History

Fact Explanation
Generalized muscle pain Majority of magnesium is contained in the bones, muscles and soft tissues. [1] Extracellular fluid only 1% of the total body magnesium. [3] Magnesium involves in the muscle functions, oxygen uptake, energy production, and electrolyte balance. [2] Deficiency causes severe progressive skeletal muscle pain. Neuromuscular excitability can be due to increased intracellular calcium as magnesium deficiency impairs the calcium pump and sodium/calcium exchange across the cell membrane. [2] Most frequently calf muscles are involved. Then hamstring, quadriceps, abdominal recti, pectoral and upper limbs are involved in a decreasing frequency.
Restless leg syndrome [5] Severe muscle pain is a feature of magnesium deficiency. [1] In this condition there is a feeling of discomfort when sitting or lying down. They also have crawling, tingling, itching, tugging and pain in the calves, thighs and feet.
Severe abdominal cramps [5] With severe deficiency the spasms may become intense and frequent. This may be confused with the surgical pathologies. [1]
Palpitations Magnesium is needed for contraction and relaxation of muscles. Deficiency of the Mg can result in arrhythmias. [1]
History of physical training Though there is a redistribution of magnesium immediately after exercise, long term physical training reduces the magnesium levels and causes deficiency state. [2]
Shortness of breath Due to congestive heart failure associated with weak contractile function of cardiac tissue. [1]
Ansomnia, fatigue and lethrgy Magnesium is involved in the production and transportation of energy within the body. [4]
Depression, confusion [4] Neuropsychiatric manifestations of hypomagnesemia. [3]
Risk factors: malnutrition One third of the magnesium in the diet is absorbed. Malnutrition is associated with deficiency of magnesium. [1] When there is provision of magnesium <0.4mmol/day, it is a magnesium deficient diet. [3]
Risk factors: Inflammatory bowel disease, severe cholestatic liver disease and pancreatic disease Reduced absorption. [3]
Diuretic therapy and renal diseases Remaining amount of magnesium, after absorption to the body is magnesium is excreted by the kidney. [1]
Prolonged diarrhoea Increased loss of magnesium. [3]
Alcoholism Reduced intake, absorption and increased loss by diarrhoea and vomiting are the causes for magnesium deficiency. [3,6]
References
  1. BILBEY DL, PRABHAKARAN VM. Muscle cramps and magnesium deficiency: case reports. Can Fam Physician [online] 1996 Jul:1348-1351 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2146789
  2. NIELSEN FH, LUKASKI HC. Update on the relationship between magnesium and exercise. Magnes Res [online] 2006 Sep, 19(3):180-9 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17172008
  3. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822
  4. SARTORI SB, WHITTLE N, HETZENAUER A, SINGEWALD N. Magnesium deficiency induces anxiety and HPA axis dysregulation: Modulation by therapeutic drug treatment Neuropharmacology [online] 2012 Jan, 62(1):304-312 [viewed 14 September 2014] Available from: doi:10.1016/j.neuropharm.2011.07.027
  5. O'KEEFFE ST, NOEL J, LAVAN JN. Restless legs syndrome in the elderly. Postgrad Med J [online] 1993 Sep, 69(815):701-703 [viewed 14 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2399773
  6. POIKOLAINEN K, ALHO H. Magnesium treatment in alcoholics: A randomized clinical trial Subst Abuse Treat Prev Policy [online] :1 [viewed 14 September 2014] Available from: doi:10.1186/1747-597X-3-

Examination

Fact Explanation
Tachycardia Increased heart rate in arrhythmias. [1]
Increased blood pressure Due eto increased vascular smooth muscle tone. [1]
Depressed mood Neuropsychiatric manifestations of hypomagnesemia. [1]
Nystagmus Neuropsychiatric manifestations of hypomagnesemia. [1]
Ataxia Neuropsychiatric manifestations of hypomagnesemia. [1]
Chovstek's sign Tapping on the face at a point just anterior to the ear and just below the zygomatic bone produces twitching of the ipsilateral facial muscles; this is a positive Chvostek's sign [3] that is suggestive of neuromuscular excitability caused by hypocalcemia. [3]
Trousseau's sign [3] Elicited by inflating a sphygmomanometer cuff above systolic blood pressure for several minutes and observing muscular contraction including flexion of the wrist and metacarpophalangeal joints, hyperextension of the fingers, and flexion of the thumb. This is considered to be due to neuromuscular excitability caused by hypocalcemia. [2]
Muscle fasciculations Neuromuscular manifestation of hypomagnesemia. [1]
References
  1. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822
  2. MEININGER MICHAEL E., KENDLER JASON S.. Trousseau's Sign. N Engl J Med [online] 2000 December, 343(25):1855-1855 [viewed 12 July 2014] Available from: doi:10.1056/NEJM200012213432506
  3. COOPER MS, GITTOES NJ. Diagnosis and management of hypocalcaemia BMJ [online] 2008 Jun 7, 336(7656):1298-1302 [viewed 14 September 2014] Available from: doi:10.1136/bmj.39582.589433.BE

Differential Diagnoses

Fact Explanation
Leptospirosis Clinical signs of leptospirosis are acute febrile illness of sudden onset, severe general malaise, muscular pains and conjunctival suffusion. They may have a history of exposure to muddywater. Farmers, gem pit workers, hunters are at increased risk of getting the disease. [4] Investigations include proteinuria, raised erythrocyte sedimentation rate, and leucocytosis with neutrophilia with alteration of liver enzymes if the liver is involved. [1]
Hypocalcemia [3] Parathyroid hormone deficiency [3] , resistance/ vitamin D deficiency, hypoalbuminemia and hyperphosphatemia are causes for hypocalcemia. It also can be due to loop diuretics, bisphosphonates, antibiotics, antiepileptic drugs etc. Chvostek’s sign and trousseau’s signs are classic signs of hypocalcemia. [3]
Hypokalemia Weakness and fatigue, muscle cramps and pain, polyuria and features like psychosis, delirium, hallucinations, depression are the manifestations of hyperkalemia. Mineralocorticoid excess, cushing syndrome, steroid therapy, renal artery stenosis, hyperglycemia and diuretics [2] are some of the causes for hypokalaemia.
References
  1. KOBAYASHI Y. Human leptospirosis: management and prognosis. J Postgrad Med [online] 2005 Jul-Sep, 51(3):201-4 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16333193
  2. ROBB JD, DELARGY MA, NOLAN M, TOMKIN GH. Hypokalaemia: Bartter's syndrome or pseudo-Bartter's syndrome? J R Soc Med [online] 1984 May, 77(5):384-386 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1439885
  3. COOPER MS, GITTOES NJ. Diagnosis and management of hypocalcaemia BMJ [online] 2008 Jun 7, 336(7656):1298-1302 [viewed 14 September 2014] Available from: doi:10.1136/bmj.39582.589433.BE
  4. WAITKINS SA. Leptospirosis as an occupational disease. Br J Ind Med [online] 1986 Nov, 43(11):721-725 [viewed 14 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1007745

Investigations - for Diagnosis

Fact Explanation
Serum magnesium concentration Is usually reduced. Reference range for Mg is 0.7-1.5mmol/L [1] But a normal serum magnesium can be present even in the presence of deficiency as majority of body magnesium is in the bones and soft tissues.
Urinary magnesium This is also reduced, in magnesium deficiency. [2]
References
  1. BILBEY DL, PRABHAKARAN VM. Muscle cramps and magnesium deficiency: case reports. Can Fam Physician [online] 1996 Jul:1348-1351 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2146789
  2. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822

Investigations - Fitness for Management

Fact Explanation
Full blood count As the patient complains of severe myalgia, it is important to exclude the other conditions that can present with myalgia. eg:- leptospirosis will have neutrophilia [1] with reduced platelet counts, dengue will have neutropenia with reduced platelet count.
References
  1. KOBAYASHI Y. Human leptospirosis: management and prognosis. J Postgrad Med [online] 2005 Jul-Sep, 51(3):201-4 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/16333193

Investigations - Followup

Fact Explanation
Serum electrolytes Due to the risk of electrolyte imbalance. [1]
Electrocardiogram Due to the risk of arrhythmia. [1]
References
  1. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822

Investigations - Screening/Staging

Fact Explanation
Electrocardiogram Digoxin mediated arrhythmias and malignant supraventricular and ventricular arrhythmias can occur. Prolongation of QT interval, ventricular fibrillation can be seen. [1]
Serum electrolytes Magnesium affects the balance of the other ions such as sodium, potassium and calcium. It can causes hyperkalemia, hypocalcemia and hypophosphatemia. [1]
References
  1. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822

Management - General Measures

Fact Explanation
Supportive maangement Bed rest should be prescribed in the initial stages. [1]
Improving dietary intake Recommended Nutrient Intake (RNI) for magnesium should be around 220mg/day for a female and 260 mg/day for a male. [1] Meat, seafood, dairy products, nuts and cereals are good sources of magnesium. [2]
Prevention of magnesium deficiency Spironolactone and amiloride diuretics have a magnesium sparing effect and therefore can be used as long term diuretics if needed. Addition of magnesium 6-15mmol/day in parenteral nutrition is also important. [2]
References
  1. NIELSEN FH, LUKASKI HC. Update on the relationship between magnesium and exercise. Magnes Res [online] 2006 Sep, 19(3):180-9 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17172008
  2. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822

Management - Specific Treatments

Fact Explanation
Muscle relaxation Orphenadrine and acetaminophen is used for the muscle relaxation. [1]
Magnesium oral suppliments Can be used to treat muscle pain and disabilities due to magnesium deficiency occurring with continuous magnesium loss. eg:- magnesium gluconate, magnesium glucoheptonate [1]
Magnesium sulphate infusion Magnesium intravenous infusion is given as 6-15g of 50% magnesium in 1000 microliters of normal saline according to the age and body weight of the patient [1] This is used in emergency situations as acute myocardial infarctions.
Management of complications Complications to be anticipated are arrhythmias, hypertension, seizures and electrolyte imbalances etc. They need specific management. [2]
References
  1. BILBEY DL, PRABHAKARAN VM. Muscle cramps and magnesium deficiency: case reports. Can Fam Physician [online] 1996 Jul:1348-1351 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2146789
  2. BERKELHAMMER C, BEAR RA. A clinical approach to common electrolyte problems: 4. Hypomagnesemia. Can Med Assoc J [online] 1985 Feb 15, 132(4):360-368 [viewed 12 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1345822