A possible hypophosphatemia-induced, life-threatening encephalopathy in diabetic ketoacidosis: a case report

Association of Hypophosphatemia during Continuous Kidney Replacement Therapy and Clinical Outcomes: A Systematic Review and Meta-Analysis

INTRODUCTION

Hypophosphatemia is a common and potentially severe complication of continuous kidney replacement therapy (CKRT), but the evidence on the correlation between hypophosphatemia occurring during CKRT and clinical outcomes remains limited.

METHODS

Electronic databases (PubMed, Embase, Web of Science, and the Cochrane database) were searched from inception to March 1, 2024. All possible studies that examined the following outcomes were included: all-cause mortality, mechanical ventilation, intensive care unit (ICU) stay, and CKRT duration.

RESULTS

A total of 8,631 patients from eight cohort studies were included. There was no statistical association between hypophosphatemia during CKRT and all-cause mortality in critically ill patients (OR 0.82, 95% CI 0.57-1.18, p = 0.28, I2 = 83%). However, hypophosphatemia was associated with longer duration of mechanical ventilation (WMD 80.30 h, 95% CI 31.37-129.22, p = 0.001, I2 = 60%). Furthermore, a longer length of ICU stay (WMD 2.76 d, 95% CI 2.50-3.02, p < 0.00001, I2 = 36%) and CKRT duration (WMD 51.51 h, 95% CI 2.69-100.34, p = 0.04, I2 = 96%) were observed in patients with hypophosphatemia.

CONCLUSIONS

The association between hypophosphatemia and mortality in patients receiving CKRT was insufficient. However, hypophosphatemia during CKRT might be associated with adverse clinical outcomes for critically ill patients.

Food Coma: Hyperammonemic Encephalopathy From Refeeding Syndrome

Hyperammonemic encephalopathy (HAE) from extrahepatic causes is increasingly being recognized. Refeeding syndrome is characterized by severe fluid and electrolyte shifts following the reintroduction of nutrition. We describe the case of a 67-year-old man with bilateral maxillary sinus squamous cell carcinoma on nivolumab who became comatose after initiation of enteral feeding. Initial workup was notable for severe hypophosphatemia (<1 mg/dL) and markedly elevated ammonia (226 µmol/L). Neuroimaging was unrevealing. Correction of hypophosphatemia did not improve mental status. Ammonia levels briefly decreased while holding enteral feeding but worsened again on resumption. High-volume continuous renal replacement therapy was recommended but deferred in accordance with family wishes. We hypothesize that HAE may have been precipitated by a combination of refeeding-induced high nitrogen burden and limited detoxification via the urea cycle and extrahepatic pathways in the setting of severe protein-energy malnutrition and underlying malignancy. Nivolumab could have contributed as well.

Respiratory failure in a diabetic ketoacidosis patient with severe hypophosphatemia

Phosphate is essential in regulating human metabolic processes, and severe hypophosphatemia can induce neurologic and hematological complications and result in respiratory failure and cardiac dysfunction. Therefore, correction of severe hypophosphatemia can be pivotal in the management of diabetic ketoacidosis (DKA). We report the case of a 14-year-old female who was diagnosed with type 1 diabetes and referred to our institute for treatment of DKA. Although the patient received fluid and continuous insulin administration according to the current DKA treatment protocol, generalized tonic seizures and cardiac arrest developed. After cardiopulmonary resuscitation, the patient recovered and was stable. Within 16 hours after DKA treatment, the patient developed respiratory failure with severe hypophosphatemia that required mechanical ventilation. Concurrent neurologic evaluation revealed no specific abnormalities. The patient recovered without any complications after correcting the hypophosphatemia. We suggest vigilant monitoring of the phosphate level in DKA patients and active replacement when required.

Respiratory failure in diabetic ketoacidosis

Respiratory failure complicating the course of diabetic ketoacidosis (DKA) is a source of increased morbidity and mortality. Detection of respiratory failure in DKA requires focused clinical monitoring, careful interpretation of arterial blood gases, and investigation for conditions that can affect adversely the respiration. Conditions that compromise respiratory function caused by DKA can be detected at presentation but are usually more prevalent during treatment. These conditions include deficits of potassium, magnesium and phosphate and hydrostatic or non-hydrostatic pulmonary edema. Conditions not caused by DKA that can worsen respiratory function under the added stress of DKA include infections of the respiratory system, pre-existing respiratory or neuromuscular disease and miscellaneous other conditions. Prompt recognition and management of the conditions that can lead to respiratory failure in DKA may prevent respiratory failure and improve mortality from DKA.

Refeeding encephalopathy in a patient with severe hypophosphataemia and hyperammonaemia

The refeeding syndrome is a potentially fatal condition that affects multiple organ systems. It is the consequence of fluid and electrolyte shifts that may occur in a malnourished patient following the introduction of nutrition therapy. The most prominent characteristic is hypophosphataemia. Although hyperammonaemia is usually seen in decompensated liver cirrhosis or acute liver failure, it may occur in other settings. We report a clinical case of prolonged and severe encephalopathy accompanied by hypophosphataemia and hyperammonaemia in a 59-year-old woman with no preexisting liver disease, urea cycle defects or portosystemic shunting. We suggest that these biochemical abnormalities were caused by uncontrolled refeeding and that the clinical picture was consistent with refeeding encephalopathy.

[Hypophosphatemia complicated with neurological manifestations during hematopoietic reconstitution]

We report the case of a 52-year-old woman who developed neurological manifestations secondary to severe hypophosphatemia during hematopoietic reconstitution after induction for acute lymphoblastic leukemia. A high cellular uptake of phosphate may be seen in situations with a rapid cell proliferation such as hematopoietic reconstitution, and phosphatemia should be carefully monitored in such situations.

Disturbance of inorganic phosphate metabolism in diabetes mellitus: clinical manifestations of phosphorus-depletion syndrome during recovery from diabetic ketoacidosis

The acute effects of intracellular phosphate depletion and hypophosphatemia on organs and tissues in and during recovery from diabetic ketoacidosis (DKA) have been reviewed. When insufficient phosphate and/or oxygen are available for high energy phosphate synthesis, cell homeostasis cannot be maintained and cell integrity may be impaired. The clinical consequences are recognized as occasional cause of morbidity and mortality. Although phosphate repletion has not been routinely recommended in the treatment of DKA, physicians should be aware of these clinical conditions and phosphate repletion in such situations should be considered.

Hypophosphatemia-induced seizure in a child with diabetic ketoacidosis

We report an unusual case of hypophosphatemia-related seizure in a child with diabetic ketoacidosis (DKA). A 1-year-old type 1 diabetic boy with hyperglycemia, ketoacidosis, and dehydration was admitted to the pediatric intensive care unit. After having received fluid replacement using isotonic solution with added potassium and continuous intravenous insulin administration according to the protocol for DKA, the patient was conscious, awake, and fed with breast milk. After 20 hours of pediatric intensive care unit stay, he presented 2 tonic-clonic seizures followed by apnea. One hour later, he had cardiorespiratory arrest, requiring cardiovascular support and mechanical ventilation. Serum phosphorus concentration was 1.0 mg/dL, and severe hypophosphatemia was diagnosed. Subsequent to intravenous phosphate replacement, he showed improved neurological and hemodynamic statuses. No other cause of cerebral complication was found. He had no neurologic lesions and was discharged. Although hypophosphatemia is a common complication of DKA treatment, phosphate supplementation has not been routinely recommended in the treatment of DKA. Early recognition and treatment of severe hypophosphatemia in the treatment of DKA are important to reduce the risk of neurological complications.