Duodenal distension caused by a week duodenum peristalsis resulting in stabbing pain under the right rib cage due to compression of the vena cava inferior.

This 41-year-old female patient experienced sudden pain below the right rib cage after an episode of feverish and watery diarrhoea and subsequent flight with an aircraft.

The stabbing pain in the medial clavicular line started while the aircraft was ascending and persisted throughout the flight. The patient suddenly experienced difficulty breathing, with only short, shallow breaths due to a blocked inhalation.

The pain persisted for the last several months and is now a dull and constant one, but increases during standing. The patient also experienced a burning sensation on the right side of the tongue.

Despite undergoing two gastroscopies, two colonoscopies and an MRI of the abdomen and lab investigations , the standard diagnostics yielded no specific results.

The functional ultrasound with the PixelFlux technique quickly revealed the source of the symptoms: a compression of the vena cava by the massively enlarged descending portion of the duodenum.

The compression of the vena cava was accompanied by a severe left renal vein compression and a compression of the left common iliac vein as well as a median arcuate ligament syndrome. It is a long-standing and well-established fact that compression syndromes run together.

The combination of compression is, however, a significant factor that can cause specific sequelae.

Severe celiac trunk compression with changing flow acceleration in various positions of the diaphragm-here in expiration 296 cm/s vs 96 cm/s within the aorta

Flow volume measurements of the internal iliac veins clearly show a suppression of the left pelvic venous drainage compared to the right one as a sign of a relevant left sided outflow obstruction due to a May-Thurner syndrome

The compression site of the vena cava inferior matched the punctum maximum of the pain sensation, which was controlled by one finger palpation under sonographic guidance. This ruled out a proper Wilkie syndrome. After food uptake, the peristalsis of the horizontal portion was strong enough to lift up the SMA and transport sufficient amounts of duodenal content without any correlated symptoms.

The burning of the tongue is likely a gastro-esophageal reflux caused by the constant distension of the duodenum and the subsequent increase in intragastric pressure.

In the present patient, the left renal vein compression forced the congested left renal venous blood to run down the left ovarian vein and subsequently cross the pelvic organs to enter the venous return.  After passing the uterus and vagina, the blood enters the right internal iliac vein and is added to the normal blood flow volume from the lower hemisphere, which is conventionally transported by the vena cava inferior.

The additional volume from the left kidney overstrained the caval transport capacity. The patient experienced an increase in pain below the right rib cage and towards the right groin when she exercised and stood upright. This was due to an increase in renal blood flow and pooled venous volume of the lower body hemisphere.

The acute onset of symptoms after an episode of severe watery diarrhoea, fever and subsequent dehydration is explained as follows:

Dehydration reduces the tension of the vena cava, making it easier to compress. The viral infection of the intestines caused disturbed peristalsis and the distension of the duodenum at the outset, which combined to cause the clinical onset of vena cava compression.