1. THE IMPORTANCE OF KNOWING HOW TO READ A "TICKET”
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Iamele L, Cappello S, Pipino M, Caccetta L, Minafra G, Carbone M, Insalata M, Giancola A, Ventrella F
S.C. Medicina Interna Ospedale “G. Tatarella” – Cerignola, ASL FG
Direttore dott. Francesco Ventrella
A 77 year-old man is hospitalized for anorexia, pain and brachial-crural left functional impotence. A month before NSTEMI (PCI + stent). During the hospitalization he presented dyspnea and general malaise.
The following blood tests were abnormal: CA125 [x2], ferritin [x4], total protein 4.9 g/dl [ ], AST [x2], uric acid [x 1.5], LDH [x2], calcium [x1.5]. Three ABGs were performed with detection of hyperlactatemia and normal pH (fig. 1).
Lactate levels are commonly evaluated in acutely ill patients. Although most often used in the context of evaluating shock (fig. 2), lactate levels can be elevated for many reasons. While tissue hypoperfusion may be the most common cause of elevation, many other etiologies or contributing factors exist. Clinicians need to be aware of the many potential causes of lactate level elevation as the clinical and prognostic importance of an elevated lactate level varies widely by disease state. Moreover, specific therapy may need to be tailored to the underlying cause of elevation. Hyperlactatemia may be associated or not with acidosis (lactic acidosis), and may reflect increased production or decreased clearance. It differs Type A by increased anaerobic production (hypoperfusion / tissue hypoxia) and Type B by increased aerobic production (SIRS-sepsis, diabetes, drugs/toxics, inborn metabolic deficiency, hematologic malignancies) or by decreased clearance (hepatic or renal insufficiency or medication ). Hyperlactatemia with normal pH is more often due to sepsis or drugs, those with acidosis to hypoperfusion, hypoxia, toxics.
The diagnostic study excluded the common causes of hyperlactatemia!
Hyperlactatemia in malignant disease is uncommon and generally in hematologic malignancies;(1-3) hyperlactatemia in solid malignancies, not receiving chemotherapy, is rare (14 cases from 1978 to 2006).(4)
Figure 1: Arterial Blood Gas
In order to discover the cause of hyperlactatemia, a total body TC was performed (figure 3): "extended abdominal heteroplasia from initial uncertain origin (pancreas?) with lumbo-aortic lymph node and bone metastases with pathological fractures of the third left rib and left ischiopubic and ileopubic ramus”.
Figure 2: Lactate levels, BP and mortality
Conclusion
Elevated lactate levels can be caused by a variety of conditions, including shock, sepsis, cardiac arrest, trauma, seizure, ischemia, diabetic ketoacidosis, thiamine deficiency, malignancy, liver dysfunction, genetic disorders, toxins, and medications.
Elevated lactate levels have been associated with increased mortality rates in a variety of diseases, such as sepsis, trauma, and cardiac arrest.
Decreased lactate clearance has been found to be associated with increased mortality rates in sepsis, postecardiac arrest, trauma, burns, and other conditions
When approaching the patient with an elevated lactate level, the possibility of a multifactorial etiology must be considered.
Despite its imperfect sensitivity and specificity, the lactate assay remains a clinically useful test that can alert a clinician to underlying hypoperfusion in need of immediate treatment or an etiology not readily apparent on initial evaluation.
In conclusion always evaluate all parameters of the ABG: they help in the diagnosis, even in not critical patients.
Figure 3: CT scan
1) Vernon C, LeTourneau JL.Lactic Acidosis: Recognition,Kinetics, and Associated Prognosis. Crit Care Clin 2010; 26: 255–83
2) Andersen LW et al. Etiology and Therapeutic Approach to Elevated Lactate Levels. Mayo Clin Proc 2013; 88:
3) Ruitz LP et al. Type B Lactic Acidosis Secondary to Malignancy: Case Report, Review of Published Cases, Insights into Pathogenesis, and Prospects for Therapy. The Scientific World Journal 2011;11:1316–24
4) de Groot R et al. Type B lactic acidosis in solid malignancies.The Netheland Journal of Medicine 2011,69:120-3