My hospitalized patient with sepsis has persistently elevated lactic acid despite volume resuscitation, source control, and adequate oxygenation. What could I be missing?

Although the causes of lactic acidosis are legion (eg, sepsis, tissue hypoperfusion, ischemic bowel, malignancy, medications, liver dysfunction), thiamine deficiency (TD) is an often-overlooked cause of persistently elevated serum lactic acid (LA) in critically ill hospitalized patients,1 reported in 20-70% of septic patients.2  Septic shock patients may be particularly at risk of TD because of increased mitochondrial oxidative stress, decreased nutritional intake and presence of comorbid conditions (eg,  alcoholism, persistent vomiting).3

Early recognition of TD in hospitalized patients may be particularly difficult because of the frequent absence of the “classic” signs and symptoms of Wernicke’s encephalopathy (eg, ataxia, cranial nerve palsies and confusion) and lack of readily available confirmatory laboratory tests.4

TD-related lactic acidosis should be suspected when an elevated LA persists despite adequate treatment of its putative cause(s) (4,5). Administration of IV thiamine in this setting may result in rapid clearance of LA.3-5

TD causes lactic acidosis type B which is due to the generation of excess LA, not impairment in tissue oxygenation, as is the case for lactic acidosis type A. Thiamine is an essential co-factor in aerobic metabolism, facilitating the conversion of pyruvate to acetyl-CoA which enters the citric acid (Krebs) cycle within the mitochondria. In TD, pyruvate does not undergo aerobic metabolism and is converted to LA instead, leading to lactic acidosis.

Bonus pearl: Did you know that because of its limited tissue storage, thiamine stores may be depleted within only 3 weeks of reduced oral intake!

References

  1. O’Donnell K. Lactic acidosis: a lesser known side effect of thiamine deficiency. Practical Gastroenterol March 2017:24.   https://www.practicalgastro.com/article/176921/Lactic-Acidosis-Lesser-Known-Side-Effect-of-Thiamine-Deficiency
  2. Marik PE. Thiamine: an essential component of the metabolic resuscitation protocol. Crit Care Med 2018;46:1869-70. https://journals.lww.com/ccmjournal/Fulltext/2018/11000/Thiamine___An_Essential_Component_of_the_Metabolic.23.aspx
  3. Woolum JA, Abner EL, Kelly A, et al. Effect of thiamine administration on lactate clearance and mortality in patients with septic shock. Crit Care Med 2018;46:1747-52. https://journals.lww.com/ccmjournal/Fulltext/2018/11000/Effect_of_Thiamine_Administration_on_Lactate.5.aspx
  4. Kourouni I, Pirrotta S, Mathew J, et al. Thiamine: an underutilized agent in refractory lactic acidosis. Chest 2016; 150:247A. https://journal.chestnet.org/article/S0012-3692(16)56459-9/pdf
  5. Shah S, Wald E. Type B lactic acidosis secondary to thiamine deficiency in a child with malignancy. Pediatrics 2015; 135:e221-e224. http://pediatrics.aappublications.org/content/135/1/e221

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My hospitalized patient with sepsis has persistently elevated lactic acid despite volume resuscitation, source control, and adequate oxygenation. What could I be missing?

Should I continue nadolol in my patient with cirrhosis and refractory ascites?

Under certain circumstances, you may need to! Although nonselective beta blockers (NSBBs), such as nadolol and propranolol, have been the cornerstone of medical treatment of portal hypertension in preventing variceal bleeding in patients with cirrhosis for decades, recent reports of their association with worsening survival, increased risk of hepatorenal syndrome and acute kidney injury in patients with refractory ascites or spontaneous bacterial peritonitis [SBP]) 1,2 have added controversy to their routine use in end-stage cirrhosis.

This is because patients with end-stage cirrhosis may be highly dependent on their cardiac output (particularly the heart rate) in maintaining an adequate arterial blood pressure 3-5 and the negative inotropic and chronotropic effects of NSBBs blunt this compensatory mechanism. The result is a drop in the cardiac output that may be particularly significant in the presence of conditions already associated with hypotension, such as sepsis, spontaneous bacterial peritonitis (SBP), or hemorrhage, further increasing the risk of renal hypoperfusion and hepatorenal syndrome.3

Although 2 meta-analysis studies failed to find an association between NSBBs and increased mortality among patients with cirrhosis and ascites, 6,7 serious concerns over the adverse effects of these drugs in at least a subset of patients has not waned.  Some have recommended reducing NSBB dose or discontinuing treatment in patients with refractory ascites or SBP and any of the following parameters: 4

  • Systolic blood pressure <90 mmHg
  • Serum creatinine >1.5 mg/dL
  • Hyponatremia <130 mmol/L

Similar recommendations were made by a 2015 consensus conference on individualizing the care of patients with portal hypertension.

In the absence of randomized-controlled studies, it seems prudent to proceed with more caution when using NSBBs in patients with end-stage cirrhosis and watch closely for any signs of hypotension or renal function deterioration.

References

  1. Serste T, Njimi H, Degre D, et al. The use of beta-lackers is associated with the occurrence of acute kidney injury in severe hepatitis. Liver In 2015;35:1974-82. https://www.ncbi.nlm.nih.gov/pubmed/25611961
  2. Mandorfer M, Bota S, Schwabl P, et al. Nonselective beta blockers increase risk of hepatorenal syndrome and death in patients with cirrhosis and spontaneous bacterial peritonitis. Gastroenterol 2014;146:1680-90. https://www.sciencedirect.com/science/article/pii/S0016508514003060?via%3Dihub
  3. Garcia-Tsao G. The use of nonselective beta blockers for treatment of portal hypertension. Gastroenterol Hepatol 2017;13: 617-19. http://www.gastroenterologyandhepatology.net/archives/october-2017/the-use-of-nonselective-beta-blockers-for-treatment-of-portal-hypertension/
  4. Reiberger T, Mandorfer M. Beta adrenergic blockade and decompensated cirrhosis. J Hepatol 2017;66: 849-59. https://www.ncbi.nlm.nih.gov/pubmed/27864004
  5. Giannelli V, Lattanzi, Thalheimer U, et al. Beta-blockers in liver cirrhosis. Ann Gastroenterol 2014;27:20-26. https://www.ncbi.nlm.nih.gov/pubmed/24714633
  6. Facciorusso A, Roy S, Livadas S, et al. Nonselective beta-blockers do not affect survival in cirrhotic patients with ascites. Digest Dis Sci 2018;63:1737-46. https://link.springer.com/article/10.1007%2Fs10620-018-5092-6
  7. Njei B, McCarty TR, Garcia-Tsao G. Beta-blockers in patients with cirrhosis and ascites: type of betablocker matters. Gut 206;65:1393-4. https://gut.bmj.com/content/gutjnl/65/8/1393.full.pdf
  8. De Franchis R. Expanding consensus in portal hypertension. Report of the Baveno VI Consensus Workshop: stratifying risk and individualizing care for portal hypertension.  J Hepatol 2015;63:743-52.  https://www.ncbi.nlm.nih.gov/pubmed/26047908  

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Should I continue nadolol in my patient with cirrhosis and refractory ascites?