A zebra revealed: The “other” complications of anesthesia

A 6-month-old male with Poland syndrome and normal development presented with lethargy, hypotonia, andshock He was admitted to the ICU with presumptive Mycoplasma/Coronavirus (non-SARS-CoV2) PCR-positivesepsis Due to persistent hypotonia despite fluid resuscitation, he was given botulism immune globulin forpossible infantile botulism Though hemodynamic and laboratory values improved, his persistent hypotoniaand newly developed areflexia prompted concern for alternative neurologic etiologies necessitating a brainand spine MRI with propofol sedation Twenty-four hours after sedation, he had acute decompensationrequiring intubation, pressor support, and continuous renal replacement therapy due to severe lactic acidosis On exam, he was irritable Vitals showed desaturations and bradycardia He exhibited respiratory distress withpoor secretion clearance and increased work of breathing Extremities were cool, capillary refill was delayed,and distal pulses were weak Neurologic exam demonstrated diffuse hypotonia and severe head lag He hadweakness of palate elevation and a hoarse, weak cry Strength was diminished throughout and worse in thelower extremities compared to the upper extremities Reflexes were absent in the lower extremities anddiminished in the upper extremities Initial laboratory analysis revealed ketotic hypoglycemia to 38 mg/dL Venous blood gas showed anion gap metabolic acidosis with incomplete compensatory respiratory alkalosis(Table 1) Low level lactic acidosis (4 3mmol/L) persisted prior to sedation and abruptly worsened 24h aftersedation with lactic acid peaking at 15 5 mmol/L Liver enzymes (near normal on admission) significantlyincreased (ALT 1059 U/L and AST 2798 U/L) Mycoplasma was confirmed with positive IgM and negative IgG Botulism testing returned negative Bedside echocardiogram showed poor function (normal on admission) Magnetic resonance imaging showed a symmetric myopathy (Figure 1) The differential for his persistenthypotonia was concerning for an infectious or post-infectious encephalitis or polyneuropathy, botulism,Guillain-Barre syndrome, motor neuron disease, or congenital myopathy Given persistent metabolic acidosis,there was concern for a Mycoplasma/Coronavirus (non-SARS-CoV2) infection triggering a metabolic crisisleading to his initial presentation The abrupt shock and multiorgan failure shortly after sedation suggestedthat propofol had exacerbated the crisis due to a mitochondrial metabolic disorder Rapid whole genomesequencing revealed a rare homozygous NFS1 mutation affecting the iron-sulfur complex and causingmitochondrial dysfunction, specifically in the respiratory chain I/II pathways A mitochondrial cocktail includingacetylcysteine was started, and he slowly improved At time of discharge, his cardiac and renal function hadnormalized, and his liver enzymes were nearly normal When he is unwell in the future, the priorities of hismedical management will be to decrease metabolic demands and limit anesthetic exposure Complicationscan occur after anesthetic exposure Propofol inhibits multiple respiratory complex enzymes, uncouplesoxidative phosphorylation, and reduces utilization of fatty acids Mitochondrial defects should be consideredin patients who decompensate after exposure to propofol or other anesthetics Venous blood gases Patient arrived in anion gap metabolic acidosis with incomplete respiratory compensation Initial treatmentprior to sedation normalized venous blood gas After sedation, patient abruptly worsened withuncompensated anion gap metabolic acidosis Symmetric myopathy Magnetic resonance imaging of the spine showed symmetric bilateral T2 hyperintensity and enhancement ofthe gluteus medius and paraspinal muscles (pictured above) and shoulder girdle muscles (not pictured) Thistype of symmetric myopathy can be seen in myositis, denervation injury, hereditary neuropathies,demyelinating polyneuropathies, and mitochondrial disease (Figure Presented)