Hypocalcemia differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vamsikrishna Gunnam M.B.B.S [2]

Overview

Hypocalcemia must be differentiated from tetanus, neuroleptic malignant syndrome, viral meningitis, Stiff man syndrome, strychnine poisoning and Parkinson's disease.

Differential Diagnosis

Hypocalcemia must be differentiated from other diseases causing stiffness and fever. The differentials include the following:

• Tetanus
• Stiff man syndrome
• Meningitis
• Tardive dyskinesia
• Parkinsonism
• Neuroleptic malignant syndrome

Differential Diagnosis of Tetanus

Disease	Diagnosis			Treatment
	Symptoms	Signs	Laboratory Findings
Tetanus	Tonic contraction of muscles between the spasmodic episodes Trismus or lockjaw Neck stiffness Swallowing difficulty Stiffening of the calf and pectoral muscle groups	Opisthotonos Leg extension with arm flexion Risus sardonicus respiratory distress	Not significant	Diazepam Magnesium  Human TIG
Neuroleptic Malignant Syndrome	History of intake of offending drugs e.g neuroleptics like: Fluphenazine Haloperidol Olanzapine Risperidone Autonomic instability Rigidity Disorientation Fever	Dysphagia Pallor Dyspnea Shuffling gait Agitation	Myoglobinemia Elevated LDH Elevated creatine kinase Hyperkalemia Elevated AST and ALT Hyperphosphatemia Elevated alkaline phosphatase Hyperuricemia	Supportive therapy Stop the offending agent Medical Therapy Dantrolene Amantadine Bromocriptine
Viral Meningitis	Fever Irritability Lack of appetite Lethargy Disoriented High grade fever Severe headache Stiff neck Sensitivity to bright light Nausea Vomiting	Headache Photophobia Phonophopia Pharyngitis in case of enterovirus infeciton Orchitis (In mumps) Vesicular or macular skin rash Petichiae Nuchal rigidity Signs of meningeal irritation: Kernig's sign Brudzinski's sign Altered mental status Hypotonia	CSF / plasma glucose ratio (>0.6) Lactate (mmols/l) (<2.1) Lymphocytes > granulocytes	Supportive Analgesics for pain. Acetaminophen for fever. Anti-viral therapy: Acyclovir Pleconaril
Stiff man syndrome	Marked rigidity Spasms Intermittent Painful Absent during sleep	Diaphoresis Arterial hypertension Tachypnea Cyanosis Apnea, tachypnea Respiratory arrest Dilatation of the pupils Tachycardia	CSF has Elevated IgG Oligoclonal bands Positive anti-GAD antibodies Elevated creatine kinase Normal CBC & ESR	Benzodiazepines Baclofen Vigabatrin  Valproic Acid, Neurontin Injected botulinum toxin  Prednisone, plasmapheresis, IVIG ( some success)
Drug induced (Tardive dyskinesia)	History of intake of the offending drug for at least one month Neuroleptics (antipsychotics) Metoclopramide Eye deviation Head and neck jerky movements No tonic contraction of the muscles between the spasms	Dyskinesia of the tongue and lips Dyskinesia of the limbs Dyskinesia of the neck	It is a clinical diagnosis depending on Dyskinetic movements Hx of > 1 month of antipsychotic use Labs may be done to rule out other differentials	Stop the offending agent Benztropine Benzodiazepines Injection of botulinum toxin Valbenzine Tetrabenazine
Strychnine poisoning	Hx of up to date tetanus immunizations History of intentional or accidental intake Strychnos nux vomica seeds Rodenticide	Hypervigilance Anxiety Mydriasis Hypereflexia Clonus Facial and neck stiffness	Blood assay Tissue assay Urine assay	Initial stabilization High dose Benzodiazepines Intubation and airway securing
Hypocalcaemia	Muscle twitching and cramping Circumoral and extremity paresthesia or tingling Altered mental status Irritability Depression Psychosis Seizure	Tetany (carpopedal spasm) Latent tetany Trousseau sign of latent tetany  Chvostek's sign  Hyperactive tendon reflexes	Decreased blood calcium levels	Two ampules of intravenous calcium gluconate 10% is given slowly in a period of 10 minutes, or If hypocalcemia is severe, calcium chloride is given instead Maintenance doses of both calcium and vitamin-D
Parkinson's disease	Stiffness Inability to write Jerky movements at rest Constipation Sleeping difficulty Walking difficulty	Tremor Rigidity Bradykinesia Postural instability Shuffling gait	Clinical diagnosis Improvement with dopaminergic therapy confirms diagnosis	Symptomatic therapy Dopamine agonists Levodopa Amantadine MAO inhibitors COMT inhibitors Anticholinergics