Stumped by the Shunt

Nidhi Rohatgi, MD, MS* and Dean Winslow, MD, Stanford University School of Medicine, Stanford, CA

Meeting: Hospital Medicine 2016, March 6-9, San Diego, Calif.

Abstract number: 766

Categories: Adult, Clinical Vignettes Abstracts

Case Presentation:  63-year-old female admitted to neurosurgery for lumboperitoneal (LP) shunt placement for cerebrospinal fluid (CSF) leak, 35 days after craniotomy for epidermoid tumor resection. Patient had no relevant prior history. After LP shunt placement, the patient reported positional headache between postoperative day (POD) 0-4, back pain starting POD 5, intermittent drowsiness, nausea, and diffuse intense sharp abdominal pain starting POD 6. Hospitalist was consulted for abdominal pain. Patient was afebrile with WBC of 14,000 on POD 6. On abdominal exam, there was diffuse tenderness with voluntary guarding, no rebound. CT abdomen/pelvis with contrast on POD 7 showed mild postoperative ileus, LP shunt without evidence of dislocation, and distended gallbladder with sludge but no wall thickening or pericholecystic fluid. By POD 8 morning, abdomen was tender in the left lower quadrant and right upper quadrant (RUQ) with guarding. By POD 8 evening, the RUQ abdominal tenderness worsened with radiation to the back. Tmax was 37.7°C. WBC was 11,100, total bilirubin 0.2, AST 16, ALT 32, ALP 110, and normal lipase. The patient was started on empiric piperacillin/tazobactam for possible acute cholecystitis. Between POD 9-10, RUQ abdominal pain improved but she continued to remain intermittently drowsy. By POD 11, she became more somnolent, with severe diffuse abdominal pain, and nausea. Tmax was 37.9°C with WBC of 16,800. All opiates were discontinued. Noncontrast CT head showed interval enlargement of the ventricles. LP shunt settings were adjusted. Between POD 12-13, the patient appeared more awake, abdominal pain and nausea improved. On POD 14, increasing somnolence with worsening abdominal pain were noted. LP shunt tap revealed purulent CSF with gram-negative rods. Culture revealed pansensitive Pseudomonas aeruginosa. LP shunt was removed on POD 14. She was treated with a prolonged course of antibiotics till POD 72 as she continued to have symptoms of residual meningitis with MRI findings of leptomeningitis, ventriculitis, and pus in the ventricles. A ventriculoperitoneal shunt was placed on POD 72.

Discussion: Most cases of gram-negative meningitis in adults are postoperative, presenting 2-10 days after surgery.  The rate of shunt infection is reported to be 1-18%. The clinical presentation of shunt related meningitis is subtle; fever being the most common symptom followed by shunt malfunction presenting as nausea, vomiting, headache, and mental status changes. Intraluminal infection of peritoneal CSF shunts may present with abdominal pain or acute peritonitis. Meningismus may not be prominent, as the infected CSF in the ventricles does not communicate with CSF in the subarachnoid space. Imaging modalities of choice in acute complicated meningitis are MRI and CT head, with and without contrast. 

Conclusions: This case demonstrates the importance of maintaining a high index of suspicion for meningitis in patients with CSF shunts as the clinical presentation may be subtle, and may present as an acute abdomen in peritoneal CSF shunt infections.

To cite this abstract:

Rohatgi N, Winslow D. Stumped by the Shunt. Abstract published at Hospital Medicine 2016, March 6-9, San Diego, Calif. Abstract 766. Journal of Hospital Medicine. 2016; 11 (suppl 1). https://www.shmabstracts.com/abstract/stumped-by-the-shunt/. Accessed July 24, 2019.

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