Fahr’s Syndrome

At a glance

Very rare degenerative neurologic syndrome characterized by microcephaly, mental and growth retardation, seizures and dystonic movements, and athetosis with evidence of multiple intracranial calcifications in parts of the gray and dentate nuclei, particularly of smaller brain vessels.

Incidence

First described by the German neurologist Karl Theodor Fahr in 1930.

Synonyms

Cerebral Nonarteriosclerotic Calcification; Idiopathic Basal Ganglia Calcification; Fahr Intracerebral Calcinosis; Fahr Disease; Morbus Fahr Ferrocalcinosis; Nonarteriosclerotic Cerebral Calcifications; Striopallidodentate (SPD) Calcinosis.

Nature

Presence of idiopathic intracranial calcifications has been recognized for many years. The heterogeneous nature of the disease was later recognized and genetic conditions occurring in infants were included.

History

The initial report by Fahr was about an adult.

Genetic inheritance

Autosomal recessive and autosomal dominant transmission have been reported. In some cases, the condition appears to be sporadic and may result from an unidentified infection during pregnancy affecting the developing fetus.

Pathophysiology

Pathogenesis is unclear, but a few hypotheses have been stated, such as the possible role of abnormal iron transport, fetal viral infection, and hypoparathyroidism.

Diagnosis

Diagnosis of exclusion after ruling out common causes of microcephaly with intracranial calcifications, such as TORCH (toxoplasmosis, other agents, rubella, cytomegalovirus, herpes simplex) infection, varicella virus, and cytomegalovirus infections.

Clinical aspects

Children affected with the disease present normal development at birth but subsequently demonstrate poor psychomotor developmental progress in the preschool period. Seizures appear early in life and are of variable nature. Patients affected present severe microcephaly, hypotonia, spasticity, and growth retardation. Some children also have thrombocytopenia and hepatosplenomegaly manifesting shortly after birth, which most often last for only a few weeks and then resolve spontaneously. The CT scan of the brain may show cerebral atrophy, dilated ventricles, calcifications, and a lower density of white matter consistent with dysmyelination. Hypoparathyroidism may be associated with this disorder. Clinical course and outcome are highly variable.

Precautions before anesthesia

If the child needs surgery in the first few weeks of life, obtain a complete blood count (CBC) to rule out anemia and thrombocytopenia. Blood calcium should be checked to rule out hypocalcemia caused by hypoparathyroidism.

Anesthetic considerations

Locoregional anesthesia should be avoided in case of thrombopenia.

Pharmacological implications

Presence of undetermined cause for hepatomegaly should limit the use of inhalational agent likely to affect the liver (eg, halothane). Hepatic enzyme induction may occur in the presence of anticonvulsant, so the dose of some drugs, such as neuromuscular relaxants, may ...