“Superior Mesenteric Artery Syndrome: Insights into Diagnosis and Management”

Dr.Ghaniya KC , Dr.Vinitha Prasad, Dr.Stefy Sunny DrShela Sany ,DrC Jayakumar
AIMS- Kochi

Thirteen year old boy presented with complaints continuous non-projectile and non-bilious vomiting of three weeks’ duration, mostly occurring after meals.
The vomiting was associated with decreased appetite and a significant weight loss of 6 kg over two months. Additionally, the patient experienced epigastric pain post vomiting.

Medical History
No significant hostel in the past
Clinical Examination
-Vital Signs:Stable
PICCLE normal
Cervical lymphadenopathy present
Auxology
Weight: 27.5 kg (below 3rd percentile)
Height:152 cm (25th-50th percentile)
BMI: 11.4 kg/m² (below 3rd percentile)

-Abdominal Examination abdomen soft, bowel sounds normal.No hepato splenomegaly

  • Systemic Examination :Respiratory, cardiovascular, and neurological examinations were unremarkable.

Differential Diagnosis

  • Acid peptic doses disease
    Diabetes
    Pancreatic pathology
    IBD
    Aneroxianervosa
    Subacute intestinal obstruction
    ICSOL
    Functional Gastrointestinal Disorder
  • Superior Mesenteric Artery Syndrome (SMAS)

Investigations
Labs
TC – 5.94 ku/ml, Neutrophils – 37.2%, Lymphocytes – 52.2%, Hb – 13.7 g/dl, Platelets – 338 ku/ml
Liver Function Tests, Renal Function Tests, Thyroid Function Tests:Normal
Gastric Aspirate for Gene Xpert : Negative

  • Echocardiogram :Normal
  • Abdominal Ultrasound : Normal
  • Brain MRI: Normal
  • Contrast-enhanced CT Abdomen :Revealed compression of the D3 segment of the duodenum between the SMA and abdominal aorta, hepatomegaly, and minimal ascites.

Endoscopic Findings
Upper endoscopy showed evidence of duodenitis, and a nasojejunal (NJ) tube was placed for feeding.

Diagnosis
The patient was diagnosed with Superior Mesenteric Artery Syndrome based on clinical presentation and imaging findings.

Management
Conservative Management:
The initial approach focused on conservative therapy:

  • Frequent small meals supplemented with high-calorie liquid
  • Postural therapy
  • NJ tube feeding with special formula delivered via a pump for 16-20 hours daily to ensure adequate caloric and fluid intake was fine for this child
    Loss of fat between Aorta andSMA will aggravate the obstruction

Nutritional Goals: The primary objective was to achieve weight gain to restore the mesenteric fat pad, increase the angle between the SMA and aorta, and alleviate the compression.

Potential Next Steps:If conservative measures prove ineffective within 6 to 8 weeks, and if the patient experiences worsening symptoms, severe pain, or intolerance to gastrointestinal feeding, surgical intervention will be considered.

Discussion
SMAS is a rare entity with an incidence of 0.013% to 0.3%, more commonly affecting females and those with a slender build after acute weight loss. This condition occurs when the third part of the duodenum is compressed between two arteries – abdominal aorta (AA) and one of its branches called the SMA. The SMA provides blood supply to the small intestines and the first part of the colon. Compression of the SMA against the AA can prevent duodenal contents from draining into the jejunum

CT angiography or MRI can measure the angle between the AA and the SMA. The normal angle is 25 – 60 degrees while with SMA syndrome is reduced to 7 – 22 degrees. The distance between the AA and the SMA is normally 10 – 28 mm but with SMA syndrome it is reduced to 2 to 8 mm. Some people with SMA syndrome may be born with this abnormality and diagnosed as infants or preteen children.

The clinical presentation often mimics small bowel obstruction, with symptoms such as vomiting, nausea, early satiety, anorexia, and abdominal pain.
Conservative management is preferred, aiming for nutritional rehabilitation and weight gain. Surgical intervention is reserved for cases unresponsive to medical management.

Conclusion
This case highlights the importance of considering SMAS in the differential diagnosis of pediatric patients presenting with persistent vomiting and significant weight loss. Early recognition and a multidisciplinary approach to management are crucial for improving outcomes in affected individuals.

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