Case Presentation: A 34-year-old woman presented with three months of worsening abdominal pain resulting in decreased oral intake and 30-lb weight loss. Over the prior month, she also developed altered mental status. The patient had a positive tuberculin skin test (TST) in the past year with no evidence of pulmonary disease on chest imaging. She had an aunt with pulmonary tuberculosis (TB).
On exam, she was a thin woman with generalized abdominal pain. Lipase level was 819 units/L (0-160). She was treated for pancreatitis but her abdominal pain persisted. Her mental status worsened and confabulation was noted.
HIV testing returned negative. Lumbar puncture was obtained and CSF did not reveal an obvious cause of mental status changes. Albumin was 1.7 gm/dL and thiamine level was 12.1 nmol/L (normal 74-222). MRI of the brain returned with thalamic changes consistent with Wernicke encephalopathy. Abdominal CT scan revealed a normal pancreas and multiple large, necrotic lymph nodes scattered throughout the abdomen and pelvis. Excisional lymph node biopsy was performed. Cultures returned positive for mycobacterium tuberculosis. She was diagnosed with tuberculous lymphadenitis and started on rifampin, isoniazid, pyrazinamide and ethambutol. Mental status improved with long-term, high dose intravenous thiamine supplementation.
Discussion: Abdominal pain is a common complaint encountered by the general internist. This patient met the diagnostic criteria for acute pancreatitis with elevated lipase and characteristic abdominal pain making initiation of treatment for this diagnosis reasonable. However, lack of clinical improvement and absence of pancreatic inflammation on imaging prompted the clinician to investigate further. Moreover, multiple large necrotic lymph nodes on abdominal imaging and the chronic malnutrition evident on initial exam and labs suggested an alternative diagnosis.
Clinical presentation for abdominal TB includes abdominal pain, weight loss, changes in bowel habits, fever, hepatomegaly, and ascites. The presence of recent positive TST, exposure to TB in the past, and necrotic lymph nodes made TB a consideration for the cause of her presenting issues. To definitively diagnose extrapulmonary tuberculosis, a tissue biopsy and AFB culture or TB-PCR is needed.
Wernicke encephalopathy from thiamine deficiency is classically associated with alcohol abuse. It can also occur in non-alcoholic patients with poor nutritional status. Abdominal TB results in alterations in gut mucosa that can result in malabsorption. Hypomagnesemia, which was also present in this case, has also been linked to Wernicke encephalopathy secondary to its role as cofactor for thiamine activation.
Conclusions: Abdominal tuberculosis often poses a diagnostic challenge, as its presentation is associated with nonspecific symptoms. Given the typical delay in diagnosis, this chronic infection can lead to malnutrition resulting in complications like thiamine deficiency.