This case report describes a woman in her 30s who developed severe complications after undergoing gastric bypass surgery for weight loss. She experienced serious nerve damage and brain problems caused by a severe vitamin B1 (thiamine) deficiency. Her symptoms included persistent nausea, vomiting, and progressive leg weakness. After receiving high-dose vitamin B1 treatment and physical therapy for 8 weeks, her leg strength improved, though she still needs help walking. This case highlights an important risk that people who have gastric bypass surgery need to know about and monitor carefully.

The Quick Take

  • What they studied: A single patient who developed serious nerve and brain damage from vitamin B1 deficiency after weight loss surgery
  • Who participated: One woman in her 30s who had recently undergone Roux-en-Y gastric bypass surgery
  • Key finding: The patient had dangerously low vitamin B1 levels (28 nmol/L compared to the normal range of 70-108 nmol/L), which caused nerve damage in her legs and brain inflammation. After aggressive vitamin B1 treatment, her condition improved but didn’t fully resolve.
  • What it means for you: If you’re considering or have had gastric bypass surgery, it’s crucial to monitor your vitamin B1 levels and take supplements as recommended by your doctor. This case shows that vitamin deficiencies after weight loss surgery can be serious and may cause permanent damage if not caught early.

The Research Details

This is a case report, which means doctors documented the medical history and treatment of one specific patient. The patient came to the emergency room with severe nausea, vomiting, and leg weakness that had been getting worse over 6 weeks. Doctors performed physical exams, brain and spine imaging (MRI scans), blood tests, spinal fluid tests, and nerve function tests to figure out what was wrong.

The doctors found that the patient had extremely low levels of vitamin B1 (thiamine), a nutrient that’s essential for nerve and brain function. They also discovered evidence of nerve damage in the lower back and legs, and signs of brain inflammation. After identifying the problem, they treated her with high doses of vitamin B1 and gave her physical therapy for 8 weeks.

Case reports are important because they document unusual or serious situations that doctors might not see often. They help alert the medical community to potential problems and can lead to more research.

This research matters because gastric bypass surgery is a common weight loss procedure, but it can prevent the body from absorbing certain nutrients properly. By documenting this serious case, doctors can better understand the risks and help other patients avoid similar complications. It also shows why vitamin monitoring is so important after weight loss surgery.

This is a case report describing one patient, which is the lowest level of scientific evidence. However, case reports are valuable for identifying rare or serious complications that might not show up in larger studies. The doctors performed thorough testing (imaging, blood work, nerve studies) to confirm their diagnosis, which strengthens the reliability of their findings. Readers should understand that this describes one person’s experience and may not apply to everyone who has gastric bypass surgery.

What the Results Show

The patient presented with a combination of symptoms affecting her nervous system. She had persistent nausea and vomiting for 6 weeks, along with progressive weakness in both legs. Physical examination showed unusual eye movements (upbeat nystagmus), partial paralysis of the legs, loss of reflexes in the lower legs, and decreased sensation in her lower limbs.

Blood tests revealed the root cause: vitamin B1 deficiency with a level of 28 nmol/L, which is less than half the normal minimum of 70 nmol/L. Nerve testing showed damage to the nerves in the lower back and legs (lumbosacral polyradiculopathy). Brain and spine imaging were surprisingly normal, even though the patient had signs of brain inflammation.

After receiving aggressive vitamin B1 supplementation and 8 weeks of physical rehabilitation, the patient’s leg strength improved. However, she did not fully recover and still requires assistance to walk. This shows that while treatment can help, the damage from severe vitamin deficiency may not be completely reversible.

Additional tests ruled out other possible causes of the patient’s symptoms. Tests for antibodies associated with autoimmune nerve disease were negative. Spinal fluid analysis showed no signs of nerve root inflammation. These negative findings helped confirm that vitamin B1 deficiency was the actual cause of the problem, not other diseases.

Vitamin B1 deficiency after gastric bypass surgery is a known but uncommon complication. This case is notable because it shows how severe the consequences can be when deficiency goes undetected and untreated for several weeks. Previous research has documented that people who have gastric bypass surgery are at higher risk for various vitamin deficiencies, but serious cases like this one highlight why careful monitoring is essential.

This is a single case report, so the findings apply only to this one patient and may not represent what happens to other people. We don’t know how common this complication is or whether certain people are at higher risk. The case doesn’t tell us how long the patient had been deficient before symptoms appeared, or whether earlier treatment might have prevented permanent damage. Additionally, we don’t have long-term follow-up information about whether the patient continued to improve after the 8-week treatment period.

The Bottom Line

If you have had or are planning to have gastric bypass surgery: (1) Take all recommended vitamin supplements, especially B vitamins, as directed by your surgeon (HIGH confidence); (2) Get regular blood tests to check your vitamin levels, particularly vitamin B1, as recommended by your doctor (HIGH confidence); (3) Report any symptoms like persistent nausea, vomiting, weakness, numbness, or unusual eye movements to your doctor immediately (HIGH confidence); (4) Work with a dietitian who specializes in post-surgery nutrition (MODERATE confidence).

This case is most relevant to people who have had or are considering gastric bypass surgery. It’s also important for doctors who care for post-surgery patients to recognize these symptoms early. Family members of people who have had this surgery should also be aware of warning signs. This case is less relevant to people who haven’t had weight loss surgery, though it illustrates the importance of vitamin B1 in general health.

In this case, symptoms developed over 6 weeks after surgery. Improvement in leg strength began after starting high-dose vitamin B1 treatment, but full recovery took at least 8 weeks of treatment and rehabilitation. Some effects (the need for walking assistance) persisted even after 8 weeks, suggesting that early detection and prevention are more important than treating the problem after it develops.

Want to Apply This Research?

  • If you’ve had gastric bypass surgery, use the app to track: (1) Daily vitamin supplement intake (especially B-complex vitamins), (2) Any symptoms like nausea, vomiting, leg weakness, numbness, or tingling, (3) Dates of blood tests and vitamin level results, (4) Physical activity and walking ability to monitor for changes in strength or mobility
  • Set daily reminders in the app to take your prescribed vitamin supplements at the same time each day. Create a symptom log to record any unusual sensations or weakness. Schedule and track appointments for regular blood work to monitor nutrient levels. Use the app to communicate with your healthcare team about any concerning symptoms.
  • Establish a long-term tracking system that includes: monthly reviews of supplement adherence, quarterly symptom check-ins, tracking of scheduled lab work results (typically recommended every 6-12 months after gastric bypass), and regular notes on physical function and energy levels. Set alerts for upcoming lab appointments and supplement refills to ensure consistent monitoring.

This case report describes one patient’s experience with a serious complication after gastric bypass surgery. It is not medical advice and should not be used to diagnose or treat any condition. If you have had gastric bypass surgery or are experiencing symptoms like persistent nausea, vomiting, leg weakness, numbness, or unusual eye movements, contact your healthcare provider immediately. Always follow your surgeon’s recommendations for vitamin supplementation and monitoring after weight loss surgery. This information is for educational purposes only and does not replace professional medical evaluation and treatment.