Weakness: what it usually turns out to be

The word is the problem

In this clinic, দুর্বলতা is the single commonest thing a patient says on sitting down. It is also, on its own, close to useless diagnostically — not because patients describe things badly, but because Bengali uses one word for a range of sensations that medicine treats as entirely separate problems.

Two examples make the point, and both come up most weeks. A patient who says they feel weak, questioned properly, turns out to have vertigo — the room moves when they turn over in bed — which they had not mentioned because it did not seem like the main thing. Another turns out to have breathlessness on exertion: they can no longer climb the stairs to the first floor without stopping. Neither said “dizzy” and neither said “breathless”. Both said weak.

So the first part of the consultation is not testing. It is finding out which symptom is actually being described.

What it turns out to be, in order

The list below is the order in which these actually turn out to be the answer in this practice, which is not the order a textbook would give. It is worth stating as an order rather than a list, because it is what determines which test gets done first.

Rows 3 and 6 are the same diseases seen from two directions, and they are separated deliberately. Row 3 is how often heart and lung disease turn out to be the cause. Row 6 is how often the patient had the specific symptom of exertional breathlessness and called it weakness instead. The second is why the first is missed.

1. Anaemia — and why iron is often the wrong answer

Anaemia is first because it is genuinely common. India's National Family Health Survey found 57.2% of women aged 15 to 49 anaemic, along with 52.2% of pregnant women, 59.1% of adolescent girls and 25.0% of men.^[1]

Now the part that changes treatment, and it is the reason this section exists. Iron deficiency is not the cause of most Indian anaemia. A study measuring venous blood across eight states found that iron-deficiency anaemia accounted for less than a third of total anaemia in every group examined, reaching around 45% only in adolescent girls; in the authors' words, the major proportion in all groups was associated with other causes.^[2] The same study found venous haemoglobin gives substantially lower anaemia prevalence than the finger-prick method used in national surveys — 41% in adult women rather than 57%.

And in Bengal specifically there is a second reason not to assume iron. Across 119,336 samples analysed by HPLC in eastern India, β-thalassaemia trait was present in 4.60% and haemoglobin E trait in 3.02%, with HbE–β-thalassaemia in a further 1.16%.^[3] A community antenatal sample in Kolkata found β-thalassaemia trait in 4.61%.^[4] Both thalassaemia trait and iron deficiency produce small, pale red cells on a blood count. They are not treated the same way, and iron given to someone with thalassaemia trait does nothing useful and can cause iron overload if repeated for years.

So a low haemoglobin with a low MCV in a Bengali patient is a question, not an answer. Ferritin distinguishes most of it; HPLC settles the rest.

One further point, which is why the cause matters rather than just the number. Iron deficiency in an adult without an obvious dietary or menstrual explanation is a finding that needs its own investigation: in secondary-care series, 7.7% of patients with iron-deficiency anaemia turned out to have a gastrointestinal malignancy.^[5] Correcting the haemoglobin without asking where the iron went can bury the diagnosis for a year.

2. Uncontrolled diabetes

Second on the list because it is common, easily tested and frequently the whole explanation. India has an estimated 101 million adults with diabetes,^[6] and sustained high blood glucose produces exactly the picture patients describe as weakness: tiredness that does not lift with rest, weight loss despite eating, thirst, passing urine at night, and blurred vision that comes and goes.

Two patterns worth naming. Someone who has never been tested, presenting only with months of weakness, in whom the HbA1c is the diagnosis. And someone already on treatment whose weakness is the first sign that control has slipped — which is why an HbA1c is checked rather than assumed from the last reading.

3. Cardiac dysfunction and obstructive lung disease

These sit third, above thyroid, and that placement is deliberate. Heart failure and chronic obstructive lung disease are common in this population and both are routinely reported as weakness rather than as breathlessness — because the patient has adapted. They stopped climbing the stairs, stopped walking to the market, and what they notice is not that breathing is hard but that they can do less.

The evidence for how badly this is missed is striking. In a primary-care cohort, 72% of heart failure patients were diagnosed only during a hospital admission, after a median of seven months of symptoms — and the authors recorded that patients had attributed those symptoms to ageing or to their other conditions rather than to the heart.^[7] Fatigue was reported by 67% of them, breathlessness by 78% and ankle swelling by 44%. That is a UK cohort, so treat the proportions as indicative; the mechanism — symptoms attributed to age and reported as tiredness — is exactly what is seen here.

What is done about it costs nothing: asking specifically what the person can no longer do, examining for raised venous pressure, crackles, an added heart sound and ankle oedema, and an ECG in the same visit. Where it points that way, chest imaging, spirometry and an echocardiography referral follow.

Obstructive lung disease deserves its own mention here because of how it arises in this district — years of cooking over biomass and years of smoking both produce it, and both are often not volunteered unless asked directly.

4. Thyroid disease

Hypothyroidism is common enough to test for routinely: an eight-city Indian study of 5,360 adults found it in 10.95%, of which about a third was previously undetected, with a further 8.02% subclinical. It was three times commoner in women than men — 15.86% against 5.02% — and anti-TPO antibodies were present in 21.85%.^[8] That was an urban screening sample rather than a national estimate, so read it as an indication of scale.

The reason it sits fourth rather than first, despite being the cause everyone thinks of, is simply that the three above it are found more often. It is still tested in the first panel, because a TSH is inexpensive and the treatment is straightforward.

5. Vertigo, arriving as weakness

This is where the consultation earns its keep, because the whole problem is one of translation. The patient says weak. The history — asked for specifically — is that the room spins for a few seconds when they turn over in bed, sit up, or look up at a shelf. That is benign paroxysmal positional vertigo, and it is diagnosed at the bedside with a positional test and often treated in the same visit with a repositioning manoeuvre.

Two things are worth knowing about how this usually goes elsewhere. First, it is routinely mistreated. In a population study of people with this condition, 78% had consulted a doctor — but 45% received no treatment at all, 27% were given drugs for vertigo, only 10% received a positioning manoeuvre, and only 8% received effective treatment.^[9] In a series of patients who eventually reached a specialist balance clinic, 61% had already had more than two primary-care consultations, 76% had had an MRI scan, a quarter had been given betahistine, and repositioning manoeuvres appeared nowhere in the primary-care record.^[10]

Second, the manoeuvre works, though not as well as the figure people quote. A Cochrane review of 11 trials found complete resolution of vertigo in 56% after the Epley manoeuvre against 21% with sham or no treatment, an odds ratio of 4.42.^[11] The commonly repeated “80% cured in one visit” has no traceable source. A real 21-to-56 percentage-point shift, from a manoeuvre that takes two minutes and costs nothing, is worth having on its own terms.

Not all dizziness is benign, and age matters. Among dizziness presentations, dangerous underlying disorders were found in 15% overall — 20.9% in those over 50 against 9.3% in those under — and about a fifth of dizziness presentations were cardiovascular rather than inner-ear in origin.^[12] So dizziness with weakness on one side, difficulty speaking, double vision, a severe headache, or fainting is assessed as an emergency, not as vertigo.

6. Exertional breathlessness, arriving as weakness

The same translation problem as vertigo, and clinically more consequential. The question that opens it is not “are you breathless” — the answer is usually no — but what can you no longer do that you could do six months ago. The answers that matter: stopping halfway up the stairs, no longer walking to the market, sleeping propped on more pillows than before, waking at night short of breath.

Where that history is present, the assessment is the one in section 3, and it is not deferred. New exertional breathlessness in a person with diabetes or high blood pressure is one of the more important things this clinic looks for, because it is the point at which heart failure is still early.

7. Vitamin B12 and other deficiencies

Last on the list, which is not to say unimportant — it is to say that it is where people usually start, and starting there is why the rest gets missed.

Vitamin B12 deficiency is worth testing for, and there are two causes that are systematically overlooked because they are iatrogenic. Long-term metformin lowers B12: in a long-running trial cohort the odds of low B12 rose by 13% for each year of metformin use, and at five years low or borderline levels were present in 19.1% of metformin users against 9.5% of controls.^[13] Long-term acid-suppressing medicines do the same: two years or more of a proton pump inhibitor carried an odds ratio of 1.65 for B12 deficiency, rising to 1.95 at higher doses.^[14] Both effect sizes come from Western cohorts, but the drugs and the mechanism are the same everywhere — and between them they describe a very large number of patients in this clinic, since long-term metformin and long-term acidity medicines are two of the commonest prescriptions in the district.

Vitamin D is tested too, and here it is worth being honest about the evidence rather than repeating the usual figure. The best pooled estimate for deficiency in Indian adults is about 67%, but the studies behind it are overwhelmingly urban clinic samples with enormous variation between them, and there is no nationally representative survey of vitamin D in Indian adults at all.^[15] The widely quoted 70 to 80% comes from a narrative review rather than a measurement. The level is measured before treating because the dose and duration depend on how low it is, and because unmeasured supplementation can raise calcium and cause stones.

Why a tonic is not the answer

The default treatment for weakness in India is a haematinic or multivitamin syrup, and it is worth explaining why this clinic does not start there.

An analysis of 621 haematinic preparations available on the Indian market found only 24% to be rational — 81% of oral solid formulations and 75% of oral liquids were not. Sixty formulations contained less than 33 mg of elemental iron per dose, meaning three or more doses a day would be needed to deliver a therapeutic amount, and many carried additional ingredients that the authors described as having nothing to do with blood formation. The rational preparations cost more than the irrational ones.^[16]

So the objection is not philosophical. A tonic that contains too little iron to treat iron deficiency, given to someone whose anaemia is not iron deficiency in the first place, for a symptom that is actually early heart failure, is three failures stacked on top of each other — and the patient feels no better, concludes that nothing works, and comes back six months later.

Where a deficiency is demonstrated, it is replaced properly, at an adequate dose, for an adequate duration, and the level is rechecked.

How much testing is justified

An honest complication, because there is good evidence pointing the other way and it should not be hidden.

The best systematic review of tiredness in general practice found that serious organic disease explained only 4.3% of cases, with anaemia in 2.8% and malignancy in 0.6% — while depression accounted for 18.5%. The authors concluded that extensive investigation is justified only when the history or examination points somewhere, and that attention is better directed at mood and circumstances.^[17]

That finding is sound and it does not transfer here unchanged. It comes from Western primary care, where background anaemia prevalence is low. In a district where 57% of women are anaemic, a haemoglobin is a far higher-yield test than the same test in Germany, and the same is true of an HbA1c in a country with 101 million people with diabetes. The panel used here is wider than that review would suggest, and the reason is the population, not enthusiasm for testing.

What does transfer is the second half of the conclusion. Low mood, poor sleep, grief, financial strain and caring for an unwell relative all produce genuine physical exhaustion, and they are asked about — not as a diagnosis of exclusion once the tests come back normal, but as part of the same conversation.

When weakness needs seeing sooner

Most weakness is not urgent. These are the exceptions.

Sudden weakness of one side of the body, difficulty speaking, drooping of one side of the face, or sudden loss of vision — this is a stroke, and it is an emergency. Call 108 and go directly to hospital; do not wait for an appointment.

Also needing prompt assessment rather than a routine appointment: weakness with breathlessness at rest or chest discomfort; weakness with fainting or near-fainting; weakness with black stools or visible bleeding; weakness with unintentional weight loss, particularly more than about 5% of body weight in six months; weakness with fever lasting more than a week; and weakness that has come on rapidly over days rather than gradually over months.

And one that is easy to dismiss: weakness in someone taking several regular medicines, which is often the medicines themselves. Bring every strip.