Murmurs Made Easy

For the purpose of this post, I shall fast forward the examination of the heart to auscultation of the heart murmurs. 

We begin auscultation of the precordium by placing the stethoscope over the mitral area. 

A hand drawn picture of the anterior chest with the location of each valves

One very important step which is often overlooked or neglected by medical students is the instruction to the patient to breathe in and breathe out slowly. Personally, I would let my stethoscope to remain over each valve area for a total duration of 2 breathing cycles (i.e. breathe in-breathe out-breathe in-breathe out) before moving to the next valve area. 

Let us recap the basic physiological changes that affect murmurs during breathing. During inspiration, the increased thoracic cavity volume lowers intrathoracic pressure thus increases venous return to the right side of the heart. This will cause an increase in murmur intensity for tricuspid and pulmonary valve disorders. 

On the other hand, expiration reduces the thoracic cavity volume and thus increases arterial outflow from the left side of the heart. This will cause an increase in murmur intensity for mitral and aortic valve disorders. 

This basic concept is very important and will help guide you to eliminate and narrow down possible differentials for every murmur heard over any particular valve area as I will explain next. 

Let us begin at the mitral valve area. Place the diaphragm of the stethoscope over the mitral valve area. Regardless whether you hear any murmurs or not, I would encourage you to do the breathing manouvres for at least 2 breath cycles as mentioned above. If there are any soft murmurs, this manouvre will enhance or increase the murmur intensity. 

If there is a murmur heard over the mitral area, below are the possible causes:

1. Mitral regurgitation (MR)

2. Mitral stenosis (MS)

3. Aortic stenosis (AS)

4. Tricuspid regurgitation (TR)

5. Ventricular septal defect (VSD)

To help differentiate between the causes, here is how the breathing manouvre will help narrow down the diagnoses. 

If during inspiration, the murmur heard over the mitral area becomes louder, then it can be concluded that the murmur is actually originating from the neighbouring tricuspid valve. Therefore the murmur detected over the mitral valve can be ignored. The murmur will then be best heard over the tricuspid area after completing the mitral valve examination. 

If during expiration, the murmur heard over the mitral area becomes louder, then it can be concluded that the murmur is unlikely to originate from the tricuspid valve or VSD. Only 3 possibilities remain i.e. MR, MS or AS. To differentiate between the 3 possible source of the expiratory phase murmur heard over the mitral valve area, the student will need to time the murmur by palpating the carotid or radial pulse. If the expiratory murmur coincides with the diastolic phase, then the only diagnosis possible would be a MS murmur. Next step is to listen and verify that the murmur is indeed a mid diastolic murmur (MDM) of MS i.e. switching to the bell of the stethoscope and listening for the MDM with the patient lying left lateral.

If the expiratory murmur coincides with the systolic phase, then you have ruled out MS. So all that is left would be either MR or AS. To differentiate between this two, listen to the systolic murmur carefully and decide if its a pansystolic murmur (PSM) or an ejection systolic murmur (ESM). A PSM would classically have a soft S1 with the systolic murmur extending throughout systole. An ESM, on the other hand, would have a clearly heard S1 and the systolic murmur would be heard in mid systole. 

If it is a PSM, then the diagnosis would be a MR. This can be further confirmed by auscultating the axillae for radiation of the MR murmur. If it is a ESM, then the only diagnosis possible would be an AS murmur. An AS murmur can sometimes be heard all the way to the left axillae as well. This phenomenon is called the Gallarvardin phenomenon. 

If there no variation in the murmur intensity between inspiration and expiration, time the murmur by palpating the carotid or radial pulse. A systolic murmur that does not vary with inspiration or expiration heard over the mitral area can only be caused by a VSD. Once you have completed the mitral valve examination, confirm the earlier heard murmur which will be best heard over the lower left sternal edge. This will confirm the presence of a VSD. 

 

Over the tricuspid valve area, the same manouvres as above should be applied. If a PSM is heard over the tricuspid valve area, there are only 3 possibilities: a TR, a VSD or a loud MR. Remember, the chest cavity and specifically the heart isnt a very large structure. Therefore any loud murmur can practically be heard everywhere. If the PSM increases intensity during inspiration, the PSM is confirmed to be from the tricuspid valve i.e. a TR. If the PSM is louder during expiration, then the murmur is a radiation from the mitral valve i.e. a MR. But if the murmur does not change with either inspiration or expiration, then the PSM could be from a VSD. 

 

Over the pulmonary valve area, it is unusual to hear a PSM. But you could detect a ESM of pulmonary stenosis (PS). This is, however, uncommon for undergraduate examinations. An early diastolic murmur (EDM) of pulmonary regurgitation (PR) is even more rare. Both PS and PR murmurs will be louder during inspiration. Also, do look out for machinery or continuous murmurs near the pulmonary valve area. This may indicate presence of a Patent Ductus Arteriosus (PDA). The machinery murmur of a PDA is often heard over the upper left chest area just below the left clavicle. This area is often close to the pulmonary valve area.

Over the aortic valve area, it is also uncommon to hear a PSM. Look out for ESM of aortic stenosis (AS) and EDM of aortic regurgitation (AR). Both AR and AS murmurs will be louder during expiration. AR murmur can be further verified by presence of EDM which is best heard over the Erb's space or second aortic space over the left sternal edge with the patient leaning forward. AR murmurs are usually accompanied by other peripheral signs like Corrigan's sign (bilateral prominent carotid arterial pulsations), a collapsing pulse as well as wide pulse pressure. AS murmurs can sometimes radiate to both carotid arteries and this feature should be looked for and examined routinely in patients with AS murmurs. However, AS due to aortic sclerosis (degenerative cause) may not always have radiation to both carotids. The ESM murmur may be localised to the aortic valve area only. It is important to take note of this. In real life practice, the ESM of AS can sometimes be heard over the pulmonary valve area as well. This may confuse the unsuspecting student. However this confusion can be avoided when patient is asked to inspire and expire slowly. If the ESM heard over the pulmonary valve area is louder during inspiration as mentioned earlier, then the ESM is likely due to PS. If the ESM over the pulmonary valve area is louder during expiration, then the ESM is likely to originate from the neighbouring aortic valve i.e. an AS.

CCE.

Cushing's syndrome

Cushing's syndrome is a favourite appearance in the medical examinations. 

Often, the stem would be to "look and proceed". Often the diagnosis would be easily suspected. 

From head to toe, the clinical findings are as below:

1. Depression or psychosis

2. Cataracts

3. Acne

4. Rounded facies

5. Hirsuitism in females

6. Central obesity

7. Increased supraclavicular fat pads

8. Increase dorso-cervical fat pad

9. Acanthosis nigricans

10. Purple striae at anterior abdomen or axillary skin folds or thighs

11. Easy skin bruising

12. Osteoporosis

13. Diabetes mellitus (look for finger prick marks at finger tips, funduscopy for diabetic retinopathy changes)

14. Hypertension (offer to check patient's blood pressure using manual sphygmomanometer)

15. Hypogonadism (menstrual disturbances, impotence)

16. Proximal muscle weakness (myopathy)

17. Thin arms and legs

Once the diagnosis of Cushing's syndrome is made, investigations will be focused on determining the aetiology of Cushing's syndrome i.e ACTH-dependent (ACTH secreting pituitary tumours/ ectopic ACTH-secreting tumours) versus ACTH-independent (adrenal causes or exogenous steroid exposure). A differential of a person with Cushingoid appearance would be pseudo-Cushing's which can be seen with persons with obesity or chronic alcoholism.

CCE.

Diabetes Mellitus - How to Approach a Patient with Diabetes Mellitus in the Long Case Examination (History Taking)

Diabetes Mellitus (DM) is a common entity nowadays and therefore it should be well known by every healthcare practitioner particularly the clinicians. 

Similarly, diabetes mellitus is also a common appearance in the medical examinations. They may appear in various forms e.g.  target organ damage, complications related to treatment, as well as psychosocial issues surrounding the condition itself. 

For the undergraduate final examinations, students can expect to encounter cases where a patient presents with a particular complaint related to a target organ damage. For example the patient may present with numbness affecting the feet or even blurred vision affecting one or both eyes. The student is expected to get a competent and complete history pertaining to the presenting complaint as well as establish the diagnosis of diabetes mellitus and whether there are presence of other target organ damage occurring concomitantly with the presenting complaint.

So, let us refresh our memories with regards to diabetes mellitus and its complications.

Diabetes mellitus are broadly categorised into 2 types (for the undergraduate level, at least):

Type 1 - Autoimmune cause, due to premature loss of pancreatic beta islet cells

Type 2 - Acquired cause, usually due to insulin resistance as a result of increased adipocity, hormonal dysregulation etc.

There are other types as well e.g Maturity Onset of Diabetes in the Young (MODY), Gestational diabetes, Double Diabetes (mixture of both Types 1 and 2 in the same patient) etc. But those are for another topic and discussion as it can be complex. 

In general, the differentiating factor between Types 1 and 2 Diabetes Mellitus is age of onset. Type 1 typically occur in the young, usually pre adolescent age whereas Type 2 diabetes occur in adulthood (in general). However this distinctive factor is no longer clearcut and we are seeing younger patients with Type 2 diabetes due to lifestyle and the ever increasing waistline among youngsters. 

After tackling the presenting complaint, you can add the following information within the history of presenting illness (HOPI) segment. 

Enquire and explore regarding complications resulting from diabetes mellitus:

MACROVASCULAR:

• Coronary artery disease
• Ask about chest pains (categorise according to Canadian Cardiovascular Society classification), dyspnoea (categorise according to New York Heart Association classification), pedal oedema, orthopnoea, paroxysmal nocturnal dyspnoea etc
• Cerebrovascular disease
• Ask about facial assymetry, unilateral limb weakness, speech impairment, dysphagia, memory impairment (vascular dementia)
• Peripheral arterial disease
• Claudication pains, resting pains, digital cyanosis or gangrene

MICROVASCULAR:

• Retinopathy
• Ask about scotomas, blurred vision, floaters, visual field defects
• Nephropathy
• Ask about frothy urine, pedal oedema, facial puffiness, periorbital oedema, dyspnoea, uremia (nausea/ vomiting/ anorexia/ chest pains (pericarditis) / abdominal pains (uremic peptic ulceration)/ altered sensorium or seizures (uremic encephalopathy), dialysis, renal transplantation)
• Neuropathy - somatic and autonomic
• Ask about numbness affecting extremities especially the foot, pressure ulcers, digital gangrene, foot deformities, postural giddiness, recurrent vomiting (gastroparesis)
• Sexual dysfunction - erectile dysfunction (a sensitive issue due to the taboo among Asian customs, but if approached professionally and you are able to obtain information regarding this issue, many patient's will be grateful and of course, impress the examiners)

METABOLIC:

• Hyperglycemia
• Ask about polyuria, polydipsia, unintentional weight loss, nocturia (not to be mistaken with prostatism - diabetic polyuria have good amd large volume urine stream due to osmotic diuresis whereas prostatism nocturia have weak urine stream with the usual lower urinary tract symptoms e.g. terminal dribbling, hesitancy etc). 
• Diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic syndromes (HHS)
• Ask about symptoms of hyperglycemia plus dyspnoea (may suggest acidotic breathing), sweet fruity breath smell (ketone breath), altered sensorium (HHS) or involuntary limb movements (hemichorea hemiballismus due to HHS) ** diabetic emergencies will not appear for exams, rest assured 😏
• Hypoglycemia
• Ask about hand tremors, hunger pangs, diaphoresis, agitation/ anxiety/ restlessness, syncope and coma (unlikely to appear in the exams as you wont be able to clerk the patient!!) 

In the review of systems segment, can explore regarding any health problems from head to toe which may be the cause of diabetes mellitus e.g. connective tissue disorders e.g. SLE/  rheumatoid arthritis or chronic lung disease (asthma/COPD) (chronic steroid usage), acromegaly, Cushing's syndrome. If the patient is young, presence of concomitant connective tissue disease (s) may suggest an autoimmune cause of DM. 

In the family history segment, explore about strong family history of DM. 

For past medical history or surgical history segment, enquire about history of pancreatitis, pancreatic tumours or pancreatic surgery. Also about any pituitary tumour resection (pituitary Cushing's or Acromegaly), adrenal tumour (Adrenal Cushing's) resections. 

In the drug history section, can check with the patient regarding their medication list and compliance. Patients may know the medications they are on and the dosages. Alternatively, patients may be provided a prescription slip and will be instructed to show the medical student upon request. If there is element of non-compliance, be sure to enquire the reason behind the behaviour. Very often, the patient may inform of some adverse side effects as a result of taking that particular medication which causes the non-compliance. For example, the patient may be non-compliant to metformin because of bloating or frequent loose stools. 

Physical examination of the patient with diabetes mellitus requires a comprehensive approach from head to toe similar to history taking. There will be many areas to cover and therefore, it will be covered in the next post "Diabetes Mellitus - How to Approach a Patient with Diabetes Mellitus in the Long Case Examination (Physical Examination)". 

CCE.