Rare diseases · Sign or symptom
Metabolic acidosis
HP:0001942
What it means
Metabolic acidosis (MA) is characterized by a fall in blood pH due to a reduction of serum bicarbonate concentration. This can occur as a result of either the accumulation of acids (high anion gap MA) or the loss of bicarbonate from the gastrointestinal tract or the kidney (hyperchloremic MA). By definition, MA is not due to a respirary cause.
The Henderson-Hasselbalch method defines metabolic acidosis by the presence of an acid-base imbalance associated with a plasma bicarbonate concentration below 20 mmol/L. The association of this imbalance with decreased pH is called acidemia, which is often described as severe when the pH is equal to or below 7.20. Arterial blood gas measurements can be performed in patients with a decreased plasma bicarbonate level so as to eliminate respiratory alkalosis, confirm the diagnosis of metabolic acidosis, and test for mixed acidosis.
Rare diseases that can present with this51
Very common80–99%
17- 3-hydroxy-3-methylglutaric aciduria
- Amish lethal microcephaly
- Beta-ketothiolase deficiency
- Cardiomyopathy-hypotonia-lactic acidosis syndrome
- Colchicine poisoning
- Congenital lactic acidosis, Saguenay-Lac-Saint-Jean type
- D-glyceric aciduria
- Ethylene glycol poisoning
- Fructose-1,6-bisphosphatase deficiency
- Generalized pseudohypoaldosteronism type 1
- Hawkinsinuria
- HSD10 disease, neonatal type
- Isolated glycerol kinase deficiency
- Isovaleric acidemia
- Methanol poisoning
- Mitochondrial myopathy-lactic acidosis-deafness syndrome
- Primary hyperoxaluria type 1
Common30–79%
18- Adult acute respiratory distress syndrome
- Bacterial toxic-shock syndrome
- Familial hypoaldosteronism
- Fanconi-Bickel syndrome
- HSD10 disease, infantile type
- Hydroxykynureninuria
- Lujo hemorrhagic fever
- Malignant hyperthermia of anesthesia
- Malonic aciduria
- Microvillus inclusion disease
- Neurodegeneration due to 3-hydroxyisobutyryl-CoA hydrolase deficiency
- Neuroleptic malignant syndrome
- Primary hyperoxaluria
- Pyridoxamine-5-phosphate deficiency-developmental and epileptic encephalopathy
- Pyruvate carboxylase deficiency
- Sepsis in premature infants
- Short chain acyl-CoA dehydrogenase deficiency
- Yellow fever
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.