrate shows some symptomatic relief, suggesting a possible common etiology with erectile dysfunction.

Other, less common, etiologies are Lyme disease polio, TB.

Streptococcus pneumoniae (aka pneumococcus) is the most common bacterial etiology of meningitis in children beyond 2 months of age(1-3 per 100,000).

Conjunctivitis is most commonly caused by viral infection, but bacterial infections, allergies, other irritants and dryness are also common etiologies for its occurrence.

Also another relatively common neoplastic etiology is meningiomas.

The most common etiology for CRAO is carotid artery atherosclerosis.

The most common etiology is multiple sclerosis.

Gallstones are the single most common etiology of acute pancreatitis.

Alcohol is the single most common etiology of chronic pancreatitis.

After 3 weeks he developed classic symptoms of the acute phase of the disease, thus establishing a common etiology (cause) for these two diseases.