A Case of Hypothyroid Myopathy

DR. PRIYA KUBENDIRANDR. PRIYA KUBENDIRANM 1 UNITM 1 UNIT

PROF. DR. MAGESH KUMAR PROF. DR. MAGESH KUMAR

CASE PRESENTATIONCASE PRESENTATION

A 45 year old female was admitted on 08.11.10 with

C/O : Difficulty in walking - 6 months Difficulty in lifting her arms – 5 months Difficulty in holding her head erect – 4

months

H/O PRESENT ILLNESS :

6 months ago, the patient noticed that she had difficulty climbing stairs

difficulty in getting up from squatting position difficulty in walkingAround a month later, she was unable to lift her

arm above her headAfter 2 months she was unable to hold her head

erectGradually progressive weakness over the past 6

monthsNo history s/o distal weakness of upper & lower

limbs

h/o difficulty in turning from side to side in bed

h/o difficulty in getting up from bedNo h/o noticing any difference in limb sizeNo history s/o cranial n involvementNo h/o sensory disturbancesNo h/o bowel/bladder disturbancesNo h/o cramps/ pain in the limbsNo h/o diurnal variation h/o facial puffiness +h/o retrosternal chest pain burning, aggravated by food

h/o abdominal pain upper abdomen, burning typeh/o constipation +h/o loss of appetiteNo h/o loss of weightNo h/o feverNo h/o skin rash / joint pain

PAST HISTORY : No h/o similar illness Not a known case of DM/SHT/PT/BA/IHD No h/o any drug intake / surgeries

PERSONAL HISTORY : Mixed diet Unmarried Attained menopause before 4 years Not a tobacco/betel nut chewer

FAMILY HISTORY : No h/o similar illness

SUMMARIZING….

A 45 year old female has presented with gradually progressive weakness of proximal muscles over the past 6 months

POSSIBILITIES….???

Endocrine – thyroid parathyroid adrenal Drug induced myopathy Inflammatory – Polymyositis /

dermatomyositis Infectious Connective tissue disorders - SLE Myasthenia gravis Inherited - Limb girdle muscular dystrophy

GPE : Conscious, oriented VITALS : Afebrile Voice was hoarse PR – 76/ min Hydration fair BP – 110/70 mm

hg Facial puffiness RR – 16 cycles /

min Pale Macroglossia Anicteric No neck swelling No cyanosis/clubbing Icthyosis in lower limbs No pedal edema No lymphadenopathy

SYSTEMIC EXAMINATION :

RS - NVBS heard no added soundsCVS - S1 S2 heard no added soundsP/A - distended divarication of recti + soft, epigastric tenderness + no organomegaly

CNSHMF - normalCRANIAL NERVES - normalMOTOR SYSTEM – RIGHT LEFT

BULK UPPER LIMB

AE 20 cm 20 cm

BE 19 cm 18.5 cm

LOWER LIMB

AK 35 cm 35 cm

BK 28 cm 27 cm

TONE UPPER LIMB

normal normal

LOWER LIMB

normal normal

POWER

RIGHT LEFT

Neck 2

UL Shoulder Flexors 3 3

Extensors 3 3

Abduction 3 3

Adduction 3 3

Elbow 4- 4-

Wrist 5 5

Hand grip 100% 100%

LL Hip Abduction 2 2

Adduction 2 2

Flexion 2 2

Extension 2 2

RIGHT LEFT

LL Knee 3 3

Ankle 5 5

EHL 5 5

RIGHT LEFT

SUPERFICIAL

Corneal + +

Conjuctival

+ +

Abdominal

- -

Plantar flexor flexor

DEEP Biceps + +

Triceps + +

Supinator + +

Knee + +

Ankle + delayed relaxation

+ delayed relaxation

REFLEXES

Coordination – impaired due to weaknessGait – walks with support

SENSORY - touch, pain, temperature position, vibration sense

CEREBELLUM – normalSPINE & CRANIUM - normal

normal

PROBABLE DIAGNOSIS…??

Endocrine – thyroid parathyroid adrenal Drug induced myopathy Inflammatory – Polymyositis /

dermatomyositis Infectious SLE Myasthenia gravis

IMPRESSION : PROXIMAL MUSCLE WEAKNESS + DELAYED RELAXATION OF DTR NO SENSORY / CRANIAL NERVES

INVOLVEMENT F/S/O HYPOTHYROIDISM

HYPOTHYROID MYOPATHY

INVESTIGATIONS :

CBC Hb – 10.7 gm% TC – 6600 DC – P70 L30 ESR – 5/12 PCV – 30 PLT – 1 lakh

RBS – 96 mg%B. Urea – 22S. Creatinine – 0.8

S. Electrolytes :

Na – 134 meq/L K - 4.4 Cl – 86 Hco3 – 21

ECG – NSR, complete RBBBCXR – Lt side eventration of diaphragmELISA for HIV1,2 – non reactiveS. lipid profile total chol – 224 mg/dl TGL – 141

HDL – 46 LDL – 150 VLDL – 28P smear- normocytic normochromic anemia WBCs & platelets normal

USG ABDOMEN – normal study

ECHO - no RWMA normal LV systolic function normal valves mild PE no e/o tamponade

ANA - negativeRF – negativeS. calcium - 9 mg/dl

Neurological consult :

Proximal myopathy + Slow relaxation of ankle jerk +Hoarseness of voice

Suggested : S. CPK TFT EMG

? HYPOTHYROID MYOPATHY

TFT : T3 < 10 ng/dl (60-200) T4 < 0.30 μg/dl (4.5 – 12) TSH > 150 μIU/ml (0.3-5.5)

S. CPK – 1014 u/l

Anti TPO - 13.80 IU/ml (0-34)

NCS

Motor (CMAPs) & sensory (SNAPs) NORMAL

EMG EMG done in Rt quadriceps, Lt quadriceps, Rt

biceps,

Rt EDB In the above muscles, Insertional activity normal Spontaneous activity – no abnormal waves seen MUP’s were of low amplitude about 37 μV Interference pattern – recruitment complete with

low amplitude

S/O MYOPATHIC PATTERN

SPONTANEOUS ACTIVITY

MOTOR UNIT POTENTIALS

INTERFERENCE PATTERN

FINAL DIAGNOSIS

HYPOTHYROIDISM HYPOTHYROID MYOPATHY EVENTRATION OF LEFT DIAPHRAGM

MANAGEMENT

T. Eltroxin 100 μg od

250 μg od

T. Ranitidine 150 mg 1 bd

As suggested by endocrinologist

COURSE IN THE COURSE IN THE HOSPITALHOSPITAL

Neuromuscular symptoms present in 30 – 80 % of patients with hypothyroidism

Weakness is observed in 1/3rd of patientsIncidence – 5.6% in a study of 53 patients

with acquired muscle disease

Muscle cramping Proximal symmetrical muscle weakness Muscle stiffness Muscle enlargement – Kocher Debre

Semilaigne Hoffman’s Delayed relaxation of DTR (85%)

PATHOPHYSIOLOGY Muscle involvement may be caused by

changes in muscle fibres from fast twitching type II to slow twitching type I fibres

deposition of glycosaminoglycanspoor contractility of actin–myosin units low myosin ATPase activitylow ATP turnover in skeletal muscleinvolvement of the muscle membrane

PSEUDOMYOTONIC REFLEX

The rate-limiting step in muscle relaxation is reuptake of calcium by the sarcoplasmic reticulum, which is dependent on calcium ATPase content (SERCA-1) of the muscle fibre.

Calcium ATPase activity of fast twitch variety of muscle fibre is decreased in hypothyroidism producing delayed relaxation, the pseudomyotonic reflex.

serum CK levels - 2 to 6 fold though marked elevation up to the range of 20,000- 25,000 U/L may be seen (thyroid deficiency permits leakage across muscle membranes and possibly due to actual muscle necrosis)

EMG – normal or myopathic The MUAPs are generally polyphasic

with reduced amplitude and duration. Early recruitment may also be observed

NCS – normal may show f/s/o mild neuropathy

Biopsy – non specific changes. Fiber atrophy is noted, and increased

numbers of internal nuclei, glycogen aggregates, and deposition of mucopolysaccharides in the connective tissue

MANAGEMENT

Levothyroxine replacement Myopathy improves within 2-3 weeks, but

may take months to resolve completelyEMG findings revert with treatment

References :-Harrison 17/e-Emedicine sources-DeJong