Lentiform fork sign due to severe metabolic acidosis

Abstract

DescriptionAn 11-month-old, developmentally normal, female infant presented with acute-onset fever, vomiting, shallow breathing and gradually progressive lethargy for the past 2 days. There was no history of seizures, neck stiffness, focal motor deficits, cranial nerve palsies, tone changes, rash, diarrhoea, recurrent encephalopathies, abnormal body odour, recurrent infections or hospitalisations, drug or toxin ingestion. Her past and family history was not contributory. On examination, anthropometric parameters were normal for age. She had mild pallor, angular cheilitis, wrist widening, tachypnea (respiratory rate 58/min) with acidotic breathing. She was conscious with fluctuations in alertness (Glasgow Coma Scale (GCS) E4M5V2) and irritability with reduced spontaneous activity, mild hypotonia, preserved antigravity movements, brisk muscle stretch reflexes, bilateral extensor plantar response, absence of oculomotor abnormalities, cranial nerve palsies or bulbar signs and normal fundi. Rest of the systemic examination was unremarkable. A clinical diagnosis of acute febrile encephalopathy was considered.Laboratory investigations showed haemoglobin 85 g/L, platelets 86 000 cells/µL (range 150 000-400 000), total leucocyte count 9500 cells/µL (range 4000-11 000) (neutrophils 51%, lymphocytes 41%, monocytes 7% and eosinophils 1%), serum sodium 146 meq/L, potassium 4 meq/L, urea 36 mg/dL, creatinine 0.9 mg/ dL, C reactive protein 56 mg/dL (normal below 8 mg/dL), B 12 132 pg/mL (range 211-911), homocysteine 3.86 μmol/L (range 5-15), pH 7.21, serial lactate values 4.5 and 1.4 mmol/L (normal <2), ammonia 80 μmol/L and normal anion gap. Blood glucose records were normal throughout the hospital stay. Cerebrospinal fluid analysis showed no cells, glucose 149 mg/dL and protein 152 mg/ dL. Blood, urine and cerebrospinal fluid cultures were sterile. MRI of the brain showed bilateral basal ganglia involvement with characteristic lentiform fork sign and a lactate peak on magnetic resonance spectroscopy ( figure 1A-E). Urine analysis did not reveal any reducing substances, methyl malonic acid metabolites, sulfites, glycosaminoglycans or ketones. Tandem mass spectroscopy/gas chromatography was normal. Metabolic acidosis gradually improved with supportive treatment and recovery from febrile illness, and she was discharged after 2 weeks. Follow-up evaluation after 2 months showed mild bradykinesia on neurological examination, and repeat brain MRI revealed remarkable resolution of previously reported lesions.We describe a case of acute metabolic acidosis associated with acute febrile encephalopathy, bilateral basal ganglia involvement and characteristic lentiform fork sign. The cause for metabolic acidosis was probably recurrent vomiting for the past 2 days associated with poor intake and lethargy. Underlying infection or overwhelming sepsis was also a contributory factor to the initial acidosis. Severe metabolic acidosis, with or without hypoxia and ischaemia, leads to changes in the cerebral microvascular anatomy and blood-brain b...

Neuroimaging Spectrum of Severe Hypernatremia in Infants with Neurological Manifestations

“…The classical lentiform fork sign with basal ganglia hyperintensities was not seen in any patient, and the acidosis did not correlate with ODS. 21 Hence, recognition of these radiological patterns of injury gives a clue toward underlying severe hypernatremia. In the ideal setting, the resolution of these changes with correction for hypernatremia should be looked for.…”

Case Report: A case of encephalopathy presenting the lentiform fork sign on MRI in a diabetic dialysis patient - diabetic uremic syndrome or metformin-related encephalopathy?

“…The lentiform fork sign is rare but non-specific. Thus, a differential diagnosis should be considered (Table 1) 8,[11][12][13][14][15] , of which ME or DUS may be the cause in the present case.…”

“…In particular, diabetic dialyzed patients can present with bilateral symmetrical low densities in the basal ganglia on brain computed tomography (CT), with a bilateral symmetrical hyperintensity in the same area and a lentiform fork sign on T2-weighted MRI [4][5][6][7][8][9][10] . In addition to diabetic uremic syndrome (DUS) 4,5 , the lentiform fork sign can be observed in severe metabolic acidosis [11][12][13] , dialysis disequilibrium syndrome 14 , and metforminassociated encephalopathy (ME) 6,7 . The pathogenic basis of this sign is considered to relate to cytotoxic edema based on the severity of metabolic acidosis 8,11 .…”

Case Report: A Case of Encephalopathy Presenting the Lentiform Fork Sign on MRI in a Diabetic Dialysis Patient

“…In particular, diabetic dialyzed patients can present with bilateral symmetrical low densities in the basal ganglia on brain computed tomography (CT), with a bilateral symmetrical hyperintensity in the same area and a lentiform fork sign on T2-weighted MRI [4][5][6][7][8][9][10] . In addition to diabetic uremic syndrome (DUS) 4,5 , the lentiform fork sign can be observed in severe metabolic acidosis [11][12][13] , dialysis disequilibrium syndrome 14 , and metforminassociated encephalopathy (ME) 6,7 . The pathogenic basis of this sign is considered to relate to cytotoxic edema based on the severity of metabolic acidosis 8,11 .…”