Management of Lactic Acidosis in a Patient with Severe Psoriasis
Immediately discontinue methotrexate if the patient is taking it, as metformin-associated lactic acidosis requires prompt discontinuation and urgent hemodialysis, while the severe psoriasis should be managed with infliximab or acitretin once the lactic acidosis is stabilized.
Immediate Management of Lactic Acidosis
The first priority is addressing the life-threatening lactic acidosis, regardless of the psoriasis severity:
Discontinue any metformin immediately if the patient is taking it, as metformin-associated lactic acidosis is characterized by elevated blood lactate (>5 mmol/L), anion gap acidosis, and metformin plasma levels generally >5 mcg/mL 1
Institute prompt hemodialysis in patients with confirmed or strongly suspected metformin-associated lactic acidosis, as metformin is dialyzable with clearance up to 170 mL/min under good hemodynamic conditions, and hemodialysis has often resulted in reversal of symptoms and recovery 1
Provide general supportive measures in a hospital setting, as lactic acidosis is associated with high mortality and treating the underlying causes is the only warranted intervention 2
Avoid sodium bicarbonate administration, as it increases lactate production and is of little value in type A lactic acidosis 3
Critical Medication Review for Psoriasis
Once the patient is stabilized from lactic acidosis, review all medications that may have precipitated or worsened either condition:
Never use systemic corticosteroids for psoriasis management, as they precipitate erythrodermic psoriasis, generalized pustular psoriasis, or very unstable psoriasis upon discontinuation, potentially causing fatal deterioration 4, 5
Discontinue lithium, chloroquine, or mepacrine if the patient is taking them, as these may cause severe, potentially fatal deterioration of psoriasis 6, 5
Avoid beta-blockers and non-steroidal anti-inflammatory agents if possible, as they may precipitate or worsen psoriasis 6
Management of Severe Psoriasis After Stabilization
For severe psoriasis (>10% body surface area or significant quality of life impact), systemic therapy is required 7:
Infliximab is the preferred first-line biologic therapy, particularly if the patient has generalized pustular or erythrodermic psoriasis, as it demonstrates superior efficacy with rapid and often complete disease clearance at standard dosing of 5 mg/kg infused at weeks 0,2, and 6, then every 8 weeks thereafter 4, 5
Acitretin (25-50 mg daily) is the preferred conventional systemic agent if biologics are not immediately available or contraindicated, with response times as early as 3 weeks, particularly effective for pustular psoriasis 7, 4
Avoid methotrexate initially in this clinical scenario, as the patient has just experienced lactic acidosis and methotrexate has absolute contraindications including significant hepatic damage, anemia, leucopenia, and thrombocytopenia—conditions that may be present or developing in the context of severe lactic acidosis 5
Cyclosporine (2.5-5 mg/kg daily) may be considered if renal function is normal and blood pressure is controlled, achieving response in approximately 3 weeks, but requires careful monitoring given the recent metabolic crisis 4
Pretreatment Assessment Before Initiating Systemic Therapy
Before starting any systemic psoriasis therapy after lactic acidosis resolution:
Screen for active or latent tuberculosis, hepatitis B, and fungal infections before initiating biologics like infliximab, due to increased infection risk 4
Obtain complete blood count, lipid panel, and liver function tests before initiating acitretin, with ongoing monitoring of lipids and hepatic function 4
Obtain baseline serum creatinine and blood pressure before initiating cyclosporine, with regular monitoring of both parameters due to glomerulosclerosis and hypertension risk 4
Assess renal function with eGFR to ensure it is >45 mL/min/1.73 m² before considering any renally-cleared medications, given the recent lactic acidosis episode 1
Common Pitfalls to Avoid
Do not delay hemodialysis if metformin-associated lactic acidosis is suspected—prompt dialysis is recommended to correct acidosis and remove accumulated metformin 1
Do not use systemic corticosteroids as a "bridge therapy" while waiting for other systemic agents to work, as this can precipitate severe disease exacerbation upon discontinuation 4, 5
Do not restart metformin (if it was the cause) until renal function is stable with eGFR >45 mL/min/1.73 m², and even then, carefully reassess the benefit-risk ratio 1
Do not underestimate the severity of either condition—patients with generalized pustular or erythrodermic psoriasis require hospital admission due to risk of systemic involvement and potential mortality 4